KR102458201B1 - Method for manufacturing circuit board and circuit board manufactured by the method - Google Patents

Abstract

A method for manufacturing a printed circuit board that minimizes dielectric loss due to high-frequency signals and prevents loss of high-frequency signals by laminating a plurality of base sheets on which an adhesive layer and a heat-resistant layer are formed on a rigid film having a low dielectric constant, and manufactured by the method A printed circuit board is presented. The suggested printed circuit board manufacturing method includes the steps of preparing a base sheet, laminating a plurality of base sheets, and bonding the laminate on which the plurality of base sheets are stacked by heat pressing, and preparing the base sheet includes: Forming an adhesive layer on one surface of the rigid polypropylene film, forming a thin heat-resistant layer on the other surface of the rigid polypropylene film, and forming an electrode unit on one surface of the thin-film heat-resistant layer.

Description

Printed circuit board manufacturing method and printed circuit board manufactured thereby

The present invention relates to a method of manufacturing a printed circuit board and a printed circuit board manufactured by the method, and more particularly, to a method of manufacturing a printed circuit board used as a circuit using a high frequency, and a printed circuit board manufactured by the method.

In general, a printed circuit board is a board that can be flexibly bent by forming a circuit pattern on a thin insulating film, and is widely used in portable electronic devices and automation devices or display products that require bending and flexibility when mounted.

In general, a printed circuit board is manufactured by bonding or die-casting a copper foil to a polyimide (PI) film. At this time, since the polyimide film has characteristics such as high mechanical strength, heat resistance, insulation and solvent resistance, it is often used as a base material for printed circuit boards.

On the other hand, as the use of services that transmit large-capacity information in real time, such as video calls, movie viewing, and real-time broadcasting, increases, portable terminals are equipped with circuits for transmitting large-capacity information using high-frequency bands (eg, GHz). is being mounted

However, when a high-frequency signal is transmitted using a printed circuit board made of a polyimide film, there is a problem in that a signal loss of the high-frequency signal occurs due to an inherent dielectric loss of the material.

In other words, since the polyimide film has a high dielectric constant, dielectric loss occurs during transmission and reception of high-frequency signals, resulting in loss of high-frequency signals, resulting in interruptions in the use of services such as video calls, movie viewing, and real-time broadcasting. have.

In addition, a printed circuit board made of a film having a low dielectric constant can minimize the loss of high-frequency signals, but since the heat resistance is lowered due to the low melting temperature, the SMT (Surface Mounter Technology) process for mounting high-frequency devices There is a problem in that the surface is melted by a high temperature of about 250° C. and a defect occurs.

In addition, since the film having a low dielectric constant and high heat resistance is formed at a high price, there is a problem in that the manufacturing cost of the printed circuit board increases, thereby losing competitiveness in the market.

Korean Patent Laid-Open Patent No. 10-2016-0097948 (Title: Flexible printed circuit board and manufacturing method thereof)

The present invention has been proposed in view of the above circumstances, and by laminating a plurality of base sheets on which an adhesive layer and a heat-resistant layer are formed on a rigid film having a low dielectric constant, the dielectric loss due to the high-frequency signal is minimized, and the loss of the high-frequency signal is reduced. An object of the present invention is to provide a printed circuit board manufacturing method and a printed circuit board manufactured thereby.

That is, the present invention forms a base sheet by forming an adhesive layer and a heat resistance layer on polypropylene (PP) having a low dielectric constant, and by stacking a plurality of base sheets to minimize dielectric loss due to high frequency signals, An object of the present invention is to provide a method for manufacturing a printed circuit board to prevent loss, and a printed circuit board manufactured by the method.

In order to achieve the above object, the method for manufacturing a printed circuit board according to an embodiment of the present invention includes the steps of preparing a base sheet, laminating a plurality of base sheets, and heat-pressing a laminate in which a plurality of base sheets are laminated to adhere to each other. and preparing the base sheet includes forming an adhesive layer on one surface of the rigid polypropylene film, forming a thin heat-resistant layer on the other surface of the rigid polypropylene film, and forming an electrode part on one surface of the thin-film heat-resistant layer including the steps of In this case, the rigid polypropylene film may be a CPP (Casted polypropylene) film.

Preparing the base sheet may further include forming a corona layer on the other surface of the rigid polypropylene film before the step of forming the thin heat-resistant layer.

Forming the electrode part includes forming a thin film seed layer on one surface of the thin heat resistant layer, forming a plating layer on one surface of the thin film seed layer, and etching the thin film seed layer and at least a portion of the plating layer to form an electrode part. can do.

The forming of the thin heat resistant layer may include coating a liquid polyimide on one side of the corona layer formed on one side of the rigid polypropylene film to form a thin heat resistant layer.

In the step of forming the adhesive layer, an adhesive layer, which is a composite material in which polypropylene and an additive are mixed, may be formed. In this case, the additive may be acrylate.

The method may further include forming one or more through-holes penetrating the bonded laminate in the bonding step, and forming a connection plating layer on the surface of the through-hole and upper and lower surfaces of the laminate.

The step of forming the connecting plating layer includes forming a first connecting plating layer on the surface of the through hole and the upper and lower surfaces of the laminate through electroless plating, and forming a second connecting plating layer on the surface of the first connecting plating layer through electroless plating. may include steps.

The method of manufacturing a printed circuit board according to an embodiment of the present invention may further include forming a circuit pattern on at least one surface of the laminate by etching a portion of the connection plating layer.

In the bonding step, it may be heated above the melting temperature of the adhesive layer formed at the bottom of the base sheet.

In order to achieve the above object, the printed circuit board manufactured by the printed circuit board manufacturing method according to the embodiment of the present invention is a printed circuit board manufactured by the above-described printed circuit board manufacturing method, and a plurality of base sheets having rigidity comprises a laminated body and a circuit pattern formed on the upper surface of the laminate, and the base sheet includes a rigid polypropylene film, an adhesive layer formed on the lower surface of the rigid polypropylene film, a heat-resistant layer formed on the upper surface of the rigid polypropylene film, and a heat-resistant layer It may include an electrode part formed on the upper surface. In this case, the rigid polypropylene film may be a CPP (Casted polypropylene) film.

The base sheet may further include a corona layer interposed between the rigid polypropylene film and the electrode part.

The heat-resistant layer may be polyimide.

The printed circuit board according to an embodiment of the present invention may further include a through-hole that passes through the laminate and connects the electrode part formed inside the laminate and the electrode part formed on the upper surface of the laminate.

The electrode unit may include a thin film seed layer formed on the heat-resistant layer, a plating layer formed on the upper surface of the thin film seed layer, and a connection plating layer formed on the plating layer. In this case, the connection plating layer may be formed on the upper surface of the plating layer, one side of the thin film seed layer, and the inner wall of the through hole penetrating the laminate, and the first connection formed on the upper surface of the plating layer, one side of the thin film seed layer, and the inner wall of the through hole. It may include a second connection plating layer formed on the surface of the plating layer and the first connection plating layer.

According to the present invention, a method for manufacturing a printed circuit board and a printed circuit board manufactured thereby can minimize dielectric loss due to high frequency signals and prevent loss of high frequency signals by stacking a plurality of base sheets having a low dielectric constant. It works.

In addition, the printed circuit board manufacturing method and the printed circuit board manufactured thereby form a low dielectric constant compared to the conventional printed circuit board constituting the base sheet with polyimide by forming a base sheet using a rigid polypropylene film to form a dielectric There is an effect that it is possible to manufacture a hard-type printed circuit board having mechanical strength while minimizing loss.

In addition, the printed circuit board manufacturing method and the printed circuit board manufactured by the method have an effect of forming a heat-resistant layer on the base sheet, thereby manufacturing a printed circuit board having a low dielectric constant and high heat resistance.

1 to 3 are views for explaining a printed circuit board manufacturing method according to an embodiment of the present invention.
4 and 5 are views for explaining the step of preparing the base sheet of FIG.
6 is a view for explaining the step of plating the connection plating layer of FIG.
7 is a view for explaining a printed circuit board according to an embodiment of the present invention.

Hereinafter, the most preferred embodiment of the present invention will be described with reference to the accompanying drawings in order to describe in detail enough that a person of ordinary skill in the art can easily implement the technical idea of the present invention. . First, in adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 to 3, the printed circuit board manufacturing method includes the steps of preparing a base sheet 100 (S100), laminating a plurality of base sheets 100 (S200), a hot pressing step (S300), Forming the through-hole 200 ( S400 ), plating the connection plating layer 300 ( S500 ), and forming a circuit pattern ( S600 ) are included.

4 and 5, the step of preparing the base sheet 100 (S100) is a step of preparing the rigid polypropylene film 110 (hereinafter, the rigid PP film 110) (S110), the rigid The step of forming the adhesive layer 120 on the lower surface of the PP film 110 (S120), the step of forming the corona layer 130 on the upper surface of the rigid PP film 110 (S130), the thin film on the corona layer 130 Forming the heat-resistant layer 140 (S140), forming the thin-film seed layer 150 on the thin-film heat-resistant layer 140 (S150), forming the plating layer 160 on the thin-film seed layer 150 Step S160 , and etching the thin film seed layer 150 and the plating layer 160 to form an electrode part ( S170 ).

In the step of preparing the rigid polypropylene film 120 ( S110 ), a rigid PP film 110 having a low dielectric constant that is a dielectric loss is prepared. At this time, the rigid PP film 110 may be composed of a CPP (casted polypropylene) film having a predetermined mechanical strength or a CPP film to which nylon (Nylon) is added, and is formed to a thickness of about 30 μm.

In the step of forming the adhesive layer 120 ( S120 ), an adhesive layer 120 for adhesion with another base sheet 100 is formed on the lower surface of the rigid PP film 110 . That is, the adhesive layer 120 is formed of a composite material in which the same material (ie, polyimide) as the rigid PP film 110 (ie, polyimide) and an additive (eg, acrylate, etc.) are mixed in order to increase the adhesive force between the polymer and the metal. do.

To explain this in detail, since the printed circuit board is configured by stacking a plurality of base sheets 100 , the adhesive layer 120 is an electrode part exposed on the upper surface of another base sheet 100 (that is, copper, which is a metal material). and a thin heat-resistant layer 140 (ie, polyimide made of a polymer material).

Accordingly, the adhesive layer 120 is formed of a composite material in which additives such as polyimide and acrylate are mixed in order to increase adhesion between the metal electrode part and the polymer material thin heat-resistant layer 140 .

In the step of forming the corona layer 130 ( S130 ), the corona layer 130 is formed on one surface (ie, the upper surface) of the rigid PP film 110 . That is, in the step of forming the corona layer 130 ( S130 ), the corona layer 130 is formed on one surface of the rigid PP film 110 through corona treatment to facilitate coating of the thin heat-resistant layer 140 .

In the step of forming the thin-film heat-resistant layer 140 ( S140 ), the thin-film heat-resistant layer 140 is formed on one surface (ie, the upper surface) of the corona layer 130 . That is, the step of forming the thin heat-resistant layer 140 ( S140 ) is performed in order to improve the heat resistance of the printed circuit board and the deposition properties of the electrode part (ie, the thin-film seed layer 150 and the plating layer 160 ). ) to form a thin heat-resistant layer 140 on one surface.

In the step of forming the thin-film heat-resistant layer 140 ( S140 ), a polyimide liquid is coated on the upper surface of the corona layer 130 through a gravure process, etc. to form the thin-film heat-resistant layer 140 . In this case, the thin-film heat-resistant layer 140 is formed to a thickness of about 1 μm. In the thin film heat resistant layer 140, polyimide has a high dielectric constant with a high dielectric loss, but as it is formed as a thin film, the effect on the overall dielectric constant of the base substrate is insignificant, so the base substrate can form a low dielectric constant with low dielectric loss. .

In the step of forming the thin film seed layer 150 ( S150 ), the thin film seed layer 150 is formed on one surface of the thin heat resistant layer 140 . That is, the step of forming the thin film seed layer 150 ( S150 ) is a mixed material obtained by mixing nickel-copper (NiCu) and copper (Cu) on the upper surface of the thin-film heat-resistant layer 140 through a deposition process or a sputtering process. Alternatively, the thin film seed layer 150 made of nickel copper (NiCu) is formed.

In the step of forming the plating layer 160 ( S160 ), the plating layer 160 is formed on the thin film seed layer 150 . In this case, in the step of forming the plating layer 160 ( S160 ), the plating layer 160 is formed on the thin film seed layer 150 by electroplating copper (Cu). In this case, the thin film seed layer 150 and the plating layer 160 are elements constituting the electrode part, and are formed to a thickness of about 5 μm.

In the forming of the electrode part, an electrode part is formed on the heat-resistant layer 140 by removing a portion of the thin film seed layer 150 and the plating layer 160 through an etching (etching) process.

In the above description, in this case, the step (S120) of forming the adhesive layer 120 has been described as being performed first, but it may be performed simultaneously with the step of forming the heat-resistant layer 140 or may be performed after forming the electrode part, each It can also be performed in the middle of a step.

In the step of stacking the plurality of base sheets 100 ( S200 ), the plurality of base sheets 100 prepared in step S100 are stacked. In this case, in the step of stacking the plurality of base sheets 100 ( S200 ), the plurality of base sheets 100 are stacked so that the electrode parts are aligned through an alignment process.

In the hot pressing step (S300), the plurality of base sheets 100 are adhered (compressed) to each other by applying heat and pressure in a stacked state. At this time, in the hot pressing step (S300), the plurality of base sheets 100 are adhered (compressed) by heating and simultaneously pressing heat above the melting temperature of the adhesive layer 120 corresponding to the lower surface of the base sheet 100 .

Here, since the polyimide composite material constituting the adhesive layer 120 has a melting temperature of about 165° C. or higher, the hot press step (S300) is pressurized while heating heat of about 165° C. or higher.

Accordingly, in the hot pressing step (S300), only the adhesive layer 120 of the base sheet 100 is melted or a portion of the lower surface of the rigid PP film 110 and the adhesive layer 120 are melted and exposed to the top of the other base sheet 100. It adheres to the heat-resistant layer 140 and the electrode part.

At this time, when a material having a low resin flow is used as the adhesive layer 120 , since the space formed between the electrode part and the heat-resistant layer 140 is not filled with the adhesive layer 120 , the adhesive layer 120 is constant. It is preferably formed of a material having the above resin flow.

In the step of forming the through-hole 200 ( S400 ), one or more through-holes 200 passing through the laminate in which the plurality of base sheets 100 are stacked are formed. That is, the step of forming the through hole 200 ( S400 ) is one for electrically connecting (ie, energizing) the electrode parts formed inside the laminate and the electrode parts formed outside the laminate through punching in the laminate. The above through hole 200 is formed.

In the step of plating the connection plating layer 300 ( S500 ), the connection plating layer 300 is applied to the through hole 200 and the upper surface of the base sheet 100 stacked on the top (that is, the electrode part and the thin-film heat-resistant layer 140 ). plated That is, in the step of plating the connection plating layer 300 ( S500 ), the connection plating layer 300 for electrically connecting (ie, conducting) the electrode parts formed inside the laminate and the electrode parts formed outside the stack through the through hole 200 . ) is plated.

Referring to FIG. 6 , the plating of the connection plating layer 300 ( S500 ) may include plating the first connection plating layer 320 and plating the second connection plating layer 340 .

The plating of the first connection plating layer 320 includes the through-hole 200 in order to electrically connect (ie, form conductivity) the electrode parts formed inside the laminate and the electrode parts formed outside the laminate through electroless chemical copper plating. The first connection plating layer 320 is formed by plating copper on the inner wall and the upper surface of the base sheet 100 stacked on the top.

In the plating of the second connection plating layer 340 , the second connection plating layer 340 is formed on the surface of the first connection plating layer 320 through electrolytic copper plating. Through this, the second connection plating layer 340 reinforces the electrical connection (ie, conductivity) of the first connection plating layer 320 .

In the step of forming the circuit pattern ( S600 ), a circuit pattern is formed on the upper surface of the printed circuit board by etching a portion of the connection plating layer 300 . That is, in the step of forming the circuit pattern ( S600 ), a part of the connection plating layer 300 is removed through a masking process and an etching process to form a circuit pattern.

Meanwhile, the method of manufacturing a printed circuit board may further include forming a protective layer on the printed circuit board on which the circuit pattern is formed.

In the step of forming the protective layer, the coating solution is applied to the surface of the heat-resistant layer 140 of the base sheet 100 stacked on top of the circuit pattern and then cured to cover and protect the circuit pattern and the heat-resistant layer 140 surface. to form

At this time, the protective layer is composed of a coating solution of the same series as that of the heat-resistant layer 140 of the base sheet 100 (eg, a composite material including polyimide), so that the adhesion between the heat-resistant layer 140 and the circuit pattern is reduced. It is preferable to be more firmly integrated with the heat-resistant layer 140 and the circuit pattern.

In addition, the printed circuit board manufacturing method may further include the step of forming the electrode portion (S170). In this case, in the step of forming the electrode part ( S170 ), after removing a part of the protective layer, the electrode part may be formed by plating a conductive material such as copper on the corresponding area.

Referring to FIG. 7 , the printed circuit board manufactured by the printed circuit board manufacturing method includes a laminate in which a plurality of base sheets 100 are laminated and then laminated, and a circuit pattern formed on the upper surface of the laminate.

As the laminate is configured by stacking a plurality of base sheets 100, the adhesive layer 120, the rigid PP film 110 formed on the adhesive layer, the corona layer 130 formed on the rigid PP film 110, The heat-resistant layer 140 formed on the corona layer 130 and the electrode portion formed on the heat-resistant layer 140 are repeatedly stacked.

The circuit pattern is composed of an electrode portion formed on the base sheet 100 stacked on the top of the stack and a connection plating layer 300 plated on the electrode portion (that is, the first connection plating layer 320 and the second connection plating layer 340). do. In this case, the circuit pattern is electrically connected (ie, energized) with the electrode part formed inside the laminate through the connection plating layer 300 formed on the inner wall of the via hole.

According to the above-described configuration, the printed circuit board is composed of a low dielectric constant substrate with low dielectric loss, and since the base sheet 100 includes the rigid PP film 110 , a hard type substrate having a predetermined mechanical strength. is composed of

The printed circuit board is formed by forming the adhesive layer 120 of a composite material containing an additive (eg, acrylate) in polypropylene, and forming a plating layer 160 (that is, a thin film seed layer 150) for constituting an electrode part or a circuit pattern. ) and the inner plating layer 160) can be smoothly deposited.

As described above, the method for manufacturing a printed circuit board and the printed circuit board manufactured by the method can minimize dielectric loss due to high frequency signals and prevent loss of high frequency signals by stacking a plurality of base sheets having a low dielectric constant. It works.

In addition, the printed circuit board manufacturing method and the printed circuit board manufactured thereby form a low dielectric constant compared to the conventional printed circuit board constituting the base sheet with polyimide by forming a base sheet using a rigid polypropylene film to form a dielectric There is an effect that it is possible to manufacture a hard-type printed circuit board having mechanical strength while minimizing loss.

In addition, the printed circuit board manufacturing method and the printed circuit board manufactured by the method have an effect of forming a heat-resistant layer on the base sheet, thereby manufacturing a printed circuit board having a low dielectric constant and high heat resistance.

Although the preferred embodiment according to the present invention has been described above, it can be modified in various forms, and those of ordinary skill in the art can make various modifications and modifications without departing from the claims of the present invention. It is understood that it can be implemented.

100: base sheet 110: rigid PP film
120: adhesive layer 130: corona layer
140: heat-resistant layer 150: thin film seed layer
160: plating layer 200: through hole
300: connection plating layer 320: first connection plating layer
340: second connection plating layer

Claims (20)

preparing a base sheet;
stacking a plurality of base sheets; and
Including the step of adhering by heating and pressing a laminate in which a plurality of base sheets are stacked,
The step of preparing the base sheet,
forming an adhesive layer on one surface of the rigid polypropylene film;
forming a thin heat-resistant layer on the other surface of the rigid polypropylene film; and
and forming an electrode part on one surface of the thin-film heat-resistant layer. According to claim 1,
The step of forming the electrode part,
forming a thin-film seed layer on one surface of the thin-film heat-resistant layer;
forming a plating layer on one surface of the thin film seed layer; and
and etching at least a portion of the thin film seed layer and the plating layer to form an electrode part. According to claim 1,
The forming of the thin heat resistant layer is a printed circuit board manufacturing method of forming a thin heat resistant layer by coating a liquid polyimide on one side of the corona layer formed on one side of the rigid polypropylene film. According to claim 1,
forming one or more through-holes penetrating the laminate bonded in the bonding step; and
and forming a connection plating layer on the surface of the through hole and on the upper and lower surfaces of the laminate. 5. The method of claim 4,
The step of forming the connection plating layer,
forming a first connection plating layer on the surface of the through hole and upper and lower surfaces of the laminate through electroless plating; and
and forming a second connection plating layer on the surface of the first connection plating layer through electroplating. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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