JPH04276687A - Multilayer metal base substrate - Google Patents

Abstract

PURPOSE:To obtain a multilayer metal base substrate adapted for mounting an electronic device component such as a power module hybrid IC with a control function, which has excellent adhesive strength of a multilayer substrate to a metal base substrate and particularly excellent heat resistance, and easy manufacture. CONSTITUTION:A multilayer metal base substrate wherein a conductor 31 for connecting via a through hole is provided on a metal base substrate 3 through an insulating layer 32, a multilayer substrate 1 is adhered thereon through adhesive 2, the multilayer substrate has a conductor layer 13 only on a part corresponding to a through hole forming position to the adhesive surface, and the conductor layer can be connected to the conductor layer for connecting via the through hole in the base substrate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer metal base substrate with excellent adhesive strength suitable for mounting electronic device components such as power modules with control functions and hybrid ICs.

0002

[Prior Art] Metal-based substrates, which are made of metals such as aluminum and have excellent heat dissipation properties, are often used as substrates for mounting heat-generating circuit components such as power circuits.
In order to make it possible to mount more functional circuit components, a multilayer metal base board has been proposed in which a rigid or flexible multilayer board is bonded to a metal base board.

Conventionally, as shown in FIG. 2, the multilayer metal base substrate described above has a conductor circuit 41 for mounting circuit components or a conductor layer for circuit formation on the surface, and the adhesive surface has a conductor circuit 41 for mounting circuit components or a conductor layer for circuit formation. Solid conductor layer 4 for the purpose of shielding etc.
3 with adhesive 5 through its adhesive surface.
It is known that the metal base substrate 6 is bonded to the metal base substrate 6 by the above method. However, the adhesive strength between the multilayer board and the metal base board, especially after being heated, is poor, and the adhesive strength decreases when circuit components are soldered, causing the multilayer board to easily peel off.

0004

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer metal base substrate that has excellent adhesive strength between a multilayer substrate and a metal base substrate, and particularly has excellent heat resistance.

[0005]

[Means for Solving the Problems] The present invention provides a conductor layer for through-hole connection on a metal base substrate via an insulating layer, and a multilayer substrate is bonded thereon via an adhesive. The multilayer board is characterized in that it has a conductor layer on the adhesive surface only in the portion corresponding to the position where the through hole is formed, and that the conductor layer is in a state where it can be connected to the conductor layer for through hole connection in the metal base board. The present invention provides a multilayer metal-based substrate.

[0006]

[Function] As mentioned above, by forming a conductor layer for the purpose of circuit connection, electromagnetic shielding, etc. on the metal base substrate, and reducing the conductor portion on the adhesive surface of the multilayer substrate, the adhesive with the metal base substrate can be improved. It is possible to achieve strong adhesion using the adhesive, and it can also be used for purposes such as circuit connection and electromagnetic shielding.

[0007]

EXAMPLE A multilayer metal base substrate according to the present invention is illustrated in FIG. 1 is a multilayer substrate, 2 is an adhesive layer, and 3 is a metal base substrate. The multilayer substrate 1 has a conductor circuit 11 on one side (surface) of an insulating base material 12, and partially has a conductor layer 13 on the other side (adhesive surface). The metal base substrate 3 has a conductor layer 31 on a metal plate 33 via an insulating layer 32 for the purpose of circuit connection, electromagnetic shielding, etc. Furthermore, S is
This is a through hole formed in a multilayer metal base substrate.

[0008] A multilayer board has a conductor circuit for mounting circuit components or a conductor layer for forming a circuit on its surface, and has a conductor layer only in the portion corresponding to the formation position of the through hole on the adhesive surface. is used.

[0009] The multilayer substrate may be a rigid type having a base material such as a glass plate or a ceramic plate, or
A flexible type having a base material such as a plastic film may also be used. The conductors forming the circuit are generally made of metals such as copper, nickel, gold, and aluminum, or composites of these metals by plating, cladding, etc., but are not limited to these. It's fine.

[0010] The conductor layer on the adhesive surface of the multilayer substrate is provided only in the portion corresponding to the formation position of the through hole. The formation can be performed, for example, by an etching method using a resist and a pattern mask.

[0011] As the metal base substrate, aluminum,
Appropriate materials such as an insulating substrate based on a metal such as iron or copper or a composite thereof, or a metal plate without an insulating layer can be used. In the case of an insulating substrate, a conductor layer for the purpose of circuit connection, electromagnetic shielding, etc. may be provided on the insulating layer. When the metal base substrate does not have an insulating layer, an insulating layer is separately provided, and a conductive layer for the purpose of circuit connection, electromagnetic shielding, etc. is provided on the insulating layer. Note that the conductor layer for the purpose of circuit connection, electromagnetic shielding, etc. is generally provided in a solid state, but is not limited to this and may be in an appropriate pattern state. The pattern can be formed by, for example, the etching method described above.

[0012] The adhesive used for bonding the multilayer substrate and the metal base substrate is preferably one having excellent heat resistance. There is no particular limitation on the type. Generally, for example, epoxy adhesive, acrylic adhesive, polyimide adhesive, etc. are used.

[0013] The bonding process between the multilayer substrate and the metal base substrate is performed so that the conductor layer on the adhesive surface of the multilayer substrate can be connected to the conductor layer for through-hole connection in the metal base substrate. That is, for example, there are methods that use an adhesive sheet with holes in positions corresponding to the conductor layer parts on the adhesive surface of a multilayer board, and methods that use an adhesive sheet that has holes in positions corresponding to the parts of the conductor layer on the adhesive surface of a multilayer board, and methods that apply adhesive through a pattern mask to the parts of the conductor layer on the adhesive surface of a multilayer board. The connection is handled so that it is not obstructed by the adhesive, such as by avoiding the application of adhesive at the corresponding location. In addition,
The connection process between the upper and lower conductor layers may be performed by an appropriate method such as a method of supplying a conductive material such as solder through a formed through hole (S).

Example 1 A polyimide film with a thickness of 35 μm was coated on both sides of a 100 μm thick polyimide film.
A multilayer board that uses a double-sided FPC made by bonding μm copper foil and processes the copper foil on one side by etching using a pattern mask and resist resin to have a conductor layer only in the portion corresponding to the through hole formation position. was formed. Next, a 100 mm thick plate was placed on a 2 mm thick aluminum plate.
On a metal base board, a conductor layer made of copper foil with a thickness of 35 μm is provided on an insulating layer made of a high heat conductive resin with a thickness of 35 μm for the purpose of circuit connection, electromagnetic shielding, etc. The above multilayer substrate was thermally bonded at 180° C. for 60 minutes at 20 kg/cm2 via an epoxy adhesive sheet (Vyralux, manufactured by DuPont) with holes provided at predetermined positions to obtain a multilayer metal base substrate. . Note that the adhesive surface of the multilayer substrate is a surface on which a conductor layer is provided at a portion corresponding to the through hole formation position.

Comparative Example A polyimide film with a thickness of 35 μm was coated on both sides of a 100 μm thick polyimide film.
Same as Example 1, using a double-sided FPC made by bonding μm copper foil, and processing the copper foil on one side by etching method using a pattern mask and resist resin for the purpose of circuit connection, electromagnetic shielding, etc. A multilayer substrate with a conductive layer was formed, and it was placed on a 2 mm thick aluminum plate. An epoxy adhesive sheet (Vyralux, DuPont) at 180℃ x 60 minutes x 2
A multilayer metal base substrate was obtained by thermal bonding under the condition of 0 kg/cm2. Note that the adhesive surface of the multilayer board is a surface on which a conductor layer is provided for the purpose of circuit connection, electromagnetic shielding, etc.

[0016] The multilayer metal base substrates obtained in Evaluation Test Example 1 and Comparative Example were
The multilayer board was heated by floating it in a solder bath at 10°C for 10 minutes, and changes in the appearance and peel strength of the multilayer board were examined.

The results are shown in Table 1.

[Table 1]

[0018]

According to the present invention, it is possible to obtain a multilayer metal base substrate that has excellent adhesion between the multilayer substrate and the metal base substrate, particularly its heat resistance, and is easy to manufacture.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a sectional view of a conventional example.

[Explanation of symbols]

1: Multilayer board 11: Surface side conductor circuit 12: Base material 13: Conductor layer on the adhesive side 2: Adhesive layer 3: Metal base board 31: Conductor layer 32: Insulating layer 33: Metal plate

Claims (1)

[Claims] Claim 1: A conductor layer for through-hole connection is provided on a metal base substrate via an insulating layer, and a multilayer substrate is bonded on top of the conductor layer via an adhesive. 1. A multilayer metal base substrate having a conductor layer only in a portion corresponding to a hole formation position, the conductor layer being in a state connectable to a conductor layer for through-hole connection in the metal base substrate.