JP2012227422A - Method of manufacturing metal housing integrated type circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a metal housing integrated type circuit board which facilitates a close attachment of a board to the metal housing and allows an efficient dissipation of heat.SOLUTION: A method of manufacturing a metal housing integrated type circuit board comprises: a step in which a wiring board 14, on one side of which a circuit is formed and on the other side of which an adhesive layer 3 is laminated, is attached to a metal housing 7 by means of the adhesive layer; a mounting step in which a semiconductor package 8 is mounted on the circuit after the step for attachment; and a reflow step in which reflow is performed, after the mounting step, with the wiring board, metal housing, and semiconductor package integrated.

Description

  The present invention relates to a method for manufacturing a metal housing integrated circuit board.

  In recent years, electronic devices have been further reduced in size, weight, and functionality, and accordingly, high integration and miniaturization of wiring are rapidly progressing.

  Light emitting diodes (LEDs: Light Emitting Diodes (hereinafter sometimes simply referred to as “LEDs”)) are able to obtain large light energy with low power consumption, and are attracting attention as backlights for lighting and liquid crystal displays due to their long life characteristics. ing. However, LEDs generate a large amount of heat during light emission, and as a result, if the operating temperature rises, the advantages of the LED, such as a decrease in light emission efficiency and a shortened life, are lost. How to escape is an important issue.

  In order to improve heat dissipation, a metal substrate is often used for the circuit board on which the LED is mounted. However, between the insulating layer for forming the circuit and the metal substrate, and between the metal substrate and the metal housing. Each heat resistance is large, and the rate of heat dissipation is limited.

  Examples of a method for suppressing the thermal resistance of the insulating layer include a method of improving the thermal conductivity of the insulating layer or reducing the thickness of the insulating layer.

  In addition, in order to suppress the thermal resistance between the metal substrate and the metal housing, a method of increasing the thermal contact such as grease or pressure sensitive adhesive sheet called TIM (Thermal Interface Material) which increases the number of fixing screws is used. (For example, see Patent Documents 1 and 2). In this case, the close contact state between the metal substrate and the metal housing, the close contact state between the metal substrate, the TIM, and the metal housing are important. However, if there are factors such as circuit formation or mounting of the LED package, the metal substrate may be warped or distorted, or it may not be pressed down sufficiently because the LED package is mounted. However, there was a problem that heat dissipation was deteriorated.

JP 2006-308738 A JP 2008-166406 A

  Under such circumstances, the present invention can easily attach a wiring board to a metal casing, and can efficiently dissipate heat released from a semiconductor to the metal casing. A method for manufacturing a circuit board is provided.

As a result of intensive studies to solve the above problems, the present inventors have reached the present invention. That is, the present invention
<1>: a step of affixing a wiring board having a circuit formed on one surface and having an adhesive / adhesive layer on the other surface to a metal housing with the adhesive / adhesive layer;
A mounting step of mounting a semiconductor package on the circuit after the pasting step;
After the mounting step, a reflow step of reflowing the wiring board, the metal casing and the semiconductor package as a unit;
A method of manufacturing a metal substrate integrated circuit board having
<2>: The method of manufacturing a circuit board integrated with a metal housing according to <1>, wherein the semiconductor package is an LED package;
<3>: The wiring board has a copper foil for circuit formation having a thickness of 5 μm to 105 μm, an insulating layer containing a polyimide resin having a thickness of 5 μm to 25 μm, an adhesive / adhesive layer having a thickness of 3 μm to 25 μm, and a carrier film. <1> or <2> a method for producing a circuit board integrated with a metal housing according to <1>, which is obtained by forming a circuit on wiring board materials laminated in this order;
<4>: The wiring board is a copper foil for circuit formation having a thickness of 5 μm to 105 μm, an insulating layer containing a polyimide resin having a thickness of 5 μm to 25 μm, an adhesive layer having a thickness of 3 μm to 25 μm, and a thickness of 18 μm to 500 μm. <1> or <2> obtained by forming a circuit on a wiring board material in which a metal foil, a 3 μm to 250 μm thick adhesive / adhesive layer, and a carrier film are laminated in this order Manufacturing method of a circuit board integrated with a metal casing;
<5>: The method for producing a circuit board integrated with a metal housing according to any one of <1> to <4>, wherein the reflow step cures the adhesive / adhesive layer having thermosetting properties;
<6>: The method of manufacturing a circuit board integrated with a metal housing according to any one of <1> to <4>, wherein the reflow step melts the adhesive / adhesive layer that is a hot-melt type;
Is to provide.

  That is, according to the present invention, a wiring board can be easily brought into close contact with a metal casing, and a heat-released semiconductor can efficiently dissipate heat to the metal casing. A manufacturing method can be provided.

It is a figure which shows the outline of the process flow concerning this invention. It is a figure which shows the outline of the process flow of another aspect concerning this invention.

In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. .
In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.

  The method of manufacturing a circuit board integrated with a metal housing according to the present invention comprises a wiring board having a circuit formed on one surface and a pressure-sensitive adhesive layer laminated on the other surface. A step of attaching to the body, a mounting step of mounting a semiconductor package on the circuit after the attaching step, and a reflow step of integrally reflowing the wiring board, the metal casing and the semiconductor package after the mounting step. And can include other steps as necessary.

In the present invention, since the wiring board is attached to the metal casing before the semiconductor package is mounted on the circuit, the entire surface of the wiring board can be pressed against the metal casing. Therefore, it is easy to attach the wiring board to the metal casing, and the adhesion between the metal casing and the wiring board can be improved.
In addition, when the adhesive / adhesive layer has thermosetting properties, or a hot-melt adhesive / adhesive layer, a metal casing to which a wiring board is attached by the adhesive / adhesive layer; By reflowing the semiconductor package mounted on the circuit as a single unit, the wiring board, the metal housing, and the semiconductor package can be integrated together, reducing the overall man-hours. The manufacturing efficiency can be improved.

Further, a wiring board in which a copper foil for circuit formation having a thickness of 5 μm to 105 μm, an insulating layer containing a polyimide resin having a thickness of 5 μm to 25 μm, an adhesive / adhesive layer having a thickness of 3 μm to 25 μm, and a carrier film are laminated in this order. Material, copper foil for circuit formation 5 μm to 105 μm thick, insulating layer containing polyimide resin 5 μm to 25 μm thick, adhesive layer 3 μm to 25 μm thick, metal foil 18 μm to 500 μm thick, 3 μm By using a specific wiring board material such as a wiring board material in which an adhesive / adhesive layer having a thickness of 250 μm and a carrier film are laminated in this order, a thin and flexible wiring board can be obtained. It is also possible to improve the likelihood of the processing accuracy of the metal casing.
Further, by using the specific wiring board material, the number of layers from the semiconductor package to the metal casing can be reduced and the thickness can be reduced, so that the thermal resistance can be reduced.

A method for manufacturing a metal housing integrated circuit board according to the present invention will be described below.
In addition, although preferred embodiment of this invention is described in detail using drawing, the manufacturing method of this invention is not limited to described embodiment.

  FIG. 1 shows a process flow according to a method for manufacturing a metal housing integrated circuit board 16. In this process flow, the steps ((f) to (h)) of preparing the wiring board 12 with the carrier film, the step (a) of peeling the carrier film 4 of the wiring board 12 with the carrier film, and the carrier film 4 were peeled off. A step (b) of temporarily attaching the subsequent wiring board 14 to the metal housing 7 and a step of attaching the wiring board 14 temporarily attached to the metal housing 7 to the metal housing 7 (c); A mounting step (d) for mounting the semiconductor package 8 via the metal paste layer 6 after the pasting step, and a reflow step for reflowing the wiring board 14, the metal housing 7 and the semiconductor package 8 together after the mounting step ( e).

<Paste process>
In the attaching step, the wiring board 14 is attached to the metal housing 7.
The wiring board 14 used in the pasting process has the circuit wiring 15 and the metal paste layer 6 formed on one surface and the adhesive / adhesive layer 3 on the other surface. This wiring board 14 can be prepared, for example, by the following preparation process.

[Preparation process]
In the preparation step, a step of forming the circuit wiring 15 on the circuit forming metal foil 1 of the wiring board material 11 (circuit formation step (f)), a step of applying the metal paste to form the metal paste layer 6 (metal paste) Application step (g)), and a step of dividing into individual wiring boards 12 with a carrier film (single step (h)). The wiring board 12 with a carrier film obtained in the preparation process is subjected to the next pasting process. The metal paste application step (g) can be performed in any order as long as it is after the circuit formation step (f) and before the mounting step (d) for mounting the semiconductor package 8. In FIG. 1, the case where it performed between the circuit formation process (f) and the fragmentation process (h) was illustrated as an example which reduces a man-hour by batch printing.

The wiring board material 11 used in the preparation step is configured by laminating a circuit forming metal foil 1, an insulating layer 2, an adhesive / adhesive layer 3, and a carrier film 4 in this order.
By using such a layer structure, the wiring board material 11 is excellent in heat dissipation and insulation.
Although it does not specifically limit as a kind of wiring board material 11, From a viewpoint of the convenience at the time of sticking the wiring board 14 to the metal housing | casing 7, what has a flexibility after forming a circuit is preferable. Thereby, when affixing the wiring board 14 to the metal casing 7, the wiring board 14 itself can be curved, and the adhesion between the wiring board 14 and the metal casing 7 can be improved.

  Although there is no restriction | limiting in particular as the kind of metal foil 1 for circuit formation, For example, copper, aluminum, tin etc. are mentioned. Among these, a copper foil is preferable from the viewpoints of circuit processability, thermal conductivity, and electrical conductivity, and further, a non-roughened copper foil is more preferable from the viewpoints of withstand voltage and insulation reliability.

  Although there is no restriction | limiting in particular as thickness of the metal foil 1 for circuit formation, From a viewpoint of handling, it is preferable that they are 5 micrometers-105 micrometers, and it is more preferable that they are 9 micrometers-70 micrometers. The thickness of the metal foil 1 for circuit formation can be selected in accordance with the power used.

  The type of resin constituting the insulating layer 2 is not particularly limited as long as it can electrically insulate the wiring board 14 from the metal casing 7. For example, polyimide resin, polyamideimide resin, aromatic polyester resin, epoxy resin And polymer alloy of acrylic resin. Among these, it is preferable to include a polyimide resin from the viewpoint of heat resistance, chemical resistance, and flexibility.

  The thickness of the insulating layer 2 is not particularly limited, but is preferably as thin as possible in view of heat dissipation from the viewpoint of heat dissipation. For example, the thickness is preferably 5 μm to 25 μm, and more preferably 5 μm to 10 μm. When the thickness of the insulating layer 2 is 5 μm or more, it is preferable to form a layer having no defect, thereby ensuring a dielectric breakdown voltage. When the thickness is 25 μm or less, it is preferable because the thermal resistance can be reduced.

  The insulating layer 2 may be an insulating layer formed and cured in advance using the circuit forming metal foil 1 as a base material, or may be an insulating thermosetting adhesive layer also serving as the following adhesive / adhesive layer 3. . It is preferable to use an insulating layer of a cured product in advance because it is possible to select an insulating layer with outgas at the time of curing. In addition, an insulating thermosetting adhesive layer that also serves as an adhesive / adhesive layer makes the laminated structure simple. This is preferable. Moreover, since the insulating layer 2 has adhesiveness, when the insulating layer 2 is laminated on the metal foil 1 for circuit formation, the thickness can be selected according to the application, and it is laminated without sandwiching air by a press or a laminator. It becomes possible to do.

  The type of the adhesive / adhesive layer 3 is not particularly limited, but an epoxy resin or an acrylic resin is preferable from the viewpoint of adhesiveness / adhesiveness, and a polyamide resin, a polyimide resin, a polyamideimide resin, and a polyurethane resin are preferable from the viewpoint of heat resistance. Among them, a polyamide-imide resin is more preferable, and a silicone-modified polyamide-imide resin is particularly preferable from the viewpoint of stress relaxation. These may be a mixture of a polymer alloy or the like, or may be used alone. Further, from the viewpoint of stress relaxation, it is preferable to include an acrylic resin having a low crosslinking density.

  In the present invention, the adhesive / adhesive layer 3 means at least one of a pressure-sensitive adhesive layer and an adhesive layer. The adhesive / adhesive layer 3 is preferably a thermosetting adhesive / adhesive layer or a hot-melt adhesive / adhesive layer. Examples of the thermosetting adhesive / adhesive layer include acrylic / epoxy polymer alloys, polyamideimide resins, and silicone-modified polyamide resins. Examples of the hot-melt type adhesive / adhesive layer include PCS-LT manufactured by Shin-Etsu Chemical Co., Ltd., and Scotch-Weld (registered trademark) hot melt adhesive 3748V0 manufactured by Sumitomo 3M Limited. However, when using a hot-melt adhesive layer, the heat-resistant temperature is lower than that of the thermosetting adhesive / adhesive layer, and depending on the melting point of the metal paste, it may not be able to withstand the reflow process. By selecting a metal paste having a melting point lower than the heat resistance temperature of the adhesive to be used, it is possible to use even a sticky / adhesive layer having a low heat resistance.

  The thickness of the adhesive / adhesive layer 3 is not particularly limited. For example, the thickness is preferably 3 μm to 25 μm, preferably 3 μm to 10 μm from the viewpoint of adhesive strength and thermal resistance, and from the viewpoint of thermal resistance. More preferably, it is 3 μm to 5 μm. When the thickness of the adhesive / adhesive layer 3 is 3 μm or more, the adhesive strength can be secured, and when the thickness is 25 μm or less, the thermal resistance becomes small.

In the wiring board material 11, the carrier film 4 is disposed on a surface different from the surface on which the circuit forming metal foil 1 is disposed. The wiring board material 11 is provided with the carrier film 4 so that the handleability is improved.
Examples of the carrier film 4 include a thermoplastic film, a release resin-coated metal foil, and the like, and examples thereof include a polyester film, a polyimide film, and a resin-coated aluminum foil. The material of the carrier film 4 is not particularly limited. However, the carrier film 4 can withstand the curing temperature of the solder resist 5 used in the circuit formation step (f) described later, and is a material that is not affected by the etching chemical during circuit formation. If it exists, the part which becomes unusable because the uncured resin is eroded due to the penetration of the chemical solution is reduced, which is preferable because the yield is greatly improved. Further, from the viewpoint of chemical resistance, the end face of the wiring board material 11 may be stretched with polyimide tape or the like, and the chemical resistance of the adhesive / adhesive layer 3 can be covered by stretching. It is preferable because elution of uncured components can be suppressed. Further, it is preferable to stretch the end face because the interaction between the adhesive / adhesive layer 3 and the carrier film 4 is weak and the penetration of the chemical solution can be suppressed even when the end face is easily turned over.
Moreover, there is no restriction | limiting in particular as thickness of the carrier film 4, However, It is preferable that it is the thickness of 10 micrometers-150 micrometers, and the thickness of 10 micrometers-50 micrometers is easy to peel off the thickness of parts other than a carrier film, and a carrier film. It is more preferable from the relationship. As the thickness of the carrier film 4, a suitable film thickness that can be easily peeled in the process can be selected in accordance with the equipment for the peeling process described later. If the carrier film is too thick, the strength of the carrier film is too strong compared to the laminate of the insulating layer 2 and the adhesive / adhesive layer 3 after the circuit is formed. Insufficient strength makes handling difficult.

In addition, the wiring board material 11 may have another layer as needed, and examples of the other layer include a metal foil for a support. An embodiment using a wiring plate material having a metal foil for support will be described later.
The wiring board material 11 is not limited to a sheet shape but is wound into a roll shape, and can be used for continuous machining and pasting.

  In addition, the manufacturing method in particular of the wiring board material 11 is not restrict | limited, For example, the method as described in Unexamined-Japanese-Patent No. 2007-273729 can be referred.

-Circuit formation process-
In the circuit formation step (f), circuit wiring 15 is formed on the circuit forming metal foil 1 of the wiring board material 11.

There is no restriction | limiting in particular as a method of forming the circuit wiring 15 in the wiring board material 11, It can follow a well-known method. For example, unnecessary portions of the circuit forming metal foil 1 may be removed by etching to form the circuit wiring 15, and the solder resist 5 may be applied and cured by a screen printing method or the like to produce a circuit protective film. Specifically, the method described in JP 2010-266518 A can be applied.
The solder resist 5 prevents the solder from adhering to places other than the places where soldering is necessary, and prevents the circuit forming metal foil 1 from being exposed to the air. It also functions as a permanent protective film. Therefore, the solder resist 5 is required to have properties such as adhesion, electrical insulation, solder heat resistance, solvent resistance, and chemical resistance. For example, SN-9000 manufactured by Hitachi Chemical Co., Ltd. PSR (registered trademark) -4000W10, PSR-9000FLX (registered trademark), etc. are suitable.

-Metal paste application process-
In the metal paste application step (g), the metal paste is applied to the circuit wiring 15 on the wiring board material 11 to form the metal paste layer 6.

Although it does not specifically limit as a kind of said metal paste, A solder paste, a silver paste, etc. are mentioned. Examples of the method for applying the metal paste include a method using a dispenser, a screen printing method, and an ink jet printing method.
In addition, about conditions, such as a viscosity of a metal paste in the case of a metal paste provision process, it does not specifically limit, It can apply to a well-known method.

-Individualization process-
In the separation process, the wiring board material 11 on which the metal paste layer 6 is formed is separated into individual wiring boards 12 with a carrier film (h). There are no particular limitations on the method of dividing, but, for example, the circuit board is cut into individual shapes by cutting the outer shape of each circuit formation region of the wiring board material 11 to which the metal paste is applied.

In the singulation step, cutting or punching by dicing using a saw or laser dicing may be performed, but punching is preferably performed from the viewpoint of workability.
In addition, about conditions, such as a pressure in the case of the process of the said singulation process, it changes with kinds of apparatus etc. to be used, and can follow a well-known method.

  In the individualization step, the wiring board material 11 may be individualized according to the size of the metal casing 7, and the size of the individualization is not particularly limited. Further, it is preferable to perform cutting and punching so that the end face of the carrier film is floated during the singulation because the carrier film is easily peeled off during the following sticking process.

<Paste process>
The wiring board 12 with a carrier film obtained in the preparation step is then subjected to a pasting step. The pasting step includes a peeling step (a), a temporary pasting step (b), and a conforming step (c), and the wiring board 14 having the metal paste layer 6 on the surface is pasted to the metal casing 7.
The metal housing 7 has a metal plate and is not particularly limited as long as it is a three-dimensional metal body, and is appropriately selected according to the purpose. Examples of the metal that can be used for the metal housing include aluminum, copper, brass, and stainless steel. Among these, aluminum and copper are preferable from the viewpoint of heat dissipation.

In a peeling process (a), the carrier film 4 arrange | positioned on the surface of the wiring board 12 with a carrier film provided from the preparation process is peeled. The wiring board 14 which does not have the carrier film 4 is obtained by a peeling process.
As a peeling method of the carrier film 4, it can apply to a well-known method according to the size of an individual piece, a sticking installation, the tackiness of the adhesive / adhesive layer 3, and the like.

In the temporary attachment step (b), the wiring board 14 is temporarily attached to the metal housing 7.
Temporary sticking is a process in which a flexible roll such as a fingertip or rubber, a laminator, a press or the like is used so that air does not enter so that the wiring board 14 is in close contact with the metal housing 7, and the adhesive / adhesive layer 3 In order to adjust the tackiness, it may be appropriately cooled or heated. In the present invention, “temporary bonding” means that the wiring board 14 is fixed to the metal housing 7 by the adhesive / adhesive layer 3 of the wiring board 14 regardless of the cured state of the adhesive / adhesive layer 3. means.
In the conforming step (c), the wiring board 14 temporarily attached to the metal casing 7 is adapted to the metal casing 7. In the present invention, “accommodate” means that the adhesiveness between the wiring board 14 and the metal casing 7 by the adhesive / adhesive layer 3 is increased while applying moderate pressure. In other words, it may be a batch operation with the above-described temporary sticking step (b), and is a step in which a soft roll such as rubber, a laminator, a press or the like is used to apply pressure so that air does not enter. You may heat as needed in order to make the adhesive bond layer 3 soft.

  In this invention, if the wiring board 14 is affixed on the metal housing | casing 7 by the temporary sticking process (b) and the acclimatization process (c), the other sticking method will not be restrict | limited in particular. For example, a press laminating method, a continuous laminating method using a hot roll, a method of laminating and pasting, etc. may be mentioned as the pasting method. Of the pasting methods, the method of pasting and attaching the wiring board 14 is preferable because it is possible to attach the wiring board 14 while suppressing air bubbles from entering between the wiring board 14 and the metal casing 7.

In the present invention, the attaching method is not particularly limited because the semiconductor package 8 is not mounted when the wiring board 14 is attached to the metal casing 7, and the wiring board 14 can be sufficiently pressed against the metal casing 7. Because it is possible.
Moreover, adhesion can be improved by sticking so that bubbles and the like are not included at this time, and it becomes possible to prevent a decrease in heat dissipation.

  Further, in order to attach the wiring board 14 to the metal casing 7 efficiently and uniformly while suppressing variation in characteristics by the adhesive / adhesive layer 3, it is applied using a hot press or a thermal laminator under reduced pressure. It is preferable to attach.

<Mounting process>
In the mounting step (d), the semiconductor package 8 is mounted on the metal paste layer 6 of the wiring board 14 after the pasting step.
The semiconductor package 8 includes a semiconductor, terminals that electrically connect the semiconductor and the outside, and a sealing material that seals and holds the semiconductor. The terminal is not particularly limited, and for example, a conductor such as copper, solder, or the like is used. The sealing material is not particularly limited, and an epoxy resin or the like is used. The semiconductor package 8 can be obtained according to the method described in Japanese Patent Application Laid-Open No. 2007-110113.
There is no restriction | limiting in particular as a method of mounting the semiconductor package 8 in the metal paste layer 6, A well-known method can be followed. For example, a method of mounting by flip-chip connection and the like can be mentioned, and specifically, the method described in JP-A-2004-039736 can be applied.
Note that the conditions of the mounting process are not particularly limited, and vary depending on the type of the semiconductor package 8 to be mounted, and can conform to a known method.

<Reflow process>
In the reflow step (e), after the mounting step, the wiring board 14, the metal casing 7, and the semiconductor package 8 are reflowed as a unit.
By the reflow, the semiconductor package 8 is fixed on the circuit wiring 15 via the metal paste layer 6, and the metal substrate integrated circuit board 16 is obtained.

The reflow process can follow a known method. In addition, the conditions such as the temperature at the time of reflow are not particularly limited, and may vary according to the type of equipment used, the metal paste, and the like, and may conform to a known method.
Particularly preferred as the reflow method is a method of fixing the temporarily bonded wiring board 14 by curing or melting the adhesive / adhesive layer 3 using heat of reflow, which is preferable because the number of man-hours is small.

  According to this method, since the wiring board 14 is affixed to the metal casing 7 before the semiconductor package 8 is mounted on the metal paste layer 6, the wiring board 14 and the metal casing 7 can be easily adhered to each other. In addition, since the wiring board 14, the metal casing 7, and the semiconductor package 8 are reflowed as a unit, the overall man-hour can be reduced and the manufacturing efficiency can be improved. Furthermore, since the wiring board 14 is brought into close contact with the metal housing 7, heat from the semiconductor package 8 can be efficiently radiated to the metal housing 7.

  In addition, as a layer structure of the wiring board 14 in this embodiment, it is not limited to the layer structure mentioned above, The metal foil for support bodies may be included. Moreover, according to the layer structure of the wiring board 14, you may add an arbitrary process to a process flow as needed.

  FIG. 2 shows a process flow for producing a metal housing integrated circuit board 24 using a wiring board 22 having a support metal foil 10 as another embodiment of the present invention. In FIG. 2, members and processes that perform the same operations as those in the process flow shown in FIG.

When using the wiring board 22 shown in FIG. 2, the wiring board material 18 which has the metal foil 10 for support bodies is prepared in a preparatory process.
In the preparation process of the present embodiment, the circuit wiring 15 is formed on the wiring board material 18 having the support metal foil 10 (circuit formation process (f)), and the wiring board material 18 is adhered to the support metal foil 10. -Laminate the adhesive layer 3 and the carrier film 4 in this order (lamination step (i)), apply a metal paste (metal paste application step (g)), and separate the wiring board 20 with the carrier film. (Individualization step (h)). Thereby, it becomes possible to use the wiring board 20 with a carrier film obtained at the preparation process for a sticking process. In this embodiment, the steps after the pasting step are the same as the process flow for manufacturing the circuit board 16 shown in FIG.

  The wiring board material 18 used in the preparation process is configured as a cured product in which the circuit forming metal foil 1, the insulating layer 2, the adhesive layer 9, and the support metal foil 10 are laminated in this order. Yes.

Examples of the support metal foil 10 include copper, aluminum, and tin. Among these, a copper foil is preferable from the viewpoint of circuit processability, thermal conductivity, and electrical conductivity, and a non-roughened copper foil is more preferable from the viewpoints of withstand voltage and insulation reliability.
As thickness of the metal foil 10 for support bodies, it is preferable that it is 18 micrometers-500 micrometers, and it is more preferable that it is 35 micrometers-210 micrometers. When the thickness of the metal foil is 18 μm or more, it is preferable for increasing the in-plane strength. When the thickness is 500 μm or less, the followability at the time of application is increased. When the thickness is 210 μm or less, the flexibility is maintained. Further preferred.

  Although it does not restrict | limit especially as a kind of adhesive bond layer 9, From an adhesive viewpoint, an epoxy resin or an acrylic resin is preferable, and a polyamide resin, a polyimide resin, a polyamideimide resin, and a polyurethane resin are preferable from a heat resistant viewpoint, Among these, A polyamide-imide resin is more preferable, and a silicone-modified polyamide-imide resin is particularly preferable from the viewpoint of stress relaxation. These may be a mixture of a polymer alloy or the like, or may be used alone. Further, from the viewpoint of stress relaxation, it is preferable to include an acrylic resin having a low crosslinking density. Moreover, when the insulating layer 2 is an insulating thermosetting adhesive layer, the insulating layer 2 may serve as the adhesive layer 9 or may be a single layer.

  The thickness of the adhesive layer 9 is not particularly limited, but is preferably 3 μm to 25 μm, preferably 3 μm to 10 μm from the viewpoint of adhesive strength and thermal resistance, and 3 μm to 5 μm from the viewpoint of thermal resistance. More preferably. When the thickness of the adhesive layer 9 is 3 μm or more, the adhesive strength can be secured, and when the thickness is 25 μm or less, the thermal resistance is preferably reduced. Further, when the insulating layer 2 also serves as the adhesive layer 9, it conforms to the above-described thickness range of the insulating layer 2.

-Circuit formation process-
In the circuit forming step (f), circuit wiring 15 is formed on the circuit forming metal foil 1 of the wiring board material 18. The circuit wiring 15 is formed by applying a protective film to prevent the support metal foil 10 from being attacked by the chemical solution in the pattern forming / etching process, and removing the protective film before forming the protective film. Other than the above, the same as described above.

  The protective film is not particularly limited as long as the metal foil for the support is not attacked by the chemical solution, but, for example, a polyethylene terephthalate film with an adhesive material, a polyimide film with an adhesive material, or a photosensitivity used for circuit pattern formation. A film etc. are mentioned, but among these, from the viewpoint of chemical resistance and process simplicity, a polyethylene terephthalate film with an adhesive material or a polyimide film with an adhesive material is preferable.

-Lamination process-
In the lamination step (i), the adhesive / adhesive layer 3 and the carrier film 4 are laminated in this order on the surface of the support metal foil 10. About a lamination | stacking method, it selects suitably according to the kind etc. of the adhesive / adhesive layer 3, the carrier film 4, and the metal foil 10 for support bodies.
In this process flow, the adhesive / adhesive layer 3 is laminated after the circuit formation step, but there is no problem in the order of laminating the adhesive / adhesive layer 3 before and after the circuit formation. From the viewpoint of avoiding problems such as the type of the adhesive / adhesive layer 3, for example, the chemical resistance is low, or the adhesive / adhesive layer 3 is cured by heat when the solder resist 5 is cured. It is preferable to laminate the adhesive / adhesive layer 3 after the formation step and before the individualization step.

  The adhesive / adhesive layer 3 is preferably a thermosetting adhesive / adhesive layer or a hot-melt adhesive / adhesive layer. Examples of the thermosetting adhesive / adhesive layer include acrylic / epoxy polymer alloys, polyamideimide resins, and silicone-modified polyamide resins. Examples of the hot-melt adhesive / adhesive layer include PCS-LT manufactured by Shin-Etsu Chemical Co., Ltd., and Scotch-Weld hot melt adhesive 3748V0 manufactured by Sumitomo 3M Limited. However, when using a hot-melt adhesive layer, the heat-resistant temperature is lower than that of the thermosetting adhesive / adhesive layer, and depending on the melting point of the metal paste, it may not be able to withstand the reflow process. By selecting a metal paste having a melting point lower than the heat resistance temperature of the adhesive to be used, it is possible to use even a sticky / adhesive layer having a low heat resistance. Moreover, when the wettability with a solder etc. is favorable mutually, such as the metal foil 10 for support bodies, and a metal housing | casing, what applied the conductive paste, such as a solder paste, to the back surface may be sufficient. Also in this case, it can be made to adhere like the hot melt by the reflow process (e) after the mounting process (d).

  The thickness of the adhesive / adhesive layer 3 is not particularly limited, but is preferably 3 μm to 250 μm, for example, preferably 5 μm to 100 μm, and more preferably 10 μm to 50 μm. A thicker adhesive layer 9 is preferable because it can absorb surface irregularities and distortions of the metal casing and can maintain adhesion, and a thinner thickness is preferable because thermal resistance is reduced. The optimum thickness of the adhesive / adhesive layer 3 can be selected as thin as possible within the range in which adhesion can be secured in accordance with the processing accuracy of the metal casing.

  In addition, since the in-plane strength of the wiring board 22 increases as the metal foil 10 for the support body increases, the followability to the housing shape deteriorates, and the adhesive / adhesive layer 3 is thickened to ensure adhesion. Is required. The metal foil for support 10 has two functions of improving handling by securing in-plane strength and once diffusing heat generated from the package. In order to reduce the overall thermal resistance as much as possible, it is preferable to select a metal foil 10 as thin as possible as long as these two functions are sufficient.

-Metal paste application process-
In the metal paste application step (g), a metal paste is applied to the circuit wiring 15 on the wiring board material 18 to form the metal paste layer 6. As for the method of applying the metal paste, the above-mentioned matters are applied as they are.
-Individualization process-
In the separation process, the wiring board material 18 on which the metal paste layer 6 is formed is separated into individual wiring boards 20 with a carrier film (h). As for the method of applying the metal paste, the above-mentioned matters are applied as they are.
The separated wiring board 20 with a carrier film is subjected to a pasting process and after the carrier film 4 is peeled off in the peeling process (a), followed by a temporary sticking process (b) and a conforming process (c), It uses for a mounting process (d) and a reflow process (e). As a result, a metal housing integrated circuit board 24 having the support metal foil 10 is obtained.
In this circuit board 24, since it has the metal foil 10 for a support body, in addition to the effect mentioned above, handleability improves more.

  The metal housing integrated circuit board manufactured according to the manufacturing method of the present invention is not particularly limited, but can be applied to light source equipment such as an LED backlight and LED lighting.

DESCRIPTION OF SYMBOLS 1 Metal foil for circuit formation 2 Insulating layer 3 Adhesive layer 4 Carrier film 5 Solder resist 6 Metal paste layer 7 Metal housing 8 Semiconductor package 9 Adhesive layer 10 Metal foil for support body 11 Wiring board material 12 With carrier film Wiring board 14 Wiring board 15 Circuit wiring 16 Circuit board 18 Wiring board material 20 Wiring board with carrier film 22 Wiring board 24 Circuit board

Claims (6)

A step of attaching a wiring board having a circuit formed on one surface and having an adhesive / adhesive layer on the other surface to the metal casing by the adhesive / adhesive layer;
A mounting step of mounting a semiconductor package on the circuit after the pasting step;
After the mounting step, a reflow step of reflowing the wiring board, the metal casing and the semiconductor package as a unit;
Manufacturing method of circuit board integrated with metal casing having   The method for manufacturing a circuit board integrated with a metal housing according to claim 1, wherein the semiconductor package is an LED package.   In the wiring board, a copper foil for circuit formation having a thickness of 5 μm to 105 μm, an insulating layer containing a polyimide resin having a thickness of 5 μm to 25 μm, an adhesive / adhesive layer having a thickness of 3 μm to 25 μm, and a carrier film are laminated in this order. 3. The method of manufacturing a circuit board integrated with a metal casing according to claim 1, wherein the circuit board is obtained by forming a circuit on the wiring board material.   The wiring board includes a copper foil for circuit formation having a thickness of 5 μm to 105 μm, an insulating layer containing a polyimide resin having a thickness of 5 μm to 25 μm, an adhesive layer having a thickness of 3 μm to 25 μm, and a metal foil having a thickness of 18 μm to 500 μm. The metal casing according to claim 1 or 2, which is obtained by forming a circuit on a wiring board material in which a 3 μm to 250 μm thick adhesive / adhesive layer and a carrier film are laminated in this order. A method of manufacturing an integrated circuit board.   The said reflow process is a manufacturing method of the circuit board of a metal housing | casing integrated type of any one of Claim 1 to 4 which hardens the said adhesive / adhesive layer which has thermosetting property.   5. The method of manufacturing a circuit board integrated with a metal housing according to claim 1, wherein the adhesive / resin layer that is a hot-melt type melts in the reflow process.