JP2000003942A - Plating of tab tape substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive to eliminate the cause of an unarrival of a plating to the surface of a metal foil in press holes formed in a TAB tape substrate and an abnormal deposition of the plating, by a method wherein when the TAB tape substrate is dipped in a plating solution in a plating process in the manufacture of the substrate, bubbles are apt to be left in the holes, but that point is modified. SOLUTION: In a method of plating a TAB tape substrate 5, a predipping tank 1 is provided in front of a plating tank 2 and after all the parts of the substrate 5 are completely wetted with a plating solution in the tank 1, the substrate 5 is put in the tank 2 and in the tank 1, ultrosonic vibrations are applied to the plating solution and the substrate 5, which is a body to be plated, in the tank for preventing the generation of bubbles in holes bored in an insulating resin or for removing the bubbles. In a plating process in the manufacture of the substrate 5, the inhibition of the generation of bubbles in press holes formed in the substrate 5 in the plating solution and the removal of the bubbles can be conducted, an unarrival of a plating to the surface of a metal foil in the holes and an abnormal deposition of the plating are prevented and the manufacture of a good TAB tape substrate becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a plating method for manufacturing a TAB tape substrate.

[0002]

[Prior Art] Miniaturization and thinning of electrical products and electronic devices
Along with the reduction in weight and functionality, the integration of mounting structures has been increasingly spurred in order to achieve the miniaturization of IC packages and the increase in the number of pins simultaneously, realizing those needs at lower cost. As a bare chip mounting method for performing the above, a TAB method has been increasingly used mainly for LCD drivers and small information communication devices for individuals.

The TAB tape substrate used for the TAB includes a one-layer type in which a metal foil is wired by a photolithography method, and a two-layer type in which a wiring metal is wired on an insulating resin base material by plating or the like. Further, there is a three-layer type in which an insulating resin and a copper foil having a necessary hole provided by press working are bonded to each other by an adhesive to form a three-layer (three-layer) structure substrate, and wiring is performed by a photolithography method. A three-layer type TAB tape substrate is generally employed.

As shown in FIG. 3, a three-layer TAB tape substrate having a three-layer structure in which a metal foil 9 such as a copper foil and an insulating resin 8 such as a polyimide are bonded together with an adhesive 10 such as an epoxy resin system is characterized in that: A metal wiring pattern formed of a metal foil over a press hole 11 such as a device hole or a bending slit formed by press working is bridged or protrudes from an insulating resin layer 8 serving as a base material including an adhesive layer 10. It has a so-called overhang pattern 12 running or is manufactured at a relatively low cost compared to a two-layer TAB tape substrate or the like. Also, 1
It is possible to form a fine pattern with an overwhelmingly fine pitch compared to a layer TAB tape substrate.
μm pitches are mass-produced, and those having a pitch of 50 μm or less are being developed by various companies.

A typical method of manufacturing this three-layer TAB tape substrate will be described below with reference to FIGS. 4 (a) to 4 (c). First, as shown in (a), a press hole 11 having a desired shape such as a device hole or a bending slit is formed by press working in an insulating resin base material 8 to which an adhesive 10 on a film is previously bonded. Then, a photoresist 13 is applied on the metal foil 9. Next, as shown in FIG. 2B, the photoresist is irradiated with ultraviolet light onto which a photomask on which a desired wiring pattern has been drawn is projected by an exposure machine, and the wiring pattern is printed. The photoresist pattern 15 is formed by developing with a solution, for example, an alkaline solution that selectively dissolves the photoresist in the portions not described above.

Normally, since a positive type photoresist is used, the exposed portion 14 by exposure is dissolved in the developing step, and the unexposed portion 14 remains as a photoresist pattern 15. When the photoresist pattern 15 is used as an etching resist to dissolve the metal foil, for example, when a copper foil is used as the metal foil, the wiring pattern 17 shown in FIG. After the development, the backing material 16 shown in FIG. 7B is applied to the back surface so that the overhang pattern portion 12 which is a major feature of the three-layer TAB tape substrate is not etched from the back surface during the etching process. Applied as an etching resist.

After the wiring pattern 17 is formed in the etching step, the remaining unexposed portion of the photoresist 15 and the backing material 16 are dissolved or swelled by a peeling device using, for example, an alkaline solution having a higher dissolving power than a developing solution. And completely peeled off.

The circuit pattern thus formed is coated with a solder resist on a necessary portion for electrical or mechanical protection, then formed into a film, and then tin, gold, or the like depending on the use or function of the TAB tape substrate. A plating such as solder is applied to complete a TAB tape substrate. In this plating process, the plating solution and plating apparatus are selected and devised in consideration of the stability and cost of the plating reaction according to the type of plating metal to be applied. It can be roughly classified into electrolytic plating. Electroplating is performed by applying a voltage between the electrode provided in the plating solution and the metal foil of the TAB tape substrate, which is the object to be plated.
It is for reducing and precipitating the plating metal ions in the plating solution on the metal foil surface, and the plating apparatus requires a power supply device for applying current to the electrode in the plating tank and the metal foil and a rectifier for applying voltage. . At present, this electrolytic plating method is used when applying gold plating or solder plating. On the other hand, in the case of electroless plating, the plating metal ions in the plating solution are generated by the oxidation-reduction potential generated when the metal foil surface of the TAB tape substrate, which is the object to be plated, comes into contact with the plating solution. An oxidation-reduction type that reduces and precipitates on the metal foil surface of a certain TAB tape substrate, and the metal foil surface is ionized when the metal foil surface of the TAB tape substrate, which is the object to be plated, comes into contact with the plating solution, and at the same time the plating solution There is a replacement type in which metal ions are replaced on the metal foil surface as metal.Currently, when applying tin plating or the like, the latter replacement type plating solution is often used. The structure is such that the TAB tape substrate, which is the object to be plated, is merely dipped.

[0009]

However, in the above-mentioned prior art, the press hole shape of the TAB tape substrate has been diversified and miniaturized in accordance with the recent progress of miniaturization, high density and high function of TAB. When the TAB tape substrate is immersed in the plating solution in the plating process, air bubbles are likely to remain in the press holes, thereby causing non-plating or abnormal deposition on the metal foil surface in the press holes of the TAB tape substrate, and Has the problem of causing serious defects in

Therefore, the present invention solves such a problem, and an object of the present invention is to provide a TAB tape substrate with a diversified press hole shape or a reduced diameter.
A good TAB tape substrate that suppresses or eliminates the generation of air bubbles in the press holes in the plating solution in the plating process of B tape substrate manufacture, preventing non-plating and abnormal plating deposition on the metal surface in the press holes. Is to provide.

[0011]

According to the present invention, there is provided a method for plating a TAB tape substrate having a structure in which a metal foil alone or a metal foil and an insulating resin are bonded to each other. To prevent plating non-adhesion and abnormal plating deposition due to the generation of air bubbles on the surface of the substrate or the metal foil surface through holes drilled in the insulating resin, set up a pre-dip tank in front of the plating tank and set a plating solution. After completely wetting all parts of the TAB tape substrate in the plating tank, put it in the plating tank. In the pre-dip tank, the inside of the tank is used to prevent or remove air bubbles in the holes drilled in the insulating resin. Ultrasonic vibration is applied to the plating solution and the TAB tape substrate as the object to be plated.

[0012]

According to the above construction of the present invention, the plating solution and the TAB tape substrate, which is the object to be plated, are subjected to ultrasonic vibration in the plating solution pre-dip tank provided in front of the plating bath to thereby provide a metal foil surface in the press hole. Prevents or removes bubbles adhering to the TAB tape substrate and completely wets the metal foil surface of the TAB tape substrate with the plating solution. It is possible to prevent non-plating and abnormal deposition of plating due to sticking of air bubbles in the step.

[0013]

FIG. 1 is a view showing an embodiment of the present invention, in which a hoop-shaped TAB tape substrate 5 passes through a pre-dip tank 1 through a pre-dip tank 1 from left to right as viewed in the drawing.
Is transported while being guided by the transport roller 6, and is subjected to plating. The basic configuration of the plating equipment in the plating process is as follows: First, there is a degreasing tank in front of the plating tank, where the TAB tape substrate is cleaned, and then soft etching of the copper foil is performed to expose the fresh copper surface. Often plated from In that case, after the degreasing tank and the soft etching tank, water washing and draining air after the water washing are arranged, respectively, so that the processing liquid in each processing tank is not contaminated by the previous processing liquid brought in. Further, the pre-dip tank 1 is not provided in the plating apparatus of the conventional plating step, and the plating tank is subjected to the above-described degreasing treatment tank and the subsequent washing / draining or subsequent soft etching tank and the subsequent washing / draining. It is put in the tank and is plated.

In FIG. 1, the degreasing tank and the soft etching tank which are arranged before the pre-dipping tank are omitted. A pre-dip solution 3 is applied to the pre-dip tank 1. The pre-dip solution is preferably the same plating solution as the plating solution 4 in the plating tank. Except for special cases where the plating thickness is controlled, ion-exchanged water may be used. The ultrasonic vibrator 7 is installed in the pre-dip tank at a position where it can face the press hole of the TAB tape substrate 5. FIG. 1 shows a state in which the press holes are located on the lower side when the TAB tape substrate 5 is horizontal.

Ultrasonic waves need not be vibrated when the press hole of the TAB tape substrate 5 is relatively large, and the effect of preventing bubbles in the plating tank 2 is sufficient only by pre-dipping. It is also possible to select whether or not to apply an ultrasonic wave according to the specifications of the above. The apparatus is designed so that the distance from the outlet of the pre-dip tank 1 to the entrance of the plating tank 2 is as short as possible.

[0016]

As described above, according to the method for plating a TAB tape substrate of the present invention, the plating process in the TAB tape substrate manufacturing process can be performed in response to diversification or reduction in the diameter of the press hole of the TAB tape substrate. It is possible to suppress or eliminate the generation of air bubbles in the press hole in the liquid, and prevent non-plating or abnormal plating deposition on the metal surface in the press hole, thereby making it possible to manufacture a good TAB tape substrate.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a plating apparatus showing one embodiment of a plating method of the present invention.

FIG. 2 shows a three-layer T as an example of a TAB tape substrate.
Sectional drawing of an AB tape substrate.

FIG. 3 is a cross-sectional view of the TAB tape substrate in each step for explaining an example of a method for manufacturing a three-layer TAB tape substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pre-dip tank 2 Plating tank 3 Pre-dip solution 4 Plating solution 5 TAB tape substrate 6 Conveyance roller 7 Ultrasonic transducer 8 Insulating resin 9 Metal foil 10 Adhesive 11 Press hole 12 Overhang pattern 13 Photoresist 14 Photo Photosensitive portion of resist 15 Non-photosensitive portion of photoresist 16 Backing material 17 Wiring pattern

Claims (4)

[Claims] In a method for plating a TAB tape substrate having a structure in which a metal foil alone or a metal foil and an insulating resin are bonded to each other, a pre-dip tank is provided before a plating tank, and a plating solution in the pre-dip layer is provided. TAB that was completely wetted with the TAB tape substrate and then placed in the plating tank
Plating method of tape substrate. 2. The T according to claim 1, wherein the pre-dip tank and the plating tank are different tanks.
AB tape substrate plating method. 3. The T-plate according to claim 1, wherein the pre-dip tank applies ultrasonic vibration to the plating solution and the TAB tape substrate in the tank.
AB tape substrate plating method. 4. The TAB tape substrate according to claim 1, wherein the pre-dip tank and the plating tank are formed as an integrated tank, and a plating solution is sprayed on the TAB tape substrate in a region of the pre-dip layer. Plating method for TAB tape substrate.