JP2503754B2 - Film carrier tape - Google Patents

Description

The present invention relates to a film carrier tape, and more particularly to a film carrier tape for a large number of pins with a large number of terminals.

[Conventional technology]

As shown in FIG. 3, a conventional film carrier tape uses an insulating film 1b such as polyimide (hereinafter referred to as PI) having a sprocket hole 2b for carrying and positioning and a device hole 3b for inserting a semiconductor chip as a base film. After adhering a metal foil such as copper on the base film, etching is performed to form inner lead bonding leads (hereinafter referred to as ILB leads) 4b and an electric selection pad 5b having a desired shape, and the leads and the semiconductor chip. The bumps (hereinafter referred to as IC) are formed so that inner lead bonding (hereinafter referred to as ILB) can be performed by a thermocompression bonding method or a eutectic method. As for IC, electric selection and bias test are carried out in the state of film carrier tape,
Next, the lead is cut into a desired length to obtain a finished product. At this time, in the case of a large number of pins with a large number of leads, a method of leaving the insulating film 1b such as polyimide forming the film carrier tape on the outer ends of the outer leads is used in order to prevent the outer lead bonding portion of the leads from varying. There are many. The IC manufactured in this manner is outer lead bonded to a bonding pad on a printed circuit board, for example.However, when such a film carrier tape is used, the bonding man-hour can be done only once regardless of the number of leads, and therefore speed is improved. quickly,
Further, since it is easy to automate the assembly by bonding and the electric selection work, there are advantages such as excellent mass productivity.

[Problems to be Solved by the Invention]

However, in the conventional film carrier tape, as shown in FIG. 3, the electric selection pads 5b are arranged with a constant pad size and a constant pad pitch in consideration of commonality with other types. With such a design rule,
For example, if it is 100 pins or less, it does not matter,
With film carrier tapes for 00 to 500 pins, the distance from the tip of the ILB lead to the electric selection pad 5b (hereinafter referred to as the pad) becomes longer in proportion to the number of pins, and the electrical characteristics of this wiring pattern are resistance (R ), The inductance (L) will increase. ICs with 300 to 500 pins are generally used for large-scale computers, and their high-speed operation affects their performance. Therefore, pattern design is performed according to the conventional design rules, and if pad 5b is placed, R and L increase. As a result, there was a problem in that it was not possible to perform accurate electrical selection of the IC itself.

[Means for solving the problem]

The film carrier tape of the present invention comprises an insulating film having a sprocket hole and a device hole, an inner bonding lead projecting into the device hole, and an electric screening provided on the insulating film in connection with the inner bonding lead. Among the electric selection pads, a signal pad for AC selection is arranged near the device hole, and other signal pads are arranged near the sprocket hole.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the present invention, showing one quarter of a film carrier tape.

A specific one of the electric selection pads 5 corresponding to a bump on a specific IC, that is, an AC selection signal pad 51 and a power supply pad 52 are arranged near the device hole 3,
The other pads 53 are arranged near the sprocket hole 2.

Since the number of pads for AC selection is limited even if the IC has a large number of pins of 300 to 500, it can be arranged in a place near the device hole.

This allows the specific pads (51, 52) to shorten the distance from the tip of the ILB lead to the pad.
For 0 to 500 pins, electrical characteristics of pad size 0.5 mm × 0.5 mm, pad pitch 1.0 mm, wiring resistance R = 100 mΩ or less, wiring inductance L = 10 nH or less can be obtained, and AC selection at high speed operation is possible. Becomes In the signal pad 53 arranged near the sprocket hole, the distance from the tip of the ILB lead to the pad becomes long, for example, the wiring resistance R ′ = 200 to 300.
mΩ, wiring inductance L '= 15 ~ 20nH, but used as a DC selection pad.

As described above, by arranging the power supply system and pads used during AC selection so that the resistance R and the inductance L are as small as possible, it is possible to perform accurate electrical selection work for high-speed operation ICs that cannot be handled by conventional film carrier tapes. Becomes

 FIG. 2 is a plan view showing a second embodiment of the present invention.

Among the electric selection pads, the signal pad 5a1 is arranged near the device hole 3a, and the power pad 5a2 is arranged near the sprocket hole 2. The power pad 5a2 is electrically connected by the through holes 6 and 8 and the back conductor 7. By adopting such a pad arrangement, the signal pad is not only a specific pad (for example, an AC selection pad), but can also have low resistance and low inductance as a whole, and the power supply pad can be separated from the tip of the ILB lead by a distance. Although it becomes longer, the resistance R and the inductance L can be made equal to those of the signal pads or can be made smaller by the shape of the back conductor because they are connected by the back conductor and the through hole of the base film. By arranging the pads of the film carrier tape as described above, it becomes possible to reduce the impedance of the pads on the film carrier tape, and it becomes possible to accurately correspond to the electrical selection of the high speed operation IC.

〔The invention's effect〕

As described above, the film carrier tape of the present invention is 300 to 500 pins by arranging the other than the signal pad for AC sorting among the electrical sorting pads formed on the base film near the sprocket hole. Even if a large number of pins are used, the distance from the ILB lead to the signal pad for AC selection should be kept as short as possible, and these parasitic resistance (R) and inductance (L)
And so on. This has the effect of enabling accurate electrical sorting of film carrier tapes for high-speed operation ICs.

[Brief description of drawings]

1 and 2 are plan views of a first embodiment and a second embodiment of the present invention, respectively, and FIG. 3 is a plan view of a conventional example. 1,1a, 1b …… Insulating film, 2,2a, 2b …… Sprocket hole, 3,3a, 3b …… Device hole, 4,4a, 4b …… ILB lead, 5,5a, 5b …… For electrical selection Pads, 51,53,5a1 …… Signal electric selection pad, 52,5a2 …… Power supply electric selection pad, 6,8 …… Through hole, 7 …… Back conductor.

Claims (2)

(57) [Claims] 1. An insulating film having a sprocket hole and a device hole, an inner bonding lead protruding into the device hole, and an electrical selection pad connected to the inner bonding lead and provided on the insulating film. A film carrier, characterized in that, of the electric selection pads, a signal pad for AC selection is arranged near the device hole, and other signal pads are arranged near the sprocket hole. tape. 2. The film carrier tape according to claim 1, wherein the plurality of power supply pads are connected to the back surface conductor of the insulating film through the through holes and are electrically connected to each other.