JPS6038291Y2 - Printed wiring board for chip mounting - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a method for directly mounting semiconductor and integrated circuit chips (hereinafter simply referred to as 1 chip) by counterbore cutting the chip mounting area. The present invention relates to a printed wiring board for mounting a chip, which has a recess that allows proper insertion.

[Conventional technology]

Conventionally, chips have been mounted on a ceramic substrate or a metal plate lead frame in a protruding state, packaged, and mounted on a printed wiring board.

On the other hand, recent technological advances in wire bonding and wire bonding have made it possible to develop and implement a method for directly mounting a chip on a printed wiring board made of a plastic substrate.

In conventional printed wiring boards, chips are mounted and bonded on the same smooth surface of the printed wiring board, so the conventional method is as follows: There were some drawbacks.

That is, as one method for manufacturing a conventional printed wiring board, a conductive circuit is formed on the printed wiring board in advance, and then electrolytic plating such as electrolytic nickel plating, electrolytic gold plating, electrolytic silver plating, etc. is applied.

According to this method, electronic circuit products with relatively high precision and reliability can be obtained, so it is a method that is often applied particularly to printed wiring boards on which chips are directly mounted.

At this time, after forming conductor circuits on the printed wiring board, all the conductor circuits are connected in advance with conductive wires in order to perform electrolytic plating, and then the conductive wires are connected to external lead wires and electrolytic plating is applied. After the completion of electrolytic plating, it is necessary to remove unnecessary circuit parts other than those necessary as conductor circuits when actually used among the conductive wires that are unnecessary.

In this case, it is common practice to lead the conductive wire outside the outline of the printed wiring board and remove it by punching using a press or the like after electrolytic plating is completed.

However, when the conductor circuit becomes complex, it is not possible to set all the conductive lines outside the outline line, and in such cases, an isolated conductor circuit remains inside the outline line, and this part is electrolytically plated. There is a drawback that this is not done.

Therefore, it has not been possible to manufacture a printed wiring board with high precision and reliability using the above conventional method.

In addition, when a chip is mounted and bonded on the surface of a printed wiring board, where all the surfaces of the board are flat at the same level, as in conventional printed wiring boards, and then sealed with resin, resin flows around the chip and this resin outer periphery. There are disadvantages such as the wires tend to be uneven and it is difficult to mount other electronic components on the printed wiring board.

[Problem to be solved by the invention 1 The purpose of the present invention is to eliminate and improve the shortcomings of the conventional technology. Among the conductor circuits for electrolytic plating that are no longer needed after being used as lead wires for electrolytic plating on the inside and outside of the wire, counterboring the conductor circuits for electrolytic plating that are concentrated only on the inside of the punched outline wire. The present invention provides a printed wiring board for mounting a chip, which can be removed by cutting to form a recess for mounting the chip.

[Means for solving problems]

In order to eliminate and improve the above problems, this invention
A printed wiring board for mounting a chip on which a conductor circuit is formed by electrolytic plating, and the conductor circuit for electrolytic plating is formed on the inside and outside of the punched outline line, which becomes unnecessary after being used as a lead wire for electrolytic plating. The electrolytic plating conductor circuits inside the punched outline are arranged in a concentrated manner, and a recess for chip mounting is formed by removing the concentrated electrolytic plating conductor circuits by counterbore cutting. The company adopted a method of providing printed wiring boards for mounting chips.

Note that the printed wiring board for chip mounting according to the present invention can be applied to any one of single-sided, double-sided, and multilayer printed wiring boards.

Further, the shape and dimensions of the chip mounting recess formed can be arbitrarily set.

Usually, it is preferable to perform counterbore cutting to a shape and size slightly larger than the chip to be mounted.

The depth of the recess can also be set arbitrarily.

Also, the number of recesses is 1 in one pattern of the printed wiring board.
One or more pieces may be formed.

In other words, in order to solve the drawbacks of the conventional technology, the present invention removes a part of the electrolytic plated lead wires that are centrally arranged inside and outside the punched outline of the printed wiring board, and also uses counterbore cutting to create a chip mounting area. It is characterized by forming a recessed portion.

Note that the counterbore cutting process as used in the present invention is a process whose main purpose is cutting to form a counterbore recess using an end mill or router.

Then, the chip is mounted in the recess, the chip is fixed to the bottom of the recess by wire bonding, and the chip circuit and the printed wiring board are electrically connected by wire bonding or other methods.

However, the chip mounting method and bonding method are not particularly limited.

Next, the printed wiring board according to the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a perspective view of the printed wiring board before cutting with a counterbore and punching out the outline with a press.

The printed wiring board shown here is a double-sided printed wiring board and has a complicated conductor circuit, so this is an example in which a conductive wire is installed as a lead wire for electrolytic plating even within the boundary of the counterbore cutting process.

In this drawing, 1 is a printed wiring board, 2 is an outline line punched by a press, 3 is a counterbore cutting boundary line, 4 is a conductive line within the counterbore cutting boundary, 4' is a conductive line outside the counterbore cutting boundary, and 5 is a conductive line outside the counterbore cutting boundary. is a conductor circuit, 6 is a through hole hole, 7 is a conductor circuit
is a terminal for electrolytic plating.

Then, while removing a part of the lead wire for electrolytic plating that becomes unnecessary after being used as a lead wire for electrolytic plating, which is a feature of this invention, the chip mounting area is counterbore cut to create a recess for chip mounting. form.

The result is shown in a drawing as shown in the perspective view of FIG.

The above-mentioned FIG. 2 shows a printed wiring board that is punched out using a press after counterbore cutting the printed wiring board.

Here, 8 is a recess for mounting a chip formed by counterbore cutting.

FIG. 3 is a perspective view showing an example of a double-sided printed wiring board in which two counterbores are cut in one pattern to form a recess into which a chip can be properly inserted.

As described above, in the printed wiring board for chip mounting of the present invention, the conductive wires as lead wires for electrolytic plating of the conductor circuits are arranged intensively within the boundary where counterbore cutting is to be performed, and the electrolytic plating After performing this, the conductor circuit portion of the lead wire for electrolytic plating, which becomes unnecessary, is removed by counterbore cutting, and a recessed portion for mounting the chip is formed.

At this time, there may be an embodiment in which a conductive line outside the outline is also used.

Therefore, in the case of printed wiring boards that have advanced and complicated conductor circuits, such as gold-plated printed wiring boards, electrolytic plating is applied after forming the conductor circuits in advance. The lead wires can be arranged in a concentrated manner and removed at the same time by counterbore cutting to form a recess for mounting the chip.

In this way, the chip can be mounted in the recess and bonded at a horizontal plane level without the chip protruding, and when sealing with resin, the flow of resin can be stopped within the range of the outer periphery of the recess. can.

[Action and effect]

As described above, according to the present invention, a chip can be mounted on the surface of a printed wiring board very conveniently without interfering with the mounting or packaging of other electronic components.

Furthermore, due to the nature of the wire bonding, when performing wire bonding or wire bonding, the horizontal plane of the surface of the printed wiring board and the horizontal plane of the chip surface when the chip is mounted in the recess are almost at the same level as the surface of the printed wiring board. Since it is possible to make a highly accurate and reliable electrical connection between the circuit of the chip and the cut part of the conductor circuit, it is much more precise and reliable than when bonding is done using the conventional method, which does not make electrical connections on the same horizontal plane. It also has excellent effects such as providing highly reliable electronic circuit products.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the printed wiring board before counterbore cutting and punching out the outline using a press according to the present invention;
3 and 3 are perspective views of a printed wiring board for mounting a chip according to the present invention, in which a recess is formed by counterbore cutting at a location where a chip is to be mounted. In the above drawings, 1 is a printed wiring board, 2 is a punched outline, 3 is a counterbore cutting boundary line, 4 is a conduction line within the counterbore cutting boundary, 4' is a conduction line outside the counterbore cutting boundary, and 5 is a conductor. 6 is a through hole, 7 is a terminal for electrolytic plating, and 8 is a recess for mounting a chip formed by counterbore cutting.

Claims (1)

[Scope of utility model registration request] A printed wiring board for mounting a chip on which a conductor circuit is formed by electrolytic plating, and the conductor circuit for electrolytic plating is formed on the inside and outside of the punched outline line, which becomes unnecessary after being used as a lead wire for electrolytic plating. The electrolytic plating conductor circuits inside the punched outline are arranged in a concentrated manner, and by removing the concentrated electrolytic plating conductor circuits by counterbore cutting, a recess for chip mounting can be formed. A printed wiring board for mounting chips, which is characterized by: