KR100940169B1 - Method for manufacturing a printed circuit board by foriming a hardening resin layer - Google Patents

Abstract

The present invention discloses a method of manufacturing a printed circuit board to form a cured resin layer.

A printed circuit board manufacturing method according to the present invention comprises the steps of: (A) forming a cured resin layer on the upper surface of the insulating layer of the base substrate having an insulating layer; (B) forming a protrusion pattern on the cured resin layer; (C) pressing the protruding pattern to impregnate the insulating layer; (D) removing the protrusion pattern to form an intaglio pattern; (E) curing the insulating layer; And (F) filling the inside of the intaglio pattern with a conductive material to form a circuit pattern. According to the present invention, since the cured resin layer is formed on the insulating layer, there is an advantage that the photosensitive resist can be stably bonded to the upper part of the insulating layer.

Printed circuit board, cured resin layer, thermosetting resin, photocurable resin

Description

Method for manufacturing a printed circuit board by foriming a hardening resin layer

The present invention relates to a method of manufacturing a printed circuit board, and in particular, the present invention relates to a method of manufacturing a printed circuit board to form a cured resin layer.

Recently, as the weight reduction, miniaturization, thinning, and high performance of mobile electronic devices such as mobile phones and digital cameras are rapidly progressing, and as the speed and density of LSI packages are required, the density of build-up substrates is required. Currently, flip chip substrates use a semi-additive process (SAP) method for circuit formation in order to increase wiring density of the substrate. However, in order to conveniently form microcircuits, studies on methods other than the SAP method are being conducted.

However, as shown in FIG. 1, in the conventional method of manufacturing a multilayer printed circuit board using the SAP method, as the circuit becomes finer, the insulating layer 112 and the surface etching for flash etching and roughness formation after dry film removal are formed. An undercut 113 is formed in which the lower portion of the contacting circuit pattern 111 is eroded, thereby degrading signal transmission and lowering reliability.

In order to solve such a problem, a technique for forming a circuit by forming a trench in an insulating layer and filling a conductor in the trench by an imprint method and a laser processing process has been recently studied.

However, the imprint method is expensive and there is a lot of difficulty in separating the mold from the insulating layer after the transfer of the mold. In addition, in order to harden while pressing the resin into the mold, there is a problem that the press takes a lot of time and the productivity is low. And the laser process has the problem that the equipment itself is not only expensive but also requires an expensive aluminum mask or dielectric mask to form a circuit.

Korea Patent Registration No. 761706 is a printed circuit formed by patterning a photosensitive resist on the top of an insulating layer in the same pattern as the final circuit pattern and pressing it to impregnate the insulating layer to form micro grooves and plate the inside of the micro grooves to form a circuit pattern. A manufacturing method is disclosed. According to this, since the circuit pattern is wrapped in the insulating layer, there is a small probability that undercut occurs.

However, according to Korean Patent Registration No. 761706, a circuit pattern must be impregnated into the insulating layer, and thus a process of stacking and patterning the photosensitive resist should be performed on the insulating layer in a softened state. However, since the insulating layer is in a soft state, there is a problem in that adhesion to the photosensitive resist is inferior and a circuit pattern formed is unstable.

The present invention has been made to solve the problems of the prior art as described above, and provides a method of manufacturing a printed circuit board in which peeling does not occur because a circuit pattern is impregnated into an insulating layer.

In addition, the present invention provides a method of manufacturing a highly reliable printed circuit board to form a cured resin layer on top of the insulating layer to stably attach the photosensitive resist on the insulating layer.

A printed circuit board manufacturing method according to the present invention comprises the steps of: (A) forming a cured resin layer on the upper surface of the insulating layer of the base substrate having an insulating layer; (B) forming a protrusion pattern on the cured resin layer; (C) pressing the protruding pattern to impregnate the insulating layer; (D) removing the protrusion pattern to form an intaglio pattern; (E) curing the insulating layer; And (F) filling the inside of the intaglio pattern with a conductive material to form a circuit pattern.

As a preferable feature of the present invention, the insulating layer is made of a thermosetting resin, and in the step (A), the cured resin layer is formed by applying heat to the upper surface of the insulating layer.

In another preferred aspect of the present invention, the insulating layer is made of a thermosetting resin, and in the step (A), the cured resin layer is formed by irradiating light after forming a photocurable resin layer on the upper surface of the insulating layer. It is formed by.

As another preferable feature of the present invention, in the step (A), the cured resin layer is formed by laminating a cured resin layer on the upper surface of the insulating layer using a carrier.

As another preferred feature of the invention, the step (B), (B-1) the step of laminating a dry film on the upper surface of the cured resin layer; And (B-2) forming the protruding pattern by partially removing the dry film by an exposure and development process.

As another preferable feature of the present invention, there is further included a step of removing the cured resin layer (G) between the step (D) and the step (E).

As another preferred feature of the invention, the step (F), (F-1) the step of laminating the seed layer on the surface of the intaglio pattern; And (F-2) filling plating the intaglio pattern by electroplating.

As another preferable feature of the present invention, the cured resin layer has a thickness of 1 to 3 µm.

As another preferable feature of the present invention, in the step (C), the insulating layer is in a soft state.

In another preferred embodiment of the present invention, the heat is applied to the surface of the insulating layer in such a manner as to contact the insulating layer, and the thickness of the cured resin layer is controlled by adjusting the time that the heating plate contacts the insulating layer. It is in doing it.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, the terms or words used in this specification and claims are not to be interpreted in a conventional and dictionary sense, and the inventors may appropriately define the concept of terms in order to best describe their own invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

According to the present invention, the circuit pattern of the printed circuit board is impregnated in the insulating layer, there is an advantage that the separation of the circuit pattern does not occur.

Further, according to the present invention, since the cured resin layer is formed on the insulating layer, there is an advantage that the photosensitive resist can be stably bonded to the upper part of the insulating layer.

Hereinafter, a preferred embodiment of a method of manufacturing a printed circuit board according to the present invention will be described in detail with reference to the accompanying drawings. Throughout the accompanying drawings, the same or corresponding components are referred to by the same reference numerals, and redundant descriptions are omitted.

2 is a diagram illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention in a process order. 3 is a view illustrating an embodiment in which some processes are added to the embodiment shown in FIG. 2.

First, as shown in FIG. 2A, a base substrate 10 having an inner circuit pattern 13 is provided. Although the inner circuit pattern 13 is illustrated as being formed on one surface of the base substrate 10 in the present embodiment, it may be formed on both sides, and the inner circuit pattern 13 may not be formed. In addition, the base substrate 10 may be a multilayer printed circuit board formed by stacking a plurality of insulating layers and a plurality of circuit layers.

As shown in FIG. 2B, an insulating layer 30 is formed on the base substrate 10. In this embodiment, the insulating layer 30 is made of a thermosetting resin, and the insulating layer 30 is heated to a softening temperature and laminated on at least one surface of the base substrate 10. Of course, the insulating layer 30 may be laminated on both sides of the base substrate 10 as necessary. Generally, since the thermosetting resin to be laminated is cured at about 180 ° C., when the insulating layer 30 made of the thermosetting resin is laminated, the thermosetting resin is heated while maintaining about 100 ° C., and the insulating layer 30 is not removed even after the lamination is completed. Leave to hardened state. This is to allow the external circuit pattern to be transferred to the insulating layer 30 later.

The insulating layer 30 may be made of a composition in which one or more thermosetting resins are mixed. The thermosetting resin composition consists of a composition in which resins such as an epoxy resin, a cyanic acid ester resin, a bismaleimide resin, a polyimide resin, and a functional group-containing polyphenylene ether resin are used alone or in combination of two or more thereof. Various additives can be added to a thermosetting resin composition. For example, various additives such as thermoplastic resins, organic fillers, inorganic fillers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, glossing agents, polymerization initiators, etc. are added according to the purpose and use. In addition, a flame retardant, flame retardant with bromine, non-halogen (non-halogen) type of flame retardant can be used, and non-flame retardant can also be used. The thermosetting resin composition is cured by heating itself, but a curing agent or a thermosetting catalyst may be added to the thermosetting resin composition in order to increase the curing rate and improve productivity.

Thereafter, as shown in FIG. 2C, the high temperature heating plate 53 is brought into contact with the upper surface of the insulating layer 30 to form the cured resin layer 50.

As described above, since the insulating layer 30 made of the thermosetting resin starts to harden at 180 ° C or higher, the temperature of the heating plate 53 should be 180 ° C or higher. The heating plate 53 is a plate member which consists of metal preferably. As will be described below, since the cured resin layer 50 should be easily broken by the press, it is preferable that the thickness t is thinly formed, for example, about 1-3 mu m. The thickness t of the cured resin layer 50 formed can be controlled by adjusting the time for which the heating plate 53 is in contact with the insulating layer 30. That is, when the heating plate 53 is in contact with the insulating layer 30 for a long time, the thickness t of the cured resin layer 50 is formed thick.

Thereafter, as shown in FIG. 2D, a photoresist is applied on the cured resin layer 50 and exposed and developed to form a protruding pattern 73. At this time, although the insulating layer 30 is in an uncured state, since the cured resin layer 50 is in a cured state, the protruding pattern 73 may be firmly attached to the upper portion of the insulating layer 30. The protruding pattern 73 has the same pattern as the circuit pattern 77 (refer to FIG. 2H) to be formed in a later process, and is removed by a process to be described later to form a groove corresponding to the circuit pattern 77. The position of the protrusion pattern 73 relative to the inner circuit pattern 13 may be important in the process of manufacturing the protrusion pattern 73, which will be described below with reference to FIG. 3. Therefore, when the protrusion pattern 73 is formed, the reference position is set in the inner circuit pattern 13, and then the protrusion is observed while observing the relative positions of the protrusion pattern 73 and the inner circuit pattern 13 using a back light. The position of the pattern 73 is precisely adjusted.

Next, as shown in FIG. 2E, the protruding pattern 73 is transferred to the insulating layer 30 using the press plate 90.

The protruding pattern 73 is buried inside the insulating layer 30 by pressing the insulating layer 30 in a vacuum state using a press plate 90 such as a stainless plate having a flat surface while heating the insulating layer 30 to a softening temperature or more. Be sure to As a result, only one surface of the protruding pattern 73 is exposed to the outside, and the other surface is surrounded by the insulating layer 30. Thereafter, the press plate 90 is removed. In the method of manufacturing a printed circuit board according to the present embodiment, since the surface is pressed by the flat press plate 90, the pressure is evenly transmitted to the insulating layer 30, thereby preventing warping or warping of the entire substrate. And since it pressurizes in a vacuum state, foam | bubble etc. do not generate | occur | produce in the insulating layer 30 etc.

Thereafter, as shown in FIG. 2F, the protruding pattern 73 impregnated in the insulating layer 30 is removed. The protruding pattern 73 embedded in the insulating layer 30 is removed by melting or swelling peeling. Usually, although sodium hydroxide solution is used for peeling of a photosensitive photoresist, when peeling is difficult by heating, an amine peeling agent or a solvent can also be used. When the protruding pattern 73 is removed, an intaglio pattern 75 corresponding to the circuit pattern 77 is formed.

Next, as shown in FIG. 2G, the cured resin layer 50 is removed and the insulating layer 30 is cured. Here, it will be understood that subsequent processes may be performed without removing the cured resin layer 50.

Then, as shown in FIG. 2H, when the insulating layer 30 is cured, metal plating is performed on the intaglio pattern 75, and if necessary, a portion of the plating layer is removed to smooth the surface of the substrate. Preferably, copper plating is performed to fill the intaglio pattern 75 to form the circuit pattern 77. It is possible to form a seed layer inside the intaglio pattern by an electroless plating method, and to fill the intaglio pattern by electroplating. The circuit pattern 77 may be exposed to the outside so as to be electrically connected to a passive element such as a resistor, a capacitor, or the like, or an active element such as an IC. In addition, another circuit layer may be stacked on the circuit pattern 77.

In addition to the plating, the conductive pattern may be filled in the intaglio pattern 75 using a mask to form the circuit pattern 77. The conductive paste is preferably a paste containing a powder of silver and copper. In addition to the above method, a method of filling a conductive material in the intaglio pattern 75 is various, and is not limited to this embodiment.

3 illustrates an embodiment in which a via hole 75 ′ penetrating through the insulating layer 30 is formed after the step of removing the cured resin layer 50 described with reference to FIG. 2G.

As shown in FIG. 3G, a via hole 75 ′ connected to the inner circuit pattern 13 may be formed in the intaglio pattern 75. This is why the inner circuit pattern 13 should be considered when forming the protruding pattern 73. A via hole 75 'is formed to connect to the inner circuit pattern 13 of the base substrate 10 by using a laser drill or a CNC (Computer Numerical Control) drill. If a CNC drill is used, the desmear process and the deburring process may be further performed. After the via hole 75 'is formed, the insulating layer 30 made of a thermosetting resin is cured.

As shown in FIG. 3H, when plating is performed on the intaglio pattern 75 including the through hole 75 ′, a via 77 ′ conducting the inner circuit pattern 13 is formed.

4 is a diagram illustrating a method of manufacturing a printed circuit board according to another embodiment of the present invention in order of process. The description overlapping with the above-described embodiment is omitted here.

As shown in FIG. 4A, a base substrate 10 having an inner circuit pattern 13 having an insulating layer 30 is provided.

As shown in FIG. 4B, the photocurable resin layer 55 is formed on the upper surface of the insulating layer 30. The photocurable resin is a resin cured by light irradiation, and may be, for example, a photocurable dry film. The dry film is laminated on the insulating layer 30 using a laminator. It is preferable that the thickness of a dry film is about 1-3 micrometers so that thickness t of the cured resin layer 50 may be set to about 1-3 micrometers as mentioned above.

Thereafter, as shown in FIG. 4C, light (A; ultraviolet ray) is irradiated and cured on the photocurable resin layer 55 to form a cured resin layer 50.

Next, as shown in FIG. 4D, the photosensitive resist is laminated on the cured resin layer 50, exposed and developed to form the protruding pattern 73. The process is the same as in the above-described embodiment.

5 is a diagram illustrating a method of manufacturing a printed circuit board according to still another embodiment of the present invention in the order of process. The description overlapping with the above-described embodiment is omitted here.

As shown in FIG. 5A, a cured resin layer 50 bonded to a carrier 57 and a base substrate 10 having an inner circuit pattern 13 having an insulating layer 30 formed thereon is provided. The cured resin layer 50 of the present embodiment may be made of a thermosetting resin or a photocurable resin, and laminated on the carrier 57 using a laminator.

Thereafter, as illustrated in FIG. 5B, the cured resin layer 50 is laminated on the upper surface of the insulating layer 30 using the carrier 57. 5C is a diagram illustrating a state in which the cured resin layer 50 is laminated on the insulating layer 30.

Next, as shown in FIG. 5D, the photosensitive resist is laminated on the cured resin layer 50, exposed and developed to form the protruding pattern 73. The process is the same as in the above-described embodiment.

On the other hand, the present invention is not limited to the described embodiments, it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or variations will have to belong to the claims of the present invention.

1 is a cross-sectional view illustrating a circuit pattern in which an uncut is generated according to a conventional semiadditive method.

Figure 2 is a process diagram of a printed circuit board manufacturing method according to an embodiment of the present invention to form a cured resin layer with a heating plate.

3 is a flowchart illustrating a case where a circuit pattern of the embodiment illustrated in FIG. 2 includes a via hole.

Figure 4 is a process diagram of a printed circuit board manufacturing method according to another embodiment of the present invention to form a cured resin layer using a photocurable resin.

5 is a process diagram of a method of manufacturing a printed circuit board according to another embodiment of the present invention in which a cured resin layer is formed using a carrier.

<Description of Major Symbols in Drawing>

10 Base Board 13 Inner Circuit Pattern

30 insulation layer 50 cured resin layer

53 Heating Plate 55 Photocurable Resin Layer

57 Carrier 73 Extrusion Pattern

75 Engraved Pattern 77 Circuit Pattern

90 press plates

Claims (10)

(A) forming a cured resin layer on the upper surface of the insulating layer of the base substrate having the insulating layer in the semi-cured state; (B) forming a protrusion pattern on the cured resin layer; (C) pressing the protruding pattern to impregnate the insulating layer; (D) removing the protrusion pattern to form an intaglio pattern; (E) curing the insulating layer; And (F) a method of manufacturing a printed circuit board, including forming a circuit pattern by filling an inside of the intaglio pattern with a conductive material. The method of claim 1, The insulating layer is made of a thermosetting resin, and in the step (A), the cured resin layer is formed by applying heat to the upper surface of the insulating layer. The method of claim 1, The insulating layer is made of a thermosetting resin, and in the step (A), the cured resin layer is formed by forming a photocurable resin layer on the upper surface of the insulating layer and then irradiating light. . The method of claim 1, In the step (A), the cured resin layer is formed by laminating a cured resin layer on the upper surface of the insulating layer using a carrier. The method of claim 1, Step (B) is, (B-1) laminating a dry film on the upper surface of the cured resin layer; (B-2) A method of manufacturing a printed circuit board comprising the step of forming the protrusion pattern by partially removing the dry film by an exposure and development process. The method of claim 1, Between (D) and (E), the method of manufacturing a printed circuit board further comprising the step of (G) removing the cured resin layer. The method of claim 1, Step (F) is, (F-1) stacking a seed layer on a surface of the intaglio pattern; (F-2) A method of manufacturing a printed circuit board comprising the step of fill plating the intaglio pattern by electroplating. The method of claim 1, The thickness of the cured resin layer is a manufacturing method of a printed circuit board 1 to 3㎛. The method of claim 1, In the step (C), the insulating layer is a manufacturing method of a printed circuit board softened. The method of claim 2, And heating the surface of the insulating layer in such a manner that the heating plate is in contact with the insulating layer, and controlling the thickness of the cured resin layer by controlling the time that the heating plate contacts the insulating layer.

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