JPH0623039Y2 - Circuit module mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to a mounting structure of a circuit module, and in particular, to improvement of a connection structure between an external connection land and an external connection terminal of a multilayer circuit board, due to electromagnetic interference between signals on the external connection land. For the purpose of preventing crosstalk, it has a conductor pattern consisting of a signal pattern and a ground pattern, and is made by stacking inner and outer layer boards, and for external connection of the signal pattern provided at the edge of the intermediate inner layer board. A multilayer circuit board having a notch for exposing the land so that the land can be connected and a plurality of via holes connected in parallel with the ground pattern around the external connection land, and an external connection for accommodating the multilayer circuit board. A metal case with a lid having external connection terminals corresponding to the land on the side wall,
The multi-layer circuit board is housed in the metal case with a lid and fixed to the bottom surface of the case to ground the ground pattern, and the external connection land and the external connection terminal are connected to each other, and the metal lid is used as the external connection land. It is configured to be brought close to and sealed.

[Industrial application field]

 The present invention relates to improvement of a mounting structure of a circuit module.

For example, in a circuit module in which a circuit board having a high-frequency circuit of a high frequency band is housed in a metal case of a communication device, an external connection portion of the circuit board that transmits a high-speed signal has a high signal speed. There is a demand for a mounting structure that does not cause crosstalk due to electromagnetic interference.

[Conventional technology]

Conventionally, as shown in the perspective view of FIG. 3 and the side sectional view of FIG. 4, a circuit module is composed of a multilayer circuit board 11 and a metal case 12 with a lid.

The multilayer circuit board 11 includes a conductor pattern 11a, that is, a signal pattern 11a-1 and a ground pattern 11a-2, and is formed by stacking outer layer boards 11b and 11c.

The ground pattern 11a-1 and the signal pattern 11a-2 are
Each is electrically connected by a via hole 11d penetrating the multilayer circuit board 11 as needed.

The signal pattern 11a-1 includes an external connection land 11a-11 on the surface of the multilayer circuit board 11, that is, on the edge of the surface of the front-side outer layer board 11c-2.

The metal case with lid 12 has a space for exactly accommodating the multilayer circuit board 11 on the surface of which an electronic component 14 such as an LSI is mounted, and the external connection terminal 1 corresponding to the external connection land 11a-11.
3, that is, a coaxial connector is detachably provided in the side wall 12a, and a metallic lid 12c for sealing the opening is provided.

In the multilayer circuit board 11, an electronic component 14 such as an LSI is mounted on the front surface and is put in a metal case 12 with a lid, and the back side outer layer board 11c-1 is grounded together with a grounding pattern 11a-2 by a conductive adhesive (not shown).
Ground by fixing to the case bottom surface 12b with, the coaxial connector 13 is inserted into the side wall 12a and soldered to the external connection land 11a-11, and the opening is sealed with the metal lid 12c to seal the circuit module. It is completed.

[Problems to be solved by the device]

However, according to the above mounting structure, the external connection land for transmitting a high-speed signal is present on the surface of the multilayer circuit board, and the lid is separated from the external connection land due to the height of the mounted electronic components. However, there is a problem that crosstalk occurs due to electromagnetic interference between signals. As one means for solving this problem, there is a means for attaching a copper foil or a film containing ferrite magnetic powder to the signal portion to shield the signal portion, but this has a drawback that it absorbs a certain frequency and the frequency band is narrow. There is also a problem that processing and workability are poor and manufacturing costs increase.

In view of the above problems, it is an object of the present invention to provide a circuit module mounting structure capable of preventing crosstalk due to electromagnetic interference between signals on an external connection land.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the circuit module mounting structure of the present invention comprises an inner layer substrate and an outer layer substrate which are laminated with a conductor pattern including a signal pattern and a ground pattern, and an edge of an intermediate inner layer substrate. A multi-layer circuit board having a plurality of via holes connected in parallel around the external connection land and having a notch that exposes the external connection land of the signal pattern provided in the portion, A metal case with a lid that accommodates the multilayer circuit board and has external connection terminals corresponding to external connection lands on the side wall, and the multilayer circuit board is accommodated in the metal case with a lid and fixed to the bottom surface of the case to be grounded. The pattern for grounding is grounded, the external connection land and the external connection terminal are connected, and the metal lid is brought close to the external connection land for sealing. To.

[Action]

An external connection land for the signal pattern is provided on the inner layer board,
The external connection land is shielded by the conductor by providing the via hole connected to the ground pattern in parallel around the external connection land and providing the metal lid close to the external connection land. As a result, crosstalk due to electromagnetic interference can be prevented.

〔Example〕

Hereinafter, the gist of the present invention will be described in detail with reference to an embodiment shown in the drawings.

As shown in the perspective view of FIG. 1 and the side sectional view of FIG.
The circuit module is composed of a multilayer circuit board 1 and a metal case 2 with a lid.

The multilayer circuit board 1 is made of ceramic and has a conductor pattern 1
In other words, the outer layer substrates 1b and 1c are stacked and configured by including a, that is, the signal pattern 1a-1 and the ground pattern 1a-2.

The signal pattern 1a-1 and the ground pattern 1a-2 are electrically connected by via holes 1d penetrating the multilayer circuit board 1 as needed.

The inner layer board 1b-1 located in the middle of the multilayer circuit board 1 has an external connection land 1a-11 of the signal pattern 1a-1 at the edge thereof.
Equipped with.

The inner layer substrate 1b-2 and the front surface side outer layer substrate 1c-1 which are stacked above the inner layer substrate 1b-1 on which the external connection lands 1a-11 are formed include an external connection land 1a-11 and an external connection terminal described later. Three
Smallest notch for connecting and exposing
1e and a plurality of via holes 1d-1 connected in parallel around the external connection land 1a-11 and connected to the ground pattern 1a-2.

The notch 1e and the via hole 1d-1 are punched in advance in the state of the green sheet before sintering and lamination.

The metal case 2 with a lid has a space for exactly accommodating the multilayer circuit board 1 on the surface of which an electronic component 4 such as an LSI is mounted, and the external connection terminal 3 corresponding to the external connection land 1a-11, that is, a coaxial connector. Is detachably pierced through the side wall 2a, and a metallic lid 2c for sealing the opening is provided. The inner surface of the lid 2c, which is located on the external connection land 1a-11, is made particularly close to the surface of the front surface side outer layer substrate 1c-1, and is protruded inward so as to enhance the shielding effect.

The multi-layer circuit board 1 has an electronic component 4 such as an LSI mounted on the front surface thereof and is placed in a metal case 2 with a lid, and the back side outer layer substrate 1c-2 is grounded with a conductive adhesive (not shown) along with a grounding pattern 1a-2. It is grounded by being fixed to 2b, the coaxial connector 3 is inserted into the side wall 2a, and is soldered to the external connection land 1a-11 by laser heating, and the opening is sealed with a metal lid 2c to seal the circuit module. It is completed.

In this way, the external connection lands for the signal pattern are provided on the inner layer substrate, and the external connection lands are surrounded by the ground pattern, the grounded via hole, and the close metal lid to connect to the external connection. Since the land for use is shielded by these conductors, crosstalk due to electromagnetic interference can be prevented.

[Effect of device]

As described above in detail, according to the present invention, the signal pattern and the external connection land are provided on the inner layer substrate, and the ground pattern, the via hole, and the metal lid are provided around the external connection land. By arranging the surroundings, a shield is provided, crosstalk due to electromagnetic interference is prevented, and particularly, the crosstalk characteristic of a high-speed signal can be improved at a low cost, which is extremely useful in practice.

[Brief description of drawings]

 FIG. 1 is a perspective view of an embodiment according to the present invention, FIG. 2 is a side sectional view of FIG. 1, FIG. 3 is a perspective view of a prior art, and FIG. 4 is a side sectional view of FIG. In the figure, 1 is a multilayer circuit board, 1a is a conductor pattern, 1a-1 is a signal pattern, 1a-11 is an external connection land, 1a-2 is a ground pattern, and 1b, 1b-1, 1b-2 are inner layers. Substrate, 1c is outer layer substrate, 1c-1 is front side outer layer substrate, 1c-2 is back side outer layer substrate, 1d and 1d-1 are via holes, 1e is notch, 2 is metal case with lid, 2a is side wall, 2b is a bottom surface of the case, 2c is a lid, and 3 is an external connection terminal (coaxial connector).

Claims (1)

[Scope of utility model registration request] 1. A signal pattern (1a-1) and a ground pattern
(1a-2) with a conductor pattern (1a) consisting of, the outer layer substrate (1b, 1c) is laminated, the signal pattern (1a provided on the edge of the intermediate inner layer substrate (1b-1) -1) Land for external connection
(1a-11) is provided with a notch (1e) that is exposed so that it can be connected, and a plurality of via holes (1d-) connected to the ground pattern (1a-2) around the external connection land (1a-11). A multilayer circuit board (1) provided with 2) in parallel, and an external connection terminal accommodating the multilayer circuit board (1) and corresponding to an external connection land (1a-11)
(3) is provided on the side wall (2a) with a metal case (2) with a lid, the metal case (2) with a lid stores the multilayer circuit board (1) and is fixed to the bottom surface (2b) of the case. Ground the ground pattern (1a-2), connect the external connection land (1a-11) and the external connection terminal (3), and attach the metal lid (2c) to the front side outer layer substrate (1c
-1) The circuit module mounting structure characterized by being brought close to and sealed.