JPH0672248U - Lead frame - Google Patents

Abstract

(57) [Abstract] [Purpose] A lead frame for a metal base substrate in which inverted L-shaped leads having a flat portion at the upper end having two kinds of long and short lead portions are alternately arranged in the tie bar portion [Structure] 1 Reference numeral 2 denotes an inverted L-shaped lead portion having a long lead portion 3 and a flat portion on the upper end, and reference numeral 2 denotes an inverted L-shaped lead portion having a short lead portion 4 and a flat portion on the upper end. The leads 1 and 2 are alternately arranged and connected to the same tie bar portion 5, and the gap portion between the flat portion 6 and the flat portion 7 provided at the upper ends of the leads 1 and 2 forms the sandwiching portion 8. Is forming. The metal base substrate 9 on which the mounting components are mounted is sandwiched between the sandwiching portions 8 and soldering processing is performed to solder only the flat portions 7 of the leads 2 to the metal base substrate 9. Subsequently, the leads 1 and 2 were cut from the tie bar portion 5, and the stepped lower end portion 10 of the lead portion 4 of the shorter lead 2 was faced up to mount the required mounting components. It is inserted into the sub-board 11 and a dip or manual soldering process is performed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lead frame, and more particularly, to a lead frame structure for a metal base substrate.

[0002]

[Prior art]

 Conventionally, a metal-based substrate is often used for a large power circuit in which a printed wiring board has a shortage of heat radiation. The structure of this metal base substrate is such that an insulating layer is adhered on a metal base that is a metal material with good thermal conductivity, mainly aluminum, iron alloy, copper, etc., and copper foil is etched on this insulating layer. A layer is formed, and a solder resist layer is formed on the copper foil layer. The metal base substrate having the above structure is characterized in that the heat of the heat generating portion is easily transferred to the peripheral portion of the metal base substrate, but it is an element having a heat-sensitive characteristic in the place adjacent to the high power circuit. However, in this case, FIG. 2 is a cross-sectional view of a main part of an example of a conventional lead frame. As shown in FIG. After mounting, the sandwiching portion 18 of the F-type lead frame 12 is attached to the sub-board 21, and the lead portion 14 of the lead-frame 12 is bent to form the sub-board 21 into a surface mounting component shape. It was mounted on the metal base substrate 19. However, if the lead portion 14 of the lead frame 12 is not bent well, the lead portion 14 may float when mounted on the metal base substrate 19, and the sub-board 21 may be mounted at the same time as other mounting components. In that case, it is not possible to confirm the soldering state of the element hidden under the sub-board 21, so that the sub-board 21 is often soldered to the metal base board 19 later by hand.

[0003]

[Problems to be solved by the device]

 The present invention has been made in view of such a point. If the lead portion of the lead frame is not bent well, the lead portion may float when mounted on a metal base substrate, or other mounted components. At the same time, when a sub-board is mounted, a lead frame is provided in which the soldering state of the element hidden under the sub-board cannot be confirmed.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention connects two types of inverted L-shaped leads, each having a flat portion at the tip and having different lengths, to a tie bar portion continuously, and between the flat portions of the two types of leads. The gap is formed to be approximately the same as the thickness of the metal base substrate to form a sandwiched portion, the metal base substrate is soldered to the sandwiched portion, and then the tie bar portion is cut off to form the longer one. Of the shorter lead is inserted into the sub-board with the stepped lower end formed on the lead part of the shorter lead facing upward. The width of the flat portion and the lead portion having a required length is increased.

[0005]

[Action]

 Since the lead frame according to the present invention is configured as described above, two types of inverted L-shaped leads each having a flat portion at the tip and having different lengths are consecutively connected to the tie bar portion. After forming a sandwiched part in the gap between the flat parts and soldering the metal base substrate to the sandwiched part, the tie bar part is cut to remove the long lead and to remove the short lead. Since the stepped lower end portion formed on the lead portion is inserted into the sub-board, it is not necessary to bend the lead frame lead portion to mount the sub-board on the metal base board, and the metal base board is not required to be bent. It is possible to mount the sub-board after confirming the solder state of other mounted components.

[0006]

【Example】

 Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view and a sectional view of an essential part of an embodiment of a lead frame of the present invention. In the figure, 1 is an inverted L-shaped lead having a flat portion 6 at the tip having a long lead portion 3, and 2 is an inverted L-shaped lead portion having a flat portion 7 having a short lead portion 4. Is. The two types of leads 1 and 2 having different lengths are alternately arranged and connected to the same tie bar portion 5. The sandwiching portion 8 is formed by making the gap between the flat portion 6 and the flat portion 7 provided at the upper ends of the leads 1 and 2 approximately the same as the thickness of the metal base substrate. In the above description, the longer lead 1 and the shorter lead 2 are alternately arranged and connected to the tie bar portion 5. However, since the longer lead 1 may be sandwiched by the metal base substrate, the number of the leads should be reduced. The ratio may be reduced to one for two shorter leads. The required mounting components are mounted in advance, and the metal base substrate 9 that has been subjected to reflow processing is sandwiched between the sandwiching portions 8 composed of the flat portions 6 and 7 described above, and soldering processing by dipping is performed. . At this time, the flat portion 7 of the shorter lead 2 is soldered to the conductor land portion of the corresponding metal base substrate 9, while the flat portion 6 of the longer lead 1 corresponds to it. Since the metal base substrate 9 has no conductor land portion, it is not soldered. After soldering the sandwiching portion 8 to the metal base substrate 9, the same tie bar portion 5 in which the leads 1 and 2 are alternately arranged is cut to remove the longer lead 1. , The lead portion 4 of the shorter lead 2 has the stepped lower end portion 10 facing upward, and is inserted into the mounting hole provided in the sub-board 11 on which the required mounting components are mounted in advance, and the dip or hand mounting is performed. Perform solder processing.

[0007]

[Effect of device]

 As described above, in the lead frame according to the present invention, two types of leads having different lengths of the inverted L-shaped lead having the flat portion at the tip are connected to the tire portion. , Forming a sandwiching part in the gap between the flat parts of the two types of leads, soldering the metal base substrate to the sandwiching part, and then cutting the tie bar part to remove the longer lead. Since the stepped lower end formed on the lead part of the shorter lead is inserted into the sub-board, it is necessary to bend the lead part of the lead frame to mount the sub-board on the metal base substrate. In addition, since the sub-board can be mounted after checking the soldering state of other mounted components mounted on the metal base board, problems due to bending of the lead part do not occur and the metal board The scan board can be easily used.

[Brief description of drawings]

FIG. 1 is a side view and a sectional view of an essential part of an embodiment of a lead frame of the present invention.

FIG. 2 is a sectional view of an essential part of an example of a conventional lead frame.

[Explanation of symbols]

 1 lead 2 lead 3 lead portion (long) 4 lead portion (short) 5 tie bar portion 6 flat portion 7 flat portion 8 sandwiching portion 9 metal base substrate 10 lower end portion 11 sub substrate

Claims (2)

[Scope of utility model registration request] 1. An inverted L-shaped lead having a flat portion at its tip and two kinds of leads having different lengths are continuously provided to a tie bar portion, and a gap portion between the flat portions of the two kinds of leads is formed on a metal base substrate. The sandwiched part is formed by making it approximately the same as the thickness,
After soldering the metal base substrate to the sandwiched portion, the tie bar portion is cut, the longer lead is removed, and the stepped lower end portion of the lead portion formed on the shorter lead is turned upward. The lead frame is characterized in that it is inserted into the sub-board. 2. The lead frame according to claim 1, wherein the width of the flat portion of the shorter lead and the width of the lead portion having a required length are increased in order to support the sub-board.