JP2002206181A - Method of manufacturing two-metal layer tbga or fpcb (fbwb) by reel to reel from tape or flexible material lined with copper foil on both sides - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of reforming copper foil to the copper foil which does not reflect lasers and drilling blind holes by a direct laser drilling method. SOLUTION: The copper foil is formed to easily absorb the CO2 laser, to roughen its surfaces, to dye the surfaces black and to reduce a copper thickness in order to lessen energy. Reel-to-reel treatment equipment is internally provided with three chambers for the purposes described above and the copper foil is subjected to each chemical treatment. The copper foil is thus finished to the copper foil which has a copper thickness 1 to 5 μm, surface roughness 1 to 3 μm and black color and permits drilling of only the surface to be irradiated with the laser by the direct laser drilling method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Today, PCB (PW)
B) High density in the tape industry (High Density)
It is said that FPCB, TB in it
For GA, TCSP, etc., methods have been proposed to respond rapidly. One of the technologies is to open the blind hole with a laser for the interlayer connection, and to apply the blind hole to the blind hole to make it conductive. The present invention is a method for modifying a copper foil that can be used for drilling with a carbon dioxide laser.

[0002]

2. Description of the Related Art In the case of a high-density pattern, interlayer connection can only be performed by blind vias. Use a laser to open the blind hole. The laser uses a carbon dioxide laser with a high drilling speed. However, the carbon dioxide laser is reflected by the copper and cannot penetrate the copper. That is the conclusion of today. Therefore, the blind hole is formed by the carbon dioxide gas laser in the following process in the two metal layer FPCB and TBGA using the current two metal layer material. What is written in the TBGA production process because the FPCB is not currently reel-to-reel and does not have blind hole drilling and plating processes. 1. Copper foil 1 and copper foil 2 on both sides of the insulating resin tape as shown in FIG.
The material (2 metal layer material) on which is adhered is slit into a predetermined width, and a sprocket hole is punched to facilitate transportation, positioning, and the like in the subsequent steps. 2. 2. Dry film double-sided lamination, as shown in Figure 2 3. Exposure of a drilling pattern on the surface of copper foil 2, and exposure of the entire surface of copper foil 1 FIG. 3 shows the development. 5. Etching, becomes FIG. 6. Dry film peeling, as shown in FIG. CO2 laser drilling, drilling holes in copper foil by etching, utilizing the fact that copper reflects the CO2 laser,
Copper foil is used as the resist. The laser drilling method in this step is generally called a conformal mask method. FIG. 8. Desmear, the following steps are copper plating, dry film lamination, pattern exposure, development, etching, peeling, printing, and plating.

[0003]

As described above, piercing is performed by a carbon dioxide gas laser. For this purpose, the laminating process in step 2 must be carried out from the laminating process to the peeling process.
This is costly because most of the PCB and TBGA fabrication steps are used twice. Further, by etching, a portion where the dry film is not stretched, that is, a portion of the sprocket, is free of copper by the etching.
At the end of the desmear, the sprocket holes are damaged and often damaged. In addition, electroless copper plating,
In the copper plating process, the adhesion of the plating is poor, so that the copper is peeled off, causing garbage and causing various troubles.
In addition, it is often difficult to match the position drilled for the laser mask with the position for pattern fabrication. Actually, due to the high defect rate, the price of TBGA is high,
It is hard to say that it is mass-produced. For these reasons, the establishment of the technology of the direct laser drilling method is expected.

[0004]

SUMMARY OF THE INVENTION The present invention provides an FPCB, TBGA, TCSP using a two-metal tape material.
Is to modify a copper foil 2 bonded to a copper foil adapted to a direct laser drilling method by a hole drilling by a carbon dioxide laser in a reel-to-reel processing apparatus. The process is 9. Slit to predetermined width 10. Copper foil etching processing by reel-to-reel processing equipment. 1-5 μm. As shown in FIG. 11. Roughening processing by reel-to-reel processing equipment. 1-3
μm. FIG. 12. Dye black with a reel-to-reel processing unit. 13. Sprocket hole punching. 14． Carbon dioxide laser drilling. As shown in FIG. As described above, the process becomes extremely simple. Next, in the processing apparatus of the second aspect, the tape (two metal layer materials) wound on the reel as shown in FIG. 10 enters the processing chamber from the unwinding machine, is treated with each processing solution, washed with water, dried and wound. It is wound on a reel by a take-up machine. The present invention has three processing chambers, a washing chamber is attached, and a jet port of the liquid is under the tape, so that the copper foil is reformed into a copper foil under conditions that can be drilled by a carbon dioxide laser. The discharged liquid hits the copper foil 2 from the jet port, and the tape is lifted by the force, and the tape is processed without being caught by the jet port. FIG. 11 shows the positions and dimensions of the tape and the jet port. This device is only applicable to light, reel-to-reel such as tape or flexible substrates. However, it is very useful for single-sided processing of tapes and flexible substrates.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is to continuously perform three kinds of treatments on a copper foil with three kinds of liquids. System, iron chloride, copper salt, etc. can be used. However, since the next roughening solution contains an inhibitor in a sulfuric acid hydrogen peroxide system, a sulfuric acid hydrogen peroxide system is preferred. The black dye solution forms a black oxide film on copper with an oxidizing agent such as hypochlorous acid. The thickness of the copper foil should be thin to reduce the energy of the carbon dioxide laser,
It is better to secure a minimum thickness of 1 μm required for copper plating in a later step. In the structure of the apparatus, the rinsing chamber is also cleaned from the top of the tape with a spray or the like, and the entrance of the next processing chamber is sufficiently drained with an air. In the processing chamber, an air drain nozzle is appropriately mounted in preparation for water drops from the chamber ceiling, rebound from the side, and the like. The tape that has been processed and wound with the above apparatus and processing solution can be directly punched with a carbon dioxide laser.

[0006]

As described above, according to the present invention, carbon dioxide laser drilling can be performed with a sprocket hole punch through a processing apparatus. Compared with the conventional method, the direct material cost of dry film lamination and exposure and the cost of exposure alone are reduced by about 50%. In addition, sprocket holes are hardly damaged. Positioning in the subsequent steps is much easier than in the conventional conformal mask method. In addition, the sprocket hole is also adhered to the copper, so that the sprocket hole has good adhesion and does not come off. The thin copper foil 2 allows the thickness of the copper plating to be adjusted to the fineness of the pattern. For example, if the S / L of the pattern is 30 μm / 30 μm, the copper plating thickness is set to 15 μm. Conversely, if the copper foil thickness is 12 μm,
If 5 μm is added, S / L and 30/30 μm cannot be etched. The other is that the thickness of the copper can be adjusted according to the thickness of the copper foil 1, so that the pattern etching becomes very simple. However, for copper plating, such a single-side plating device must be used. We are already doing TBGA production. What is done after the sprocket hole punch passes through the processing device is that the copper foil 1 does not have a seal mask when passing through the processing device and the copper foil 2
This is because the purpose is to apply the liquid only to the side, so that the liquid does not leak from the sprocket hole. Next, the processing device of claim 2 does not require any special cost. However, it is necessary to devise a little bit about the spout. As a result, there is no need to provide a tape or a dry film for sealing on the surface of the copper foil 1. Naturally, the cost is lower.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a commonly used two-metal layer material in which a sprocket hole has been punched for a tape.

FIG. 2 is a cross-sectional view showing a state where a conventional dry film is laminated.

FIG. 3 is a cross-sectional view showing a state where a hole pattern is developed by a conventional method.

FIG. 4 is a cross-sectional view showing a state where a hole pattern is etched by a conventional method.

FIG. 5 is a cross-sectional view showing a state where a dry film is peeled off by a conventional method.

FIG. 6 is a cross-sectional view of a conventional method (conformal mask method) in which a hole is formed by a carbon dioxide laser.

FIG. 7 is a cross-sectional view showing a state where only the single-sided copper foil has been subjected to the first-stage processing by the processing method and processing apparatus of the present invention.

FIG. 8 is a cross-sectional view showing a second surface roughening process performed by the processing method and the processing apparatus of the present invention.

FIG. 9 is a cross-sectional view of a place where a hole is punched by a carbon dioxide laser after a sprocket hole punch in the process of the present invention.

FIG. 10 is a schematic side view illustrating a reel-to-reel processing apparatus of the present invention.

FIG. 11 is a cross-sectional view showing a relationship between a jet port and a tape of the processing apparatus of the present invention.

FIG. 12 is a cross-sectional view showing a state in which copper for interlayer connection is copper-plated after filling copper in a conventional manner.

FIG. 13 is a cross-sectional view showing a state where copper for interlayer connection is plated after filling copper for filling in the present invention.

[Explanation of symbols]

 1-copper foil 2-copper foil 3-resin lumber 4-sprocket hole 5-dry film 6-blind hole 7-unwinding reel 8-winding reel 9-processing chamber 10-spout port 11-reservoir 12-pump 13 -2 Metal layer material (tape) 14-Washing chamber 15-Dryer 16-Filled copper filling 17-Interlayer connecting copper plating

Claims (2)

[Claims] 1. A method of processing a copper foil so that a blind hole can be directly drilled from a copper foil by a carbon dioxide gas laser (generally referred to as a direct laser drilling method). A processing device having three steps of thinning the copper foil 2 on the laser irradiation side without etching the copper foil 1 side by etching the copper foil thickness, roughening the surface with a roughening solution, and blackening with an oxidizing agent, A method for producing a carbon dioxide laser-drillable copper foil, that is, a color (black) with a thickness of 1 to 5 μm, a surface roughness of 1 to 3 μm, and easy absorption of laser light. 2. A processing apparatus having the above three steps, wherein a liquid fed by a pump is applied from a jet port to a lower side (copper foil 2 side) of a tape as shown in FIGS. A processing apparatus having a structure in which the liquid does not flow above the tape (the copper foil 1 side) by making the width W2 of the jet outlet smaller than the width W1 of the tape.