KR101138537B1 - Method for opening laser mask of ultra thin core and printed-circuit-board fabricated using the same - Google Patents

Abstract

PURPOSE: A method for opening a laser mask of an ultra thin core using a carrier foil and a printed-circuit-board manufactured by the same are provided to prevent damage to a copper foil pattern during a process of removing a dry film among DES processes since a carrier foil layer is used in a laser mask opening process. CONSTITUTION: A copper foil-laminated substrate coated with a carrier foil is prepared(S100). The top of the carrier foil is coated with a dry film. A laser mask opening process including a carrier foil is executed(S110). A laser drilling fixing process is executed(S120). A process of eliminating the carrier foil is executed(S130). A copper plating process is executed to plate copper in an exposed area(140). An outer layer image is formed by patterning a copper foil(S150).

Description

TECHNICAL FOR OPENING LASER MASK OF ULTRA THIN CORE AND PRINTED-CIRCUIT-BOARD FABRICATED USING THE SAME}

The present invention relates to a method of opening a laser mask of an ultra-thin substrate using a carrier foil and a printed circuit board manufactured using the same. In the subsequent DES process, a laser mask opening process is performed directly in a copper foil-coated substrate. The present invention relates to a technology that can significantly reduce the occurrence of defects.

With the development of the electronics industry, electronic components have become highly functional and miniaturized. In particular, there is an increasing demand for reducing the thickness of components mounted in order to reduce the thickness of portable terminals.

In such a situation, in order to increase the fine pattern of the multilayer printed circuit board, increase the design density of the circuit pattern, and improve the reliability, a structure for complexing the layer structure of the circuit with the change of raw materials is required. Accordingly, parts are also changed from DIP (Dual In-Line Package) type to Surface Mount Technology (SMT) type, and mounting density is also increasing.

In addition, the portable circuit board has become more complicated, and the design of the printed circuit board has become complicated due to high functionality, internet, video, and high capacity data transmission.

On the other hand, a printed circuit board includes a single-sided PCB in which wiring is formed only on one side of an insulated substrate, a double-sided PCB in which wiring is formed on both sides, and an MLB (Multi Layered Board) which is wired in multiple layers. In the past, single-sided PCBs were used because of simple components and simple circuit patterns. However, in recent years, due to increased complexity of circuits and increased demand for high-density and miniaturized circuits, it is common to use double-sided PCBs or MLBs. have.

The printed circuit board is applied with a circuit pattern for higher density, a via contact and a fine circuit wiring for electrical conduction between circuit pattern layers.

Here, a laser mask open process was performed for via contact.

The laser mask open process is a process of forming a copper foil pattern exposing a via contact region by forming a dry film before drilling on the entire surface of a printed circuit board and then performing exposure and development-etching-strip (DES) processes. .

At this time, when using a UTC (Ultra Thin Core) substrate of 0.06 mm or less, there is a problem that a large amount of breakage occurs in the copper foil pattern in the DES process.

1 to 6 are cross-sectional views showing a laser mask opening process according to the prior art.

Referring to FIG. 1, a copper foil laminated substrate 50 having copper foils 20 and 25 formed on both surfaces of a core layer 10 is provided.

At this time, the copper foil laminated substrate 50 includes carrier copper foils 30 and 35 to protect the copper foils 20 and 25.

Therefore, as shown in FIG. 2, the subsequent process is performed while the carrier copper foils 30 and 35 are removed.

Next, referring to FIG. 3, a laser mask opening process of etching the copper foil on one surface of the copper foils 20 and 25 to form the copper foil pattern 20P is performed.

At this time, in the laser mask opening process, a resist film is formed on the copper foil 20, and then the copper foil is directly patterned by using an exposure and development process.

On the other hand, when the thickness of the core layer 10 decreases, the thickness of the copper foil formed on the core layer 10 is also relatively reduced, so that the copper foil laminated substrate having the ultra-thin core is exposed and developed as described above. There is a high possibility of damage to the copper foil layer during the etching and stripping process.

Therefore, there is a problem that the continuous failure occurs in the hole through which the core layer 10 and the final upper printed circuit pattern 40P as shown in FIGS.

In this case, the yield for the printed circuit board is lowered, and even if the laser mask opening and the printed circuit board manufacturing proceed normally, there is a risk that the yield or reliability is significantly reduced.

The present invention is to damage the copper foil pattern while performing the DES process in the process of performing a laser mask open (Laser mask open) process of copper thin laminated substrate of UTC (Ultra Thin Core) product having a core layer of 0.06mm or less In order to solve the problem, it is an object of the present invention to provide a laser mask opening method using a carrier foil layer formed on the first copper foil laminated substrate.

In addition, an object of the present invention is to provide a method for manufacturing a printed circuit board by which the copper foil layer is not damaged when the printed circuit pattern is formed, thereby significantly reducing the incidence of defects.

The laser mask opening method according to an embodiment of the present invention comprises the steps of: (a) providing copper foil laminated substrates on which copper foils are formed on both surfaces of the core layer and the carrier foil is coated on the surface of the copper foil, and (b) the carrier foil. Coating a dry film thereon; (c) exposing the dry film to develop a hole portion defining a core layer through area of the copper-clad substrate; and (d) developing-etching-strip (DES). Forming a hole exposing the core layer by a process, wherein the DES process removes the dry film portion developed in the step (c) to form a dry film pattern, and masks the dry film pattern Sequentially irradiating a laser on the carrier foil and the copper foil to form a hole exposing the core layer of the hole region, and removing the carrier foil. It is characterized by including.

Here, the carrier foil is a copper layer, it is preferable to form a thickness of 15 ~ 20㎛. In addition, the core layer of the copper-clad laminate is characterized in that it has a thickness of 0.06mm or less.

Next, it is preferable to use the exposure process using UV for the exposure of the said (c) step.

In addition, the method for manufacturing a printed circuit board according to an embodiment of the present invention includes the steps of providing copper foil laminated substrates on which copper foils are formed on both surfaces of the core layer, and the carrier foil is coated on the surface of the copper foil, and the laser mask opening method described above. Forming the carrier foil pattern and the copper foil pattern by forming a hole through the core substrate of the copper foil laminated substrate using the carrier foil pattern and the copper foil pattern as a mask by using a laser drilling process; Removing a carrier foil pattern, forming a copper plating layer for plating a copper layer on the sidewalls of the hole, and patterning the copper plating layer and the lower copper foil to form a circuit pattern.

In addition, the method for manufacturing a printed circuit board according to another embodiment of the present invention includes the steps of providing a copper foil laminated substrate having copper foil formed on both surfaces of the core layer and coated with a carrier foil on the surface of the copper foil, and the laser mask opening method described above. Forming the carrier foil pattern and the copper foil pattern, removing the carrier foil pattern, and forming a hole through the core substrate of the copper foil laminated substrate using the copper foil pattern as a mask using a laser drilling process. And forming a copper plating layer for plating a copper layer on the sidewalls of the holes, and patterning the copper plating layer and the lower copper foil to form a circuit pattern.

Here, the copper plating step is characterized in that the copper foil pattern formed on the copper foil laminated substrate surface and the copper foil formed on the opposite surface are connected to each other.

The present invention uses the carrier foil layer formed on the first copper foil laminated substrate in a laser mask open process to dry the DES process in a copper foil laminated substrate of a UTC (Ultra Thin Core) product having a core layer of 0.06 mm or less. In the process of removing a film, the problem which damage to a copper foil pattern can be solved.

Therefore, in the outer layer image forming process for manufacturing a printed circuit board, it significantly reduces the incidence of defects and provides an effect of improving reliability.

1 to 6 are cross-sectional views showing a laser mask opening process according to the prior art.
7 is a flow chart showing a laser mask opening method and a printed circuit board manufacturing method according to an embodiment of the present invention.
8 to 13 are cross-sectional views illustrating a method of opening a laser mask and a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent with reference to the embodiments and drawings described in detail below. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims.

Hereinafter, a laser mask opening method and a printed circuit board manufacturing method using the same according to the present invention will be described in detail.

First, the present invention is to solve the problem of abnormality of the core layer that did not occur in the copper-clad substrate having a core layer exceeding the existing 0.06mm thickness.

When the double-sided carrier copper foil was removed on the copper-clad laminate having a core layer of 0.06 mm or less, the laser mask open process showed a high product breakage rate.

In particular, the present invention, while performing the DES process in the laser mask open process, a problem that damage to the copper foil pattern appeared, the present invention provides a laser mask open method for solving this problem.

As one example thereof, the present invention provides a method of performing a laser mask opening process in a state in which a carrier copper foil formed as a protective layer is left on the surface of a copper clad laminate substrate as it is.

Therefore, at least the copper foil pattern can be protected, and reliability of patterning the core layer and the like can be improved, and the specific practical examples are as follows.

7 is a flow chart showing a laser mask opening method and a printed circuit board manufacturing method according to an embodiment of the present invention.

First, referring to FIG. 7, a method of manufacturing a printed circuit board according to an exemplary embodiment of the present disclosure includes preparing a copper foil laminated substrate having a carrier foil coated thereon (S100), and coating a dry film on the carrier foil. (S110), the step of performing a laser mask open process including a carrier foil (S110), the laser drilling step (S120), the step of removing the carrier foil (S130), and copper plating the exposed area The copper plating step 140 and the copper foil are patterned to form an outer layer image (S150).

Here, the laser mask opening process (S110) will be described in more detail as follows.

In order to open the laser mask, a dry film is first formed on the carrier foil. At this time, since the copper layer is formed as one example of the carrier foil, there is no problem that the dry film coating formed on the copper layer is inadequate or inferior in performance compared to the process of forming a dry film on the copper foil.

Next, a dry film pattern is formed by an exposure and a DES process. In this case, the dry film pattern is a pattern defining a hole formation region through which the core layer penetrates, thereby exposing a region to be subjected to a subsequent laser drilling process.

At this time, since the dry film is developed in the DES process, the carrier foil and the copper foil are etched using the dry film pattern, and no direct damage is applied to the copper foil layer in the process of stripping the dry film pattern, thereby improving reliability of the laser mask open process. Can be improved.

Here, the carrier foil and the copper foil etching process is preferably performed by a patterning process using laser irradiation.

In the process, a direct blow was previously applied to the copper foil, but in the present invention, since the carrier foil pattern acts as a cover layer, there is no risk of damaging the copper foil.

Therefore, the subsequent laser drilling and copper plate process can be performed smoothly, and look at the specific process as follows.

8 to 13 are cross-sectional views illustrating a method of opening a laser mask and a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

Referring to FIG. 8, a UTC copper-clad laminate 150 having copper foils 120 and 125 formed on both surfaces of a core layer 100 having a thickness of 0.06 mm or less is prepared. At this time, the carrier copper foils 130 and 135 are formed on the surfaces of the copper foils 120 and 125 in order to protect the copper foils 120 and 125.

In the case of a general printed circuit board manufacturing process, the carrier copper foil is removed after proceeding, but in the present invention, the printed circuit board manufacturing process is performed as it is while the carrier copper foil remains.

In addition, in the present invention, the carrier copper foils 130 and 135 are preferably formed to have a thickness of 15 to 20 μm.

For example, when the laser mask open process was performed after removing the double-sided carrier copper foil having a thickness of 18 μm, the copper foil laminate having a core layer of 0.06 mm or less showed a failure rate of 50% or more.

Therefore, in the present invention, the carrier copper foil 130 is applied to the UTC thin plate, but the copper foil protection effect may be insufficient when the thickness of the carrier copper foil 130 is less than 15 μm. The thickness can be so thick that the patterning process can be difficult.

Next, referring to FIG. 9, the above-described laser mask opening process is performed to form the carrier copper foil pattern 130P and the upper copper foil pattern 120P.

At this time, the pattern is formed based on the upper side in the state shown in the cross-sectional view for convenience, but the pattern is formed at the bottom when rotating the screen shown 180 °, the present invention by the same as the upper and lower The present invention is not limited thereto, and the overall process flow should be judged comprehensively.

Here, in the present invention, there is no risk of damaging the upper copper foil pattern 120P in the DES process using a dry film. Thus, unlike the case of FIG. 3, the carrier copper foil pattern 130P and the upper copper foil pattern 120P of the complete form are Can be formed.

Next, referring to FIG. 10, holes are formed in the core layer 100 using a laser drilling process. In this case, a drilling process is performed using the carrier copper foil pattern 130P and the upper copper foil pattern 120P. The carrier copper foil pattern 130P may be removed first, and a core layer 100P including a hole may be formed. .

Next, referring to FIG. 11, the carrier copper foil pattern 130P is removed while the core layer 100P including the hole is manufactured.

Next, referring to FIG. 12, a plating process is performed on the core layer 100P including the holes to form a copper plating layer 140 connecting the upper copper foil pattern 120P and the lower copper foil 125.

13, the upper circuit pattern 140P and the lower circuit pattern 125P are formed by performing an outer layer image forming process.

As a result, it is possible to form a circuit pattern of a complete form as compared to FIG. 6, it is possible to manufacture a printed circuit board including the same.

In order to examine the excellence of the laser mask opening process and the printed circuit board manufacturing method of the present invention described above, it will be described with reference to Examples and Comparative Examples as follows.

Example

After forming a 18-micrometer-thick carrier copper foil layer on the copper foil laminated substrate surface which has a 0.04 mm core layer, the laser mask open process was performed in the state which the carrier copper foil layer remained.

Comparative example

All the same conditions as in Example 1 were carried out, but the laser mask open process was performed while the carrier copper foil layer was removed.

Printed circuit board manufacturing process for each of the above Examples and Comparative Examples was carried out 10 times, and then whether or not a defect occurred was summarized as follows.

1 time Episode 2 3rd time 4 times 5 times 6th 7 times 8th 9th 10 times Example normal normal normal normal normal normal normal normal normal normal Comparative example normal normal Bad normal Bad normal Bad normal Bad Bad

As can be seen with reference to Table 1, when using the laser mask open process according to the present invention has a surface protective layer of 36㎛, no defect occurred. On the other hand, in the comparative example in which the carrier copper foil was removed, it can be seen that a defect of 50% or more occurred.

Therefore, in the method of manufacturing a printed circuit board according to the present invention, a carrier foil layer formed on a copper foil laminated substrate is used in a laser mask open process, thereby damaging the copper foil pattern in a process of removing a dry film during the DES process. Loss can solve the problem and significantly reduce the incidence of defects.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

10, 100: core layer 100P: core layer with holes
20, 25, 120, 125: copper foil 20P, 120P: copper foil pattern
25P, 125P: Lower circuit pattern 30, 35, 130, 135: Carrier foil
130P: carrier copper foil pattern 140: copper plating layer
40P, 140P Upper Circuit Pattern 50, 150: Copper Clad Substrate

Claims (8)

(a) forming copper foil on both surfaces of the core layer, and providing a copper foil laminated substrate coated with a carrier foil on the surface of the copper foil;
(b) coating a dry film on top of the carrier foil;
(c) exposing the dry film to develop a hole portion defining a core layer through area of the copper clad laminate substrate; And
(d) forming a hole exposing the core layer by a DEEP-Dtching-Strip (DES) process;
The DES process may include removing a portion of the dry film developed in step (c) to form a dry film pattern, and sequentially irradiating a laser onto the carrier foil and the copper foil using the dry film pattern as a mask to form the hole region. Forming a hole exposing the core layer of the substrate; and removing the carrier foil.
The method of claim 1,
The carrier foil is
Laser mask opening method characterized in that formed of a copper material.
The method of claim 1,
The thickness of the carrier foil
Laser mask opening method, characterized in that 15 ~ 20㎛.
The method of claim 1,
The core layer of the copper clad laminate substrate
Laser mask opening method characterized in that it has a thickness of less than 0.06mm.
The method of claim 1,
The exposure of step (c)
The laser mask opening method characterized by exposure using UV.
Preparing copper foil laminated substrates on which copper foils are formed on both surfaces of the core layer, and the carrier foil is coated on the surface of the copper foil;
Forming the carrier foil pattern and the copper foil pattern by the laser mask open method according to any one of claims 1 to 5;
Forming a hole through the core substrate of the copper foil laminated substrate using the carrier foil pattern and the copper foil pattern as a mask by using a laser drilling process;
Removing the carrier foil pattern;
Forming a copper plating layer for plating a copper layer on sidewalls of the holes; And
And patterning the copper plating layer and the lower copper foil to form a circuit pattern.
Preparing copper foil laminated substrates on which copper foils are formed on both surfaces of the core layer, and the carrier foil is coated on the surface of the copper foil;
Forming the carrier foil pattern and the copper foil pattern by the laser mask open method according to any one of claims 1 to 5;
Removing the carrier foil pattern;
Forming a hole through the core substrate of the copper-clad laminate using the copper foil pattern as a mask using a laser drilling process;
Forming a copper plating layer for plating a copper layer on sidewalls of the holes; And
And patterning the copper plating layer and the lower copper foil to form a circuit pattern.
The method of claim 6,
The copper plating layer forming step
And a copper foil pattern formed on the copper foil laminated substrate surface and the copper foil formed on the opposite surface thereof are connected to each other.

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