JPH04277635A - Connection structure of pad - Google Patents

Abstract

PURPOSE:To provide a connecting configuration for a pad which is capable of preventing a short circuit when pattern pads are formed closely adjacent to one another, and which is capable of increasing the integration of an IC and a printed board. CONSTITUTION:Pattern pads 6 are formed on a substrate, and they are connected to an IC pad 2 (not illustrated in the figure) of an IC chip 3 via lead wires 10. A rounded periphery P6 of the pattern pad 6 prevents the lead wire 10 from being curved when it is caught by an angled pad. Thus, this configuration hinders a contact between the lead wires, which are adjacent to one another, and permits the formation of the pattern pads 6 proximately to one another.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting pads to lead wires, and more particularly to a connection structure that can increase the degree of integration.

0002

2. Description of the Related Art A bonding pad located on an integrated circuit (IC) is shown in FIG. An IC chip 3 is fixed to the base substrate 7 of the IC, and this IC chip 3 is connected to a plurality of I
It is equipped with a C pad 2. On the other hand, each I
Pattern pads 4 corresponding to the C pads 2 are also formed, and these pattern pads 4 and the IC pads 2 are connected by lead wires (not shown). That is, the IC chip 3 receives current from or is supplied with current from the pattern pad 4 through the lead wire, is mounted on a printed circuit board (not shown), and performs a predetermined electrical operation.

A capillary or the like is used to connect the IC pad 2 and the pattern pad 4 using lead wires. This capillary 5 performs predetermined wiring by moving while leading out the lead wire 10 from the lead-out hole 5T at the tip, as shown in FIG. 3A. When connecting, first,
One end P2 of the lead wire 10 is connected and fixed to the IC pad 2 by thermocompression bonding using the capillary 5. Then, the capillary 5 moves in the direction of arrow 90 while leading out the lead wire 10, and performs wiring toward the pattern pad 4. In order to wire the lead wire 10 close to the base substrate 7, the capillary 5 is once lowered during movement to form a proximal wiring portion P3.

The capillary 5 is positioned on the pattern pad 4, and the lead wire 10 is fixed to the pattern pad 4 by thermocompression bonding. Thereafter, the lead wire 10 is cut by the capillary 5. FIG. 3B shows a state in which the lead wire 10 is cut and the other end P4 is fixed. In this way, the IC pad 2 and the pattern pad 4 are electrically connected by the lead wire 10. Incidentally, the IC chip 3 may be directly fixed on the printed circuit board (not shown), but in this case as well, the connection to the pattern pads on the printed circuit board and the lead wires 10 is made in the same manner.

[0005]

SUMMARY OF THE INVENTION The conventional pad connection structure described above has the following problems. The pattern pad 4 located on the base substrate 7 of the IC has a corner L4 as shown in FIG. 3B. For this reason, the lead wire 10 may be caught on this corner L4, forming an abutting portion P8, and may be wired in a large curve.

Possible causes of the lead wire 10 getting caught in the corner L4 include twisting of the lead wire 10 itself led out from the capillary 5, misalignment of the fixed position of the IC pad 2 or the pattern pad 4, and the like. Due to the arrangement relationship between the IC pad 2 and the pattern pad 4, when the lead wire 10 is led obliquely to the pattern pad 4, the contact portion P8 is particularly likely to be formed.

If the lead wires 10 are wired in a large curve as described above, the adjacent lead wires 10
There is a risk that they may come into contact and cause a short circuit. Therefore, in order to avoid such a short circuit, the spacing S4 between each pattern pad 4 is generally
is formed relatively large, and has a structure such that even if a contact portion P8 occurs in the lead wire 10, adjacent lead wires 10 do not come into contact with each other. If the spacing S4 between the pattern pads 4 is made wide, there is a problem that the degree of integration in the entire IC decreases. A similar problem occurs when the IC chip 3 is directly fixed onto the printed circuit board, resulting in a decrease in the degree of integration of the printed circuit board.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pad connection structure that can prevent short circuits while arranging pattern pads close to each other and increase the degree of integration of ICs and printed circuit boards.

[0009]

[Means for Solving the Problems] A pad connection structure according to the present invention includes a first pad located on an integrated circuit chip held on a substrate and to which a first end of a connection lead is fixed; In a pad connection structure, the pad connection structure includes a second pad that is located at the second end of the connection lead and is connected to the second end, which is the other end of the connection lead. It is characterized by being formed in a curved shape.

0010

[Operation] In the pad connection structure according to the present invention, the outer periphery of the second pad to which the second end of the connection lead is guided is formed in a curved shape. Therefore, no corner is formed on the outer periphery of the second pad, and the connection lead will not be caught in the corner and wired in a curved shape. That is, it will not come into contact with adjacent connection leads and cause a short circuit.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pad connection structure according to the present invention will be described. FIG. 1 shows a patterned pad 6 as a second pad in the present invention. This pattern pad 6 is connected to a lead wire 10 which is a connection lead by a capillary 5 or the like.
are guided and connected. As shown in FIG. 3A, the capillary 5 performs predetermined wiring by moving while leading out the lead wire 10 from the lead-out hole 5T at the tip. The lead wire 10 generally has a thickness of 18 μm to 127 μm.
m is used.

For connection, first, one end P2, which is the first end of the lead wire 10, is thermocompressed with the capillary 5, and connected and fixed to the IC pad 2 of the IC chip 3 (see FIG. 3A). Then, the capillary 5 moves in the direction of arrow 90 while leading out the lead wire 10, and connects the lead wire 10 to the pattern pad 4.
guide.

The IC chip 3 is held on the substrate, but the I
In addition to being held on the base board 7 of C, it may also be mounted directly on a printed circuit board (not shown). In this case, the pattern pad 6 will be formed on the printed circuit board. As the printed circuit board, a glass epoxy board, a phenol board, a flexible pattern board, a lead frame, or the like is used.

As shown in FIG. 1, the outer peripheral portion R6 of the pattern pad 4, through which the lead wire 10 is guided, is formed in a semicircular shape. Then, the lead wire 10 passes through the outer peripheral portion R6 of the pattern pad 4, is located on the pattern pad 4, and is fixed by thermocompression bonding of the capillary 5. After the other end P6, which is the second end of the lead wire 10, is fixed, the capillary 5
cuts the lead wire 10. The outer periphery R6 of the pattern pad 4 is semicircular and has no corners, so the lead wires 10 will not be caught in the corners and wired in a curved shape. That is, there is no possibility that the lead wires 10 adjacent to each other will come into contact with each other and cause a short circuit.

In this way, in the present invention, the lead wire 1
Since there is no risk of short circuit due to contact between pads 4 and 4, the spacing S6 between each pattern pad 4 can be made small, making it possible to increase the degree of integration of ICs and printed circuit boards. By increasing the degree of integration, electronic devices can be made smaller. In the above embodiment, the outer circumferential portion R6 of the pattern pad 4 is formed in the semicircular shape shown in FIG. Good too.

[0016]

In the pad connection structure according to the present invention, no corner is formed on the outer periphery of the second pad, and the connection lead is not caught in the corner and wired in a curved shape. That is, it will not come into contact with adjacent connection leads and cause a short circuit. Therefore, the second pads to which the connection leads are connected can be disposed close to each other, and the degree of integration of the integrated circuit can be increased.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a patterned pad in a pad connection structure according to the present invention.

FIG. 2 is a plan view showing an IC chip and pattern pads located on the IC.

FIG. 3 is a side view and a plan view for explaining the outline of an IC pad connection structure.

[Explanation of symbols] 2...IC pad 3...IC chip 4, 6...Pattern pad 7...Base board 10...Lead wire P2...One end P4, P6...other end R6...Outer periphery

Claims (1)

[Claims] 1. A first pad located on an integrated circuit chip held on a substrate and to which a first end of a connection lead is fixed; a second pad located on the substrate and to which the other end of the connection lead is fixed; A pad connection structure including a second pad whose end is guided and connected, characterized in that the outer periphery of the second pad, through which the second end of the connection lead is guided, is formed in a curved shape. Pad connection structure.