JP2757593B2 - Manufacturing method of film carrier device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film carrier device having a via hole.

[0002]

2. Description of the Related Art In recent years, TAB (tape carrier type), in which an IC chip is mounted on a film carrier and mounted, has been used in response to the trend toward thinner and higher density mounting of ICs. In such a TAB, for example, a signal layer is provided on the upper surface of an insulating layer such as a polyimide film, and a power supply layer is provided on the lower surface. However, via holes are provided for the purpose of wiring from the power supply layer on the lower surface.

As a means for connecting via holes formed in a film carrier device, there is a conventional method of forming a copper film layer 5 by coating copper by sputtering as shown in FIG. That is, for example, a copper foil 1 having a thickness of 25 μm, an adhesive layer 2, and a via hole 4 formed in an insulating layer 3 having a thickness of 75 μm are connected by a copper film layer 5 having a thickness of 4 μm by a sputtering method. In FIG. 8, for example, copper foils 1 and 7 each having a thickness of 35 μm are attached to both surfaces of a polyimide insulating layer 3 having a thickness of 75 μm with epoxy adhesives 2 and 6, respectively.
A through hole 8 of 2 to 0.6 mm is formed, and as a connection method, a plating layer 9 is formed by a copper electroplating method or an electroless plating method.

[0004] In the connection by the sputtering method, the polyimide insulating layer generates heat and is thermally deformed. In addition, the kind of polyimide used (for example, Kapton H, Upilex S, trade name) is used.
And the like, the adhesion of the formed copper film layer is 30 g /
cm or less, and after sputtering to improve adhesion,
Special plasma treatment was required. The plating method is
In general, although the adhesive strength is good, the kind of polyimide to be used (for example, Kapton D, Upilex S, etc.)
In some cases, there is a problem that the adhesion of the plating is poor and the reliability against thermal stress is poor. In addition, electroplating of copper takes 5 to 10 minutes, and electroless plating takes 1 to 2 hours. It takes place in a wet process, and ionic substances remain between via holes and layers, causing migration and wiring corrosion. There are also problems such as becoming.

[0005]

In view of the above-mentioned problem of the prior art in which conductive layers provided on both sides of an insulating layer of a film carrier device are electrically connected through via holes, a highly reliable and easily connectable method. Was required. The present invention addresses such a need.

According to the present invention, the electrical connection between the conductive layers is realized by forming the other conductive layer by a vapor deposition method after the protruding process of one conductive layer is performed. An object of the present invention is to provide a method of manufacturing a film carrier device having high reliability of electrical connection via via holes.

[0007]

According to the present invention, there is provided, in accordance with the present invention, first and second conductive layers on both surfaces of an insulating layer, and these conductive layers are electrically connected via via holes. A method for manufacturing a film carrier device connected to a first conductive layer , wherein the first conductive layer is formed on one surface of the insulating layer.
After attaching the copper foil, the inside of the via hole is covered with the insulating layer.
When it is formed by protruding to near the height of the other surface of
Both of the protrusions of the first conductive layer protruding into the via hole.
Vacuum evaporation method on the surface in the outgoing direction and the other surface of the insulating layer
Forming a second conductive layer made of a copper layer by the method described above. Hereinafter, the present invention will be described in more detail with reference to the drawings.

In the present invention, a copper foil sheet, a copper alloy (Cu-Zr, Cu-Sn alloy, etc.) is used as the first conductive sheet layer.
Foil sheets, 42 alloy (Fe-42% Ni alloy) foil sheets, and the like. The thickness of the first conductive sheet layer is usually 10
１５０150 μm. The insulating layer 3 may be a polyimide film known as Kapton D, Kapton H, Iupirex S, or the like, a glass epoxy, a BT resin polyester film, or the like. Usually, a polyimide film is preferably used. The thickness of the insulating layer is usually 15 to 15
0 μm.

[0009] The via hole can be usually formed by forming a photoresist layer on an insulating layer, and etching a part of the film sheet in a liquid such as hydrazine using the photoresist layer as a mask. Preferably, the diameter of the via hole is usually in the range of 0.05 mm to 2.0 mm. The reason is that it is difficult to secure a space exceeding 2.0 mm because of the multilayer wiring and the tendency for the wiring pitch to be narrow. If the diameter is smaller than 0.05 mm, the protrusion used in the present invention becomes practically difficult.

[0010] In the present invention, the first conductive sheet layer is protruded to a vicinity of the upper surface of the insulating layer by, for example, a protruding process. It is preferable that the protruding height be adjusted to the height of the upper surface of the insulating layer as much as possible. The protruding process can be performed by means selected from a metal punch, a rotary drill without a blade, a drawing process, a suction forming process, and the like. It is preferable in terms of reliability.

The second conductive layer is formed on the upper surface of the insulating layer together with the protruding first conductive sheet layer, and is electrically connected via via holes. The second conductive layer is formed by a vacuum deposition method.
It is formed. The metal deposited is copper, copper under Ni, or copper under Ti, but copper is preferred. 5 and 6
As shown in the above structure, it is also possible to improve the adhesion stability between the protruded copper foil sheet 1 and the copper layer 10 by vacuum deposition by protruding along the side wall of the via hole. After the second conductive layer is formed, resist coating, patterning, and etching of the conductive layer are performed by a conventional method to obtain a film carrier device having a multilayer structure of fine wiring.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

(Example 1) An insulating layer (polyimide: 100 μm thick) in which a via hole having a diameter of 300 μm was formed.
A copper foil sheet 1 having a thickness of 25 μm was bonded to an Ube Industries product, trade name IUPIREX S) 3 with an epoxy adhesive 2. Next, 80 via holes are protruded with a metal punch (punch diameter: 200 μm) to form a copper foil sheet layer 1.
To the upper surface of the insulating layer 3. FIG. 1 shows the structure that has been protruded. Next, a copper layer 10 having a thickness of 4 μm is formed on the upper surface of the insulating layer 3 having this structure by a vacuum evaporation method, and thereafter, a resist coating, patterning, and etching of the copper layer are performed. Created. FIG. 2 shows a structure in which the copper foil sheet 1 and the copper layer 10 are connected. For comparison, in the via hole of the same configuration,
A copper film 5 having a thickness of 4 μm was formed by a sputtering method (see FIG. 7). When the variation in the initial resistance was examined, the variation in the initial resistance in Example 1 was ± 0.1Ω, the variation in Comparative Example 1 was ± 1Ω, and the variation of the present invention was small and stable. In addition, this film carrier device is -5
When the transition of the connection resistance was examined while performing a temperature cycle test from 0 ° C. to + 150 ° C., it took 2,000 hours to conduct without conduction (disconnection due to film peeling at the via hole) than the film carrier device of Comparative Example 1. Five times longer, the reliability against thermal stress has been greatly improved.

Example 2 Copper foil sheet 7 having a thickness of 25 μm
A polyimide insulating layer (trade name: Upilex S) 3 having a thickness of 75 μm was bonded thereto via an epoxy-based adhesive layer 6, and then a through-hole having a diameter of 200 μm was punched. Then, on the other surface, a thickness of 25
The copper foil sheet 1 having a thickness of μm was attached thereto, and the copper foil sheet 1 was protruded to the upper surface of the through hole by a metal punch, and 80 places were simultaneously processed. FIG. 3 shows a cross-sectional view of the structure after the protrusion. Next, the copper foil sheet 7 on the opposite side of the protruded copper foil sheet 1 is vacuum-evaporated to a thickness of 2 mm.
A 5 μm copper layer 10 was formed. Further, resist coating and patterning were performed, and the copper layer was etched to produce a film carrier device having a two-layer fine wiring structure. In this case, unlike the through hole structure, the backing resist on the other surface does not flow to the surface due to the via hole, so that the working efficiency is improved. This film carrier device is set at -50 ° C to +1
The transition of the connection resistance was examined while performing a temperature cycle test at 50 ° C. (holding for 30 minutes). Longer, significantly improved reliability against thermal stress.

Temperature cycle (heat stress) test method: A film carrier device electrically connected through a via hole is connected to an EIAJ (Electronic Industries Association of
Japan: -50 ° C using a Futaba Scientific Cooling / Heat Cycle Tester in accordance with the standards of the Japan Electronic Machinery Manufacturers Association.
After 30 minutes at 150 ° C at a rate of 120 ° C / min.
And keep for 30 minutes. Next, the temperature is lowered to -50 ° C at a temperature lowering rate of -30 ° C / min. This cycle was repeated to determine the time at which conduction was disabled. In addition, it calculated | required by the average value of 48 tests.

[0016]

Since the present invention is configured as described above, the film carrier device provided by the present invention can reliably connect the first and second conductive layers via the via holes at the protruding portions. Therefore, reliability against heat stress has been improved. Also, the via hole is 2.0mm
The smaller the diameter, the thinner the first conductive sheet layer (copper foil layer), the easier the protruding process according to the present invention, and the more reliable the connection via the via hole. Furthermore, it is excellent in industrial mass productivity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure at a stage where a conductive layer is protruded according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a structure at a stage after the electrical connection according to the first embodiment of the present invention is completed.

FIG. 3 is a cross-sectional view showing a structure at a stage where a conductive layer is protruded according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a structure at a stage after an electrical connection according to a second embodiment of the present invention has been completed.

FIG. 5 is a cross-sectional view showing another embodiment of the protrusion processing of the present invention.

FIG. 6 is a cross-sectional view of another embodiment of the present invention, showing the structure at the stage when electrical connection to the protruding structure of FIG. 5 has been completed.

FIG. 7 is a cross-sectional view showing a structure electrically connected by a conventional sputtering method.

FIG. 8 is a cross-sectional view showing a structure electrically connected by a conventional plating method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Copper foil sheet (first conductive sheet layer) 2 Adhesive layer 3 Insulating layer 4 Via hole 5 Copper film layer 6 Adhesive layer 7 Copper foil sheet layer 8 Through hole 9 Plating layer 10 Copper layer (second conductive layer)

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor: Mamoru Mita 3-1-1, Sukekawa-cho, Hitachi-shi, Ibaraki Pref. Inside the cable plant at Hitachi Cable Co., Ltd. (72) Inventor: Masaharu Takagi, Sukegawa-cho, Hitachi-shi, Ibaraki 3-1-1, Hitachi Cable Co., Ltd. Wire Plant (72) Inventor Tomio Murakami 3-1-1, Sukekawa-cho, Hitachi City, Ibaraki Prefecture Hitachi Cable Corporation Wire Plant, (56) References JP JP-A-3-95947 (JP, A) JP-A-4-10552 (JP, A) JP-A-2-180041 (JP, A) JP-A-5-21538 (JP, A) (58) Fields studied (Int) .Cl. ⁶ , DB name) H01L 21/60 311

Claims (1)

(57) [Claims] 1. A method for manufacturing a film carrier device comprising: a first and a second conductive layer on both surfaces of an insulating layer, wherein the conductive layers are electrically connected via via holes . (1) a conductive layer, and a copper foil on one surface of the insulating layer
After attaching, the inside of the via hole is covered with the other surface of the insulating layer.
And a protrusion direction of the first conductive layer protruding into the via hole.
By vacuum evaporation on the surface of
A method for manufacturing a film carrier device , comprising forming a second conductive layer made of a copper layer .