JPH073141U - High-speed / high-frequency IC component board structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a substrate structure of an IC component capable of matching the characteristic impedances of a printed circuit board and an IC component surface-mounted on the printed circuit board in correspondence with a high-speed signal. [Structure] In a substrate structure of an IC component, a ceramic substrate 11 having a uniform thickness is fired in an inverted U shape. Connect the signal terminal lead 14 and the ground terminal lead 15 to the ceramic substrate 11
The outer surfaces of both ends including the curved portion are closely attached. The ground conductor 16 is closely bonded to the entire inner surface of the ceramic substrate 11, the projecting end is bent inward, the lower end of the ground terminal lead 15 is bonded to one of the ends, and the solder plating film 17 is provided on the outer surface of both bent parts.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a board structure in which a surface mount type high-speed / high-frequency IC component is capable of obtaining stable characteristic impedance matching with a printed board to be mounted in a signal terminal portion thereof.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, as a terminal connection structure of a signal terminal portion in a surface mount type IC component, a structure example shown in FIG. 2 is generally known. FIG. 2 shows a side cross-sectional view. An IC chip 2 is mounted on the center of the upper surface of a printed wiring board (hereinafter referred to as P, C, B) 1, and signal terminal leads 3 are provided on both edges. Also, the ground terminal lead 4 is provided via the conductor foil 5 printed on the P, C, B1 surface. Reference numeral 6 is a bonding wire, and the IC chip 2 is electrically connected to the signal terminal lead 3 and the ground terminal lead 4 via the bonding wire 6 and the conductor foil 5, respectively. . A plastic cover 7 protects the entire component. The IC component configured as described above is connected to the corresponding connection portion of the printed circuit board (not shown) by soldering the signal terminal lead 3 and the ground terminal lead 4 of the printed circuit board to transmit / receive, supply power voltage and ground ground. Connection is possible.

[0003]

[Problems to be solved by the device]

 However, although the IC components with the above configuration were able to handle signals with a relatively slow transmission rate, in recent years, transmission signals have become faster and higher in frequency, and high-speed signals are also transmitted to printed circuit boards and mounted IC components. Therefore, there has been a problem that the characteristic impedance required for transmitting high-speed signals cannot be matched in the IC component having the above-mentioned structure. To show this concretely, when transferring a high-speed signal, the characteristic impedance, which is its physical constant, must be kept constant on the transmission line to achieve what is called impedance matching. For this reason, we have decided to use a microstrip line structure or a strip line structure as a transmission line at the level of a printed circuit board on which IC parts and the like are mounted, but structural measures still need to be taken at the level of parts mounted on such a printed circuit board. The reality is that it is not considered. For this reason, the characteristic impedance cannot be matched between the printed circuit board and the surface-mounted IC components that are electrically connected to the printed circuit board, and high-speed signals are normally transmitted and received between the printed circuit board transmission line and existing IC components. Was technically insufficient to do so.

The present invention has a problem in that normal transmission and reception of high-speed signals cannot be performed due to the mismatch of the characteristic impedance between the transmission line of the printed circuit board and the existing IC component, which the conventional technique has. In order to remove the dots, the substrate of the IC component is made of a dielectric material with a constant dielectric constant, for example, a ceramic material, which is fired into an inverted U-shape with a uniform cross section, and to connect to the printed circuit board inside it. It is an object of the present invention to provide an IC component having a transmission line structure which is provided with the ground conductor of (1) and which can obtain stable specific impedance matching with the printed board.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the structure of the present invention will be described with reference to FIG. 1 corresponding to an embodiment. The present invention is a substrate structure of a surface mount IC component, and has an inverted U-shaped cross section with a constant thickness. And a ceramic substrate 11 having a mounting portion for the IC chip 12 at the center of the outer surface thereof, and a signal terminal lead 14 and a ground terminal lead 15 arranged in close contact with the outer surfaces of both ends of the substrate 11, respectively. In addition, it is provided with a ground conductor 16 which is in close contact with the entire inner surface of the substrate 11 and is bent inward at both projecting ends, is joined to the ground terminal lead 15 on one side, and is provided on the outer surface with a ground conductor 16 coated with a solder plating film. It is what

[0006]

[Action]

 In such a structure, the ceramic substrate 11 is fired with a ceramic material having an inverted U-shaped cross section, and the signal terminal lead 14 and the ground terminal lead are also provided in the curved portions 11b at both ends of the outer surface thereof. Since 15 are arranged in close contact with each other and a solid ground conductor 16 is adhered over the entire inner surface, a stable characteristic impedance can be obtained and high-speed and high-frequency signals can be transmitted and received. it can. In addition, the characteristic impedance of the transmission line can be selectively set to a desired value by adjusting the thickness and the dielectric constant of the ceramic substrate 11. Further, the bent portion 16a of the tip of the solid ground conductor 16 of the IC component provides a large conductive area with the ground of the surface-mounted printed circuit board, and a stable and reliable ground can be obtained as compared with the conventional case.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing an embodiment of a substrate structure of a high speed / high frequency IC component according to the present invention. In the figure, the substrate 11 is made of a ceramic material as a dielectric, and is fired into an inverted U-shape having a uniform thickness in cross section. The central portion 11a of the outer surface has a recess for mounting the IC chip 12, and the curved portions 11b at both ends are curved with a constant curvature and are formed to have the same thickness as the flat plate portion. Reference numerals 13 and 14 respectively denote a conductor foil printed on the ceramic substrate 11 and closely attached signal terminal leads, and the lower ends of the leads 14 are bent outward. Reference numeral 15 is a ground terminal lead, which is closely attached to the ceramic substrate 11 in the same manner as the signal terminal lead 14, and the lower end portion is bent inward to be joined to the solid earth conductor 16 which is closely attached to the entire inner surface of the ceramic substrate 11 and is also grounded. Both ends 16a, 16a of the conductor 16 are bent inward, and a solder plating film 17 is applied to the outer surface thereof. Reference numeral 18 is a bonding wire for electrically connecting the IC chip 12 and the conductor foil 13. Reference numeral 19 is a cover for protecting the surface of the IC component, which is not shown, but the four corner edges thereof. Each part has a claw hooked on the ceramic substrate 11. With the above-described configuration, the signal terminal lead 14 and the ground terminal lead 15 are closely attached from above and below with the ceramic substrate 11 having a uniform thickness interposed therebetween. The values and the like are almost constant, and the characteristic impedance of the IC component is controlled by parameters such as the thickness and width of the conductor foil 13 and the signal terminal lead 14, the thickness and the dielectric constant of the ceramic substrate 11. Therefore, according to the present embodiment, the characteristic impedance can be adjusted by selecting the thickness and the dielectric constant of the ceramic substrate 11 without changing the terminal spacing of the conventional structure (see FIG. 2), and the microstrip line can be adjusted. Since it is also possible to match the characteristic impedance on the printed circuit board side that is compatible with high speed and high frequency using a transmission line such as a structure, reflection at the connection point between the printed circuit board and surface mount IC components does not occur, and the maximum Power can be transferred.

[0008]

[Effect of device]

 As described above, according to the present invention, the following effects can be obtained. A dielectric substrate such as ceramic is fired to have an inverted U-shaped cross section with a uniform thickness, and the signal terminal lead and the ground terminal lead are arranged along the curved parts of the substrate, and the ground conductor is provided on the entire inner surface. By arranging them, a stable circuit element can be obtained along the terminal leads, which is suitable for transmitting and receiving high-speed and high-frequency signals. In addition, by adjusting the thickness and permittivity of the dielectric ceramic substrate, the characteristic impedance of the transmission line can be designed to an arbitrary value, facilitating the characteristic impedance matching with the printed circuit board. Furthermore, since the solid ground conductor of the IC component allows a large area for conduction with the printed circuit board, a more stable ground can be achieved than before, and the ground effect is significantly improved.

[Brief description of drawings]

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

FIG. 2 is a side sectional view showing a conventional configuration example.

[Explanation of symbols]

 11 Ceramic Substrate 12 IC Chip 13 Conductor Foil 14 Signal Terminal Lead 15 Ground Terminal Lead 16 Ground Conductor 17 Solder Plating Film 18 Bonding Wire 19 Cover

Claims (1)

[Scope of utility model registration request] 1. A substrate structure of a surface mount IC component, wherein the substrate is a dielectric material having a predetermined permittivity and an inverse U having a constant cross section.
In addition to forming a letter shape, an IC chip mounting part is provided in the center of the outer surface, and the signal terminal lead and the ground terminal lead are fixed to the outer surfaces of both ends of this board, and the ground conductor is adhered to the entire inner surface. A substrate structure of a high-speed / high-frequency IC component, characterized in that the ground terminal lead is connected to the ground terminal lead, and the projecting end portion of the ground conductor is bent inward and a solder plating film is applied to the outer surface.