JP3795219B2 - Method for manufacturing double-sided wiring film carrier tape - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a method for producing a TAB (Tape Automated Bonding) double-sided circuit film carrier tape for a fine wiring pattern formed on both surfaces for, in particular, to enable high-density mounting, a semiconductor having excellent high frequency characteristics This is a manufacturing method suitable for a package.
[0002]
[Prior art]
A conventional double-sided wiring film carrier tape is one in which an insulating base film is sandwiched and a signal transmission wiring is provided on one side, and a microstrip line structure layer surface, which is a solid ground layer, is provided on the opposite side. Therefore, it has been attracting attention as a TAB tape for a package suitable for high-frequency signal transmission.
[0003]
For example, Japanese Patent Application Laid-Open No. 4-239739 and Japanese Patent Application Laid-Open No. 5-326644 disclose a tape excellent in the above-described high frequency characteristics and a manufacturing method thereof. However, the tapes disclosed in these publications have fine wiring only on one side, and the opposite side is only separated by a hole such as a device hole or an outer lead hole, and is electrically separated. For this reason, there was no exposed base film region, and fine wiring could not be obtained. That is, the opposite surface has a so-called solid ground structure that does not have fine wiring, and these manufacturing methods cannot essentially form fine wiring.
[0004]
For example, in Japanese Patent Application Laid-Open No. 4-239739, conductor layers on both sides are connected by a plating method through through-holes that are through-holes. After conducting the conductor layer, pattern formation must be performed on both sides. This is because if a pattern is formed before plating, the pattern formed in the next plating process such as electroless plating is also plated, and the pattern is short-circuited and cannot be actually used. is there.
[0005]
Therefore, it is necessary to form a pattern on the surface where the through hole is opened, and a liquid photoresist having high fluidity cannot be applied as an etching mask, and it is necessary to use a dry film photoresist.
When a liquid photoresist is applied, only the liquid photoresist around the hole is particularly raised and thick due to the influence of surface tension. Since the exposure condition of the UV light is set according to the main part of the pattern forming part, the thick part around the hole is underexposed and the gap of the etching mask is insufficient. As a result, defects such as pattern shorts or insufficient pattern gaps occur.
[0006]
Another problem in the case of applying a liquid photoresist is that the thickness of the edge of the hole cannot be reversed and the thickness becomes very thin, and the base of the edge portion is exposed. When the base is exposed, the conductive plating layer is affected by the etching in the next step, increasing the connection resistance and, in some cases, disconnecting the conduction between both surfaces.
[0007]
Therefore, in order to avoid the problems of the liquid photoresist described above, a dry film photoresist must be adopted.
However, when dry film photoresist is used, the limit of wiring formation is about 100 μm pitch in mass production, and a fine wiring pattern smaller than that cannot be formed.
[0008]
Further, since the dry film photoresist is formed by a laminating method, it has a drawback that it cannot sufficiently cope with surface dents such as fine scratches.
For this reason, there is a problem that the etching solution penetrates into a portion where the dry film photoresist is not sufficiently adhered, pattern breakage or disconnection is likely to occur, and improvement in yield cannot be expected.
[0009]
As described above, as long as conduction between patterns on both sides is to be performed by plating, a dry film resist must be used, and pattern formation with a pitch of about 100 μm is the limit.
Here, in Japanese Patent Laid-Open No. 5-326644, the through hole is conducted by filling with a conductive paste, and the degree of freedom is ensured in the pattern forming process as compared with the above.
[0010]
However, in order to form a wiring with a pitch of 100 μm or less on both sides based on the method disclosed in JP-A-5-326644, an adhesive is applied to the opposite side after patterning on one side, It is necessary to process, deposit a conductor layer such as copper foil, and pattern the conductor layer.
However, this method has a problem that many voids are generated between the conductor layer and the adhesive when the conductor layer such as copper foil is attached. The cause is the unevenness of the pattern already formed on the other surface. Due to the unevenness existing on the side opposite to the layer to be deposited, air is entrained between the conductor layer to be deposited and the adhesive, and voids are generated.
[0011]
Here, an example of the manufacturing process of the conventional tape carrier for double-sided wiring TAB is shown in FIG. Hereinafter, a description will be given with reference to FIG.
A copper foil 12b is attached to an insulating film 1 such as polyimide via an adhesive 7 (a). Here, the copper foil may be directly applied to the insulating film.
Next, the adhesive 7 is applied to the other surface of the insulating film 1 (b). In this state, the connection hole 4 penetrating the front and back surfaces, the device hole, and the outer lead hole are punched at required positions by punching or the like (c). Then, a copper foil 12a is deposited (d), and a liquid photoresist is applied to the copper foil 12a for patterning to form a fine wiring pattern 13a (e). Next, the conductive paste 5 is filled in the connection hole 4 in order to connect 12b and 13a. Finally, a solder resist 6 as a protective film is formed on both surfaces (f).
[0012]
[Problems to be solved by the invention]
Conventional double-sided wiring film carrier tapes with a single-sided solid ground layer cannot cope with the higher density of wiring corresponding to the recent high integration of integrated circuits, and patterns are also formed on the solid ground side. , It cannot meet the demand to incorporate a wiring function other than the ground.
[0013]
In addition, it is possible to arrange fine wiring on both sides, and it is impossible to meet the demand for use as a packaging tape for realizing high-density mounting of semiconductors.
To meet the above requirements, a high-density wiring for the development of double-sided wiring film carrier tape can be placed on both sides have come to be required.
The present invention relates to a tape manufacturing method for TAB, and an object thereof is to provide a method of manufacturing a double-sided circuit film carrier tape which may be a 100 [mu] m pitch or less of a fine wiring pattern on the front and back surfaces both .
[0015]
[Means for Solving the Problems]
In the present invention , a double-sided wiring film carrier tape is formed simultaneously or sequentially with a step of depositing copper foil on both sides of an insulating film and a copper pattern on both sides of the wiring pattern having at least a fine pattern of 100 μm pitch or less. And a step of punching a plurality of holes at a required portion of the wiring pattern to form a connection hole, and a step of electrically connecting the wiring patterns on both sides by filling the connection hole with a conductive paste. It was made to manufacture by a manufacturing method.
[0016]
Also, the process of depositing copper foil on both sides of the insulating film, the process of forming a wiring pattern having at least a fine pattern of 100 μm pitch or less on one side of the copper foil, and the required portions of the wiring pattern Forming a connection hole by processing a plurality of holes that reach the copper foil on the surface and do not penetrate, and a wiring pattern having at least a fine pattern of 100 μm pitch or less on the copper foil on the opposite surface It has been found that it can also be produced by a production method comprising a step of forming and a step of filling the connection holes with a conductive paste and electrically connecting the wiring patterns on both sides.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A first method for producing the double-sided wiring film carrier tape of the present invention will be described with reference to FIG.
First, copper foils 2a and 2b are deposited on both surfaces of the insulating film 1 (a). Here, this deposition may be performed through an adhesive layer or directly. Either a so-called double-sided three-layer structure or a double-sided two-layer structure may be used. Alternatively, a single-sided two-layer / opposite-sided three-layer structure having an adhesive layer on only one side may be employed.
[0018]
Next, in the present invention, a liquid photoresist is applied and the copper foils on both sides are patterned to form wiring patterns 3a and 3b (b). This patterning may be performed sequentially on both sides or simultaneously on both sides.
Here, since the liquid photoresist is applied to both sides, it becomes possible to form a fine wiring pattern with a pitch of 100 μm or less.
[0019]
Then, a connection hole 4a, which is a through hole, and a hole for positioning, etc. are opened at a required location (c). This hole may be opened by punching or laser processing may be performed.
Next, the conductive paste 5 is filled into the connection holes 4a, and the wiring patterns on both sides are electrically connected (d).
[0020]
Finally, the predetermined area of the wiring pattern and the connection hole filled with the conductive paste are protected by applying a solder resist 6 (e).
Next, another method for producing the double-sided wiring film carrier tape of the present invention will be described with reference to FIG.
First, copper foils 2a and 2b are deposited on both surfaces of the insulating film 1 (a). Here, this deposition may be performed through an adhesive layer or directly. Either a so-called double-sided three-layer structure or a double-sided two-layer structure may be used. Alternatively, a single-sided two-layer / opposite-sided three-layer structure having an adhesive layer on only one side may be employed.
[0021]
Next, in this embodiment, a liquid photoresist is applied and only one side of the copper foil is patterned to form a wiring pattern 3a (b). Here, the opposite surface is left as it is, and no patterning is performed here. .
Then, using the laser processing method, adjusting the output, reaching the copper foil 2b on the back surface and preventing the copper foil on the back surface from penetrating, the connection hole 4b and the device hole, the outer lead hole, for positioning Etc. are processed into a required location (c).
[0022]
Thereafter, a liquid photoresist is applied to pattern the copper foil on the opposite surface to form a wiring pattern 3b (d).
Then, the conductive paste 5 is filled in the connection holes 4b, and the wiring patterns on both sides are electrically connected (e).
Finally, the predetermined region of the wiring pattern and the connection hole filled with the conductive paste are protected by applying a solder resist 6 (f).
[0023]
As the conductive paste, a copper paste, a silver paste, a solder paste, or the like can be applied. However, it is sufficient that the connection holes are filled and the conductive layers on both sides are electrically connected, and the present invention is not limited to these.
[0024]
【Example】
A double-sided wiring film carrier tape of the present invention was prototyped under the following conditions.
As the insulating film, a polyimide film having a thickness of 75 μm was used.
The copper foil was 15 μm thick, and a type in which the polyimide film was stacked on both sides by plating without using an adhesive was used.
[0025]
The wiring pattern was processed by applying a liquid photoresist, and a fine pattern with a pitch of 100 μm or less was processed. In this embodiment, a fine pattern with a wiring width and a gap width of 25 μm is processed.
In the first method of FIG. 1, the connection hole is processed by punching to process a through hole having a diameter of 200 μm. In another method described with reference to FIG. 2, laser processing is applied.
[0026]
In both cases of FIGS. 1 and 2, a copper paste was used as the conductive paste. As the solder resist for the protective film, a photosensitive solder resist was used in order to perform high-precision pattern processing.
The double-sided wiring film carrier tape of the present invention was prototyped under the above conditions, and it was confirmed that any method could mass-produce double-sided wiring film carrier tape having fine wiring patterns of 100 μm pitch or less on both sides.
[0027]
【The invention's effect】
The present invention makes it possible to mass-produce high-density double-sided wiring film carrier tapes with fine wiring patterns of 100 μm pitch or less on both sides with high productivity, and to mass-produce double-sided wiring film carrier tapes at low cost. It was.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a production process of a double-sided wiring film carrier tape of the present invention.
FIG. 2 is a cross-sectional view illustrating another manufacturing process of the double-sided wiring film carrier tape of the present invention.
FIG. 3 is a cross-sectional view illustrating an example of a manufacturing process of a conventional double-sided wiring TAB tape carrier.
[Explanation of symbols]
1 Insulating film
2a, 2b copper foil
3a, 3b Wiring pattern 4, 4a, 4b Connection hole 5 Conductive paste 6 Solder resist 7 Adhesive
12a, 12b copper foil
13a Wiring pattern

Claims (2)

A method of manufacturing a double-sided wiring film carrier tape used for TAB,
A process of depositing copper foil on both sides of the insulating film;
Forming simultaneously or sequentially a wiring pattern having at least a fine pattern with a pitch of 100 μm or less on both sides of the copper foil;
Forming a connection hole by processing a plurality of through holes at a required portion of the wiring pattern; and
Filling the connection holes with a conductive paste to electrically connect the wiring patterns on both sides;
A method for producing a double-sided wiring film carrier tape comprising: A method of manufacturing a double-sided wiring film carrier tape used for TAB,
A process of depositing copper foil on both sides of the insulating film;
Forming a wiring pattern having at least a fine pattern with a pitch of 100 μm or less on a copper foil on one side;
A process of forming a connection hole by processing a plurality of holes not reaching through to the copper foil on the opposite surface at a required portion of the wiring pattern;
Forming a wiring pattern having at least a fine pattern with a pitch of 100 μm or less on the copper foil on the opposite surface;
Electrically connecting the wiring patterns on both sides by filling the connection holes with a conductive paste;
A method for producing a double-sided wiring film carrier tape comprising:

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