KR20150022211A - Display panel, ic chip and liquid crystal display device having fan-shaped arrangement structure of pads and bumps - Google Patents

Abstract

Disclosed are a display panel, an IC chip and a liquid crystal display device having a fan-shaped arrangement structure of pads and bumps. A display panel according to an embodiment of the present invention includes electrode pads arranged along one direction. In the electrode pad, the pads except for a center pad around the center pad have a slope of a preset angle. Also, an IC chip according to an embodiment of the present invention includes bumps arranged along a direction of an IC. In the bump, the bumps except for a center bump around a center bump have a slope of a preset angle. Meanwhile, a liquid crystal display according to the embodiment of the present invention includes the display panel and the IC chip. The electrode pad of the display panel respectively match the bump of the IC chip. The electrode pads and the bumps which correspond to each other have a slope of the same angle. The electrode pads and the bumps are bonded for electrical connection.

Description

TECHNICAL FIELD [0001] The present invention relates to a display panel, an IC chip, and a liquid crystal display device having a fan-shaped pad and a bump array structure.

The present invention relates to a display panel, an IC chip and a liquid crystal display device having a sector-shaped electrode pad and a bump array structure, and more particularly to a display panel, an IC chip and a liquid crystal display device using electrode pads and bumps An IC chip and a liquid crystal display device for increasing a misalignment margin.

The most important factors in the display are picture quality and response speed, which is the display module. In order to speed up the response speed of the display, the IC chip is bonded directly to the panel in a small display. The method of bonding the IC chip directly to the display panel is referred to as COG (Chip on Glass).

COG bonding is one of the bonding methods used in the display module mounting technology, and is a mounting method corresponding to the miniaturization of the connection pitch due to the ultra-thin and light weight. Is a bonding technique in which bumps (conductive electrodes) are formed on an IC pad in a state of a semiconductor wafer, and these IC chips are directly connected to the display panel.

FIG. 1 is a schematic view showing a form in which a display panel and an IC chip are bonded. Referring to FIG. 1, the position where the IC chip 200 is bonded on the display panel 100 can be confirmed. In the COG method, the IC chip is bonded directly to the display panel, and a thin display device can be manufactured in comparison with a method prior to COG.

In the COG bonding process, anisotropic conductive film (ACF) is bonded to a display panel on which a circuit is drawn. Thereafter, the protective film of the ACF is removed, and the pattern of the IC chip and the pattern of the display panel are aligned and then bonded at a proper temperature and pressure, thereby completing the COG module.

In this case, the applied temperature is 170 ° C to 210 ° C, and misalignment occurs between the bump and the electrode pad after bonding because the thermal expansion coefficient of the IC chip is larger than that of the panel. Since the IC chip expands around the central portion when it expands, the misalignment that occurs at this time occurs more in the both end regions than in the central region, and such misalignment can be confirmed through FIG. 2 and FIG.

FIG. 2 shows an arrangement structure of electrode pads and bumps according to the related art, wherein the bumps formed on the IC chip and the electrode pads formed on the panel correspond one to one with each other. In this case, And the speed of response.

In addition, as the display device needs to be manufactured in a small area in accordance with the trend of low cost, large size, and high performance, the pitch is continuously made finer and therefore it is important to maximize the contact area between the electrode pad and the bump Do.

On the other hand, the electrode pads and the bumps according to the related art are formed perpendicular to the longitudinal direction (the transverse direction in the drawing) of the IC chip, and each have a constant size and an interval.

FIG. 3 shows the misalignment after the bonding of the electrode pad and the bump through the COG process. It can be seen that the degree of misalignment in both end regions A and B is larger than the misalignment in the center region.

Therefore, the contact area between the electrode pad and the bump in both end regions A and B is smaller than the contact area in the center region, which adversely affects the display quality.

As described above, when the electrode pads and the bumps are designed to be the same in the center region and the both end regions of the IC chip and the display panel, the problem caused by misalignment in the both end regions becomes larger. Therefore, .

Japanese Patent No. 0447233 'liquid crystal display device'

An object of the present invention is to provide a display panel, an IC chip and a liquid crystal display device capable of maximizing a contact area even if misalignment occurs between bumps and electrode pads.

According to an aspect of the present invention, there is provided a display panel including a plurality of electrode pads arranged along one direction, wherein the electrode pads are arranged such that the remaining pads are inclined at a predetermined angle around the center pads Respectively.

The angle may be between 0 and 45 degrees, and the plurality of electrode pads may be formed symmetrically with respect to the center pad, and the angle may be increased as the angle is away from the center pad.

Meanwhile, the IC chip according to an embodiment of the present invention includes a plurality of bumps arranged along one direction, and the bumps are formed such that the remaining bumps are inclined at a predetermined angle with respect to the center bumps.

Also, the angle may be between 0 and 45 degrees, and the plurality of bumps may be formed symmetrically about the center bump, and the angle may become larger as the angle is further away from the center bump.

According to another aspect of the present invention, there is provided a liquid crystal display device including the display panel and the IC chip, wherein the electrode pads of the display panel and the bumps of the IC chip correspond to each other with one- And the electrode pad and the bump are electrically connected by bonding.

The display panel and the liquid crystal display device according to the present invention can provide a display panel, an IC chip and a liquid crystal display device capable of maximizing a contact area even if misalignment occurs between bumps and pads in a COG bonding process.

1 is a schematic view showing a form in which an IC chip and a display panel are bonded.
2 is a schematic view showing an arrangement structure of electrode pads and bumps according to the prior art.
3 is a schematic view showing misalignment after COG bonding is performed using electrode pads and bumps arranged according to the prior art.
4 is an enlarged view showing misalignment in both end regions in Fig.
5 is a schematic view showing an arrangement structure of electrode pads and bumps according to an embodiment of the present invention.
6 is a schematic view showing misalignment after COG bonding is performed using the arrangement structure of electrode pads and bumps according to an embodiment of the present invention.
7A and 7B are detailed views showing contact areas between electrode pads and bumps according to the prior art and one embodiment of the present invention.
Figs. 8A and 8B are enlarged views showing misalignment in the left end region of Fig. 6. Fig.
9 is an enlarged view showing contact areas between the corresponding bumps and electrode pads in both end regions.
10 is a schematic view showing a gap between each bump and an interval between the electrode pads when the bump and the electrode pad according to the present invention are inclined by 45 degrees.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a display panel and a liquid crystal display device having a fan-shaped pad and a bump array structure according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the following description, only parts necessary for understanding the operation according to the embodiment of the present invention will be described, and descriptions of other parts may be omitted so as not to disturb the gist of the present invention.

In addition, terms and words used in the following description and claims should not be construed as limited to ordinary or dictionary meanings, and the terms used in the specification and claims should not be construed as meaningless, As well as the concept.

5 is a schematic view showing an arrangement structure of bumps of an electrode pad and an IC chip of a display panel according to an embodiment of the present invention.

Referring to FIG. 5, the electrode pad according to an embodiment of the present invention will be described. In the display panel, the electrode pads are arranged along one direction (the horizontal direction in the drawing) of the display panel, And the remaining pads are formed to have a slope at a predetermined angle with respect to the center pad formed in the central region of the pad.

The center pad may be a plurality of pads generated in the center region of the display panel, or one or a pair of pads positioned in the center of all the pads formed in a row.

Meanwhile, the IC chip according to an embodiment of the present invention includes a plurality of bumps arranged along one direction of the IC chip, like the display panel, and the bumps are arranged such that the remaining bumps are inclined at a predetermined angle Respectively.

The bumps formed on the IC chip are arranged in a shape corresponding to the electrode pads formed on the display panel and the corresponding electrode pads and the bumps are electrically connected to form a liquid crystal display device to be described later, Are very similar.

Referring to FIG. 5, the electrode pads and the bumps according to the embodiment of the present invention are symmetrically formed around the center pads and the center bumps to form a fan shape. Therefore, a pair of electrode pads and bumps facing each other with respect to the center pad and the center bump have the same absolute value angles.

Therefore, the bumps formed on the IC chip may be one or a pair of bumps located at the center of all the bumps formed in a row, as in the case of the electrode pads formed on the display panel.

Meanwhile, in the liquid crystal display device according to an embodiment of the present invention, the electrode pads and the bumps after the IC chip and the display panel are bonded show a shape as shown in Fig.

As described above, the present invention is intended to provide a display panel, an IC chip, and a liquid crystal display device capable of maximizing a contact area even if misalignment occurs between a bump and an electrode pad, And the array structure of the bumps are means for achieving the above object. Specific effects through the arrangement structure will be described in more detail below.

Fig. 4 is an enlarged view showing misalignment in the both end regions in Fig. 3, showing misalignment after the COG process in the case of having an electrode pad and a bump arrangement structure according to the prior art.

Referring to FIG. 4, misalignment occurring in both end regions A and B can be confirmed in more detail. In this case, when misalignment of 5 μm is generated in the outermost electrode pad 10 and the bump 20 As an example, and can be more easily understood by comparing it with the arrangement of the electrode pads and bumps in Fig.

The misalignment specification in a typical COG apparatus is defined as ± 5 μm. If the bumps that are farther in the outward direction than the electrode pads in the both end regions where the largest misalignment occurs are separated to the left or right by more than 5 μm, .

The misalignment specification may have a difference depending on equipment to be used, and an expensive equipment may have a misalignment specification to a small extent. However, in the present specification and the drawings, a general COG equipment having a misalignment specification of 5 mu m will be used as a reference.

In general, the electrode pad and the bump are formed in the same shape and size. Here, the electrode pad 10 and the bump 20 having a width of 15 mu m and a length of 100 mu m will be described as an example.

6 is a schematic view showing misalignment after COG bonding is performed using the arrangement structure of electrode pads and bumps according to an embodiment of the present invention.

Referring to FIG. 6, as can be seen in FIG. 3, the bumps are separated from each other by a predetermined distance in the outward direction relative to the corresponding electrode pads, and misalignment occurs. In the end regions A 'and B' A large misalignment occurs.

On the other hand, the misalignment occurring in the COG process is caused by the thermal expansion occurring in the longitudinal direction based on the center portion of the IC chip, and the thermal expansion occurring in the height direction of the IC chip is relatively negligible. It shall not be considered in the area calculation process.

7A and 7B are detailed views showing contact areas between electrode pads and bumps according to the prior art and one embodiment of the present invention.

Referring to FIG. 7A, in the left end region A, the bump 20 is shifted to the left by 5 占 퐉 as compared with the electrode pad 10, (10 占 퐉) × length (100 占 퐉) = 1,000 占 퐉 ² .

As described above, since 5 탆 is a misalignment specification of a general COG equipment, it means that normal bonding can be recognized until a contact area of at least 1,000 탆 ² is secured.

Meanwhile, FIG. 7B shows a state in which the electrode pad and the bump are in contact with each other at a predetermined angle according to an embodiment of the present invention. As in the case of FIG. 7A, a case where a misalignment of 5 mu m occurs will be described as an example.

The contact area S is as follows when the electrode pad and the bump are inclined by θ with respect to the height direction (vertical direction in the figure) of the display panel and the IC chip.

S = B x C

 = (15-A ') x (100-A)

 = (15-5cos?) X (100-5sin?)

According to the above equation, the angle θ in accordance with increases from 0 degrees to 90 degrees, the contact area can be seen that increases in 1,000㎛ ² to 1,425㎛ ^2, according to one embodiment of the invention the electrode pad and the bump predetermined size It can be seen that a wider contact area is obtained as compared with the arrangement according to the prior art.

Figs. 8A and 8B are enlarged views showing misalignment in the left end region of Fig. 6. Fig.

8A and 8B are diagrams illustrating a case where the angle between the electrode pad and the bump with respect to the height direction of the IC chip 200 is 30 degrees and 45 degrees, respectively, when a misalignment of 5 mu m is generated, And areas S1 and S2.

As described above, it is assumed that misalignment occurs only in the longitudinal direction of the IC chip, and misalignment of 5 mu m, which is a misalignment specification in general equipment, is generated.

In this case, the contact area has a rectangular shape as shown in the figure, and can be calculated by a simple expression of (15 탆 - A) x (100 탆 - A).

First, in the case of FIG. 8A,

A = 5 mu m x cos 60 DEG = 2.5 mu m,

A '= 5 mu m x cos 30 DEG = 4.33 mu m,

S1 = (15 占 퐉 - 4.33 占 퐉) 占 (100 占 퐉 - 2.5 占 퐉)? 1040.33 占 퐉 ²

.

On the other hand, in the case of FIG. 8B,

A = 5 占 퐉 占 cos45 占 3.54 占 퐉,

S2 = (15 mu m-3.5 mu m) x (100 mu m-3.5 mu m) 1105.43 mu m ²

.

The contact areas S1 and S2 when the angle between the electrode pads and the bumps are 30 ° and 45 ° are 40.33 ㎛ ² and 105.43 탆 ² wider than those of the conventional arrangement having no inclination, Of products can be expected.

Further, as described above, the influence due to the thermal expansion of the IC chip is greater in the both end regions than in the central region, so that the contact area between the electrode pad and the bump becomes narrower in both end regions.

8A and 8B, in the arrangement of the electrode pads and bumps according to the embodiment of the present invention, it is preferable that the angle increases as the distance from the center pad increases.

The angle is increased in proportion to the distance from the center pad or a plurality of electrode pads are grouped into a group from the center area to equalize the angles of the electrode pads belonging to the same group, Embodiments in which the angle of the pad is made smaller may also be possible.

9 is an enlarged view showing the maximum misalignment distance for obtaining a contact area when there is no angle when the angle between the electrode pad and the bump is 45 degrees.

It has been previously described that the contact area between the electrode pad and the bump satisfying the misalignment specification in the general COG equipment is 1,000 μm ² . Accordingly, when the arrangement of the electrode pads and bumps inclined at a certain angle is used, the misalignment distance that can ensure a contact area of at least 1,000 μm ² is obtained. As a result, the arrangement of the electrode pads and the bumps according to the present invention It is possible to explain whether or not the effect of the present invention is improved.

Referring to FIG. 9, the contact area S3 is assumed to be 1,000 占 퐉 ² , the slope of the electrode pad and the bump is 45 占 and the misalignment distance is represented by M.

The maximum misalignment distance M is obtained by the same calculation as the method calculated in FIGS. 8A and 8B.

Using the equations S3 = (15 占 퐉 A 占 100 占 퐉 A = 1000 占 퐉 ² and A = M 占 sin45 占 the maximum misalignment distance M is about 6.04 占 퐉, The contact area of 1000 mu m < ² > is ensured when misalignment of 6.04 mu m occurs.

The misalignment distance is about 1.04 μm more than 5 μm, which is a small value. However, since the numerical value is improved by 20% or more in comparison with 5 μm in micro-fine processing, a large gain can be seen in the misalignment margin. Even if misalignment of 占 퐉 occurs, it is not classified as defective, so productivity can be expected to be improved.

10 is a schematic view showing the interval between the bumps and the interval between the electrode pads when the bumps are tilted by 45 degrees according to the present invention.

Referring to FIG. 10, as the angle increases, the gap between the bump and the bump, and the electrode pad and the electrode pad become farther apart. When the angle is 45 degrees, the interval is about 1.4 times as large as the case where there is no angle .

Since the width of the IC chip on which the bumps are formed can not be increased beyond a predetermined length, if the bumps and the electrode pads have a slope of more than a predetermined angle, the pitch is excessively large. In the example, it is limited to 45 degrees.

Meanwhile, a liquid crystal display device according to an embodiment of the present invention includes a display panel including an electrode pad having the arrangement structure as described above, and an IC chip including bumps, wherein the electrode pad of the display panel and the IC The bumps of the chip correspond to each other on a one-to-one basis, and the electrode pads and the bumps corresponding to each other have the same gradient, and the electrode pads and the bumps are electrically connected by bonding.

Therefore, the liquid crystal display device specifically includes an electrode pad or an array of bumps as shown in FIG. 5, and the bonded shape of the electrode pad and the bump after performing the COG process is as shown in FIG. 6 .

In the liquid crystal display device, some of the bumps are shifted outward by a predetermined distance from the corresponding electrode pads, which is caused by the thermal expansion of the IC chip. And since the effect of this thermal expansion is greater in both end regions than in the central region, the distance becomes larger as the distance from the central pad or the central bump is increased.

100: display panel 200: IC chip
10: electrode pad 20: bump

Claims (10)

And a plurality of electrode pads arranged along one direction of the display panel, wherein the electrode pads are formed such that the remaining pads have a slope at a predetermined angle with respect to the center pads.
The method according to claim 1,
Wherein the angle is between 0 and 45 degrees.
The method according to claim 1,
Wherein the plurality of electrode pads are formed symmetrically with respect to the center pad.
The method according to claim 1,
And the angle increases as the distance from the center pad increases.
And a plurality of bumps arranged along one direction of the IC chip, wherein the bumps are formed such that the remaining bumps are inclined at a predetermined angle with respect to the center bumps.
6. The method of claim 5,
And the angle is between 0 and 45 degrees.
6. The method of claim 5,
Wherein the plurality of bumps are symmetrically formed about the center bumps.
6. The method of claim 5,
And the angle increases as the distance from the center bump increases.
A display panel according to any one of claims 1 to 4; And
An IC chip according to any one of claims 5 to 8;
/ RTI >
The electrode pads of the display panel and the bumps of the IC chip correspond to each other in a one-to-one correspondence, and the electrode pads and the bumps corresponding to each other have the same gradient, and the electrode pads and the bumps are electrically connected by bonding. .
10. The method of claim 9,
Wherein the bonding uses a COG bonding technique.

Images