KR20110072666A - Printed circuit board with single-layer using bump structure and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A single layer printed circuit board and a manufacturing method thereof are provided to implement the thin flat structure of the printed circuit board, by implementing a structure of comprising an internal metal bump performing the role of a via and a solder ball junction. CONSTITUTION: An insulating layer(110) for insulating a printed circuit board is prepared. An adhesive layer(120) is formed on the top surface of the insulating layer. The adhesive layer is formed with an adhesive material. A pad hole(130) is formed. The pad hole penetrates through the insulating layer and the adhesive layer. A meal seed layer(140) is formed on the top surface of the adhesive layer and the insulating layer. A circuit pattern(160) is formed on the top of the metal seed layer.

Description

Printed circuit board with single-layer using bump structure and manufacturing method of the same}

The present invention relates to a manufacturing process of a single layer printed circuit board and a structure of the printed circuit board.

A printed circuit board (PCB) is a printed circuit board pattern formed of a conductive material such as copper on an electrically insulating substrate, and refers to a board immediately before mounting an electronic component. In other words, in order to mount many kinds of electronic components on a flat plate, it means a circuit board in which a mounting position of each component is determined and a line pattern connecting the components is printed and fixed on the flat surface. Such printed circuit boards generally include a single-layer PCB and a build-up board in which multilayered PCBs are formed, that is, multilayer PCB substrates.

A method of manufacturing a conventional single layer PCB will be described with reference to FIGS. 1A and 1B as follows. FIG. 1A is a flowchart illustrating a manufacturing process of a single-layer double-sided printed circuit board for forming a circuit on both sides of an insulating substrate, and FIG. 1B is a conceptual diagram showing a structure in which solder balls are formed on the printed circuit board.

Specifically, as in step S1, holes H are drilled to connect electrical signals to copper foils on both sides based on CCL 10 (Copper Clad Laminate) in which copper foils are laminated on both surfaces of the insulating layer. do. Next, using the electroless copper plating and electrolytic copper plating on the surface of the hole (H) and the CCL processed in step S3 to form a plating layer to electrically connect the copper foils on both sides. Thereafter, a UV photosensitive dry film for forming a circuit is coated and UV is selectively irradiated to form a circuit (S 4 step), and then a PSR (Photoimagable Solder resist) for insulation is applied. The surface to be mounted is subjected to surface treatment such as gold plating to complete the product (S 5 ~ S 6 steps).

However, the processing of the via hole in the above-described process is performed by using a fine laser drill. In this case, the via hole must be formed separately in each layer. In the case of a large-area printed circuit board, The work takes a very long time.

In addition, the plating process on the hole and the entire surface is difficult to form a uniform plating layer, and a lot of noise due to the high electrical resistance, which makes it difficult to apply such a manufacturing method in a high reliability product range. do. In particular, there is a problem in that productivity decreases due to long working hours such as hole processing and plating processes.

In particular, referring to the printed circuit board having the structure illustrated in FIG. 1B, the solder ball pad 13 connected to the circuit pattern 11 and the via 12 formed on the insulating substrate 11 and functioning as a solder ball joint surface 13 is illustrated. And a solder ball 17 bonded to the solder ball pad 13.

However, in the above-described structure, there is a limitation in miniaturization of the size of the solder ball according to the implementation of the solder ball pad 13, which acts as a barrier to the implementation of the fine pitch, and furthermore, the process of implementing the solder ball pad is added to increase the complexity of the process. There is a problem that results. In particular, the solder ball pad 13 is implemented as a structure that protrudes to the outside of the insulating layer, it is also a disadvantage that the implementation of the fine pattern is more difficult.

The present invention has been made to solve the above-described problem, an object of the present invention is to overcome the difficulties of the implementation of the fine pitch by implementing the solder ball pad in the double-sided printed circuit board using the solder ball, to remove the pad portion that serves as the solder ball pad It is possible to reduce the pitch of the solder ball, and to provide a printed circuit board and a manufacturing process having a structure having an internal metal via serving as a via and at the same time a solder ball joint.

According to one aspect of the present invention, a pad hole is formed in an insulating layer and a metal seed layer is formed on the insulating layer. Filling the pad hole with a metal material; forming a circuit pattern on the metal seed layer; and forming a circuit pattern on the metal seed layer.

In particular, in the above-described manufacturing process, the first step is to form an adhesive layer on the insulating layer and to process a pad hole to form a metal seed layer using the adhesive layer, or to perform thermal compression after the pad hole processing. It may be formed by bonding a metal seed layer on top of the insulating layer.

In addition, the metal seed layer of the first step may be formed of any one or two or more of Cu, Au, Ni, Pd, In, Ti, Sn or a polymer material exhibiting conductivity.

In addition, the metal material filling the pad hole in the second step may be any one of Cu, Ag, Sn, Au, Ni, Pd. In this case, the filling method may be any one of electroless plating, electroplating, screen printing, sputtering, evaporation, inkjetting, dispensing, or a combination thereof.

In addition, in the above-described manufacturing process, the three steps may be performed to form a circuit pattern layer including one or more material layers of Cu, Ag, Sn, Au, Ni, and Pd.

The method may further include removing a metal seed layer other than the circuit pattern after the three steps in the above-described manufacturing step, and further comprising applying a solder resist to the printed circuit board. Can be.

In addition, in the above-described manufacturing process, the method may further include forming a surface treatment layer on at least one of the exposed surface of the metal material filling the pad hole or the circuit pattern surface. In this case, the surface treatment layer may be formed using a single layer or any one of Cu, Ni, Pd, Au, Sn, Ag, Co, binary, or raw alloys thereof on at least one of the exposed surface or the circuit pattern surface. It can be formed by plating in multiple layers.

The printed circuit board by the above-described manufacturing process can be formed by having the following structure.

Specifically, the circuit pattern formed on the insulating layer; A metal bump penetrating the insulating layer and directly connected to the circuit pattern; The surface of the other end not connected to the circuit pattern of the metal bump may have a structure exposed to the surface of the insulating layer.

Particularly, in the above-described structure, the adhesive layer formed on the surface of the insulating layer except for the connection portion between the metal bump and the circuit pattern may be further formed between the circuit pattern and the insulating layer.

In particular, in the above-described structure, the adhesive layer may be made of a thermosetting, photocuring, or UV curing adhesive material. In addition, the circuit pattern, Cu, Au, Ni, Pd, In, Ti, Sn, any one or two or more materials or a first metal layer formed of a conductive polymer material; A second metal layer formed on the first metal layer and made of at least one of Cu, Ag, Sn, Au, Ni, and Pd; Can be made.

In addition, the metal bumps may be made of Cu, Ag, Sn, Au, Ni, Pd.

In the printed circuit board according to the present invention, the surface of the other end of the metal bump may be a single layer or a multilayer plating layer using any one of Cu, Ni, Pd, Au, Sn, Ag, and Co, or a binary or raw alloy thereof. Can be formed.

In addition, the printed circuit board according to the present invention may be formed in a structure in which a solder resist layer is formed on at least one or more upper portions of the circuit pattern and an area except the plating layer.

According to the present invention, by overcoming the difficulty of the fine pitch implementation by implementing the solder ball pad in the printed circuit board using the solder ball, it is possible to reduce the pitch of the solder ball by removing the pad portion that serves as the solder ball pad, the role of the via and at the same time solder ball It is also possible to implement a structure having an inner metal bump serving as a junction portion to realize a thinner printed circuit board.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. In the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and duplicate description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

2A and 2B show a flow chart and process diagram of the manufacturing process according to the present invention.

Specifically, the manufacturing process of the single-layer printed circuit board according to the present invention comprises the steps of forming a pad hole in the insulating layer largely, and forming a metal seed layer on the insulating layer; Filling a metal material into the pad hole; And forming a circuit pattern on the metal seed layer.

In particular, the first step is formed by forming a pad hole on the insulating layer and bonding the metal seed layer to the insulating layer using thermocompression, or by forming an adhesive layer on the insulating layer and processing the pad hole on the metal. It is possible to implement by bonding the seed layer. The former step corresponds to a general process, hereinafter, an embodiment of the present invention will be described based on a process performed through an adhesive layer.

That is, in the first step as an embodiment using an adhesive layer, an insulating layer 110 for an insulating material of a printed circuit board is prepared (P 0), and then an adhesive layer formed of an adhesive material on an upper surface of the insulating layer 110. 120 is formed (P 1), and the pad hole 130 penetrating the insulating layer and the adhesive layer is processed. The insulating layer 110 may be formed of various insulating material layers including a prepreg, and the Cu layer is removed by etching from a copper foil composite (CCL) used for manufacturing a printed circuit board without going through a separate manufacturing step. It is also possible to utilize the remaining insulation layer.

In addition, the adhesive layer 120 may be formed by coating or laminating an adhesive material on one surface of the insulating layer 110. The adhesive material includes a material of thermosetting, photocuring, ultraviolet (UV) curing type. In particular, the adhesive material is preferably a material having a low resin flow during curing. Examples of such a material may be a bonding sheet for a flexible printed circuit board (FPCB), a low flow prepreg.

The thermosetting adhesive material may be formed from a resin in which one or two or more selected from epoxy resins, cyanic acid ester resins, bismaleed resins, polyimide resins, functional group-containing polyphenylene ether resins, and cyanic acid ether resins are combined.

In addition, the main component of the above-mentioned thermosetting adhesive material is not cured by free radicals, but is not particularly limited as long as it is a resin that has a three-dimensional network structure and can be firmly adhered to the adherend as it is heated. Do not. Examples thereof include epoxy resins, unsaturated polyester resins, thermosetting acrylic resins, phenol resins, diaryl phthalate resins, polyurethane resins, and the like. These thermosetting resins can be used alone or in combination of two or more. In particular, they have a relatively low melt viscosity before curing, and are easy to apply to the attaching process, and can exhibit opposite characteristics of high heat resistance after curing. Epoxy resins can be used suitably in that they can be used. As the epoxy resin, various conventionally known epoxy resins can be used, but in general, those having a molecular weight of 300 to 5000 are preferable, and solid epoxy resins having a molecular weight of 500 to 2000 that are easy to control adhesive surface stickiness are used. For example, bisphenol A type, bisphenol F type, bisphenol S type, cancelled bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphtharene type, florene type, phenol novolak Bifunctional or polyfunctional epoxy resins such as type, cresol novolak type, trishydroxyphenylmethane type and tetraphenylmethane type can be used, but bisphenol A type which is relatively excellent in physical properties such as curability, adhesiveness and heat resistance and moisture resistance. , Cresol novolak type and phenol novolak type epoxy resins are preferable, and these may be used alone or in combination of two or more thereof. In addition, the thermosetting adhesive material may further include a curing agent, and may be used without particular limitation as long as it is a compound having at least one activated hydrogen in a molecule as a component that promotes a curing reaction. As an example, an imidazole series or a polyisocyanate series , Amine, amide, acid anhydride, or phenol-based curing agents, and may be used alone or in combination of two or more thereof. Preference is given to using phenolic curing agents. For example, phenol novolak resins, cresol novolak resins, bisphenol A novolak resins, phenol aralkyl resins, poly-p-vinylphenol t-butylphenol novolak resins, naphthol novolak resins and the like may be appropriately used.

The UV curable adhesive material includes an ultraviolet curable adhesive, and for example, a material in which an acrylate functional monomer, a UV photoinitiator, a colorant, a dispersant, etc. may be mixed based on a UV curable acrylate resin. .

The pad hole 130 may be implemented by processing the hole through the surface of the insulating layer.

In the subsequent step of the first step, a metal seed layer may be formed on the upper surface of the insulating layer 110 and the adhesive layer 120 in which the pad hole 130 is formed. For example, the Cu foil of the thin film may be implemented by laminating by laminator or by bonding the layers by heating or pressing to completely harden the adhesive material. The metal seed layer may be formed using any one or two or more of Cu, Au, Ni, Pd, In, Ti, Sn, or a conductive polymer material, and may be implemented with a thickness of 1 to 3 μm ( P step 2).

Next, as a second step, a process of filling the pad hole 130 with the metal material 150 is performed (step P3). The filling of the metal material 150 may be performed using any one of electroless plating, electroplating, screen printing, sputtering, evaporation, ink jetting, dispensing, or a combination thereof. The filling material may be any one of Cu, Ag, Sn, Au, Ni, and Pd. The filled metal material layer will be described below as a 'metal bump'.

Thereafter, as a third step, a process of forming a circuit pattern on the metal seed layer 140 is performed (step P4). The circuit pattern may be formed by forming a pattern with a photosensitive material layer such as a DFR, performing plating thereon, and then etching the same to form a circuit pattern.

Thereafter, in step P5, the metal seed layer 140 ′ used to implement the circuit pattern is removed. In the removal method, after the circuit pattern is implemented, the copper foil layer may be removed by using half etching or flash etching.

In the next step, the solder resist layers 170 and 171 are formed on the substrate surface on which the circuit pattern is implemented and the opposite surface, and the exposed circuit pattern 160 surface or the metal bump (metal material layer) 150 described above. Perform surface treatment on the surface of the. The surface treatment is generally carried out by plating Au or the like. Alternatively, the plating layers 180 and 181 may be formed by plating a single layer or a multilayer using any one of Cu, Ni, Pd, Au, Sn, Ag, and Co, or a binary or raw alloy thereof. The plating layer 181 may then function as a region to which solder balls are bonded.

The structure of the printed circuit board according to the present invention implemented in the above-described manufacturing process with reference to the structure shown in step P6 is as follows.

The printed circuit board according to the present invention does not have a solder ball pad region existing in the conventional printed circuit board, and the surface of the metal bump formed of a metal material layer serving as a via replaces this function. In addition, the solder ball pad is not present, the pitch of the solder ball can be reduced as much as the pitch of the metal material layer, there is an advantage that can form a plurality of patterns in the same area.

In particular, as described above, the present invention forms a structure in which the upper portion of the insulating layer and the circuit patterns thereon are directly connected to the lower portion through the metal bumps, and solder balls are directly formed on the lower surfaces of the metal bumps. It can be implemented in a structure that can be applied in a bonded manner, when the adhesive layer is used as a medium of the metal seed layer as an example of the manufacturing process described above, may be formed in the structure of the adhesive layer on the completed printed circuit board.

Specifically, the structure in which the arrangement of the adhesive layer is removed from the structure shown in step P 6 is also included in one embodiment of the present invention as described above. Hereinafter, the adhesive layer will be described using the structure in which the adhesive layer is formed.

The printed circuit board according to the present invention includes a circuit pattern 160 formed on the insulating layer 110 and a metal bump 150 directly connected to the circuit pattern 160 through the insulating layer. In particular, between the circuit pattern 160 and the insulating layer 110, characterized in that it comprises an adhesive layer 120 formed on one surface of the insulating layer except for the connection portion of the metal bump and the circuit pattern. The adhesive layer 120 is a layer formed by the manufacturing process according to the present invention to improve the efficiency of the manufacturing process.

In addition, the circuit pattern may include a first metal layer used as a metal seed layer in a manufacturing process and a second metal layer formed on the metal seed layer. The first metal layer 140 ′ may be formed of any one or two or more of Cu, Au, Ni, Pd, In, Ti, Sn, or a polymer having excellent conductivity, and may have a thickness of 1 μm to 3 μm. Can be.

In addition, the second metal layer 160 may be formed on the first metal layer 140 ′ and be formed of one or more materials of Cu, Ag, Sn, Au, Ni, and Pd.

In addition, the metal bump 150 described above may be made of Cu, Ag, Sn, Au, Ni, Pd. The surface of the metal bump, which is not connected to the above-described circuit pattern, is exposed to the outside of the insulating layer, and the plating layer 181 is preferably formed on the exposed surface. In addition, the plating layer 181 may be composed of a single layer or multiple layers using any one of Cu, Ni, Pd, Au, Sn, Ag, Co, or binary, raw alloys thereof. The solder ball 190 is bonded to the metal bump surface on which the plating layer 181 is formed.

In addition, a solder resist layer 170 may be formed on at least one upper surface of the circuit pattern to protect the circuit pattern 160 of the printed circuit board, and further, a metal may be formed on the opposite side where the circuit pattern is formed. The solder resist layer 171 may be further formed in an area except the exposed surface of the bump. A portion of the circuit pattern 160 may be further formed with a plating layer 180, in which case the plating layer may be formed using any one of Cu, Ni, Pd, Au, Sn, Ag, Co, or a binary or raw alloy thereof. It may be composed of a single layer or multiple layers as described above.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

1A is a flowchart illustrating a manufacturing process of a conventional printed circuit board, and FIG. 1B is a conceptual diagram illustrating a structure in which solder ball bonding is performed on a structure of a conventional printed circuit board.

2A and 2B illustrate a flow chart and process diagram of a manufacturing process of a single layer printed circuit board according to the present invention.

Claims (17)

Forming a pad hole in the insulating layer and forming a metal seed layer on the insulating layer; Filling a metal material into the pad hole; Forming a circuit pattern on the metal seed layer; Method of manufacturing a single-layer printed circuit board comprising a. The method according to claim 1, The first step, Forming an adhesive layer on the insulating layer and processing a pad hole to form a metal seed layer using the adhesive layer; And bonding the metal seed layer to the upper portion of the insulating layer using thermocompression after the pad hole processing. The method according to claim 1 or 2, The first step, The metal seed layer manufacturing method of a single layer printed circuit board, characterized in that the Cu, Au, Ni, Pd, In, Ti, Sn, any one or two or more of the material or conductive polymer material. The method of claim 3, The metal material of the second step, Method for manufacturing a single-layer printed circuit board, characterized in that the filling using any one of Cu, Ag, Sn, Au, Ni, Pd. The method of claim 4, wherein the second step, Characterized in that the filling step using any one or a combination of electroless plating, electroplating, screen printing, sputtering, evaporation, inkjetting, dispensing Method of manufacturing single layer printed circuit board. The method of claim 3, The third step, A method of manufacturing a single layer printed circuit board, comprising the step of forming a circuit pattern layer composed of at least one material layer among Cu, Ag, Sn, Au, Ni, and Pd. The method according to claim 6, After the step 3, further comprising the step of removing a metal seed layer other than the circuit pattern. The method of claim 7, The method of claim 1, further comprising the step of applying a solder resist to the printed circuit board. The method according to claim 8, And forming a surface treatment layer on at least one of an exposed surface of the metal material filling the pad hole or the circuit pattern surface. The method according to claim 9, The surface treatment layer may be formed in a single layer or multiple layers using any one of Cu, Ni, Pd, Au, Sn, Ag, Co, or a binary or raw alloy thereof on at least one of the exposed surface or the circuit pattern surface. A method of manufacturing a single layer printed circuit board, characterized in that the plating treatment is performed. A circuit pattern formed on the insulating layer; A metal bump penetrating the insulating layer and directly connected to the circuit pattern; The surface of the other end which is not connected to the circuit pattern of the metal bump is a single layer printed circuit board, characterized in that the structure is exposed to the surface of the insulating layer. The method of claim 11, Between the circuit pattern and the insulating layer, Single layer printed circuit board, characterized in that the adhesive layer is formed on the surface of the insulating layer except for the connection portion of the metal bump and the circuit pattern. The method according to claim 12, The adhesive layer is a single layer printed circuit board made of a thermosetting, photo-curing, or UV-curable adhesive material. The method according to any one of claims 11 to 13, The circuit pattern, A first metal layer formed of any one or two or more materials of Cu, Au, Ni, Pd, In, Ti, Sn, or a conductive polymer material; A second metal layer formed on the first metal layer and made of at least one of Cu, Ag, Sn, Au, Ni, and Pd; Single layer printed circuit board, characterized in that consisting of. The method according to claim 14, The metal bumps are Cu, Ag, Sn, Au, Ni, Pd single layer printed circuit board, characterized in that. 16. The method of claim 15, The surface of the other end of the metal bump is a single layer, characterized in that the plated layer is formed in a single layer or multiple layers using any one of Cu, Ni, Pd, Au, Sn, Ag, Co or binary, raw alloys thereof. Printed circuit board. 18. The method of claim 16, Single layer printed circuit board, characterized in that the solder resist layer is formed on at least one upper portion of the circuit pattern and the region except the plating layer.

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