JPH04164343A - Film carrier tape - Google Patents

Abstract

PURPOSE:To shorten the distance from an ILB lead to a pad for a signal for AC selection and reduce inductance, by arranging pads except the pad for a signal for AC selection, out of pads for electrical selection formed on a base film, in the vicinity of sprocket holes. CONSTITUTION:Specified pads corresponding with specified bumps on an IC out of pads 5 for electrical selection, i.e., a pad 51 for a signal for AC selection and a pad 52 for a power supply are arranged in the vicinity of a device hole 3. Pads 53 except the above ones are arranged in the vicinity of sprocket holes 2. The number of the pads for AC selection is restricted even in the case of an IC whose number of pins is as large as 300-500, so that said pads can be arranged in the vicinity of the device hole. Thereby, as to the specified pads 51 and 52, the distances from the tips of ILB leads 4 to the pads can be shortened, so that accurate electrical selection in a film carrier tape of a high speed operation IC is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film carrier tape, and more particularly to a film carrier tape for multiple pins having a large number of terminals.

[Conventional technology]

As shown in Figure 3, the conventional film carrier tape is
An insulating film 1b made of polyimide (hereinafter referred to as PI) or the like having a sprocket hole 2b for transportation and positioning and a device hole 3b for inserting a semiconductor chip is used as a base film, and a metal foil such as copper is not bonded onto this base film. , an inner lead bonding lead (hereinafter referred to as ILB lead) 4b having a desired shape by etching.
and an electrical selection pad 5b, and these leads and bumps of a semiconductor chip (hereinafter referred to as IC) are bonded by inner lead bonding (hereinafter referred to as IL) by thermocompression bonding or eutectic method.
(denoted as B). The IC is subjected to electrical screening and bias testing in the form of a film carrier tape, and then the leads are cut to the desired length to create a finished product. At this time, in the case of multiple pins with a large number of leads, in order to prevent the outer lead bonding part of the leads from becoming loose, a method is used in which the insulating film 1b made of polyimide or the like that constitutes the film carrier tape is left at the outer end of the outer lead. There are many. The IC manufactured in this way is, for example, outer lead bonded to a bonding pad on a printed circuit board, but when such a film carrier tape is used,
It has advantages such as high speed because only one bonding process is required regardless of the number of leads, and excellent mass productivity because it is easy to automate bonding assembly and electrical selection work.

[Problem to be solved by the invention]

However, in conventional film carrier tape, the third
As shown in the figure, the electrical selection pads 5b are arranged at a constant pad size and at a constant pitch between pads, taking into consideration commonality with other products.

In the case of such design rules, for example, if the number of pins is 100 or less, there is no problem, but for example, with a film carrier tape for 300 to 500 pins, the distance from the tip of the ILB lead to the electrical selection pad 5b (hereinafter referred to as pad) becomes longer in proportion to the number of pins, and the electrical characteristics of this wiring pattern include an increase in resistance (R) and inductance (L). ICs compatible with 300 to 500 bins are generally used in large computers, and high-speed operation determines their performance. Therefore, if the pattern is designed using conventional design rules and pad 5b is placed, R and L will increase. There is a problem in that accurate electrical selection of the accompanying IC itself cannot be performed.

[Means to solve the problem]

The film carrier tape of the present invention includes an insulating film having a sprocket hole and a device hole, an inner bonding lead protruding into the device hole, and an electrical screening film connected to the inner bonding lead and provided on the insulating film. Among the electrical 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 explained with reference to the drawings.

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

Among the electrical sorting pads 5, a specific one corresponding to the bump on the specific c, that is, the electric current sorting pad 5
1 and the power supply pad 52 are placed near the device hole 3, and the other pads 53 are placed near the sprocket hole 2! has been done.

Since the number of pads for AC sorting is limited even in an IC with a large number of pins, such as 300 to 500 bins, they can be placed close to the device hole.

This allows the specific pads (51, 52) to shorten the distance from the ILB lead tip to the pad. For example, in the case of 400 to 500 pins, the pad size is 0.5 m.
Wiring resistance R at mx0.5mm, pad pitch 1.0mm
Electrical characteristics such as L = 100 mΩ or less and wiring inductance L = 10 nH or less can be obtained, making it possible to perform AC sorting during high-speed operation. The signal pad 53 placed near the tin rocket hole has a long distance from the tip of the ILB lead to the pad, and has a wiring resistance R' = 200 to 300 mΩ, for example.
, the wiring inductance L'=15 to 20 nH,
Used as a DC sorting pad.

As mentioned above, by arranging the pads used in the power supply system and AC sorting so that the resistance R and inductance L are as small as possible, it is possible to perform accurate electrical sorting of high-speed operation ICs that cannot be handled with conventional film carrier tapes. becomes.

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

Among the electrical selection pads, the signal pad 5al is arranged near the device hole 3a, and the power supply pad 5a2 is arranged near the sprocket hole 2. This power pad "5a2" has a through hole 6.8 and a back conductor 7.
electrically connected. By arranging the pads in this way, it is possible to reduce the resistance and inductance of the signal pads not only in specific pads (for example, AC selection pads) but also as a whole, and the power supply pads can be placed at a distance from the ILB lead tip. Although it is longer, the resistance R and inductance can be made equal to or lower than those of the signal pad because they are connected by the back conductor and through-hole of the base film. By arranging the pads on the film carrier tape in this manner, the impedance of the pads on the film carrier tape can be reduced, and electrical selection of high-speed operation ICs can be performed accurately.

〔Effect of the invention〕

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

[Brief explanation of the drawing]

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, l'b--insulating film, 2.
2a. 2b... Sprocket hole, 3.3a, 3b...
Device hole, 4.4a, 4b-I LB lead, 5
．． 5a, 5b...Electric screening pad, 51°53.5
al...Paint for signal electrical sorting, 52°5a2.
...Electrical selection pad for power supply, 6, 8...Through hole, 7...Back conductor.

Claims (1)

[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 screening device connected to the inner bonding lead and provided on the insulating film. pad, and among the electrical selection pads,
A film carrier tape characterized in that a signal pad for AC sorting is arranged near the device hole, and other signal pads are arranged near the sprocket hole. 2. The film carrier tape according to claim 1, wherein the plurality of power supply pads are connected to the back conductor of the insulating film through through holes and are electrically connected to each other.