KR101189367B1

KR101189367B1 - Ball mask and method for manufacturing printed circuit board using the same

Info

Publication number: KR101189367B1
Application number: KR20100134555A
Authority: KR
Inventors: 김남열; 신동준; 정창하
Original assignee: 엘지이노텍 주식회사
Priority date: 2010-12-24
Filing date: 2010-12-24
Publication date: 2012-10-09
Also published as: KR20120072693A

Abstract

According to an embodiment of the present invention, a ball mask may include a first mask having a first opening formed in a region corresponding to a mounting point of a conductive ball, and at least one first opening formed on the first mask and formed in the first mask. It includes a second mask that covers.

Description

Ball mask and manufacturing method of printed circuit board using same {BALL MASK AND METHOD FOR MANUFACTURING PRINTED CIRCUIT BOARD USING THE SAME}

The present invention relates to a ball mask and a method of manufacturing a printed circuit board using the same.

Generally, a method of connecting a chip to an external substrate such as a printed circuit board (PCB) or a wafer level package (WLP) includes a wire bonding method and an automatic tape bonding method. Tape Automatted Bonding Method (TAB), Flip Chip Method, and the like are used.

Hereinafter, the wafer bumping process will be described in order with reference to the process flowcharts of FIGS. 1A to 1E.

First, a wafer W on which a circuit pattern is formed is prepared, and a flux mask 1 for applying flux on the upper portion of the wafer W is placed. The flux mask 11 has a plurality of openings 2 corresponding to the bumping regions for each die of the wafer W (FIGS. 1A and 1B).

Subsequently, when the flux 3 is removed after the flux 3 is applied to the entire upper surface of the flux mask 10 by using a screen printing technique, a predetermined flux pattern is formed on the surface of the wafer W (FIG. 1C). ).

Next, a metal mask 4 for bumping is positioned on the wafer W. The metal mask 4 also has a plurality of openings 5 corresponding to the respective die bumping regions of the wafer W. As shown in FIG. The metal mask 4 is provided so as to be spaced apart from the wafer W by a predetermined interval in order to prevent contact with the flux 3 (Fig. 1D).

The operator then pours a plurality of solder balls 6 on top of the metal mask 4, brushing the brush balls 6, and seating the solder balls 6 in each opening 5 of the ball mask 4. Meanwhile, the remaining solder ball 5 is wiped out to the outside of the ball mask 4 (FIG. 1E).

Finally, when the metal mask 5 is removed, the solder balls 6 are attached to each bumping area of the wafer W by the flux 3, and then the solder balls (reflow) are processed through a reflow process. 6) is bonded to the wafer (W).

2 illustrates a metal mask used for the bumping.

Referring to FIG. 2, the metal mask 4 is formed of a metal material and has an opening 5 corresponding to the bumping area. In addition, the opening 5 is formed to correspond to the diameter of the solder ball (5).

However, the diameters of the bumping area and the solder ball 5 are different according to the printed circuit board, and thus there is a problem in that the metal masks, which are relatively expensive according to the printed circuit board, must be manufactured.

The embodiment provides a new mask and a method of manufacturing a printed circuit board using the same.

In addition, the technical problems to be achieved in the embodiments of the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned above have ordinary knowledge in the technical field to which the embodiments proposed from the following description belong. Will be clearly understood to him.

In addition, the second mask has a second opening that exposes at least one first opening formed in the first mask.

In addition, the first opening and the second opening is formed with a different width, preferably the first opening is formed with a width smaller than the width of the second opening.

In addition, the first and second openings may be formed in any one of an ellipse, a circle, a triangle, a rectangle, and a polygon.

In addition, the first mask is a mask formed of a metallic material, and the second mask is a mask or a dry film formed of a metallic material.

In addition, an adhesive is formed on at least one surface of the second mask.

Meanwhile, a method of manufacturing a printed circuit board using a ball mask according to an embodiment of the present invention includes preparing a substrate on which a pad is formed, and using a first mask having a first opening formed on the pad corresponding to a mounting area of the conductive ball. Placing a second mask over the first mask, the second mask covering at least one of the first openings formed in the first mask, over the first mask to which the second mask is attached; And dropping the ball to seat the conductive ball on the pad.

In addition, attaching the second mask may include attaching a second mask having a second opening to expose the first opening of at least one of the first openings formed in the first mask.

In addition, the first opening portion and the second opening portion are formed to have different widths, and preferably, the width of the first opening portion is smaller than the width of the second opening portion.

The first mask may be a mask formed of a metal material, and the second mask may be any one of a mask and a dry film formed of a metal material.

The method may further include compressing an upper surface of the conductive ball seated on the pad.

According to the embodiment of the present invention, all printed circuit boards can be manufactured using one general-purpose mask, thereby reducing the unit cost.

1A to 1E are cross-sectional views illustrating a method for manufacturing a printed circuit board of the prior art.
2 is a view showing a metal mask according to the prior art.
3 is a diagram illustrating a first mask and a second mask according to an embodiment of the present invention.
FIG. 4 is a view illustrating a ball mask formed using a plurality of masks shown in FIG. 3.
5 is a cross-sectional view illustrating a printed circuit board according to an exemplary embodiment of the present invention.
6 to 13 are cross-sectional views illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION 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. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

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 .

Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

The present invention is economical and reliable by forming a circuit pattern on the seed layer using the seed layer formed on the insulating plate, and forming a bump on the circuit pattern using the same seed layer as the seed layer used to form the circuit pattern. Provides an advantageous circuit board from the side.

Hereinafter, a ball mask and a method of manufacturing a printed circuit board using the same will be described with reference to FIGS. 3 to 13.

3 is a diagram illustrating a first mask and a second mask according to an embodiment of the present invention.

Referring to FIG. 3, a ball mask according to an embodiment of the present invention may include a first mask 16 having a first opening 161 formed in a region corresponding to a mounting point of a conductive ball, and a first mask 16. The second mask 17 may cover at least one of the first openings 161 formed therein.

In the first mask 16, a first opening 161 is formed in an area corresponding to a mounting point of the conductive ball.

The first opening 161 has the same width as the diameter of the conductive ball or larger than the diameter of the conductive ball. At this time, the first opening 161 is preferably formed to have a width slightly larger than the diameter of the conductive ball in order to pass the conductive ball.

The first mask 16 is formed on a substrate. At this time, the first mask 16 is preferably formed of a metal material for the stable mounting of the conductive ball. In other words, the first mask 16 is formed of a metal material as described above so that the first mask 16 can be easily separated without damaging the substrate.

At this time, the first openings 161 formed in the first mask 16 are also formed in regions other than the mounting point of the conductive balls.

In other words, in the first mask 16, a first opening 161 is formed in a region corresponding to the mounting point of the conductive ball that satisfies all product standards. To this end, a plurality of first openings 161 are formed in the first mask 16 at intervals of about 1 to 2 μm.

At this time, an opening corresponding to a point where the conductive ball is to be mounted is substantially present among the first openings 161 formed in the first mask 16, and an opening corresponding to the unmounted point of the conductive ball may also exist.

The second mask 17 covers an opening corresponding to an unmounted point of the conductive ball among the first openings 161.

More preferably, the second mask 17 exposes a first opening 161 corresponding to a mounting point of the conductive ball among the first openings 161, and a first opening corresponding to the unmounted point of the conductive ball. It has a second opening 171 covering 161.

The second mask 17 may be formed of a metal material in the same manner as the first mask 16. However, in order to reduce cost, the second mask 17 is preferably a dry film which is cheaper than a metal material.

FIG. 4 is a view illustrating a ball mask formed using a plurality of masks shown in FIG. 3.

Referring to FIG. 4, in accordance with an embodiment of the present invention, a ball mask is formed by attaching a second mask 17 having a second opening 171 over a first mask 16 having a first opening 161. .

That is, the first mask 16 is used as a general purpose mask having a first opening 161 that satisfies all product specifications.

The second mask 17 is attached to the first mask 16 and covers at least one of the first openings formed in the first mask so as to correspond to the standard of the currently manufactured printed circuit board.

In other words, the second mask 17 is attached to the first mask 16 to form a first opening (1) corresponding to the mounting point of the conductive ball among the first openings 161 formed in the first mask 16. 161 is exposed and covers the first opening 161 corresponding to the unmounted point of the conductive ball.

At this time, the second opening 171 of the second mask 17 is located in the entire area of the first opening 161 (a) corresponding to the mounting point of the conductive ball, and is located at the unmounted point of the conductive ball. The second opening 171 of the second mask 17 is not positioned in at least one region of the corresponding first openings 161 and b to be covered.

In this case, the second opening 172 may be formed to have a width larger than the width of the first opening 161.

That is, when the width of the first opening 161 is greater than the width of the second opening 172, a portion of the second mask 17 is exposed between the first openings 161, thereby printing The separation process from the circuit board is unlikely to be performed normally.

In addition, the second mask 17 may be replaced with another mask meeting the product standard. That is, the second mask 17 may be replaced with another mask to expose only the first opening 161 of the first mask 16 corresponding to the standard of the printed circuit board currently manufactured.

In other words, the first mask 16 may be used as a general-purpose mask, and the second mask 17 may be replaced with a different mask to meet a standard of a printed circuit board manufactured.

In addition, since the second mask 17 is made of a relatively inexpensive dry film, even if the second mask is manufactured for each product standard as described above, the second mask 17 does not significantly affect the production cost.

3 and 4 illustrate that the first opening 161 formed in the first mask 16 and the second opening 171 formed in the second mask 17 have a circular shape. The first opening 161 and the second opening 171 may be formed to have any one of an oval shape, a triangle shape, a rectangle shape, and a polygon shape only as an embodiment.

As described above, according to the ball mask according to the embodiment of the present invention, it is possible to provide a ball mask that satisfies all product standards by using a first mask made of a metal material and a second mask made of a dry film. This can lower the cost of the product.

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

Referring to FIG. 5, the printed circuit board includes an insulating plate 11, a pad 15 formed on the insulating plate 11, a solder resist 14 formed on one side of the pad 150, and the pad. And a solder ball 20 seated on the 150.

The insulating plate 11 may be a supporting substrate of a printed circuit board on which a single circuit pattern is formed, but may also mean an insulating layer region in which one circuit pattern is formed among printed circuit boards having a plurality of stacked structures.

When the insulating plate 11 means 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 11.

The insulating plate 11 may be a thermosetting or thermoplastic polymer substrate, a ceramic substrate, an organic-inorganic composite material substrate, or a glass fiber impregnated substrate, and when the polymer resin is included, may include an epoxy-based insulation resin. It may alternatively include polyimide resin.

A plurality of pads 12 are formed on the insulating plate 11. The pad 12 serves as a solder ball seating area for mounting the device.

A solder resist 14 is formed on the insulating plate 11 to expose a portion of the formed pads 12.

In addition, the solder balls 20 are seated between the formed solder resists 14, that is, on the pads 15.

6 to 13 are cross-sectional views illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

6 and 7, in order to manufacture a printed circuit board, an insulating plate 11 is prepared, and a metal layer 12 is formed on the insulating plate 11.

The insulating plate 11 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 11 includes a polymer resin, the insulating plate 11 may include an epoxy-based insulating resin. Alternatively, a polyimide resin may be included.

In addition, the metal layer 12 formed on the insulating plate 11 may be formed by electroless plating on the insulating plate 11. Alternatively, a copper clad laminate (CCL) may be used.

Referring to FIG. 8, when the insulating plate 11 having the metal layer 12 is prepared, the metal layer 12 formed on the insulating plate 11 is etched to form a pad 13 on the insulating plate 11. Form. Here, the pad 13 may be formed using a conventional etching method.

9, the pad 13 is exposed, and a solder resist 14 is formed on the substrate 11.

Thereafter, referring to FIG. 10, when the solder resist is formed, a flux 15 is applied on the exposed pad 13. The flux 15 provides adhesion between the solder ball 20 seated on the pad 13 and the pad 13.

Subsequently, referring to FIG. 11, the substrate 10 to which the flux 15 is applied as described above is placed on a separate accommodating part (not shown) capable of accommodating the substrate.

When the substrate 10 is placed in the receiving portion, a ball mask is formed on the substrate 10.

The ball mask may be formed to be spaced apart from the solder resist 14 or the pad 13 formed on the substrate 10 by a predetermined interval, thereby preventing a wound occurring in the solder resist 14 or the pad 13 in advance. have.

In this case, the ball mask is formed of a first mask 16 and a second mask 17.

A plurality of first openings 161 are formed in the first mask 16, and a plurality of second openings 171 are formed in the second mask 17.

The first opening 161 exposes the pad 13 formed on the substrate 10. At this time, since the first opening 161 is formed in the first mask 16 which is used for general purposes, other areas other than the pad 13 are also exposed.

Accordingly, the second mask 17 exposes the first opening 161 formed on the pad 13 using the second opening 171 and covers other exposed areas except the pad 13. .

That is, the ball mask is formed by attaching the second mask 17 having the second opening 171 on the first mask 16 having the first opening 161. The first mask 16 is a general purpose mask having a first opening 161 that satisfies all product specifications.

In addition, the second mask 17 is attached to the first mask 16, at least one of the first openings 161 formed in the first mask so as to correspond to the standard of the currently manufactured printed circuit board 1 covers the opening 161.

In other words, the second mask 17 is attached on the first mask 16 to correspond to the mounting point (pad formation point) of the conductive balls among the first openings 161 formed in the first mask 16. The first opening 161 is exposed and covers the first opening 161 corresponding to the unmounted point (the point at which the pad is not formed) of the conductive ball.

That is, the second opening 171 of the second mask 17 is located in the first opening 161 existing in the region where the pad 13 is formed, whereby the pad 13 is the first opening. It is exposed to the outside by the opening 161 and the second opening 171.

In addition, the second opening 171 of the second mask 17 is not located or only a part of the second opening 171 is positioned in the first opening 161 located in the region where the pad 13 is not formed. Done. In this case, the first opening 161 has a width for passing the solder ball 20, and the whole or part of the first opening 161 is covered by the second mask 17. The solder ball 20 does not pass through the region.

To this end, the first opening 161 has a width equal to or slightly larger than the diameter of the solder ball 20, so that only one solder ball 20 passes through one opening 161. Be sure to

In addition, the second opening 171 has a width larger than the width of the first opening 161.

Thereafter, referring to FIG. 12, the solder ball 20 is dropped onto the ball mask formed by the first mask 16 and the second mask 17.

The solder ball 20 drop may use a separate solder ball mounting device (not shown) which drops the sucked solder ball by releasing the vacuum while the solder ball 20 is sucked by the vacuum. .

At this time, the solder ball 20 dropped to the area exposed through the first opening 161 and the second opening 171 is pad 13 formed on the substrate 10 by the applied flux 15 It is seated on the top.

Next, referring to FIG. 13, the solder balls 20, which are not seated on the pad 13, of the dropped solder balls 20 are removed.

The solder ball removal may be performed by suctioning the solder ball 20 dropped on the substrate using a separate suction device.

That is, the suction device sucks the solder balls 20 that are not seated on the pad 13 of the substrate 10 among the dropped solder balls 20.

At this time, when the dropped solder ball 20 is sucked, the solder ball seated on the pad 13 is not sucked by the suction device by the applied flux, and remains on the pad 13 continuously. do.

Next, as shown in FIG. 14, the ball mask formed on the substrate 10 is removed.

Then, the flux applied on the pad 13 is removed through a washing process, and the upper surface of the solder ball 20 is flattened by compressing the solder ball 20 through a coin process.

As described above, according to the embodiment of the present invention, by providing a ball mask that meets all product specifications using a mask made of a metal material and a dry film that can be used for general purposes, it is possible to lower the manufacturing cost of the product have.

In addition, the preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be able to various modifications, changes, substitutions and additions through the spirit and scope of the appended claims, such modifications and modifications are the following patents It should be regarded as belonging to the claims.

10: printed circuit board
13: pad
14: solder resist
16: first mask
17: second mask
20: solder ball

Claims

A first mask having a first opening formed in a mounting region of the conductive ball and a region other than the mounting region; And
A second opening attached to one surface of the first mask and exposing a first opening formed in a mounting area of the conductive ball, and covering at least a portion of the first opening formed in a region other than the mounting area; Includes 2 masks,
The first mask is a metal mask formed on the substrate,
The second mask is a dry film attached on the first mask,
And a width of the first opening is smaller than a width of the second opening.

The method of claim 1,
And the second mask has a second opening that exposes a portion of at least one first opening formed in the first mask.

delete

The method of claim 2,
The first and second openings of the ball mask is formed in the form of any one of oval, round, triangle, square and polygon.

delete

The method of claim 1,
A ball mask having at least one surface of the second mask is formed with an adhesive for attachment to the first mask.

Preparing a substrate on which a pad is formed;
Positioning a first mask having a first opening with a first opening formed on the pad corresponding to the mounting area of the conductive ball and in a region other than the mounting area;
Attaching a second mask having a second opening formed on the first mask to cover at least a portion of the first opening formed in a region other than the mounting region while exposing the first opening formed in the mounting region of the conductive ball. step; And
Dropping the conductive ball over the second mask to seat the conductive ball over a pad located below the exposed first opening,
The first mask is a metal mask, the second mask is a dry film attached on the first mask,
The width of the first opening is less than the width of the second opening using a ball mask manufacturing method of a printed circuit board.

delete

The method of claim 8,
The first and second openings of the printed circuit board manufacturing method using a ball mask formed in any one of the shape of oval, circle, triangle, rectangle and polygon.

delete

The method of claim 8,
The method of manufacturing a printed circuit board using a ball mask further comprises the step of pressing the upper surface of the conductive ball seated on the pad.