KR20120072684A - The printed circuit board and the method for manufacturing the same - Google Patents

Abstract

PURPOSE: A method for manufacturing a printed circuit board is provided to protect the surface of a first protective layer and effectively remove the residue on the first protective layer by inserting a second protective layer to the top of the first protective layer when forming bumps. CONSTITUTION: A pad(103) is connected to a circuit pattern formed on an insulating plate(101), which is made of a thermosetting or thermoplastic polymer substrate, a ceramic substrate, or an organic-inorganic composite substrate, by patterning a copper film formed on the insulating plate. Bumps(109) are formed on the pad. A plating seed layer(108) is formed on the bumps. A first protective layer(104) covers the front side of the circuit pattern and a part of the bumps.

Description

The printed circuit board and the method for manufacturing the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to printed circuit boards, and more particularly, to a method of manufacturing a printed circuit board.

A printed circuit board (PCB) is formed by printing a circuit pattern on a electrically insulating substrate with a conductive material such as copper, and refers to a board immediately before mounting an electronic component. That is, it means the circuit board which fixed the mounting position of each component, and printed and fixed the circuit pattern which connects components on the flat surface in order to mount various types of electronic elements on a flat plate.

In addition, with the development of the electronics industry, the demand for high functionalization, miniaturization, price competitiveness, and short delivery time of electronic components is increasing rapidly. In order to cope with this trend, printed circuit board manufacturers are applying semi-additive process (SAP) to cope with the trend of thinner and denser printed circuit boards.

1A to 1E are cross-sectional views illustrating a method of manufacturing a printed circuit board according to the prior art.

First, as shown in FIG. 1A, a circuit pattern or a pad 3 is formed using a first metal layer (not shown) formed on an insulating substrate (insulation plate) 1. The first metal layer may be formed of copper, nickel, or an alloy thereof.

When the pad 3 is formed, the solder resist 4 exposing the formed pad 3 is formed on the insulating substrate 1 on which the pad 3 is formed.

Then, a mask 5 is formed on the applied solder resist 4 as shown in FIG. 1B. In this case, the mask 5 has an opening 6 exposing an upper surface of the formed pad 3.

Then, as shown in FIG. 1C, a second metal layer 7 is formed on the formed mask 5. In this case, in order to secure the adhesion between the mask 5 and the second metal layer 7, the surface treatment of the mask 5 may be performed.

Then, as illustrated in FIG. 1D, the formed second metal layer 7 is plated with a seed layer to form a bump 8 on the pad 3. In this case, the bump 8 may be formed of the same copper, nickel, or an alloy thereof as the pad 3.

Then, as shown in FIG. 1E, the mask 5 and the second metal layer 7, which are unnecessary parts, are removed through a peeling and etching process.

However, according to the prior art as described above, since there is no separate layer between the solder resist 4 and the mask 5, the surface of the solder resist 4 in the process of removing the mask (5) There is a problem that is damaged, the residue of the mask (5) on the surface of the solder resist (4) has a problem of weakening the adhesive force with the epoxy.

The embodiment according to the present invention provides a method of manufacturing a printed circuit board that does not damage the solder resist.

Technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above are clearly understood by those skilled in the art to which the embodiments proposed from the following description belong. Could be.

A method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention includes forming a pad on an insulating substrate, forming a first protective layer having an opening exposing the formed pad on the insulating substrate, and forming a pad on the insulating substrate. Forming a second protective layer having an opening exposing the pad over the protective layer, forming a mask having a window exposing the pad over the formed second protective layer, and forming the first and second protective layers And forming a bump filling the opening of the mask and the window of the mask.

In addition, the pad is formed of copper, nickel or an alloy thereof.

In addition, the openings of the first and second protective layers and the window of the mask are simultaneously formed by laser processing.

Further, the second protective layer is formed of a second metal different from the first metal forming the bumps, and the first metal is not etched by the etching solution of the second metal.

In addition, the first metal may include at least one of copper, an alloy containing copper, tin, or an alloy containing tin, and the second metal may include at least one of copper, nickel, chromium, titanium, or an alloy thereof. It includes.

In addition, the second protective layer is formed to a thickness satisfying the range of 0.1 ~ 10㎛, the first protective layer comprises a solder resist.

The method may further include forming a plating seed layer of the bump on the upper surface of the mask and the side surfaces of the first protective layer, the second protective layer, and the mask.

The method may further include removing the formed mask after the bump is formed.

The method may further include removing the second protective layer using an etchant corresponding to the metal forming the second protective layer after the mask is removed.

In addition, the second protective layer is formed by at least one of electroless chemical plating and sputtering.

In addition, the forming of the bump may include forming a bump having a shape of at least one of a triangular pillar, a square pillar, a polygonal pillar, and a circular pillar.

According to an embodiment of the present invention, the surface of the first protective layer is protected by inserting a second protective layer for protecting the first protective layer on the upper surface of the first protective layer and then performing a bump forming process. At the same time, the residue remaining in the first protective layer can be effectively removed.

In addition, by using the second protective layer it is possible to easily remove the mask layer due to the pitch pitch progress, it is possible to improve the interlayer matching between the first protective layer and the mask.

1A to 1E are cross-sectional views illustrating a method for manufacturing a printed circuit board of the prior art.
2 is a cross-sectional view of a printed circuit board according to an exemplary embodiment of the present invention.
3 to 12 are cross-sectional views illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.
13 and 14 illustrate bumps and first protective layers formed by embodiments of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

In order to clearly illustrate the present invention in the drawings, thicknesses are enlarged in order to clearly illustrate various layers and regions, and parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification .

When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right over" but also when there is another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

2 is a cross-sectional view of a printed circuit board according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a printed circuit board according to an exemplary embodiment of the present invention may include an insulating plate 101, a pad 103 connected to a circuit pattern (not shown) formed on the insulating plate 101, and the pad. A bump 109 formed over the 103, a plating seed layer 108 of the bump 109, and a first passivation layer 104 covering a portion of the bump 109 and the entire surface of the circuit pattern.

The insulation plate 101 may be a thermosetting or thermoplastic polymer substrate, a ceramic substrate, an organic-inorganic composite material substrate, or a glass fiber impregnated substrate. When the insulating plate 101 includes a polymer resin, the insulation plate 101 may include an epoxy-based insulation resin. It may alternatively include polyimide resin.

A plurality of pads 103 connected to the plurality of circuit patterns are formed on the insulating plate 101. The pad 103 is formed to mount a device mounted on a printed circuit board, and means a pad 103 to which solder (not shown) is attached.

The pad 103 may be formed of a conductive material, and may be formed of an alloy including copper when the circuit pattern is formed by patterning the copper foil layer formed on the insulating plate 101.

A plurality of bumps 109 are formed on the pad 103 to cover the top surface of the pad 103. In this case, the bump 109 may be formed to have an area smaller than that of the upper surface of the pad 103 by electroplating.

In this case, the bump 109 may be formed by electroplating the plating layer 108 formed on the side of the first protective layer 104 as a seed layer. The plating layer 108 may be formed on the side surface of the first protective layer 104 by chemical copper plating.

In addition, since the bump 109 is formed by plating, the area of the upper surface of the bump 109 and the lower surface opposite to the upper surface is formed in the same structure. The bump 109 may be formed in the shape of a triangular pillar, a square pillar, a polygonal pillar, and a circular pillar having the same upper and lower surfaces.

In this case, the first protective layer 104 has an opening 107 exposing the pad 103, and the bump 109 is formed while filling the opening 107. Accordingly, the bump 109 has the same area as that of the opening 107.

Substantially, a portion of the area of the bump 109 is occupied by the plating layer 108, and thus the bump 109 may include the plating layer 108.

The bump 109 is formed of a first metal.

In this case, the first metal may be an alloy including copper and the copper, which is the same material as the pad 103, or may be an alloy including tin and the tin.

The first metal may be determined by the second metal described later.

That is, the first metal is a metal different from the second metal, and when the second metal is an alloy containing copper or copper, the first metal may be tin or an alloy containing tin.

In addition, on the contrary, the first metal may be an alloy containing copper or copper, and when the first metal is an alloy containing copper or copper, the second metal except for the alloy containing copper or copper Other metals.

Accordingly, a bump 109 formed of an alloy containing copper or copper may be present on the pad 103. Alternatively, the bump 109 formed of an alloy containing tin or tin may exist.

In this case, the bump 109 may have a shape protruding above the surface of the first protective layer 104. When the bump 109 protrudes above the surface of the first protective layer 104, the device may be easily mounted on the bump later.

The first protective layer 104 is formed on the insulating plate 101 to cover the circuit pattern and a part of the pad 103.

The first protective layer 104 is to protect the surface of the insulating plate 101, is formed on the front surface of the insulating plate 101, the opening 107 for opening the upper surface of the pad 103 to be exposed Have

In this case, the first protective layer 104 may be a solder resist.

In the manufacturing process of the printed circuit board 100, a second protective layer 105 is formed on the first protective layer 104.

The second protective layer 105 removes residues that may be present in the first protective layer 104 while preventing damage to the first protective layer 104 generated during the bump manufacturing process.

In other words, the printed circuit board according to the related art forms a mask on the first passivation layer 104, and thus forms a bump by filling the opening formed by the first passivation layer 104 and the mask.

However, when bumps are formed through the manufacturing process as described above, residues of the mask may be present on the surface of the first passivation layer 104 in a later mask removal process.

In addition, in order to reliably remove the mask from the surface of the first protective layer 104, the alkali chemical treatment time is excessively increased or the concentration is increased. (104) The surface is damaged.

Accordingly, in the embodiment according to the present invention, a second protective layer 105 for protecting the first protective layer 104 is formed on the first protective layer 104, and the second protective layer 105 is formed. After the formation of the bumps 109, the bumps 109 may be formed to protect the first passivation layer 104 and to form bumps 109 having high reliability.

A method of manufacturing the printed circuit board of FIG. 2 will be described with reference to FIGS. 3 to 14.

3 to 12 are cross-sectional views illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

In the method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention, an insulating plate 101 is prepared as shown in FIG. 3.

A plurality of circuit patterns are formed on the insulating plate 101 of FIG. 3, and a circuit pattern may also be formed under the insulating plate 101.

That is, when the insulating plate 101 refers to one insulating layer among a plurality of stacked structures, a plurality of circuit patterns (not shown) may be continuously formed on or below the insulating plate 101. Otherwise, a plurality of circuit patterns may be continuously formed on both the upper and lower portions of the insulating plate 101.

The insulation plate 101 may be a thermosetting or thermoplastic polymer substrate, a ceramic substrate, an organic-inorganic composite material substrate, or a glass fiber impregnated substrate. When the insulating plate 101 includes a polymer resin, the insulation plate 101 may include an epoxy-based insulation resin. It may alternatively include polyimide resin.

Thereafter, the conductive layer 102 is laminated on the insulating plate 101.

The conductive layer 102 may be formed by electroless plating a metal including copper on the insulating plate 101. In this case, the circuit pattern may be formed by etching the conductive layer 102.

In addition, the conductive layer 102 may use a copper clad laminate (CCL), unlike the non-electrolytic plating formed on the insulating plate 101.

When the electroconductive layer 102 is formed by electroless plating, the plating may be smoothly performed by applying roughness to the upper surface of the insulating plate 101.

The conductive layer 102 is etched in the stacked structure of the insulating plate 101 and the conductive layer 102 to form a pad 103 and a circuit pattern (not shown) of FIG. 4.

In this case, the conductive layer 102 formed on the insulating plate 101 may be formed on the upper and lower surfaces of the insulating plate 101, and accordingly, the circuit pattern (not shown) and the pad 103 may be formed. It may be formed on the lower surface of the insulating plate 101.

As described above, the circuit pattern and the pad 125 are formed on at least one surface of the insulating plate 101, and the first protection to fill the circuit pattern formed on the insulating plate 110 as shown in FIG. Form layer 104. In this case, the first protective layer 104 may be a solder resist.

The first protective layer 104 is formed by filling the pad 103 formed as well as the circuit pattern.

Next, as shown in FIG. 6, a second protective layer 105 is formed on the first protective layer 104 to protect the first protective layer 104.

In this case, the second protective layer 105 may be formed of at least one metal of copper, nickel, chromium, titanium, or an alloy thereof.

That is, at least one of copper, nickel, chromium, titanium, or an alloy thereof is electrolessly chemically plated or sputtered on the first protective layer 104 to form the second protective layer 105.

In this case, the second protective layer 105 is formed on the first protective layer 104 to a thickness satisfying the range of 0.1 ~ 10㎛.

Next, as shown in FIG. 7, a mask 106 is formed on the second protective layer 105.

The mask 106 may include any one of a dry film, ABF, and an RCC. At this time, it is preferable that the mask 106 uses a dry film having strong heat resistance.

Next, as shown in FIG. 8, the first protective layer 104, the second protective layer 105, and the mask 106 are laser processed to expose the pad 103 formed on the insulating plate 101. The opening 105 is formed.

The laser process is highly flexible, can process complex shapes or small quantities of products without expensive mold costs, and is also suitable for prototyping as it is suitable for the recent market situation of small quantity production of various kinds.

The laser process concentrates optical energy on the surface to melt and evaporate a part of the material, and takes a desired shape. The laser process can easily process complex formations by a computer program, and a composite material that is difficult to cut by other methods. Can be operated. Cut diameters as small as 0.005 mm are possible, and the thickness range is wide.

As a laser drill for the above laser process, it is preferable to use a YAG (Yttrium Aluminum Garnet) laser, a CO2 laser, or an ultraviolet (UV) laser. The YAG laser is a laser capable of processing both a copper foil layer and an insulating layer, and the CO2 laser is a laser capable of processing only an insulating layer.

In this case, it is preferable that the laser process uses the ultraviolet (UV) laser so that a small aperture can form the opening 107.

The opening 107 may include an opening of the first passivation layer 104, an opening of the second passivation layer 105, and a window of the mask 106.

That is, the first passivation layer 104, the second passivation layer 105, and the mask 106 are sequentially stacked, and the openings 107 are formed using the ultraviolet laser, thereby forming the first passivation layer. An opening of 104, an opening of the second protective layer 105, and a window of the mask 106 can be simultaneously formed in one process.

In another embodiment, the opening of the first passivation layer 104, the second passivation layer 105, and the window of the mask 106 may be formed by a plurality of processes, respectively.

For example, after the first protective layer 104 is formed on the pad 103, an opening may be formed in the first protective layer 104 to expose the pad 103. In addition, a second passivation layer 105 having the same opening as the opening formed in the first passivation layer 104 may be formed on the first passivation layer 104. In addition, a mask 106 having the same window as the opening of the second protective layer 105 may be formed on the second protective layer 104.

The position of the formed opening 107 is determined by the position of the pad 103 formed on the insulating plate 101.

That is, the opening 107 is formed at the position where the pad 103 is formed. In this case, the opening 107 is formed to expose only a part of the pad 103.

In other words, the opening 107 is formed to have a width smaller than the width of the pad 103, so that the edge region of the pad 103 is protected by the first protective layer 104.

Subsequently, as shown in FIG. 9, a plating layer 108 is formed on an upper surface of the mask 106 and on side surfaces of the first protective layer 104, the second protective layer 105, and the mask 106. The plating layer 108 may be formed by chemical copper plating.

The chemical copper plating may be performed in the order of a degreasing process, a soft corrosion process, a precatalyst process, a catalyst process, an activation process, an electroless plating process, and an anti-oxidation process.

In addition, the copper plating is divided into heavy copper plating (Heavy Copper, 2㎛ or more), medium copper plating (Medium Copper, 1 ~ 2㎛), light copper plating (Light Copper, 1㎛ or less) according to the thickness, here, medium copper plating Alternatively, the plating layer 108 that satisfies 0.5 to 1.5 μm is formed of light copper plating.

Next, as illustrated in FIG. 10, the bump 109 is formed by filling the opening 107 formed by drilling the first protective layer 104, the second protective layer 105, and the mask 106.

The bump 109 may be formed by filling the entire opening 107 by an electroplating process. Alternatively, the bump 109 may be formed by filling only a part of the opening 107.

In the embodiment of the present invention, the bump 109 is formed by filling the entire opening 107. However, this is only an example, and only a part of the opening 107 is buried to form the bump 109 so that the surface of the first protective layer 104 and the surface of the bump 109 are coplanar. It could be placed in the

In this case, the bump 109 may be formed by plating an alloy including the same copper as the pad 103.

Alternatively, the bump 107 may be formed by plating an alloy including tin. That is, the bump 107 may be formed of only tin, may be formed of an alloy in which tin and palladium are mixed at a predetermined ratio, and may be formed of an alloy including silver in addition to tin and palladium.

When the bump 107 is formed of an alloy including the copper, solder may be additionally formed on the bump 107 later.

In addition, when the bump 107 is formed of an alloy including tin, the bump 107 itself may serve as a solder.

However, the material of the bump 109 is determined by the material of the second protective layer 105 formed on the first protective layer 104.

In other words, when the second protective layer 105 is formed of the first metal, the bump 109 is formed of a second metal different from the first metal constituting the second protective layer 105.

When etching either the second protective layer 105 or the bump 109, the second protective layer 105 or the bump 109 is formed of another metal by the etching solution for etching. .

For example, when the second protective layer 105 is formed of a first metal and a first etching solution is used to etch the first metal forming the second protective layer 105, the bump ( 109 is preferably formed using a second metal that is not etched in the first etching solution.

In addition, when the bump 109 is formed of a second metal and a second etching solution is used to etch the second metal forming the bump 109, the second protective layer 105 may be formed of the second metal. It is preferable to form using the 1st metal which is not etched also in 2 etching solution.

Next, an etching process is performed as shown in FIG. 11 to selectively remove a portion of the plating layer 108 and the formed bumps 109 formed on the upper surface of the mask 106.

That is, when the bump 109 is formed, the plating layer 108 used as the seed layer is selectively removed. In this case, the plating layer 108 may be removed from the upper surface of the mask 106 by a flash etching process.

Next, as shown in FIG. 12, the mask 106 formed on the second protective layer 105 is removed.

When the mask 106 is removed, the second protective layer 105 formed on the first protective layer 104 is removed.

In this case, when the etching solution corresponding to the metal forming the second protective layer 105 is used to remove the second protective layer 105, the bump 109 is not etched by the etching solution. Since it is formed of a metal, only the second protective layer 105 can be effectively removed.

13 is a view illustrating a bump and a first protective layer formed by an embodiment of the present invention.

Referring to FIG. 13, it can be seen that a printed circuit board manufactured according to the related art has a residue of a mask stacked for forming the bumps around the first protective layer.

However, in the printed circuit board manufactured by the present invention, it is possible to confirm that no residue is present on the first protective layer by performing a bump manufacturing process after stacking the second protective layer on the first protective layer.

14 is a view showing a first protective layer formed by an embodiment of the present invention.

Referring to FIG. 14, according to the prior art, it may be confirmed that damage to the first protective layer occurs in the process of removing the mask, thereby lowering the reliability of the printed circuit board.

However, according to the embodiment of the present invention, since the bump is formed using the second protective layer stacked on the first protective layer, a stable and reliable printed circuit board may be manufactured without damaging the first protective layer. It becomes possible.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: printed circuit board
101: insulation plate
103: pad
104: protective layer
106, 206: plating layer
107, 207, 208: bump

Claims (15)

Forming a pad over the insulating substrate;
Forming a first protective layer having an opening exposing the formed pad on the insulating substrate;
Forming a second protective layer having an opening exposing the pad over the first protective layer;
Forming a mask having a window exposing the pad on the formed second protective layer; And
And forming bumps filling the openings of the first and second protective layers and the windows of the mask. The method of claim 1,
The pad is a method of manufacturing a printed circuit board formed of copper, nickel or alloys thereof. The method of claim 1,
The openings of the first and second protective layers and the window of the mask are formed by laser processing. The method of claim 1,
The openings of the first and second protective layers and the window of the mask are formed at the same time. The method of claim 1,
The second protective layer is a manufacturing method of a printed circuit board formed of a second metal different from the first metal forming the bump. 6. The method of claim 5,
And the first metal is not etched by the etching solution of the second metal. 6. The method of claim 5,
The first metal is a method of manufacturing a printed circuit board comprising at least one of copper, an alloy containing copper, tin or an alloy containing tin. 6. The method of claim 5,
The second metal is a manufacturing method of a printed circuit board comprising at least one of copper, nickel, chromium, titanium or alloys thereof. The method of claim 1,
The second protective layer is a manufacturing method of a printed circuit board formed to a thickness satisfying the range of 0.1 ~ 10㎛. The method of claim 1,
The first protective layer is a manufacturing method of a printed circuit board comprising a solder resist. The method of claim 1,
And forming a plating seed layer of the bumps on the upper surface of the mask and on the first protective layer, the second protective layer, and the side surfaces of the mask. The method of claim 1,
And removing the formed mask after the bump is formed. 13. The method of claim 12,
And removing the second protective layer by using an etching solution corresponding to the metal forming the second protective layer after the mask is removed. The method of claim 1,
The second protective layer is a method of manufacturing a printed circuit board formed by at least one of the electroless chemical plating method or sputtering method. The method of claim 1,
Forming the bumps
Forming a bump having a shape of at least one of a triangular pillar, a square pillar, a polygonal pillar and a circular pillar.

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