JPH02275651A - Transfer method of bump - Google Patents

Abstract

PURPOSE:To position a bump and a lead easily, and to improve the accuracy of positioning by forming a first mark to a film, on which the bump is placed, and shaping a second mark to either film of upper and lower and left and right films. CONSTITUTION:First marks 2a are formed to films, which are located inside the bump forming region 2 of a bump forming substrate 3 and on which bumps 1 are placed in either one of each of the upper and lower and left and right sections on the inside, and second marks 2b are shaped to films in the other of either of each upper and lower and left and right section. Consequently, the accuracy of these marks 2a, 2b is made higher than the formation of the bumps 1, and the dispersion of the marks is made smaller than the formation of the bumps. Accordingly, the recognition of positions and the positioning of the bumps 1 and leads 5 are facilitated and errors to the recognition of positions can also be reduced by transferring the bumps 1 while using the marks 2a, 2b as references, and positioning accuracy to inner leads can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a bump transfer method, and more particularly, to a method for manufacturing a tape carrier with bumps used in a semiconductor device manufactured by a tape carrier method (TAB). This invention relates to improvements in bump transfer methods.

[Prior Art] Generally, in the TAB method, a metal foil such as copper is laminated on the surface of a thin film-like tape made of synthetic resin such as polyimide, and a large number of leads are formed by etching this. Then, a gold bump or the like is transferred and adhered to the tip end portion of each lead or the terminal portion of the semiconductor chip, and the lead and the semiconductor chip are bonded via the gold bump or the like. Thereafter, each lead is separated from the tape to obtain a semiconductor chip with leads.

In the manufacturing method of such semiconductor devices, it is necessary to transfer and adhere bumps to the lead tips or terminals of the semiconductor chip in advance, but the conventional bump transfer method for this purpose uses a bump-formed substrate. The bumps formed here are then transferred to the leading ends of the tape carrier leads. For this transfer, first, the bumps on the substrate are monitored and recognized with a camera, etc., the tips of the leads and the bumps are aligned, and then they are placed on top of each other and heated and pressed to complete the transfer process. will be held.

[Problem to be solved] In such conventional bump transfer methods, when recognizing the position of the bump on the bump forming substrate, the position of the bump is directly recognized. However, the bump is usually electroplated. The thickness is about 30±2 μm and the width is about 8
It is approximately 0±4 μm, and there are variations in its position.

Therefore, when bumps are directly recognized, positional deviations due to recognition errors are likely to occur. Further, it is difficult to align each bump and the tip of each inner lead so that they are positioned uniformly, and there is a drawback that it takes time to transfer the bumps.

The present invention solves the problems of the prior art, and aims to provide a bump transfer method that can efficiently transfer bumps.

[Means for Solving the Problems] The configuration of the bump transfer method of the present invention for achieving the above object is such that the bumps are formed inside the bump forming area where bumps are formed corresponding to the IC chip. A first mark is formed on the film of the bump forming substrate on which the bump is placed on one of the top and bottom and the left and right, and a second mark is formed on the film on the other of the top and bottom and the left and right. a mark forming step, a bump forming step of forming a bump on the film based on the formed first and second marks, and a bump forming step using the first and second alignment marks as a reference. The method includes a bump transfer step of transferring the bumps formed on the tape carrier onto the leads on the tape carrier.

[Function] In this way, the first mark is formed on the film on which the bump is placed inside the bump forming area of the bump forming substrate and on either the upper, lower, left, or right sides of this inner side. Since the second marks are formed on the film in either one of the two, these marks have higher accuracy and less variation than the formation of bumps.

As a result, by transferring the bumps using this mark as a reference, position recognition and alignment between the bumps and the leads becomes easier, and errors in position recognition can also be reduced, improving alignment accuracy with respect to the inner leads. can be done.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of the bump transfer process of one embodiment to which the bump transfer method of the present invention is applied, and FIG. 2 is an explanatory diagram corresponding to each process regarding the state of the bump and tape carrier. be.

In the bump forming substrate manufacturing process A with alignment marks shown in FIG. 1, as shown in FIG.
Bumps 1, 1.1 as shown by dotted lines are arranged to correspond to the C chip and are each arranged in a rectangular shape.
. . . Corresponding to the formation area 2, a cross-shaped punched pattern is formed inside the bump alignment mark 2.
a + 2b (hereinafter simply referred to as marks 2a and 2b), which are formed so that the intersection points of the crosses are arranged diagonally across the center.

The marks 2a and 2b formed here are shown in FIG. 2(b).
As shown by the dashed-dotted line in the side view, the bump 1 to be formed is
Assuming that the height (thickness) of the bump 1 is 30±2 μm, the Tl-Pt metal film layer 3a on which the bump 1 is mounted is thinner than this and is formed to a thickness of about 10±2 μm to 20±2 μm, as shown by the dotted line. It is often formed as a stamp.

That is, in this step, the cross-shaped mark 2a.

2b is obtained by, for example, first forming a sputtered film of T tor t on the glass substrate 3bJ- by sputtering, and then etching it in a cross shape. In addition,
An ITO film or the like may be used as the surface coating film used as the bump forming substrate.

Here, the positions of the marks 2a and 2b are such that they are placed on one side and the other side of the upper part of the bump forming area 2, respectively, and the marks 2a and 2b are placed on one side and the other side of the left and right sides, respectively. It is sufficient that
This allows you to move from the intersection of the crosses to the center of bump formation area 2 (
Alternatively, the position (or origin) can be calculated. The marks 2 a * 2 b are formed in advance on the bump forming substrate 3 in a separate process to obtain the center position of the forming region 2 in which the bumps 1 are formed at the same time as coating the surface film of the bump forming substrate 3. You may also use

In bump forming process B using the next mark as a reference, marks 2a and 2b punched out in a cross shape formed in the previous process A are used.
Based on the bump 1, 1, 1, pot, formation area 2,
As shown in FIG. 2(C), bumps 1.1, 1...
form. As a result, bumps 1°1.1·Φ· are formed on the bump forming substrate 3 corresponding to the tape carrier, and each bump is arranged in a rectangular shape, and is arranged in a manner corresponding to each IC chip. At the same time as this formation, the already formed cross-shaped mark 2a +
A bump-formed substrate 3 in which 2b is present can be obtained in this step.

FIG. 2(d) is a side view centered on the bump 1 at this time.

In the next alignment mark alignment process C with the carrier tape, the bump forming substrate 3 having such bumps with alignment marks is placed below the tape carrier 4 as shown in FIG. 2(e). and hold them in a vertical relationship.
A recognition optical system such as a camera is placed above these (
(not shown) to recognize marks 2 av 2 b. Then, the center point of the bump formation area 2 is calculated, and this center is set as the center point of the leads 5, 5, . Tip part 5 a * 5 of...
Alignment can be easily performed by positioning so that it coincides with the center of the area formed by a + and the pot. Moreover, apart from this, mark reference positions set in advance for the marks 2a and 2b can be provided and the marks 2a and 2b can be positioned at these positions. In this case, mark 2 a +
The reference position where 2b is positioned is provided in the recognition optical observation system as an alignment mark reference position corresponding to the reference position where the tape carrier 4 is positioned.

By positioning the marks 2a and 2b at these reference positions, the tip f15a of each lead 5 and the bump 1 are aligned in an average alignment state. here,
The overall relationship between each bump 1 and each lead 5 may be observed using an observation optical system, and the position may be slightly corrected as necessary.

In the next bump transfer step, the tape carrier 4 side is lowered (or the bump forming substrate 3 is raised), and the tips m5a of each lead 5 and each bump 1 are overlapped and heated and pressed (the mechanism is shown in the figure). (not shown) and transcribe these. FIG. 2(f) shows the reversed state after the transfer.

With the above method, the cross-shaped marks 2a and 2b are formed as a thin film of the Tl-Pt metal film layer 3a on which the bumps are placed, so the pattern formation accuracy is high, and variations in the bumps are reduced. becomes much smaller. Therefore, the position recognition error for this is smaller than the bump recognition error, and the alignment accuracy with respect to the inner lead can be improved. Furthermore, in this case, alignment is performed by recognizing the two cross alignment marks, which facilitates alignment and reduces the time required for alignment.

In the embodiment described above, two alignment marks are provided, but there may be any number of alignment marks as long as there are three or more, and the alignment mark is not limited to a cross-shaped pattern. Further, these alignment marks are distributed vertically and horizontally, and one of them is assigned to one of the areas below -L and on the left and right,
It is only necessary that the other one be assigned to the other of the upper and lower and left and right sides.

[Effects of the Invention] As can be understood from the above explanation, in the present invention, the film on which the bump is placed is placed inside the bump forming area of the bump forming substrate and on either the upper, lower, left or right sides of this inner side. Since a first mark is formed and a second mark is formed on the film at either the top, bottom, left or right side, these marks are
The accuracy is higher than that of bump formation, and the variation is smaller.

As a result, by transferring the bumps using this mark as a reference, position recognition and alignment between the bumps and the leads becomes easier, and errors in position recognition can also be reduced, improving alignment accuracy with respect to the inner leads. can be done.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the bump transfer process of one embodiment to which the bump transfer method of the present invention is applied, and FIG. 2 is an explanatory diagram corresponding to each degree of the shape of the bump and tape carrier. . 1... Bump, 2... Bump formation region, 2 a +
2 b... Alignment mark, 3... Bump forming substrate, 4... Tape carrier, 5... Lead, 5a
...The tip of the lead. Figures (d) (e) (f)

Claims (1)

[Claims] (1) A first layer is placed on the film of the bump forming substrate, which is inside the bump forming area where bumps are formed corresponding to the IC chip, and where the bumps are placed on either the upper, lower, left or right side of this inner side. a mark forming step of forming a mark on the film and forming a second mark on the film at one of the upper and lower and left and right sides; A bump forming step of forming a bump; and a bump transferring step of transferring the bump formed in the bump forming step to a lead on a tape carrier based on the first and second alignment marks. bump transfer method.