JP3454876B2 - Laminated conductor and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to, for example, formation of a flexible printed wiring board or TAB (Tape Aut
The present invention relates to a laminated conductor suitable for omated bonding, and more particularly to a tape-type laminated conductor that can be easily bonded to an insulating film and the like and is suitable for forming a fine conductor pattern, and a method for manufacturing the same.

[0002]

2. Description of the Related Art For example, in a structure of an electronic circuit, a so-called flexible printed wiring board is generally used for a structure of a wiring portion which is required to be bendable (flexible). Also, for example, in a personal computer, a word processor, or a television, in a wide field such as a drive circuit component of a liquid crystal display device that performs a display function or a circuit structure of an electronic notebook or a scientific calculator, a tape carrier package of a semiconductor element is used for an ASIC. It is being used as a multi-pin package. The tape carrier package or the TAB type semiconductor device (device) is formed by bonding (mounting) predetermined semiconductor devices in sequence while continuously carrying a so-called carrier tape formed by forming required lead patterns at predetermined intervals. ), Combined with the advantage that it can be mass-produced or constructed,
A lot of interest has been received and its practical application is being promoted.

By the way, the flexible printed wiring board or the carrier tape is an insulating film (insulating substrate), such as a polyimide resin film, which has little strength deterioration after solder dipping and is flexible.
The surface is formed of a laminated conductor formed by laminating a conductor film such as a copper foil and integrating the conductor film. That is, the copper foil of the copper foil-clad tape (laminated conductor) having the above configuration is
For example, it is manufactured by selectively photoetching to form a required wiring pattern group or the like, or by forming lead patterns including inner leads and out leads apart from each other.

[0004]

However, in the case of a copper foil-clad tape (laminated conductor) formed by laminating and integrating the copper foils having the above structure, there are practical problems as follows.
That is, the laminated copper foil is inferior in mechanical strength and adhesive strength to the insulating film, and since the crystal grains are relatively large, anisotropy is associated with etching on a micron order, so that a fine pattern is obtained. However, there is a problem that it is difficult to make the pattern (fine patterning). More specifically, since the copper foil is inferior in etching property when forming a wiring pattern or a lead pattern, a so-called wiring pattern or lead pattern in which a narrow wiring pattern or a lead pattern having a narrow pitch is formed so as to be insulated and separated from each other. Is very difficult to miniaturize. That is, it is not possible to sufficiently cope with the high density of the wiring pattern, the compact size of the tape carrier package, the large capacity of the multi-pin type, and the like.

For the miniaturization of the wiring pattern and the lead pattern, there is a means of reducing the thickness of the copper foil, but since the strength or hardness of the formed lead pattern is lowered, the lead pattern is deformed or cut at the time of bending. There is a problem that it becomes easier and the reliability of conduction is impaired. In particular, when the hardness of the lead pattern is insufficient, the lead pattern is likely to lose its shape, and in the case of automatic mounting, there is a possibility of causing a problem in reliability of electrical connection.

Further, the low adhesive strength to the insulating film surface causes a difficulty in forming wiring patterns and lead patterns by etching, and easily peels off when the pattern is miniaturized. Then, there is a problem that the required function cannot be performed. And
This problem of adhesiveness also brings about a disadvantage that the airtight or liquid-tight sealing property cannot be exhibited, for example, when a required semiconductor element is mounted and bonded on a carrier tape and then resin-molded.

The present invention has been made in consideration of the above circumstances, and can easily form a bond with an insulating film and has a fine pattern with high reliability having good mechanical strength and bondability. An object of the present invention is to provide a laminated conductor that can be formed with high precision and reproducibility, and a method for manufacturing the same.

[0008]

A laminated conductor according to the present invention comprises an insulative tape body and a Cr, Zr, Ti body integrally bonded to at least one main surface of the insulative tape body .
0.01 to 1.5% by weight of an additive element selected from , and a conductor layer comprising a Cu alloy containing unavoidable impurities, the additive element Cr and Zr as an essential component, the conductor layer Is at least on the bonding surface side of the insulating tape body.
Cr, Zr component forms a rich Cu alloy layer, and characterized in that it has an oxidation layer.

In addition, the method for producing a laminated conductor according to the present invention, the additive element selected from Cr, Zr, Ti (provided that Cr and Zr
0.01 to 1.5% and is referred to as essential components) Zr weight ratio, and a conductive film made of Cu alloy containing unavoidable impurities to a surface treatment with a nitric acid aqueous solution, the less surface area
A step also the Cr, Zr components are rich Cu alloy stratification, and to produce the oxide layer, the nitric acid aqueous solution of the conductor film
Characterized in that the in the surface-treated one treated surface and a step of integrally bonded to <br/> main surface of the insulating tape body.

In the present invention, if the composition ratio of the additional element (at least one of Cr, Ti and Zr) is less than 0.01% by weight, the hardness is insufficient, and if it exceeds the upper limit, the hot rolling property is deteriorated. In addition, since it does not exhibit the required conductivity, it must be selected within the above range. In addition, in order to improve rolling workability and conductivity, it is possible to add, for example, 0.005 to 0.5 wt% of Si or Ge. In addition, in consideration of the adhesion to the insulator, in order to obtain the required adhesion strength (peeling resistance) of 1.0 kg / cm or more, the conductor film surface of the laminated conductor is treated with a nitric acid aqueous solution, Part of the Cu component is removed to make an additive element (one or more of Cr, Zr, and Ti) rich layer, while a copper oxide-based film (layer) containing the additive element is generated (formed) in advance. I need to put it. Here, the formation of the oxide contributes to good adhesiveness to an insulating substrate (insulating film), for example, a polyimide resin tape, and constitutes a laminated conductor which is industrially easy to manufacture and has high reliability.・ Can be held.

The present invention was made based on the following findings. That is, a Cu alloy film (membrane) containing 0.01 to 1.5% by weight of at least one of Cr, Ti, and Zr and unavoidable impurities is treated with an aqueous nitric acid solution, an aqueous hydrochloric acid solution, or an aqueous sulfuric acid solution, and then washed with water.・ When the AES (Auger electron) spectrum was obtained for each of the cleaned surfaces, the results shown in FIGS. 1 to 3 were obtained. Here, FIG. 1 shows the case of treatment with a nitric acid aqueous solution, where Cu, Zr, Cr, and O peaks are clearly observed, and the Zr and Cr components are enriched and an oxide layer is formed. In FIG. 2 when treated with an aqueous solution of hydrochloric acid and in FIG. 3 when treated with an aqueous solution of sulfuric acid, Zr and
No Cr peak was observed, confirming that a Cu alloy layer rich in Zr and Cr components was not formed. Then, the present invention provides the conductive tape layer with rich Zr, Cr, and Ti components and by forming an oxide layer, thereby easily exhibiting good bonding and integrity with respect to the surface of the insulating tape body. It was achieved by paying attention.

[0012]

In the laminated conductor according to the present invention, a predetermined amount of at least one element of Cr, Zr and Ti forming the conductor layer, the balance being Cu and unavoidable impurities, and if necessary other elements A Cu alloy containing the required amount of additional components has appropriate hardness and etching properties, and exhibits good adhesion to the facing surface of the insulating tape. That is, the conductor layer has excellent mechanical strength and conductivity, and is firmly and closely integrated with the pair of insulating tapes as a supporting substrate, while fine etching is also possible. A highly reliable and flexible printed wiring board or carrier tape package can be easily constructed. In particular, when at least one of Si and Ge is added, the peel strength can be further improved.

[0013]

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

Examples 1-5, Reference Examples 1-7, Reference Example A-
F FIG. 4 is a cross-sectional view showing a structural example of the laminated conductor according to the present invention, in which 1 is an insulating tape body, for example, a polyimide resin film having a thickness of about 75 μm and provided with a required opening, 2 Is a conductor layer integrally supported on the main surface of the polyimide resin film 1 via an adhesive layer 3, that is, Cr, Zr, Ti selected in a range of 0.01 to 1.5% by weight.
Is a Cu-based metal foil (metal layer) having a thickness of about 35 μm, which is composed of at least one element of the above and the balance Cu and unavoidable impurities.

Then, such a laminated conductor can be manufactured as follows.

First, Cu of 99.9 wt% purity and 99.9 wt% purity of
Cr, Zr with purity 99.9wt%, Ti with purity 99.9wt%, etc.
The composition ratio (wt.
%) And high-frequency melting to produce 18 kinds of Cu alloy ingots. Here, the balance of the Cu alloy component is CU. Then, after forging these Cu alloy ingots, 900 ℃
After heating for 1 hour and hot rolling, a 2 mm thick metal plate was prepared. After removing the oxide on the surface of this metal plate, it was cold-rolled to a metal plate with a thickness of 1 mm.
After heat treatment at ℃, cold rolling is further applied to 100 mm
The width of the metal foil was 35 μm. The results of measuring the hardness (Hv) of each of these metal foils are also shown in Table 1. In addition, each evaluation shown in Table-1 was performed by hardness: Vickers Hv and conductivity: IACS%, respectively. In the evaluation, hardness of 100 or more and conductivity of 50 or more were used as a guide.

[0017]

[Table 1]

Next, each of the metal foils was treated with 0.1 to 5 N of nitric acid to remove the Cu component on the surface to remove Cr and T.
An uneven surface was formed that was rich in i and Zr components and had its surface oxidized. 5 to 7 are scanning electron micrographs showing the surface state of the metal foil, FIG. 5 shows a state after nitric acid treatment, FIG. 6 shows a state before surface treatment, and FIG. 7 shows a reference example. Shows the state after the treatment with hydrochloric acid.

Each of the etched metal foils was laminated on an insulating tape, for example, a polyimide resin film surface via an adhesive layer (for example, an epoxy resin adhesive) to form a laminated conductor. In the production of this laminated conductor, the insulating tape may be directly joined / integrated by utilizing the plasticity of the insulating tape without interposing an adhesive layer, or may be laminated by using a polyimide resin adhesive.

With respect to the laminated conductors obtained above, the peeling strength (peeling strength) between the laminated metal foil and the polyimide resin film was measured, and the results were measured. In addition, the above table is also shown.

The electric resistances of the Cu-based conductor layers (Cu alloy foils) in these laminated conductors were measured, and all had the required conductivity even when formed into a fine pattern with a width of about 60 μm. Combined with the good peel resistance, it was suitable for the production of flexible printed wiring boards and TAB packages.

Example 6 First, a polyimide resin film having a thickness of about 75 μm is prepared by applying an epoxy resin adhesive to the main surface to form and equip a required adhesive layer. The resin film was cut into a long tape having a predetermined width, for example, a width of 35 mm, and the long tape was subjected to a required punching treatment to open (cut off a part of) the semiconductor element mounting portion and the cutting region of the outer lead. After that, Cr, Zr, T selected in the range of 0.01 to 1.5% by weight
The target TA is obtained by laminating and integrating a Cu alloy foil having a thickness of, for example, about 35 μm, which is composed of at least one element of i and the balance Cu and unavoidable impurities.
The tape for B was obtained.

Next, the results of evaluating various characteristics of the TAB tape having the above-described structure as a carrier tape will be described. First, we prepared 11 types of TAB tapes with different composition of the Cu alloy foil.
The hardness and conductivity of the alloy foil (conductive layer) of the TAB tape were evaluated. On the other hand, each of the alloy foils of these TAB tapes is subjected to photo-etching treatment to form a required lead pattern with a pitch of 30 μm, and then a thin plated layer of Au or Sn is coated on the lead patterned surface. The adhesive tape was formed to obtain a carrier tape, and the hardness and conductivity of the alloy foil (conductive layer) were taken into consideration, and a comprehensive evaluation as a TAB tape was performed. The results of this series of evaluations are also shown in Table 1 above.

As can be seen from the above evaluation results, when the laminated conductor according to the present invention is used, for example, as a TAB tape,
It can be said that each of the properties required for the carrier tape is maintained, that is, high peel strength is maintained, and high strength and high conductivity that do not cause deformation such as bending even when a fine lead pattern is formed.

In the above, the thickness of the insulating tape body is 75
The μm polyimide resin film is shown as an example, but the thickness is not limited to the above example, and the material is also polyester resin, polyether ether ketone resin, polyetherimide resin, polyphenylene resin, polyacrylate resin, Other than polyimide resin, such as polyamide-imide resin, polyamide-based resin, oxide, and glass, may be used. Furthermore, the thickness of the alloy foil which comprises at least one element of Cr, Zr, and Ti selected in the range of 0.01 to 1.5% by weight ratio forming the conductor layer, the balance being Cu and unavoidable impurities, Of course, it is not limited to the above examples.

[0026]

As described above, according to the laminated conductor of the present invention, the weight ratio is selected in the range of 0.01 to 1.5%.
A Cu alloy layer composed of at least one element of Cr, Zr, and Ti, the balance of which is Cu and unavoidable impurities constitutes a conductor layer and has good mechanical properties and conductivity, The bonding surface of the insulating tape body is made of Cr, Z with good adhesion.
Since it has an oxide layer rich in r, Ti components and the like, it exhibits excellent peeling resistance or adhesiveness, and even in a finely patterned form, peeling and damage are completely avoided. On the other hand, the Cu alloy layer forming the conductor layer has a high hardness and does not easily deform even when finely patterned,
It can be said to be suitable for the construction of highly reliable and flexible printed wiring boards and carrier tape packages.

[Brief description of drawings]

FIG. 1 is an AES spectrum diagram showing the surface composition state of a Cu-based alloy conductor film (foil / membrane) treated with an aqueous nitric acid solution.

FIG. 2 is an AES spectrum diagram showing the surface composition state of a Cu-based alloy conductor film (foil / membrane) treated with a hydrochloric acid aqueous solution.

FIG. 3 is an AES spectrum diagram showing the surface composition state of a Cu-based alloy conductor film (foil / membrane) treated with a sulfuric acid aqueous solution.

FIG. 4 is a cross-sectional view showing a configuration example of a laminated conductor according to the present invention.

FIG. 5 is a scanning electron micrograph showing the surface texture of a Cu-based alloy conductor film (foil / membrane) treated with an aqueous nitric acid solution.

FIG. 6 is a scanning electron micrograph showing the surface texture of a Cu-based alloy conductor film (foil / membrane) before being treated with an aqueous nitric acid solution.

FIG. 7 is a scanning electron micrograph showing the surface texture of a Cu-based alloy conductor film (foil / membrane) treated with a hydrochloric acid aqueous solution.

[Explanation of symbols]

1 ... Insulating tape body 2 ... Conductor layer 3 ... Adhesive layer

─────────────────────────────────────────────────── ───Continued from the front page (51) Int.Cl. ⁷ Identification FI H01L 21/60 311 H01L 21/60 311W H05K 1/09 H05K 1/09 A (72) Inventor Michihiko Inaba Kawasaki City, Kanagawa Prefecture Komukai Toshiba Town No. 1 Toshiba Research & Development Center (72) Inventor Masaaki Morita No. 1 Komukai Toshiba Town No. 1, Komukai Toshiba Town, Kawasaki City, Kanagawa Prefecture (56) Reference JP 5 -82589 (JP, A) JP 5-190608 (JP, A) JP 60-94727 (JP, A) JP 62-40385 (JP, A) Koichi Teshima, Toshiharu Sakurai, Haruka Machitori, Shigemi Yamane, “High-strength, high-thermal-conductivity lead frame material CCZ”, Toshiba Review, Volume 38, No. 10 (1983), pp.929-932 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01B 5 / 14 C22 C 9/00 H01B 13/00 503 H01L 21/60 311 H05K 1/09

Claims (2)

(57) [Claims] 1. An insulating tape body , and C integrally bonded to at least one main surface of the insulating tape body ,
Additive element selected from r, Zr, and Ti in weight ratio of 0.01 to 1.5
%, And a conductor layer made of a Cu alloy containing unavoidable impurities, the additive element contains Cr and Zr as essential components, and the conductor layer has at least Cr on the bonding surface side of the insulating tape body. laminated conductor Zr component is characterized by having a form rich Cu alloy layer, and oxide layer. 2. An additive element selected from Cr, Zr and Ti (only
Cr and Zr as essential components) in a weight ratio of 0.01 to 1.5
%, And the steps conductor film made of Cu alloy containing unavoidable impurities to a surface treatment with a nitric acid aqueous solution, at least Cr surface area, Zr components are Cu alloy rich, and to produce an oxide layer, one surface-treated with the nitric acid aqueous solution of the conductor film
Method for producing a laminated conductor, wherein the square of the treated surface by comprising a step of integrally bonding the main surface of the insulating tape body.