JP2002359320A - Outer electrode pattern of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the outer electrode pattern of an electronic component of a structure that in the outer electrode pattern, the generation of a short- circuit between terminal electrodes is absolutely eliminated, a state that the terminal electrode provided on almost the central part of a printed board is soldered to the printed board also can be inspected and moreover, the defect of conduction between the terminal electrodes also can be absolutely eliminated. SOLUTION: The outer electrode pattern of a surface mount electronic component mounted on a printed board is provided with terminal electrodes positioned at the four corners of the bottom of the electronic component and a terminal electrode provided on almost the central part of the bottom and has lead-out electrodes extendedly provided on the ends on the periphery of the bottom on the terminal electrode provided on the central part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external electrode pattern of a surface mount electronic component mounted on a printed circuit board, and more particularly to an arrangement of external electrode patterns of a small surface mount electronic component having a large number of terminal electrodes.

[0002]

2. Description of the Related Art In recent years, for electronic parts mounted on a printed circuit board of a communication device, for example, a mobile phone, etc., a surface mount type electronic component (Surface Mount Device: SMD) has been widely used due to a demand for reduction in height. ing. Terminal electrodes such as input / output and GND are arranged on the bottom surface of a ceramic package or the like used for the SMD. FIG. 4 is a top perspective view of a package showing an example of a foot pattern (terminal arrangement) of the terminal electrodes, wherein 1 is a package and 2 is a terminal electrode. However, recently, the number of terminal electrodes formed on the package bottom surface has been increasing with the enhancement of functions of the SMD. For example, when six terminal electrodes are required,
A foot pattern as shown in FIG. 5 is provided.

[0003]

SUMMARY OF THE INVENTION However, SM
When the foot pattern of FIG. 5 is used, the gap s between the terminal electrodes 3 and 4 is narrow because the area of the bottom surface of the package on which the terminal electrodes are provided is reduced due to the miniaturization of D. There was a problem that occurred. To avoid this problem, it is conceivable to provide two terminal electrodes 5 at the center of the substrate as shown in FIG. 6, but there was a problem that the soldering state of the terminal electrodes 5 could not be inspected (quality judgment).

Further, a foot pattern as shown in FIG. 7 has been considered in order to prevent a short circuit between terminal electrodes and to enable an inspection of a soldering state. However, in the foot pattern shown in FIG. 7, since the width t of the terminal electrode 6 is too small, the pattern of the external terminal of the SMD package does not match the pattern of the printed board unless the mounting position accuracy of the SMD on the printed board is increased. There is a problem that conduction failure between the two is likely to occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems. In the SMD substrate external electrode pattern, there is no occurrence of short circuit between terminal electrodes, and the SMD is provided almost at the center of the substrate. It is another object of the present invention to provide a board external electrode pattern that can inspect the soldering state of the provided terminal electrodes and can eliminate any conduction failure.

[0006]

According to the present invention, there is provided an external electrode pattern of an electronic component according to the present invention.
The invention described in the above, in the external electrode pattern of the surface-mounted electronic component mounted on a printed circuit board, comprising a terminal electrode located at the four corners of the bottom of the electronic component, and a terminal electrode provided at substantially the center of the bottom, It is characterized in that the terminal electrode at the center has a lead electrode extending to the peripheral edge of the bottom.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 is a schematic perspective view of a back surface of an SMD provided with a substrate external electrode pattern according to the present invention. A terminal electrode 1 provided substantially opposite to the center of the back surface 7.
0, a castellation 11 located substantially at the center of a pair of opposed outer peripheries of the back surface 7 to a lead electrode 12 connected to the terminal electrode 10 at the center. The terminal electrodes 9 located at the four corners of the back surface 7 and the terminal electrode 10 at the center of the back surface 7 have substantially the same area, and the gap between the terminal electrodes 9 and 10 is short-circuited between the terminal electrodes due to the solder bridge. It is secured enough not to occur.

FIG. 2 is a diagram for explaining a method of mounting the SMD having the embodiment of the present invention on the printed circuit board 13 using cream solder by a reflow method. First,
As shown in FIG. 2A, cream solder is applied onto the hatched portions 14s and 15s of the patterns 14 and 15 wired on the printed circuit board 13, and then the hatched portions 14s and 15s are applied.
The SMD is mounted as shown in FIG. 2B so that the terminal electrodes 9 and 10 on the SMD back surface 7 face each other.

After the printed board 13 on which the SMD is mounted is heated at a predetermined temperature in a reflow furnace, the printed board 13 is cooled to be connected to the terminal electrodes 9 and 10 on the back surface 7 of the SMD and the printed board via cream solder. The diagonal lines 14s and 15s of the resulting pattern are fixed, and the mounting is completed without causing a short circuit due to the solder bridge.

FIG. 2C is a schematic perspective view showing a state after the SMD is mounted on the printed circuit board. Reference numerals 16 and 17 are solder fillets formed by soldering. Hereinafter, a process of forming the solder fillet 17 will be described. The terminal electrode 10 provided at the center of the back surface 7 of the SMD
At the same time as joining with the wiring pattern oblique line portion 15s on the printed circuit board by the cream solder melted in the reflow furnace,
The melted cream solder reaches the castellation 11 via the extraction electrode 12 on the SMD back surface 7 due to the property of the interfacial tension of the solder, and a fillet 17 is formed at the castellation 11 portion.

Accordingly, in the inspection of the soldering state of the terminal electrode 10 provided at the center of the SMD back surface 7, the inspection can be performed by observing whether or not the fillet formed on the castellation 11 is present.

The amount of solder applied, particularly the amount of solder used for bonding the terminal electrode 10 provided at the center of the SMD back surface 7 to the printed circuit board, reaches the castellation 11 via the extraction electrode 12. Is appropriately set.

Further, the width u of the lead electrode 12 is formed to be small, and a sufficient gap is provided between the lead electrode 12 and the terminal electrodes 9 located at the four corners of the SMD back surface 7, so that the electrode formed by the solder bridge is used. Needless to say, there is no problem that a short circuit occurs.

FIGS. 3A and 3B are top perspective views of an external electrode pattern of an electronic component showing another embodiment of the present invention. Various modifications other than those shown in FIG. 1 are possible. Therefore, it can be widely applied to electronic components such as a surface mount type oscillator and a surface mount type surface acoustic wave device which are small and require a large number of terminal electrodes.

[0015]

Since the present invention is configured as described above, the present invention according to claim 1 provides a substrate external electrode pattern of a small surface mount electronic component, wherein terminal electrodes located at four corners of the substrate and the terminal electrodes of the substrate are provided. Since the gap with the terminal electrode provided substantially at the center is sufficiently ensured, there is an excellent effect that occurrence of short circuit between the electrodes due to the solder bridge can be completely eliminated.

Further, by providing a lead electrode connected to the terminal electrode at the central portion from substantially the center of any one side of the outer periphery of the substrate, the solder reaches the outer periphery of the substrate via the lead electrode. Therefore, there is an excellent effect that the soldering state of the central terminal electrode after soldering can be inspected.

Furthermore, by making the area of each terminal electrode substantially equal, there is an excellent effect that sufficient conduction can be secured without causing conduction failure even in the conventional mounting position accuracy when mounting on a printed circuit board.

Therefore, the present invention has an excellent effect that it can be widely applied to electronic parts such as a surface mount type oscillator and a surface mount type surface acoustic wave device which are small and require a large number of terminal electrodes.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an external electrode pattern of an electronic component according to the present invention.

FIG. 2 is a diagram used to explain the present invention;
(A) is a plan view of a printed circuit board, (b) is a schematic perspective view of the SMD mounted on the printed circuit board, and (c) is a schematic perspective view of the SMD mounted on the printed circuit board and soldering is completed.

FIGS. 3A and 3B are top perspective views showing an embodiment of a substrate external electrode pattern according to the present invention.

FIG. 4 is a top perspective view showing a conventional substrate external electrode pattern.

FIG. 5 is a top perspective view showing a conventional substrate external electrode pattern.

FIG. 6 is a top perspective view showing a conventional substrate external electrode pattern.

FIG. 7 is a top perspective view showing a conventional substrate external electrode pattern.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Package 2, 3, 4, 5, 6 Terminal electrode 7 Back surface of surface mount type electronic component (SMD) 8 Castellation (recess provided on side of electronic component) 9, 10 Terminal electrode 11 Castellation 12 Leader electrode 13 Print Substrates 14, 15 Wiring pattern 14s, 15s Cream solder coated part (hatched part) 16, 17 Fillet

Claims (1)

[Claims] 1. An external electrode pattern of a surface-mounted electronic component mounted on a printed circuit board, comprising: terminal electrodes located at four corners of a bottom of the electronic component; and a terminal electrode provided at a substantially central portion of the bottom. An external electrode pattern for an electronic component, comprising a central terminal electrode and a lead electrode extending to the peripheral edge of the bottom.