JPH05102634A - External connecting terminal of circuit board - Google Patents

Abstract

PURPOSE:To easily provide a measure for circuit modification in regard to a multilayer ceramic substrate by eliminating limitation on the number of external connecting terminals (the number of I/O pads) of a multilayer ceramic substrate to improve the yield thereof. CONSTITUTION:An external terminal 22 as an external connecting terminal for a connector, an internal terminal 23 and a terminal substrate wiring 24 for connecting both terminals are provided on a terminal substrate 2 and wiring connection varying terminals 21-2 and 21-2 for realizing disconnection and alteration of wiring of the terminal substrate wiring are also provided in the course of the terminal substrate wiring. A flexible substrate 3 is provided with an I/O receiving terminal 31 for electrically coupling with I/O pad 11, an internal receiving terminal 32 for electrical coupling with the internal terminal 23 and a flexible substrate wiring 33 for coupling both receiving terminals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board external connection terminal used in an electronic device or the like, and particularly to a large-sized and high-density multilayer ceramic substrate and connector (other multilayer ceramics) used in a large computer or the like. The present invention relates to a circuit board external connection terminal for transmitting a signal between a board and a connector connected to an external circuit).

[0002]

2. Description of the Related Art Conventionally, connection between a multilayer ceramic substrate and a connector has been performed by using an I / O (Input / Output) pad and a needle-shaped metal terminal (hereinafter referred to as I / O pin) provided on the multilayer ceramic substrate. It was realized by welding (brazing) and inserting the I / O pin into the connector.

[0003]

The above-mentioned conventional technique has the following drawbacks because the I / O pins are welded to the I / O pads provided on the multilayer ceramic substrate.

I / O pins and I / O pads are I / O
Since the strength to withstand the fitting force when the O pin is inserted into the connector is required, there is a limit to the size reduction of the I / O pin, and the adhesion area of the I / O pin to the I / O pad is limited. There is a limit to how small it can be made. Therefore, the number of I / O pads that are external connection terminals in the multilayer ceramic substrate is limited, and the array density of the I / O pads depends on the internal wiring density of the multilayer ceramic substrate (particularly, high density multilayer ceramic substrate). Can't handle.

In recent years, the size of multilayer ceramic substrates has increased, and along with this, the number of I / O pins per substrate (I / O
Some pads have more than 10,000 pads. For this reason, it becomes difficult to make the welding condition of the I / O pad and the I / O pin uniform for all the I / O pins. In addition, as the number of I / O pins (I / O pads) increases, the number of defective welding defects per substrate increases, and the yield of multilayer ceramic substrates deteriorates.

In the multilayer ceramic substrate, circuit repair may be necessary after completion of the multilayer ceramic substrate in order to repair defects in the internal circuit or change the design. However, poor workability due to welding of the I / O pad and the I / O pin, and I around the circuit modification part
Since there is a risk of destroying the / O pin, it is difficult to properly respond to the need for circuit modification.

In view of the above points, an object of the present invention is to eliminate the limitation on the number of external connection terminals (the number of I / O pads) of a multilayer ceramic substrate and improve the yield of the multilayer ceramic substrate. An object of the present invention is to provide a circuit board external connection terminal that can easily cope with circuit modification related to a ceramic substrate.

[0008]

A circuit board external connection terminal of the present invention is a circuit board external connection terminal for transmitting a signal between a high-density and large-sized multilayer ceramic board and a connector. Terminals that have external and internal terminals that are connection terminals and terminal board wiring that connects between the terminals, and that have wire connection change terminals that allow disconnection or connection change of the terminal board wiring in the middle of the terminal board wiring A substrate and I on the multilayer ceramic substrate
I / O receiving terminal for electrically connecting with the / O pad, an internal receiving terminal for electrically connecting with an internal terminal on the terminal board, and a flexible substrate wiring for connecting both receiving terminals and being flexible. And a flexible substrate having a flexible shape.

[0009]

In the circuit board external connection terminal of the present invention, the terminal board electrically connects the connector and the flexible board by the external terminal, the internal terminal, and the terminal board wiring that connects the terminals. The wiring connection change terminal provided on the terminal enables disconnection and connection change of the terminal board wiring, and the flexible board having a flexible shape is electrically coupled to the I / O pad on the multilayer ceramic board. For electrically connecting the multi-layered ceramic substrate and the terminal substrate to each other by the I / O receiving terminal and the internal receiving terminal for electrically coupling with the internal terminal on the terminal substrate and the flexible substrate wiring connecting the both receiving terminals. Connecting.

[0010]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing the construction of an embodiment of a circuit board external connection terminal of the present invention. The circuit board external connection terminals of this embodiment are connected to the multilayer ceramic substrate 1 via the I / O pads 11 on the multilayer ceramic substrate 1, and include a terminal substrate 2 and a flexible substrate 3. It is composed of. The I / O pad 11, the multilayer ceramic substrate wirings 13 and 14, the wiring connection changing terminals 21-1 and 21-2, the external terminal 22, the internal terminal 2
3, the terminal board wiring 24, the I / O receiving terminal 31, the internal receiving terminal 32, and the flexible board wiring 33 are shown only one by one, respectively, but there are a plurality of each and constitute a series of connection.

The terminal board 2 includes a wiring connection changing terminal 21-1.
And 21-2, an external terminal 22, an internal terminal 23,
The terminal board wiring 24 is included.

The flexible substrate 3 has an I / O receiving terminal 3
1, internal receiving terminal 32, and flexible board wiring 33
It is configured to include and.

The multilayer ceramic substrate 1 connected to the circuit board external connection terminals of this embodiment includes an I / O pad 11, an organic insulating film 12, and multilayer ceramic substrate wirings 13 and 14. It is composed of.

FIG. 2 shows an LSI (Large Scale).
FIG. 7 is a diagram showing an assembled state in which the multilayer ceramic substrate 1 to which the Integration etc. 4 is attached and the connector 5 are connected by the circuit board external connection terminals of the present embodiment. The multilayer ceramic substrate 1 and the flexible substrate 3 are adhered and fixed by a mounting plate 101 which is an auxiliary member (mounting metal fitting).

Next, the respective structures of the circuit board external connection terminals (the terminal board 2 and the flexible board 3) and the multilayer ceramic board 1 shown in FIGS. 1 and 2 will be described. , The circuit board external connection terminals of this embodiment are formed).

1. The multilayer ceramic substrate 1 is a large-sized (for example, a scale in which the number of I / O pads 11 exceeds about 10,000) and a high-density wiring substrate. The front surface of the substrate is the mounting surface of the electronic component such as LSI 4 and the back surface of the substrate is the external connection terminal I.
/ O pad 11 is the extraction surface.

The multilayer ceramic substrate 1 includes the following constituent elements.

I / O pad 11 is a terminal on the side of the multilayer ceramic substrate 1 for electrically connecting the multilayer ceramic substrate 1 and the terminal substrate 2. The I / O pad 11 is a high-density array pad (terminal) formed by a thin film metal process and insulated from each other by an organic insulating material. The uppermost layer metal is a pre-coated low temperature brazing material (solder etc.), and a solder barrier metal, an insulating layer adhesion metal, etc. are multiplexed in the lower layer.

Organic Insulating Film 12 An insulating film (for example, a film made of a heat-resistant organic insulating material) formed on the back surface of the multilayer ceramic substrate 1 for reducing unevenness on the ceramic surface and forming a high-density array terminal I / It serves as a basis for forming the O pad 11. It also serves as a support for the multilayer ceramic substrate wiring 13.

Multilayer Ceramic Substrate Wiring 13 is a wiring that connects the I / O pad 11 and the multilayer ceramic substrate wiring 14, and the positional deviation between the I / O pad 11 and the multilayer ceramic substrate wiring 14 (multilayer ceramic Such a deviation is inevitable in the process of producing the substrate 1)
Adjust.

Multilayer Ceramic Substrate Wiring 14 Internal wiring of the ceramic portion of the multilayer ceramic substrate 1, which connects the LSI 4 and the multilayer ceramic substrate wiring 13.

2. The terminal board 2 is a printed wiring board (a board made of glass epoxy resin or the like) that is electrically connected to the connector 5. Each terminal on the terminal board 2 is connected in order of the internal terminal 23, the wiring connection change terminal 21-2, the wiring connection change terminal 21-1, and the external terminal 22 by the wiring (terminal board wiring 24) in the terminal board 2. (The paired wiring connection change terminal 21-2 and the wiring connection change terminal 21-
It is possible to break the line between 1).

The terminal board 2 includes the following components.

The wiring connection changing terminals 21-1 and 21-2 are disconnected from the terminal board wiring 24 between these terminals, or the wiring connection changing terminals 21-1 and 21-2 are cut and then the wiring connection is changed. Terminal 21-1 or 21-
2 and another wiring connection changing terminal 21-2 or 21-1 by providing new wiring (between the wiring connection changing terminal 21-1 and the wiring connection changing terminal 21-2 which are not paired). By creating a new connection relationship with the external terminal 22 and the internal terminal 23 by changing the connection relationship of the terminal board wiring 24 (disconnection or connection change of the terminal board wiring 24). is there.

External terminal 22 A low-density terminal for external connection that contacts the connector 5. The external terminal 22 has, for example, a pad shape for pressure contact with a contact pin or the like of the connector 5.

Internal terminals 23 High-density terminals on the side of the multilayer ceramic substrate 1 in the terminal substrate 2. The internal terminals 23 are formed of copper foil or the like on the terminal board 2 and are pre-coated with a low temperature braze (solder or the like).

Terminal board wiring 24 is formed of copper foil or the like on the terminal board 2, and is covered with solder resist or the like. The terminal board wiring 24 connects the wiring connection changing terminals 21-1 and 21-2, the external terminal 22 and the internal terminal 23 through a predetermined route.

3. The flexible substrate 3 is a flexible substrate such as a cable for electrically connecting the multilayer ceramic substrate 1 and the terminal substrate 2 ("flexibility" is required for the multilayer ceramic. This is to flexibly connect the board 1 and the terminal board 2 regardless of the relative positional relationship between them. The flexible substrate 3 is, for example, a wiring (flexible substrate wiring 33) and a terminal (I / I) for connecting the multilayer ceramic substrate 1 and the terminal substrate 2 to a heat resistant resin film (polyimide film or the like) that can withstand brazing.
O receiving terminal 31 and internal receiving terminal 32) are formed,
The wiring portion except the terminal portion is formed by being covered with a heat resistant resin film.

The flexible substrate 3 includes the following components.

I / O receiving terminal 31 This is a terminal on the side of the multilayer ceramic substrate 1 in the flexible substrate 3, and is a terminal in the same arrangement as the I / O pad 11 on the multilayer ceramic substrate 1. This I / O receiving terminal 31
Is formed of a copper foil or the like on the flexible substrate 3, and the surface thereof is preliminarily coated with low-temperature brazing (solder or the like).

Internal receiving terminals 32 are terminals on the side of the terminal board 2 in the flexible board 3, and are terminals in the same arrangement as the internal terminals 23 on the terminal board 2. The internal receiving terminal 32 is formed of copper foil or the like on the flexible substrate 3, and the surface thereof is preliminarily coated with low temperature brazing (solder or the like).

Flexible substrate wiring 33 is a wiring for connecting the I / O receiving terminal 31 and the internal receiving terminal 32.

Next, the operation (function) of the circuit board external connection terminal of the present embodiment thus constructed will be described.

The circuit board external connection terminals of this embodiment shown in FIGS. 1 and 2 are the LSI 4 etc. provided through the multilayer ceramic substrate wirings 13 and 14 in the multilayer ceramic substrate 1 and the I / O pad 11. From the I / O receiving terminal 31 on the flexible substrate 3.

Further, the signal is sent to the flexible board wiring 33 and the internal receiving terminal 32 on the flexible board 3 and the internal terminal 23 and the terminal board wiring 24 in the terminal board 2.
(There are wiring connection change terminals 21-1 and 21-2 on the way) to the external terminal 22 to the connector 5.

Wiring connection change terminals 21-1 and 2
It becomes possible to change the mode of signal transmission by changing the disconnection or connection of 1-2.

Finally, a method of assembling and connecting the circuit board external connection terminals (including the multilayer ceramic board 1 connected to the circuit board external connection terminals) of the present embodiment configured as described above will be described. That is, the assembly and connection are performed in the following procedure (see FIGS. 1 and 2).

The flexible board 3 is positioned and fixed to the terminal board 2 by a pressing plate or the like.

In a state where the internal terminals 23 on the multilayer ceramic substrate 2 and the internal receiving terminals 32 on the flexible substrate 3 are overlapped with each other, the low temperature brazing pre-coated on the surfaces of both terminals is heated by a hot wire or a warm air. Is reflowed (melted), and the terminals are connected.

The mounting plate 1 is attached to the multilayer ceramic substrate 1 (on which the LSI 4 has been mounted on the multilayer ceramic substrate 1 in advance) on which the mounting of the LSI 4 etc. has been completed.
01 is attached, and the terminal board 2 is further fixed to the attachment plate 101 by screws or the like.

The flexible substrate 3 is positioned and fixed to the multilayer ceramic substrate 1 by a pressing plate or the like.

In the fixed state by, the I / O pad 11 on the multilayer ceramic substrate 1 and the I / O receiving terminal 31 on the flexible substrate 3 are accurately aligned and superposed.

In the superposed state by the I / O pad 11 and the I / O receiving terminal 31 by heat rays or warm air.
The low temperature braze pre-coated on the surfaces of and is reflowed, and the terminals are connected. This completes a series of assembly and connection.

[0045]

As described above, according to the present invention, the circuit board external connection terminal is constituted by the terminal board and the flexible board, and the multilayered ceramic board and the connector are connected by the circuit board external connection terminal. It has the following effects.

Since no external force is directly applied to the I / O pad on the multilayer ceramic substrate, I
The formation density (arrangement density) of the / O pads can be increased to a scale that can sufficiently correspond to the internal wiring density of the multilayer ceramic substrate. Therefore, "the structure of the terminal lead-out portion of the multilayer ceramic substrate (existence of I / O pins in the related art) is the number of external connection terminals (I / O) of the multilayer ceramic substrate.
There is no need to limit the number of O pads).

Since the connection between the I / O pad and the I / O receiving terminal and the connection between the internal terminal and the internal receiving terminal are performed by low temperature brazing, the conventional method of brazing the I / O pin to the I / O pad has been adopted. Compared with the method, the structure of the jig (tool) for brazing can be simplified and the temperature control can be facilitated, and the fluctuation range of the manufacturing conditions of the multilayer ceramic substrate (for all I / O pads The fluctuation range) can be reduced, and the yield of the multilayer ceramic substrate can be improved.

Since the wiring connection changing terminal is provided on the terminal board, it is possible to easily cope with circuit modification related to the multilayer ceramic board.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an assembled state in which a multilayer ceramic substrate to which an LSI or the like is attached and a connector are connected by the circuit board external connection terminals shown in FIG.

[Explanation of symbols]

 1 Multilayer Ceramic Board 2 Terminal Board 3 Flexible Board 4 LSI etc. 5 Connector 11 I / O Pad 12 Organic Insulating Film 13, 14 Multilayer Ceramic Board Wiring 21-1, 21-2 Wiring Connection Change Terminal 22 External Terminal 23 Internal Terminal 24 terminal board wiring 31 I / O receiving terminal 32 internal receiving terminal 33 flexible board wiring 101 mounting plate

Claims (1)

[Claims] 1. A circuit board external connection terminal for transmitting a signal between a high-density and large-sized multilayer ceramic substrate and a connector, wherein an external terminal and an internal terminal which are terminals for external connection to the connector, and both terminals. A terminal board having a terminal board wiring for connecting between the terminals, and having a wiring connection changing terminal for disconnecting the terminal board wiring or changing the connection in the middle of the terminal board wiring; and an I / O on the multilayer ceramic board An I / O receiving terminal for electrically coupling with a pad, an internal receiving terminal for electrically coupling with an internal terminal on the terminal board, and a flexible board wiring for connecting both the receiving terminals are provided, and are flexible. And a flexible substrate having a certain shape.