JPH0621158A - Film carrier tape and inner lead bonding method - Google Patents

Abstract

PURPOSE:To prevent deviation of an inner lead due to thermal expansion of a film in a single point inner lead bonding of the inner lead of a film carrier tape and the electrode pad of a semiconductor pellet. CONSTITUTION:At the manufacturing stage of a film carrier tape, the pitch of an inner lead 4 is made smaller than that of an electrode pad 2 of a semiconductor pellet 1 from the beginning considering thermal expansion on bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film carrier tape and an inner lead bonding method, and more particularly to a film carrier tape and an inner lead bonding method for connecting an electrode pad of a semiconductor pellet and an inner lead.

[0002]

2. Description of the Related Art In conventional single point inner lead bonding (hereinafter referred to as ILB), as shown in FIG. 4, a semiconductor pellet 1 is vacuum adsorbed and fixed on a bonding stage heated to a high temperature. On the other hand, the film 3 is fixed in a state of being sandwiched by the tape clamper, and the inner pad 4 extending from the electrode pad 2 on the semiconductor pellet 1 and the metal pattern formed on the film 3
A gap (about 50 to 300 μm) with a gap is opened, and they are superposed and aligned. In this state, the electrode pad 2 and the inner lead 4 completely overlap each other when viewed from above. Here, the tool descends toward the electrode pad 2 from directly above, and the inner leads 4a and the electrode pads 2 are joined one by one by thermocompression bonding or ultrasonic combined bonding through metal projections (hereinafter referred to as bumps) 5. It

[0003]

In the above-mentioned single point ILB, the following problems have occurred with the recent finer pitch of semiconductor pellet electrodes.
That is, due to the finer pitch of the electrode pads, the tolerance for the positional deviation of the inner leads after ILB is becoming smaller and smaller, and more accurate bonding is required. However, it is a film of a film carrier tape which is currently generally used, for example,
Kapton (trade name) or Upilex (trade name) has a large coefficient of thermal expansion, and the expansion of the inner lead pitch during ILB cannot be ignored. Specifically, it is as follows. When the normal temperature is 25 ° C., the bonding stage temperature is 275 ° C., and the inner lead total pitch is 15 mm, when the leads are connected one by one with the single point ILB, the heat of the bonding stage is sequentially transferred from the leads to heat the film, The temperature of the film rises to near the stage temperature (220-230 ° C). At this time, the inner lead total pitch expands by about 6 μm for Kapton and about 4.5 μm for Upilex. Although this error itself does not have a great influence, it has a great influence on the defect rate particularly in the case of a fine pitch (60 μm or less) in consideration of errors such as bonding accuracy and lead-bump alignment accuracy.

An object of the present invention is to provide a film carrier tape and an inner lead bonding method capable of performing accurate bonding without displacement of the inner leads after ILB.

[0005]

A film carrier tape of the present invention is for a sprocket hole which is a hole for carrying and positioning, a device hole for containing a semiconductor pellet, and an outer lead bonding lead for surrounding the device hole and containing an outer lead. A lead having a predetermined shape and a pad for electrical selection are provided on an insulating film having a hole and the device hole and a suspender which is a film frame existing between the outer lead bonding lead hole and supporting the outer lead and the inner lead. In the film carrier tape having the above, the pitch of the inner leads is slightly smaller than the pitch of the electrode pads of the semiconductor pellet.

The inner lead bonding method of the present invention is performed by aligning one of the inner lead of the film carrier tape, the electrode pad of the semiconductor pellet, and the metal protrusion formed on the electrode pad. The point inner lead bonding method includes a step of performing alignment again during the bonding.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIGS. 1 (a) and 1 (b) are plan views of a film carrier tape showing the inner lead bonding method of the first embodiment of the present invention in the order of steps.

In the inner lead bonding method of the first embodiment, first, as shown in FIG.
The inner leads 4 extending from the wiring pattern formed above are aligned with the bumps 5 formed on the electrode pads 2 on the semiconductor pellet 1. The pitch of the inner leads 4 is made smaller than the pitch of the electrode pads 2 on the semiconductor pellet 1 by the amount of thermal expansion of the film 3, and the alignment is made at the end of the row of the electrode pads 2 on the semiconductor pellet 1 (see FIG. (Upper part of).

Next, if a single point ILB is sequentially performed from the inner leads 4 at the aligned ends in this state, the heat of the bonding stage is transmitted from the semiconductor pellet 1 to the bumps 5 and the inner leads 4, and the film 3
Thermally expands. Due to this thermal expansion, the pitch of the inner leads 4 expands, and as shown in FIG. 1B, the inner leads 4 whose pitch has been narrowed in advance in consideration of thermal expansion match the pitch of the electrode pads 2 and Accurate ILB is possible without causing a shift.

After that, when the bonding is completed and the temperature returns to room temperature, heat shrinkage occurs, but even if the inner lead total pitch is 15 mm, it is about 10 μm in Upilex, which does not affect the bonding property.

2 (a) to 2 (c) are plan views of a film carrier tape showing the order of steps for explaining the inner lead bonding method of the second embodiment of the present invention.

In the inner lead bonding method of the second embodiment, the inner lead 4 and the electrode pad 2 on the semiconductor pellet 1 are first aligned with each other, as in the first embodiment. However, in the second embodiment, all the inner leads 4 are aligned with the electrode pads 2 without shifting.

Next, in this state, the single point IL
When B is performed, the inner leads 4 can be bonded at first without being displaced, but eventually, as shown in FIG. 2B, the film 3 expands due to the influence of heat and the inner leads 4
Displacement begins to occur. At this time, as shown in FIG. 2C, by slightly moving the bonding stage, which holds the semiconductor pellet 1 fixedly, in the direction (direction of the arrow in the figure) for correcting the displacement of the inner lead 4, the inner lead 4 is moved. Accurate bonding is possible without causing the deviation of

As a method of moving the stage at this time, (1) the expansion amount of the film is measured in advance, and the film is mechanically moved in accordance with the progress of the bonding. (2) Immediately before bonding during bonding. Move while adjusting the lead-bump alignment.
(3) After bonding a certain number of leads, the bonding is interrupted once, the alignment of the next bonding location is corrected, and the bonding is restarted.

FIG. 3 is a principle diagram for supplementarily explaining FIGS. 2 (a) to 2 (c).

At this time, the problem is that it is difficult to move the semiconductor pellet 1 in the latter half of the bonding because the film 3 and the semiconductor pellet 1 are connected fairly firmly by the inner leads 4. That is. As shown in FIG. 3, considering the movement of the stage in the arrangement direction of the inner leads 4, the distance between the lower surface of the inner leads 4 and the surface of the semiconductor pellet 1 is 150 μm,
Inner lead length of about 600 μm, inner lead 4
Is to be pressed from above by a single point ILB tool 7 and curved in an arc shape, the margin of the inner lead 4 is calculated to be 5.92 μm, which is at least about ± 5 μm in the arrangement direction of the inner leads 4 of the semiconductor pellet 1. The movement can be performed smoothly without affecting the bonding part. Regarding the movement of the stage in the direction perpendicular to the inner lead 4, if it is about 5 μm, it is considered that there is no problem because it is within the elastic deformation range of the lead material (for example, copper). Further, since the clamper 8 for fixing the film 4 is actually about 3 mm away from the edge of the semiconductor pellet 1, the movement range in the arrangement direction of the inner leads 4 of the semiconductor pellet 1 is limited by the deflection of the film 3 itself. It seems that it will spread further.

As described above, it is possible to move the semiconductor pellet 1 in the front-rear direction and the left-right direction during bonding by at least about 5 μm.

[0019]

As described above, according to the present invention, in the inner lead bonding for connecting the film carrier tape and the semiconductor pellet, the pitch of the inner leads is slightly smaller than the pitch of the electrode pads of the semiconductor pellet, or By performing the alignment again during the bonding, there is an effect that the electrode pad and the inner lead can be accurately bonded without displacement.

[Brief description of drawings]

FIG. 1 is a plan view of a film carrier tape showing the inner lead bonding method according to the first embodiment of the present invention in the order of steps.

FIG. 2 is a plan view of a film carrier tape showing the inner lead bonding method according to the second embodiment of the present invention in the order of steps.

FIG. 3 is a principle diagram supplementarily explaining FIG. 2;

FIG. 4 is a plan view of a film carrier tape showing an example of a conventional inner lead bonding method in the order of steps.

[Explanation of symbols]

 1 Semiconductor pellet 2 Electrode pad 3 Film 4 Inner lead 5 Bump 6 Bonding tool mark 7 Single point ILB tool 8 Tape clamper

Claims (2)

[Claims] 1. A sprocket hole which is a hole for carrying and positioning, a device hole in which a semiconductor pellet is inserted, and an outer lead bonding lead hole which surrounds the device hole and in which an outer lead is inserted and the device hole and the outer lead bonding lead. A film carrier tape having a lead of a predetermined shape and a pad for electrical selection on an insulating film having a suspender which is a film frame for supporting the outer lead and the inner lead, which is present between the hole and the electrode of the semiconductor pellet. A film carrier tape, wherein the pitch of the inner leads is slightly smaller than the pitch of the pads. 2. A single-point inner lead bonding method in which the inner lead of the film carrier tape, the electrode pad of the semiconductor pellet, and one of the metal protrusions formed on the electrode pad are aligned with each other. An inner lead bonding method comprising a step of performing alignment again during bonding.