JP2868779B2 - TAB tape - Google Patents

Description

The present invention relates to a tape for TAB (Tape Automated Bonding).

(Prior Art) TAB tapes are formed by forming a conductor pattern on a thin base film made of synthetic resin. The TAB tape can form conductor patterns at extremely high density, which makes it suitable for increasing the number of pins, and when bonding to a semiconductor chip, the entire lead can be bonded all at once without using wires. There are various advantages such as the ability to perform effective bonding.

TAB tapes consist of one layer consisting of only a conductor layer, two layers consisting of a conductor layer and a base film, and three layers consisting of a conductor layer, a base film, and an adhesive layer for bonding these layers. , Is roughly divided into three.
In the two-layer TAB tape, the conductor layer and the base film are joined without using an adhesive, and the manufacturing method is different from that of the three-layer TAB tape.

FIG. 5 shows a conventional example of a three-layer TAB tape. 1 in the figure
, A base film; 2, a conductor pattern; and 3, an adhesive for bonding the base film 1 and the conductor pattern 2. The base film 1 is provided with required holes such as a device hole 4 and a sprocket hole 5. In this example, the inner lead portion extends inward from the peripheral edge of the device hole 4 so that the inner lead and the IC chip can be directly bonded.

In order to manufacture a three-layer TAB tape, usually, an adhesive is applied to the base film, necessary holes are formed in the base film by punching, a copper foil is laminated as a conductor layer, and the copper foil is stipulated. To form a conductive pattern on the base film.

(Problems to be Solved by the Invention) As described above, TAB tapes are formed by forming conductor patterns such as inner leads at a very high density, and are usually directly bonded to a semiconductor chip. The inner lead is formed so as to extend inside the inside. In order to prevent deformation of the conductor pattern, the plating thickness of the conductor layer is appropriately set to maintain strength, but the base film may deform during handling when carrying the product. May cause deformation of the inner lead.

The conductor pattern formed on TAB tape is much finer and denser than the conductor pattern formed on conventional lead frames, etc., so even the inner leads may be slightly deformed or misaligned. When you do
There is a problem that accurate bonding is not performed.

As another problem, when bonding the TAB tape and the semiconductor chip, a bonding bump is provided on either the semiconductor chip or the inner lead, and the connection is performed by thermocompression bonding via the bump. , Conventional TAB
Since the base of the inner lead is merely bonded to the base film, the inner lead is unstable, and it is difficult to form a bump on the inner lead.

Therefore, the present invention has been made to solve the above problems, and the object thereof is to be able to effectively prevent deformation and displacement of the inner leads and to finely form the conductor pattern, Another object of the present invention is to provide a TAB tape film that can easily form bumps on inner leads.

(Summary of the Invention) In the present invention, in order to solve the above-mentioned problems, conventionally, a three-layer TAB tape is composed of a base film, a conductor layer, and an adhesive layer. It is characterized in that a thin film having electrical insulation is interposed in the middle.

That is, the TAB tape of the present invention has a conductor pattern such as a copper foil or the like on a base film in which required holes such as device holes and sprocket holes are formed via a thin film having electrical insulation. A protective coating is formed on the conductor pattern located on the side not joined to the thin film and facing the device hole, and a bump is formed on the inner lead of the conductor pattern through the coating. It is characterized by being formed.

Also, a conductor portion such as a copper foil is formed in a required conductor pattern via a thin film having electrical insulation on a base film in which required holes such as device holes and sprocket holes are formed. On the unbonded side, a protective coating is formed on the conductor pattern located opposite to the device hole, the thin film is penetrated, and bumps are formed on the inner leads of the conductor pattern. Features.

Example 1 FIGS. 1A to 1C are explanatory views showing a TAB tape according to the present invention and a method for manufacturing the same.

FIG. 1A is a cross-sectional view of a joined body of a conductor portion and a thin film. In FIG. 1, reference numeral 10 denotes a conductor portion, and 12 denotes a thin film joined to the conductor portion 10. As the thin film 12, a film having electrical insulation such as polyimide is used.
The joined body of the thin film 12 and the thin film 12 is formed by using a copper foil as the conductor portion 10 and laminating the copper foil and the thin film 12 using an adhesive, or by sputtering, vapor deposition or plating on the thin film 12. There is a method of forming the conductor portion 10 according to the following.

Next, as shown in FIG. 1 (b), a base film 14 is attached to the joined body of the conductor portion 10 and the thin film 12.
The base film 14 serves as a support for the conductor portion 10 and the thin film 12, and necessary holes such as device holes 16 and sprocket holes 18 are previously formed in the base film 14. These holes can be accurately formed by ordinary punching. Reference numeral 20 denotes an adhesive for bonding the thin film 12 and the base film 14. After joining the base film 14, the conductor portion 10, and the thin film 12 in this manner, a predetermined conductor pattern is formed on the conductor portion 10. As a method for forming a conductor pattern, a conventional method for forming a conductor pattern can be applied as it is. For example, by providing a resist pattern on the conductor portion 10 and removing unnecessary portions of the conductor portion, as shown in FIG. Thus, a TAB tape having the conductive pattern 10a formed thereon is obtained.

In the figure, 10b shows the inner lead of the conductor pattern. The thin film 12 is stretched on one surface of the device hole 16 as shown in the figure, and the inner leads 10b are adhered and supported by the thin film 12.

FIG. 1D shows a state in which the IC chip 22 is bonded to the TAB tape and mounted on the substrate 24. In this example, bumps 23 are formed on the IC chip 22 side, and the IC chip 22 is bonded to the inner lead 10b on the side opposite to the device hole 16. The outer peripheral portion of the base film 14 is cut off and remains as a support ring 14a. The external leads 10c of the conductor pattern 10a are connected to the conductor patterns 25 on the substrate 24. In this TAB tape, since the inner leads 10b are adhered and supported by the thin film 12, there is a feature that the deformation of the inner leads 10b can be effectively prevented.

Embodiment 2 FIG. 2 (a) is a cross-sectional view of a TAB tape having bonding bumps formed on inner leads 10b.

Conductor part 10 on base film 14 via thin film 12
The steps up to the formation are the same as in the manufacturing method described in the first embodiment. Next, a conductor pattern is formed by forming a resist pattern on the conductor portion to form a conductor pattern and removing an unnecessary portion of the conductor portion.At this time, the conductor pattern corresponds to a portion of the inner lead portion 10b where a bump is to be formed. After forming a resist layer on the thin film 12 to be formed, holes are formed by dry etching, the conductor is partially exposed, and plating is performed to form the bumps 26.

FIGS. 2 (b) and 2 (c) show a method of forming a bump on the inner lead. As a method of projecting the bump from the inner lead, the thin film 12 is formed on the film before the hole is formed by etching. The plating is carried out with the resist 28 left (FIG. 2 (b)). After the plating, the resist 28 is removed to remove the bump 26 from the thin film 12.
Can be projected.

Thus, the bump can be formed corresponding to the position of the inner lead 10b because the conductor pattern 10a is formed on the thin film 1
This is because they are securely supported by the positioning and are surely positioned. Even after the formation of the bumps 26, the inner leads 10b are supported on the thin film 12, and the effect of preventing deformation of the inner leads 10b is the same as in the first embodiment.

FIG. 2D shows an example in which an IC chip is bonded to a TAB tape provided with the bumps 26 and mounted on a substrate 24. In the TAB tape carrier having bumps according to the present embodiment, the IC chip 22 is formed in the device hole 16 of the base film 14.
Bonded to the side.

Embodiment 3 The embodiment shown in FIG. 3 is an example in which a conductor pattern 10a formed on a thin film 12 is coated and further provided with bumps. Conductor pattern 10 on base film 14
The steps up to the formation of a are the same as in the above embodiments.

In FIG. 3A, reference numeral 30 denotes a coating covering the conductor pattern 10a. This coating can be provided by printing or the like.

FIG. 3B shows a state in which bumps 32 for bonding are provided on the coating surface side of the inner leads 10b.
When the bumps 32 are provided, a resist layer is further formed on the coating 30 to form two layers, and the resist and the coating 30 at positions corresponding to the inner leads 10b are etched to form holes, thereby exposing the surface of the inner leads 10b. Plating. Then, the bump 32 can be formed by removing only the upper resist layer.

FIG. 3 (c) shows a state in which the portion 36 corresponding to the external lead portion of the conductor pattern 10a of the coating 30 has been removed by etching in order to bond the TAB tape to the IC chip and mount it on the substrate.

FIG. 3D shows a state where the IC chip is bonded to the TAB tape and then mounted on a substrate. IC chip 22
Is connected to the inner lead 10b via the bump 32, and the external lead 10c of the conductor pattern 10a is connected to the circuit pattern 25 on the substrate 24. In the third embodiment, the conductor pattern 10
The bumps 32 were formed on the side where the coating 30 was applied.
It is of course possible to form bumps on the thin film 12 side. That is, if a method of coating the conductor pattern 10a is adopted, the IC chip can be formed in either a face-up or face-down form.

When the conductor pattern 10a is covered with the coating 30 as in the third embodiment, the inner lead 10b is further supported by the coating 30 as compared with the case where only the thin film 12 is used. The prevention effect is further improved. Another effect of the coating is that migration of copper in the conductor pattern 10a can be prevented.

In each of the embodiments described above, the example in which the tip of the inner lead is disposed at the peripheral portion of the device hole is described. However, in the above-described TAB tape, the conductor pattern is supported by the thin film 12, so that the It is possible to draw out the inner lead to the inner central part for a long time. As described above, the inner lead can be drawn out to the inner central portion of the device hole, so that the arrangement range of the inner lead can be expanded, the inner lead pattern can be selected, and various patterns can be selected. There is a great effect that the deformation of is eliminated. Furthermore, this makes it possible to widely use not only the peripheral portion of the IC chip but also the entire surface of the IC chip for connection.

Further, as shown in each of the above embodiments, since the conductor pattern is always bonded to the thin film 12, the conductor pattern can be reinforced by the strength of the thin film 12, and a conductor portion such as a copper foil when forming the conductor pattern is formed. There is an advantage that the thickness can be made extremely thin, thereby facilitating fine etching and forming an ultrafine pattern. When a fine pattern is formed, it is possible to reliably protect the conductor pattern by applying a coating as shown in the third embodiment. Also, an extremely thin conductor can be used as it is as the conductor pattern.

A TAB tape as shown in FIG. 4 is known as a TAB tape which allows the inner lead to be freely pulled out to the center of the device hole as described above and does not have to worry about deformation of the inner lead. TAB tapes need to form through-holes 33 that fill the base film 14 with conductors, so it is extremely difficult to form a fine conductor pattern, and after connection with the IC chip, the thick base film 14 The connection portion is easily peeled off due to warpage.

As described above, the present invention has been described variously with reference to preferred embodiments. However, the present invention is not limited to the embodiments, and it is needless to say that many modifications can be made without departing from the spirit of the invention. That is.

(Effect of the Invention) According to the TAB tape of the present invention, as described above, the conductor pattern provided on the base film is bonded to the base film via the thin film, so that the conductor pattern is always supported by the thin film. Thus, the conductor pattern can be reliably positioned, and it is possible to prevent the inner leads from being deformed or displaced. This facilitates handling such as transporting and carrying the TAB film. In addition, since the deformation of the inner leads can be prevented, accurate bonding can be performed, and in addition to the reliable positioning of the inner leads, the conductor pattern can be easily formed into a finer structure.

In addition, since the conductive pattern is supported on the thin film, it is easy to form a bonding bump on the inner lead portion.

[Brief description of the drawings]

1 (a) to 1 (d) are explanatory views showing a first embodiment of a TAB tape according to the present invention and a mounting state thereof, and FIGS. 2 (a) to 2 (d) are second embodiments and a mounting thereof. FIGS. 3 (a) to 3 (d) are explanatory diagrams showing a third embodiment and a mounting state thereof, FIG. 4 is an explanatory diagram showing an example of arrangement of inner leads drawn into a device hole, FIGS. FIG. 5 is an explanatory view showing a conventional TAB tape. 10 ... conductor part, 10 a ... conductor pattern, 10 b ... inner lead, 10 c ... external lead, 12 ... thin film, 14 ...
... base film, 16 ... device hole, 18 ... sprocket hole, 22 ... IC chip, 24 ... board, 26 ...
Bump, 28 ... Resist, 30 ... Coating, 32 ...
bump.

────────────────────────────────────────────────── (5) References JP-A-62-274737 (JP, A) JP-A-62-199022 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/60

Claims (2)

(57) [Claims] 1. A conductor portion such as a copper foil is formed in a required conductor pattern on a base film in which required holes such as device holes and sprocket holes are formed via a thin film having electrical insulation. A protective coating is formed on the conductor pattern located on the side not facing the thin film and facing the device hole, and bumps are formed on the inner leads of the conductor pattern through the coating. TAB characterized by
Tape. 2. A conductor film such as a copper foil is formed in a required conductor pattern on a base film in which required holes such as device holes and sprocket holes are formed via a thin film having electrical insulation. A protective coating is formed on the conductor pattern located opposite to the device hole on the side not joined to the thin film, and a bump is formed on the inner lead of the conductor pattern through the thin film. TA characterized by being
Tape for B.