KR101884431B1 - Printed circuit board and method for manufacturing the same - Google Patents

Abstract

The present invention provides a method of manufacturing a semiconductor device comprising the steps of forming a film layer having an opening portion for exposing an electrode pad on a base substrate having an electrode pad, providing a conductive sheet, pressing the conductive substrate and the base substrate, Forming a conductive post on the electrode pad by bonding the electrode pad and the conductive sheet, and removing the film layer, wherein the method can be finely pitched and has an aspect ratio of There is an advantage that a large conductive post can be realized more easily.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a printed circuit board (PCB)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board and a method of manufacturing the same, and more particularly, to a printed circuit board capable of achieving a fine pitch and a conductive post having a large aspect ratio and a method of manufacturing the same.

In recent years, with the development of the electronic industry, there has been a demand for high performance, high performance, and miniaturization of electronic components. Accordingly, demands for high integration, thinning, and microcircuit patterning are increasing in response to downsizing and technology integration in substrates for surface mount components .

Particularly, wire bonding and flip chip bonding are used for electrical connection between a semiconductor chip and a printed circuit board in the surface mounting technology of electronic components on a substrate. However, in the case of a wire bonding method , Since the module is required to be connected to a printed circuit board by using a wire, an additional process is required and a flip chip bonding method is widely used because of limitations in implementation of a fine pitch of a circuit pattern.

Here, the flip chip bonding method is a method in which an external connecting terminal (i.e., bump) made of a material such as gold, solder, or other metal is formed on a semiconductor chip and, in contrast to a conventional mounting method using wire bonding, (Flip) so that the surface faces the substrate.

Although such a flip chip bonding method has been considerably accomplished by the application of flip chip technology replacing wire bonding, miniaturization of the bump pitch is still a difficult challenge.

Accordingly, a technique of forming a metal post using an electroplating process instead of a solder paste or a solder ball has been developed in order to make the bump pitch smaller than that of the solder bump forming method. Conventionally, A solder paste was filled in the openings, the mask was removed, and the solder paste was reflowed to prepare a metal post.

However, according to the related art, it is important to accurately align the mask on the base substrate. However, there is a problem in that it is difficult to precisely align the mask on the base substrate as the circuit pattern progresses to fine pitch.

In addition, there is a problem that it is difficult to reduce the pitch of the metal post to a certain level or less and to realize a metal post having a high aspect ratio. That is, since the mask is made of metal, it is difficult to form fine holes in the mask, and there is a problem that tolerance of the mask is difficult to catch up with the speed at which the circuit pattern becomes finer.

The idea of the present invention is that a conductive sheet is pressed into a base substrate on which a film layer having an open portion is formed and the conductive sheet is inserted into the open portion and then the conductive sheet is reflowed in a state where the film layer is formed, And a conductive post having a high aspect ratio can be more easily realized, and a method of manufacturing the same.

For this purpose, a method of fabricating a printed circuit board according to an embodiment of the present invention includes forming a film layer having an opening for exposing the electrode pad on a base substrate having an electrode pad; Providing a conductive sheet; Pressing the base substrate and the conductive sheet to insert the conductive sheet into the open portion; Bonding the electrode pad and the conductive sheet to form a conductive post on the electrode pad; And removing the film layer.

The conductive sheet may be made of a soft material.

The conductive sheet may be formed of at least one of copper (Cu), silver (Ag), gold (Au), aluminum (Al), iron (Fe), titanium (Ti), tin (Sn), nickel (Ni), or molybdenum Any one or more than one alloy may be used.

The thickness of the conductive sheet may be thicker than the thickness of the film layer.

After the step of forming the film layer, the method may further include the step of applying the flux on the film layer including the open part.

And removing the conductive sheet remaining on the upper portion of the film layer without being inserted into the open portion after the step of inserting the conductive sheet into the open portion.

The step of forming the conductive posts on the electrode pads may include bonding the conductive sheets to the electrode pads by reflowing the conductive sheets.

The step of removing the conductive sheet remaining on the upper part of the film layer may be performed simultaneously with the step of reflowing the conductive sheet to bond the conductive sheet to the electrode pad.

The conductive posts may have an aspect ratio of 1.25 or more.

The forming of the film layer may include forming a resist having an opening on the base substrate having the electrode pad so that the electrode pad is exposed; And forming a film layer having an open portion for exposing the electrode pad on the resist.

According to another aspect of the present invention, there is provided a printed circuit board comprising: a base substrate having electrode pads; A resist having an opening for exposing the electrode pad on the base substrate; And a conductive post formed with a predetermined height on the electrode pad, wherein the upper surface of the conductive post has a curved surface.

The conductive posts may have an aspect ratio of 1.25 or more.

The conductive posts may be formed of any one of copper (Cu), silver (Ag), gold (Au), aluminum (Al), iron (Fe), titanium (Ti), tin (Sn), nickel (Ni), and molybdenum One or more alloys.

As described above, according to the printed circuit board and the manufacturing method thereof according to the embodiment of the present invention, the conductive sheet is pressed on the base substrate having the film layer having the open portion formed therein, the conductive sheet is inserted into the open portion, It is possible to refine the conductive sheet in the formed state to enable a fine pitch and to easily realize a conductive post having a large aspect ratio.

More specifically, exposure and development of the film layer has advantages in that it is possible to implement a fine pattern because the accuracy of alignment can be greatly improved and the processing deviation can be reduced to a very small extent, rather than aligning the mask (prior art) have.

Further, since the conventional mask is made of metal, it is difficult to form fine holes in the mask, but it is easier to process the fine holes by the exposure and development processes, so that the conductive posts having a fine pitch can be easily realized There is an advantage.

In addition, according to the prior art, since the process of reflowing the solder paste is performed after removing the mask, there is a problem that the metal post is realized in a circular shape due to the surface tension in the reflow process. However, Since the film layer guides the conductive sheet during the reflow process, there is an advantage that the conductive posts having a large aspect ratio can be more easily realized.

1 is a cross-sectional view of a printed circuit board according to an embodiment of the present invention.
FIGS. 2 to 9 are cross-sectional views illustrating a manufacturing process of a printed circuit board according to an embodiment of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a sectional view of a printed circuit board according to an embodiment of the present invention.

As shown in Fig. 1, the printed circuit board includes a base substrate 110, a resist 117, and a conductive post 142.

First, the base substrate 110 is a prepreg, a polyimide, a polyethylene terephthalate (PET), a cyanide ester (cyanide ester), an ABF (Ajinomoto Build up film or epoxy, which have low electrical conductivity and hardly pass current.

Here, the configuration of the printed circuit board as shown in FIG. 1 is merely an example, and the printed circuit board may be a single-sided printed circuit board, a double-sided printed circuit board, and a multilayer printed circuit board. Lt; / RTI >

The electrode pad 115 may be formed on the upper surface of the base substrate 110 such as a subtractive method, an additive method or a semi-additive method. And can be formed using various methods.

At this time, the electrode pad 115 may be formed of a metal such as copper (Cu), silver (Ag), gold (Au), aluminum (Al), iron (Fe), titanium (Ti), tin Mo), and the like.

The resist 117 may be formed with an opening OP for exposing the electrode pad 115 on the base substrate 110. At this time, the resist 130 may be formed of various photosensitive materials such as a photoresist, a photo solder resist, or a dry film, and may be replaced with various materials without limitation. Of course.

The conductive posts 142 may have a constant height on the electrode pad 115, and the upper surface may be a curved surface.

More specifically, the conductive posts 142 are formed by forming a film layer 120 on which an open portion CP is formed on a resist 117 to be described in detail below and forming a base layer 110 on which a film layer 120 is formed And then reflowing the conductive sheet 140 in the state that the film layer 120 is present. Since the conductive sheet 140 is reflowed in the state where the film layer 120 is present, the upper surface of the conductive post 142 may be curved.

In addition, the conductive posts 142 may have an aspect ratio of 1.25 or more. In more detail, the aspect ratio means the height h of the conductive posts 142 / the diameter of the conductive posts 142. Conventionally, there is a problem that it is difficult to form the conductive posts having a small diameter and a high height, In an embodiment of the present invention, since the film layer 120 guides the conductive sheet 140 during the reflow process, the conductive posts 142 having a large aspect ratio can be realized without disturbing the shape.

In addition, the conductive posts 142 may be formed of copper (Cu), and may be formed of a metal such as Ag, Au, Al, Fe, Ti, Sn, Ni) or molybdenum (Mo), or the like.

Hereinafter, a manufacturing process of a printed circuit board according to an embodiment of the present invention will be described.

FIGS. 2 to 9 are cross-sectional views illustrating a manufacturing process of a printed circuit board according to an embodiment of the present invention.

Referring to FIG. 2, a base substrate 110 having an electrode pad 115 is provided. At this time, a resist 117 having an opening OP may be further formed on the base substrate 110 so that the electrode pad 115 is exposed.

The base substrate 110 may be a prepreg, a polyimide, a polyethylene terephthalate (PET), a cyanide ester, an ABF (Ajinomoto) Build up film or epoxy, which have low electrical conductivity and hardly pass current.

An electrode pad 115 may be formed on the upper surface of the base substrate 110. The electrode pad 115 may be formed by a subtractive method, an additive method, or a semi-additive method And the like. At this time, the electrode pad 115 may be formed of a metal such as copper (Cu), silver (Ag), gold (Au), aluminum (Al), iron (Fe), titanium (Ti), tin Mo), and the like.

The resist 117 is a means for forming the opening OP so that the electrode pad 115 is exposed on the base substrate 110. The resist 117 may be a photoresist, a photo solder resist, (Dry Film), and the like, and may be replaced with various materials without limitation.

Next, referring to FIG. 3, a film layer 120 having an open portion (CP) exposing the electrode pad 115 is formed on the resist 117. Here, the film layer 120 may be made of various photosensitive materials such as a photoresist, a photo solder resist, or a dry film, and may be replaced with various materials Of course it is.

Next, as shown in FIG. 4, a flux 130 is applied onto the film layer 120 including the open portion CP using a spray. Here, the flux 130 is a mixed salt used for making a thin layer of a salt dissolved in the surface of a metal for the purpose of preventing the metal surface dissolved when the metal or alloy is melted from coming into contact with the atmosphere. In the example, when the metal material (conductive sheet) is bonded to the electrode pad 115 by a method such as soldering or welding, oxidation of the bonding surface is prevented so that the metal material (conductive sheet) and the electrode pad 115 are completely It is used to bond.

Then, as shown in Fig. 5, a conductive sheet 140 is provided. Here, the conductive sheet 140 may be formed of at least one selected from the group consisting of Cu, Ag, Au, Al, Fe, Ti, Sn, (Ni) or molybdenum (Mo), or one or more alloys.

At this time, the conductive sheet 140 may be made of a soft material having a low strength. For example, the conductive sheet 140 may have a lower strength than that of a general metal. If the mechanical strength of a typical metal (Young's modulus of the stainless steel) is 200 GPa, The mechanical strength (Young's modulus of the Tin) can be 50 GPa.

6, the base substrate 110 and the conductive sheet 140 are pressed to insert the conductive sheet 140 into the open portion CP of the film layer 120. Next, as shown in FIG. That is, the conductive sheet 140 is inserted into the open portion CP of the film layer 120 using a physical external force. At this time, the thickness of the conductive sheet 140 is formed thicker than the thickness of the film layer 120 So that the conductive sheet 140 can be completely inserted into the open portion CP of the film layer 120. At this time, the thickness of the conductive sheet 140 may be about several tens to several hundreds of micrometers.

7, the conductive sheet 140 remaining on the upper portion of the film layer 120 is removed, and more specifically, the conductive sheet 140 is removed from the upper surface of the film layer 120 without being inserted into the open portion CP of the film layer 120, The conductive sheet 140 remaining on the top of the layer 120 is removed by using a squeeze 150 or the like.

8, the electrode pad 115 and the conductive sheet 140 are bonded to each other to form the conductive posts 142 on the electrode pads 115. Next, as shown in FIG. More specifically, the conductive sheet 140 may be bonded to the electrode pad 115 by reflowing and melting the conductive sheet 140. At this time, when the reflow process is in progress, the film layer 120 Since the conductive sheet 140 is not removed and the conductive sheet 140 is guided, the conductive sheet 140 can maintain the existing shape and realize the conductive posts 142 having a large aspect ratio.

Meanwhile, in the embodiment of the present invention, the process of reflowing the conductive sheet 140 after sequentially removing the conductive sheet 140 remaining on the upper part of the film layer 120 has been described. However, in addition to the above- The step of removing the conductive sheet 140 remaining on the upper portion of the film layer 120 may be performed simultaneously with the step of reflowing the conductive sheet 140 to bond the conductive sheet 140 onto the electrode pad 115 It is possible.

That is, when the conductive sheet 140 remaining on the upper part of the film layer 120 is removed, the heating operation is also performed to remove the conductive sheet 140 remaining on the upper part of the film layer 120, The conductive sheet 140 can be melted and bonded at the same time.

Next, as shown in FIG. 9, the film layer 120 is removed to complete the conductive posts 142. Here, the conductive posts 142 may have an aspect ratio of 1.25 or more. In more detail, the aspect ratio means the height h of the conductive posts 142 / the diameter of the conductive posts 142. Conventionally, there is a problem that it is difficult to form the conductive posts having a small diameter and a high height, The conductive post 142 having a fine pitch can be easily realized by the exposure and development process of the film layer 120 and the film layer 120 can be formed on the conductive sheet 140 even in the reflow process, It is possible to realize the conductive post 142 having a large aspect ratio without disturbing the shape.

The foregoing detailed description is illustrative of the present invention. It is also to be understood that the foregoing is illustrative and explanatory of preferred embodiments of the invention only, and that the invention may be used in various other combinations, modifications and environments. That is, it is possible to make changes or modifications within the scope of the concept of the invention disclosed in this specification, the disclosure and the equivalents of the disclosure and / or the scope of the art or knowledge of the present invention. The foregoing embodiments are intended to illustrate the best mode contemplated for carrying out the invention and are not intended to limit the scope of the present invention to other modes of operation known in the art for utilizing other inventions such as the present invention, Various changes are possible. Accordingly, the foregoing description of the invention is not intended to limit the invention to the precise embodiments disclosed. It is also to be understood that the appended claims are intended to cover such other embodiments.

110. Base substrate 115. Electrode pad
117. Resist 120. Film layer
130. Flux 140. Conductive sheet
150. Squeegee

Claims (13)

Forming a film layer on the base substrate having the electrode pad, the film layer having an opening for exposing the electrode pad;
Providing a conductive sheet;
Pressing the base substrate and the conductive sheet to insert the conductive sheet into the open portion;
Bonding the electrode pad and the conductive sheet to form a conductive post on the electrode pad;
Removing the film layer;
And a step of forming the printed circuit board.
The method according to claim 1,
In the conductive sheet,
A method of manufacturing a printed circuit board comprising a flexible material.
The method according to claim 1,
In the conductive sheet,
(Ni), molybdenum (Mo), or at least one of copper (Cu), silver (Ag), gold (Au), aluminum (Al), iron (Fe), titanium Wherein the method comprises the steps of:
The method according to claim 1,
The thickness of the conductive sheet is,
Wherein the thickness of the film layer is larger than the thickness of the film layer.
The method according to claim 1,
After the step of forming the film layer,
Further comprising the step of applying a flux onto the film layer including the open portion.
The method according to claim 1,
After the step of inserting the conductive sheet into the open portion,
And removing the conductive sheet remaining on the upper portion of the film layer without being inserted into the open portion.
6. The method according to claim 1 or 5,
Wherein forming the conductive posts on the electrode pads includes:
And the conductive sheet is reflowed to bond the conductive sheet onto the electrode pad.
8. The method of claim 7,
Wherein the step of removing the conductive sheet remaining on the upper portion of the film layer comprises:
Wherein the step of reflowing the conductive sheet and bonding the conductive sheet to the electrode pad proceeds at the same time.
The method according to claim 1,
The conductive post may include:
And an aspect ratio of 1.25 or more.
The method according to claim 1,
Wherein forming the film layer comprises:
Forming a resist having openings on the base substrate having the electrode pad to expose the electrode pad;
And forming a film layer having an open portion for exposing the electrode pad on the resist.
A base substrate having an electrode pad;
A resist having an opening for exposing the electrode pad on the base substrate;
And a conductive post formed with a predetermined height on the electrode pad,
Wherein an upper surface of the conductive post is formed of a curved surface,
The conductive posts being in contact with the upper surface of the resist,
Wherein the conductive post diameter is larger than the opening diameter of the resist on the upper surface of the resist.
12. The method of claim 11,
The conductive post may include:
And an aspect ratio of 1.25 or more.
12. The method of claim 11,
The conductive post may include:
(Ni), molybdenum (Mo), or at least one of copper (Cu), silver (Ag), gold (Au), aluminum (Al), iron (Fe), titanium A printed circuit board comprising an alloy.

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