JPH0628275B2 - Film carrier tape - Google Patents

Description

TECHNICAL FIELD The present invention relates to a film carrier tape, and more particularly to a film carrier tape that requires high-density mounting.

[Conventional technology]

A conventional film carrier tape has an insulating film such as polyimide having a sprocket hole for transportation and positioning and a device hole which is an opening portion into which a semiconductor chip is inserted, and a metal foil such as copper adhered onto the insulating film. This metal foil is a metal projection formed on the leads and the pads for electrical selection having a desired shape by etching or the like, and provided in advance on the leads and the electrode terminals of the semiconductor chip (hereinafter referred to as IC). Inner lead bonding is performed on the bumps by a thermocompression bonding method or a eutectic method. Electrical selection and a bias test are performed in the state of this film carrier tape, and then the leads are cut into desired lengths. At this time, in the case of a large number of leads with a large number of leads, in order to prevent the outer lead bonding part of the leads from coming apart, a method of leaving an insulating film such as polyimide forming the film carrier tape on the outer ends of the outer leads should be used. There are many. In general, outer lead bonding is performed on a bonding pad on a printed circuit board or a general lead frame.

Since such a film carrier tape can be bonded at one time regardless of the number of leads, the speed is fast, and the assembling such as bonding and the automation of the electric selection work are performed, and thus the mass productivity is excellent.

[Problems to be Solved by the Invention]

In the IC inner lead bonding (hereinafter referred to as ILB) using the conventional film carrier described above, heat of about 400 ° C. to 500 ° C. is required to bond the leads of the film carrier and the bumps on the IC. When ILB is performed by this heat, the heat is transferred to the insulating film of the film carrier through the leads, and the insulating film is heated and contracted. For example, in the case of a polyimide film, this shrinkage amount is about 0.3% at 250 ° C. for 30 minutes. On the other hand, ILB
Although the heating time is several seconds, the heat is as high as about 400 ° C. to 500 ° C., so that about 0.3% of heat shrinkage similarly occurs. For example, when the length is 10 mm, the shrinkage of 30 μm occurs. Here, when the number of leads of the outer lead bonding portion is 200 to 300 or more and the pitch is 150 μm or less, the end lead portion shrinks from 22.5 μm to 33.8 μm, so that the outer lead bonding (hereinafter referred to as OLB) is adjacent. There is a drawback that it shorts with the OLB pad.

The object of the present invention is to eliminate the above drawbacks, and to preliminarily design the size of the OLB portion of the lead by correcting the heat shrinkage amount by the heat applied to the ILB of the insulating film to prevent a short circuit between the OLB pads. To provide.

[Means for Solving the Problems]

The present invention comprises a film carrier tape having leads of a predetermined pattern on an insulating film, wherein the leads have a heat shrinkage amount due to heat applied by inner lead bonding of the insulating film as a coordinate value of an outer lead. The feature is that they are added, corrected, and arranged.

〔Example〕

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

FIG. 1 is a front view of an embodiment of the present invention, showing only the first quadrant thereof. In a film carrier tape, leads 3 are provided on an insulating film 1 having sprocket holes 2 and device holes 7. Plated wiring 5 is formed. A device hole 7 is provided to provide the lead 3, and a plated wiring 5 is provided to plate the lead with Au or the like. The coordinates of the OLB part 4 of the lead 3 are
OLB portion _{4 n} Y coordinate value _{Y n} is _{Y n = Pn / (1-} α)
To be set. The pitch P between the OLB parts 4 is
The spacing between the OLBs of the leads assuming that the insulating film 1 does not shrink even with the heat required by the ILB, α is the heat shrinkage rate of the insulating film when ILB is applied, and n is the number of leads. Similarly the X-coordinate value of the 4 _'m of the OLB portion _X m =
It is P'm / (1-α).

In this way, by correcting the heat shrinkage amount of the insulating film 1 constituting the film carrier tape due to heat in the ILB and determining the coordinates of the OLB portions 4 _n and 4 ′ _m of the lead 3,
O of OLB pad and IC lead such as printed circuit board coordinates
There is an advantage that accurate alignment with the LB portion is possible and a short-circuit with an adjacent OLB pad does not occur in the case of OLB.

FIG. 2 is a partial front view of the second embodiment of the present invention, showing only the first quadrant. This embodiment is effective when the ratio of the short side to the long side of the IC is as large as 1: 2 or 1: 3. The amount of heat shrinkage of the insulating film 1 constituting the film carrier tape due to the heat of the ILB becomes larger as the distance from the center 10 of the IC becomes longer on the long side of the IC, so that the CLB portion 9 _{n of the} lead 8 _n becomes larger. To the OLB portion 9 _m of the lead 8 _m from the lead 8 _m are set in consideration of the heat shrinkage rate α. Therefore, for example, the Y coordinate value of the OLB unit 9 _m is Y = Y _n + Y _m = P · n + P (m−n) /
It is set to be (1-α).

In this way, the heat shrinkage of the insulating film 1 is large, and
By designing the film carrier tape by correcting the heat shrinkage amount only in the part that adversely affects the work B, the design man-hours can be reduced and the OLB pad on the printed circuit board and the OLB part of the IC lead can be accurately measured in the OLB work. It is possible to perform proper alignment, and in the case of OLB, there is an advantage that a short circuit with an adjacent OLB pad does not occur.

〔The invention's effect〕

As described above, the present invention corrects the heat shrinkage amount of the insulating film constituting the film carrier tape due to the heat of the ILB and sets the coordinates of the OLB portion of the lead to set the OLB on the printed circuit board or the like. Accurate alignment between the pad and the OLB part of the lead of the IC can be performed, and the adjacent OL
There is an effect that a short circuit with the B pad does not occur.
This effect is obtained by using a film carrier tape, which is a film carrier tape that requires high-density mounting, such as lead O.
The number of LB is 200 to 300 or more and the pitch is 150μ
The effect is particularly remarkable in the product type in which the dimensional accuracy of the OLB portion and the alignment accuracy in assembly are required to be m or less.

[Brief description of drawings]

1 and 2 are partial front views of the first and second embodiments of the present invention. 1 ... Insulating film, 2 ... Sprocket hole, 3 ...
... lead 4 ₁ , 4 _n , 4 ₁ , 4 _m , 4 ₁ , 4 _o ...... lead's OLB part, 5 ...... plated wiring, 6 ₁ , 6 _n ...... lead's ILB part, 7 ... insulating film Device hole, 8 ₁ , 8 _n , 8 _m ... ILB part of lead, 9 ₁ , 9
_n , 9 _m ... OLB part of lead, 10 ... Coordinate origin of insulating film.

Claims (1)

[Claims] 1. A film carrier tape having leads of a predetermined pattern on an insulator film, wherein the leads add heat shrinkage due to heat applied by inner lead bonding of the insulator film to coordinate values of outer leads. A film carrier tape characterized by being arranged after being corrected.