JP2001042785A - Packaging structure of ic chip, liquid crystal device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody a highly reliable conducting and connecting state between an IC chip and a substrate in a packaging structure of the IC chip. SOLUTION: This IC chip packaging structure 3 is constituted by packaging the IC chip 19 having bumps 23 on a substrate 18 having metallic film patterns 22 by an ACF(anisotropic conductive film) 24 in such a manner that the bumps 23 and the metallic film patterns 22 are conducted and connected to each other. The metallic film patterns 22 are patterned and formed so as to extend in the central direction of the IC chip 19 beyond the bumps 23, by which the metallic film patterns 22 of the portions having a sufficient width and thickness may be conducted and connected by evading the convergent parts and tapered thin portions formed at the front ends of the metallic film patterns 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an IC chip mounting structure in which an IC chip is mounted on a substrate. The present invention also relates to a liquid crystal device configured using the mounting structure of the IC chip. Further, the present invention relates to an electronic device including the liquid crystal device.

[0002]

2. Description of the Related Art At present, liquid crystal devices are widely used in various electronic devices such as portable telephones and portable information terminals. In many cases, the liquid crystal device is used to display images such as characters, numbers, and patterns.

In this liquid crystal device, pixels are generally formed by intersecting scanning electrodes formed on one substrate with data electrodes formed on the other substrate at a plurality of points in a dot matrix. By selectively changing the applied voltage, light passing through the liquid crystal belonging to the pixel is modulated, thereby displaying an image such as a character. In addition, in addition to or in addition to the dot pixels in the dot matrix shape, a pattern-shaped electrode such as an appropriate numeral or picture may be formed on each substrate.

In this liquid crystal device, in general, a scanning voltage is applied to a scanning electrode by a liquid crystal driving IC and a data voltage is further applied to a data electrode to modulate light passing through each selected pixel portion. Thus, an image such as a character or a number is displayed outside one of the substrates.

Various methods for connecting a liquid crystal driving IC, that is, an IC chip to a liquid crystal device have been conventionally known. For example, an IC is mounted on a relatively thin flexible printed circuit (FPC).
A chip is mounted to form an IC chip mounting structure, and the mounting structure of the IC chip is connected to a substrate which is a component of a liquid crystal device, so-called COF (Chip On FPC (Fle)).
xible Printed Circuit)) method is known.

Further, a so-called COG (Chip On Chip) having a structure in which an IC chip is directly mounted on a substrate constituting a liquid crystal device.
Glass) method is also known. In this case, the liquid crystal device itself is one of the components of the mounting structure of the IC chip.

[0007]

If the mounting structure of the COF system is taken as an example, the mounting structure of the COF system is formed by forming a metal film pattern 62 on a base layer 61 as shown in FIG. To produce an FPC 68,
By mounting the IC chip 69 in an appropriate position using the ACF 64.

[0008] The tip inside the metal film pattern 62 is an IC.
The area where the chip 69 is mounted and the IC chip 6
9, the bumps 63 formed on the active surface 69a of the IC chip 69 have the ACF6 on the tip of the metal film pattern 62.
4 for conductive connection.

In the conventional mounting structure, as shown in FIG.
The shapes and dimensions of the metal film patterns 62 are defined so as to substantially coincide with the ends of the metal film patterns 62. Further, the metal film pattern 62 is generally formed into a desired pattern by a patterning process such as etching, electrolytic plating, or the like.
In many cases, the distal end of the taper 2 is formed in a chamfered state, for example, a tapered shape 62a in a rounded chamfered state.

Further, as shown in FIG. 6B, the tip of the metal film pattern 62 formed by the above-mentioned patterning process has a thin sectional shape 6 which is cut off in a tapered shape.
2b. As described above, the tapered shape 62a and the tapered cross section 62b of the metal film pattern 62
Therefore, the conventional mounting structure has a problem that the connection reliability between the bump 63 on the IC chip side and the metal film pattern 62 on the substrate side is reduced.

The present invention has been made in view of the above problems, and has as its object to realize a highly reliable conductive connection between an IC chip and a substrate.

[0012]

Means for Solving the Problems (1) In order to achieve the above object, the mounting structure of the IC chip according to the present invention is as follows.
In an IC chip mounting structure in which an IC chip having a C-side terminal is mounted on a substrate having a substrate-side terminal so that the IC-side terminal and the substrate-side terminal are conductively connected, the substrate-side terminal is It is formed so as to extend toward the center of the IC chip beyond the IC side terminal.

According to this mounting structure, the substrate side terminal is an IC.
Since it is formed so as to extend toward the center of the IC chip beyond the side terminal, the width and thickness of the substrate side terminal are sufficiently large and constant, avoiding the tapered portion and the tapered cross-section of the substrate side terminal. The portion can be connected to the IC side terminal, and as a result, a highly reliable conductive connection state can be obtained.

(2) In the mounting structure of an IC chip having the above structure, the substrate is a substrate in which a metal film pattern as a substrate-side terminal is formed on a flexible base layer, ie, an FPC.
(Flexible Printed Circuit). F
Since the PC has flexibility, the position of the metal film pattern formed thereon is easily changed. Therefore, this FPC has IC
When a chip is mounted, a situation is likely to occur in which the position of the metal film pattern changes and the conductive connection between the metal film pattern and the IC side terminal cannot be made well. However, if the configuration as described in (1) above is employed, a sufficiently reliable conductive connection state can be obtained even for such an FPC.

(3) In the IC chip mounting structure having the above-mentioned structure, the substrate and the IC chip can be conductively connected by an anisotropic conductive adhesive.

The anisotropic conductive adhesive material is used for electrically connecting the pair of terminals anisotropically by including conductive particles in a dispersed state in the adhesive material. It is a conductive adhesive substance. If the adhesive substance is an adhesive polymer resin film, a so-called ACF (Anis)
When an adhesive substance is a paste-like adhesive, a so-called ACA (Anisotropic Conductive Adhesive: anisotropic conductive adhesive) is formed.

When an anisotropic conductive adhesive is used, the conductive particles contained therein make conductive connection between the IC side terminal and the substrate side terminal. Therefore, it is ideally desirable that as many conductive particles as possible be captured between the terminals. In this regard, in a structure in which the tapered portion 62a (FIG. 6A) and the tapered cross-section 62b (FIG. 6B) of the substrate-side terminal overlap the IC-side terminal as in the conventional mounting structure, The number of conductive particles captured between the IC-side terminal and the substrate-side terminal, that is, the capture rate of the conductive particles is reduced, and therefore, it may be difficult to obtain a highly reliable conductive connection state.

On the other hand, if the substrate side terminal is set so as to extend in the center direction of the IC chip beyond the IC side terminal as in the above (1), the tapered portion and the tapered cross section of the substrate side terminal can be formed. By avoiding this, a portion where the width and thickness of the substrate-side terminal is sufficiently large and constant can be connected to the IC-side terminal, and as a result, the capture rate of the conductive particles between the substrate-side terminal and the IC-side terminal Can be kept high and therefore
A highly reliable conductive connection state can be obtained.

(4) Regarding the mounting structure of the IC chip having the above configuration, the length of the substrate side terminal extending beyond the IC side terminal is set to ΔL, and the length of the IC side terminal in the length direction of the substrate side terminal is determined. Assuming that the corresponding length is L, it is desirable to set those dimensions to ΔL ≧ L / 5. According to this dimension setting, a portion where the width and the film thickness of the substrate-side terminal are sufficiently large and constant can be reliably corresponded as a conductive connection portion to the IC-side terminal.

(5) With regard to the mounting structure of the IC chip having the above-described structure, a plurality of types having different widths may be formed as the substrate-side terminals. In the mounting structure having such a structure, it is desirable that the length of the board side terminal extending beyond the IC side terminal is set to a length dimension inversely proportional to the width of the board side terminal. In this case, a sufficient conductive connection state can be obtained without increasing the extension of the substrate-side terminal more than necessary.

(6) Next, the liquid crystal device according to the present invention comprises:
A pair of substrates facing each other, a liquid crystal sealed between the substrates, and a mounting structure of an IC chip connected to at least one of the pair of substrates. It is a mounting structure of the IC chip described in (1) to (5).

(7) Next, the electronic device according to the present invention
In an electronic apparatus including a liquid crystal device and a housing for accommodating the liquid crystal device, the liquid crystal device includes the liquid crystal device described in (6). As such an electronic device, for example, a mobile phone, a portable information terminal, or the like can be considered.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an IC chip mounting structure according to the present invention will be described with reference to the accompanying drawings, taking as an example a case where a liquid crystal driving IC as an IC chip is mounted on an FPC. explain. An embodiment of a liquid crystal device according to the present invention will be described by taking a COF type liquid crystal device as an example. Embodiments of an electronic device according to the present invention will be described using a mobile phone as an example.

(First Embodiment) FIG.
1 illustrates one embodiment of a mounting structure of a C chip and a liquid crystal device. The liquid crystal device 1 shown here is formed by mounting an IC chip mounting structure 3 on a liquid crystal panel 2 and, if necessary, attaching a lighting device (not shown) such as a backlight or other auxiliary equipment. You.

The liquid crystal panel 2 has a pair of substrates 4a and 4b facing each other, and these substrates are adhered to each other by a sealing material 6 around them. These substrates 4
a and 4b are manufactured by forming electrodes and other necessary elements on a substrate material formed of a hard light-transmitting material such as glass or a flexible light-transmitting material such as plastic. .

In FIG. 2, for example, a first electrode 8a acting as a common electrode is formed in a predetermined pattern on a liquid crystal side surface of a substrate material 7a constituting the first substrate 4a, that is, a surface facing the second substrate 4b. Then, an overcoat layer 9a is formed thereon, and an alignment film 11a is further formed thereon. A polarizing plate 12a is attached to the outer surface of the substrate material 7a.

The liquid crystal side surface of the substrate material 7b constituting the second substrate 4b facing the first substrate 4a, ie, the first substrate 4
On the surface facing a, for example, a second electrode 8b acting as a segment electrode is formed in a predetermined pattern, an overcoat layer 9b is formed thereon, and an alignment film 11b is further formed thereon. A polarizing plate 12b is attached to the outer surface of the substrate material 7b.

The first electrode 8a and the second electrode 8b are formed of a light transmitting material such as ITO (Indium Tin Oxide) to a thickness of about 1000 Å, and the overcoat layers 9a and 9b are formed of, for example, silicon oxide. The alignment film 1 is formed of titanium oxide or a mixture thereof to a thickness of about 800 Å.
1a and 11b are made of, for example, polyimide resin
It is formed to a thickness of about 00 Å.

As shown in FIG. 1, the first electrode 8a is formed by arranging a plurality of linear patterns in parallel with each other.
It is formed in a so-called stripe shape, while the second electrode 8b
Is also formed in a stripe shape by arranging a plurality of linear patterns parallel to each other so as to intersect the first electrode 8a. A plurality of points where the electrodes 8a and the electrodes 8b intersect in a dot matrix form pixels for displaying an image. The area defined by the plurality of pixels is a display area for displaying an image such as a character.

The first substrate 4a formed as described above
As shown in FIG. 2, a plurality of spacers 13 are dispersed on one liquid crystal side surface of the second substrate 4b, and a sealing material 6 is further formed on the liquid crystal side surface of one of the substrates by, for example, printing. It is provided in a frame shape as shown in FIG.
As shown in FIG.
Are distributed. Further, a liquid crystal injection port 6a is formed in a part of the sealing material 6, as shown in FIG.

A spacer 13 is provided between the substrates 4a and 4b.
A uniform gap, for example, a gap of about 5 μm, that is, a so-called cell gap held by the liquid crystal injection port 6a is formed.
The liquid crystal 16 is injected into the cell gap through the through hole, and after the injection is completed, the liquid crystal injection port 6a is sealed with a resin or the like.

In FIG. 1, the first substrate 4a is a second substrate 4
The first electrode 8a on the first substrate 4a extends directly to the substrate overhang 4c to form a wiring pattern 17. The second electrode 8b on the second substrate 4b is connected to the substrate overhanging portion 4c via the conductive material 14 (see FIG. 2) dispersed inside the sealing material 6.
It is connected to the upper wiring pattern 17.

In practice, a large number of the electrodes 8a and 8b and the wiring patterns 17 extending from the electrodes 8a and 8b are formed at very narrow intervals over the entire surface of each of the substrates 4a and 4b.
In FIG. 1, the electrodes and the like are schematically illustrated at intervals larger than the actual intervals in order to clearly show the structure, and some of the electrodes are not illustrated. Further, the electrodes 8a and 8b formed in the region where the liquid crystal is sealed are not limited to being formed linearly, but may be formed in an appropriate pattern.

In FIG. 1, an IC chip mounting structure 3
Is a liquid crystal driving IC as an IC chip on the FPC 18.
It is formed by mounting C19. Also, FP
C18 is manufactured by forming a metal film pattern 22 as a substrate-side terminal by, for example, etching on a flexible base layer 21 formed of, for example, a polyimide resin.

A general FPC includes a three-layer FPC and a two-layer FPC.
It is known that there is a layered FPC. An FPC having a three-layer structure is manufactured by forming a metal film pattern on a base layer with an adhesive layer interposed therebetween, and each of the base layer, the adhesive layer, and the metal film pattern forms a three-layer structure. An FPC having a two-layer structure is manufactured by forming a metal film on a base layer by a film forming method such as sputtering or roll coating, and then forming the metal film in a predetermined pattern by a patterning process such as etching. , A base layer and a metal film pattern form a two-layer structure. FPC used in this embodiment
Reference numeral 18 denotes a two-layer FPC.

In FIG. 1, the tip of the metal film pattern 22 on the side of the internal area is an area for mounting the liquid crystal driving IC 19 and an area substantially equal in size to the IC chip 19. Collected by J. The liquid crystal driving IC 19 has a plurality of bumps 23 as IC-side terminals on its active surface 19a.

When mounting the liquid crystal driving IC 19 on the FPC 18, the ACF 24 as an anisotropic conductive adhesive is used.
Is adhered to the IC mounting area J, the active surface 19a of the liquid crystal driving IC 19 is adhered to the ACF 24, and the ACF 24 is
By temporarily mounting the liquid crystal driving IC 19 with a heated pressure bonding head (not shown),
The liquid crystal driving IC 19 is heated and pressed. This allows
The liquid crystal driving IC 19 is bonded to the IC mounting area J of the FPC 18.

As shown in FIG. 2, the ACF 24 is formed by dispersing conductive particles 27 in a resin film 26, and the bumps 23 of the liquid crystal driving IC 19 are formed by the conductive particles 27 by the metal of the FPC 18. It is conductively connected to the film pattern 22. The mounting structure 3 of the IC chip manufactured in this manner is connected to the substrate overhanging portion 4c of the liquid crystal panel 2 by the ACF 28, and at this time, the conductive film contained in the ACF 28 causes the metal film on the mounting structure side to be connected. Conductive connection between the pattern 22a and the wiring pattern 17 on the liquid crystal panel side is achieved.

According to the liquid crystal device 1 of the present embodiment configured as described above, the scanning voltage is applied to either the first electrode 8a or the second electrode 8b by the liquid crystal driving IC 19 for each row. Further, by applying a data voltage based on the display image to the other of the electrodes for each pixel, the light passing through each pixel portion selected by the application of both voltages is modulated, and thus the substrate 4a Alternatively, an image such as a character or a number is displayed outside 4b.

FIG. 3A is an enlarged view of a portion indicated by an arrow A in FIG. Further, FIG.
3A illustrates a cross-sectional structure taken along line BB. As shown in these figures, the metal film pattern 22 is formed so as to extend beyond the bumps 23 of the liquid crystal driving IC 19 by the dimension ΔL toward the center of the liquid crystal driving IC 19.

In the forming process, the tip of the liquid crystal driving IC 19 often becomes a tapered shape 22a with its corners chamfered. In addition, the tip portion may be in a cross-sectional state 22b in which the end portion becomes tapered. In particular, when the metal film pattern 22 is formed by etching as in the present embodiment, the tapered shape 22a is conspicuously formed, and the tapered cross section 22b may be formed.

Therefore, without taking any measures, FIG.
(A) and the conventional mounting structure shown in FIG.
If the tip of the metal film pattern 22 is aligned with the side edge of the bump 23, the effective overlapping area between the metal film pattern 22 and the bump 23 is reduced, and therefore the number of captured conductive particles 27 in the ACF 24 is reduced. As a result, the conductive connection between the metal film pattern 22 and the bumps 23 may be deteriorated. Also, as shown in FIG. 6B, the presence of the tapered cross-section 22b formed at the tip of the metal film pattern 22 reduces the number of captured conductive particles 27 and reduces the number of bumps 23.
There is also a possibility that the conductive connection between the metal film pattern 22 and the metal film pattern 22 is deteriorated.

On the other hand, as in the present embodiment shown in FIGS. 3A and 3B, the metal film pattern 22 is
3 and extends in the direction of the center of the liquid crystal driving IC 19, the width of the metal film pattern 22 is sufficiently reduced to avoid the tapered portion 22a at the tip of the metal film pattern 22 as shown in FIG. A large and constant portion can be connected to the bump 23. Further, as shown in FIG. 3B, the metal film pattern 2
The portion where the thickness of 2 is sufficiently large and constant is the bump 23
Can be connected to As a result, the metal film pattern 2
A sufficient number of conductive particles 27 can be interposed between 2 and the bumps 23, so that a highly reliable conductive connection state can be obtained between them.

According to the experiment of the inventor, in FIG. 3, the length of the metal film pattern 22 extending beyond the bump 23 is represented by ΔL, and the length of the bump 23 in the extending direction of the metal film pattern 22 is represented by L. When the extension dimension ΔL of the metal film pattern 22 is defined so that ΔL ≧ L / 5, a portion where the width and the film thickness of the metal film pattern 22 are sufficiently large and constant is reliably formed on the bump 23. I found that I could connect.

In FIG. 1, the width of the metal film pattern 22 constituting the FPC 18 is not always the same for all the metal film patterns 22. For example, the metal film pattern 22 connected to the output side of the liquid crystal driving IC 19
The width of “a” is narrow, and the width of the metal film pattern 22b connected to the input side of the liquid crystal driving IC 19 may be formed wider than that.

In such a case, the extension dimension ΔL for the narrow metal film pattern 22a is set longer than the extension dimension ΔL for the wide metal film pattern 22b.
That is, it is desirable to set the length ΔL of the metal film pattern 22 extending beyond the bump 23 so as to be inversely proportional to the width dimension of the metal film pattern 22. In this way, a sufficient conductive connection state can be obtained without increasing the extension dimension ΔL of the wide metal film pattern 22 more than necessary.

(Second Embodiment) FIG. 4 shows an embodiment of a portable telephone which is an embodiment of the electronic apparatus according to the present invention. The mobile phone 50 shown here has an antenna 5
1, speaker 52, liquid crystal device 60, key switch 53,
It is configured by storing various components such as a microphone 54 in an outer case 56 as a housing.
Further, inside the outer case 56, a control circuit board 57 on which a control circuit for controlling the operation of each of the above components is mounted is provided. The liquid crystal device 60 can be constituted by the liquid crystal device 1 shown in FIG.

In this portable telephone 50, the key switch 5
The signal input through the microphone 3 and the microphone 54, the data received by the antenna 51, and the like are input to the control circuit on the control circuit board 57. Then, the control circuit displays an image such as a number, a character, or a picture on the display surface of the liquid crystal device 60 based on the various input data, and further transmits transmission data from the antenna 51.

(Other Embodiments) The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and various modifications may be made within the scope of the invention described in the claims. Can be modified.

In the embodiment of FIG. 1, the metal film pattern 22 constituting the IC chip mounting structure 3 is patterned by etching.
The present invention can also be applied to a case where any other patterning process is considered in which the tip of the is tapered in a chamfered shape or becomes thinner in a tapered shape.

The mounting structure 3 of the IC chip shown in FIG.
Is merely an example, and the external shape, the shape of the metal film pattern, and the like can be variously modified as desired. Also, F
A variety of chip components to be mounted on the PC 18 can be selected as needed, for example, an IC chip other than the liquid crystal driving IC, a resistor, a capacitor, and other chip components.

[0052]

According to the mounting structure of the IC chip, the liquid crystal device, and the electronic apparatus according to the present invention, the terminal on the substrate such as a metal film pattern extends beyond the terminal on the IC such as a bump.
Since it is formed so as to extend in the center direction of the C chip, a portion where the width and thickness of the substrate side terminal is sufficiently large and constant is avoided, avoiding the tapered portion and the tapered cross section of the substrate side terminal. , And as a result, a highly reliable conductive connection state can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view showing an embodiment of an IC chip mounting structure and a liquid crystal device according to the present invention.

FIG. 2 is a cross-sectional view showing a mounting structure of the IC chip of FIG. 1 and a cross-sectional structure of each main part of the liquid crystal device.

3A and 3B are diagrams showing a conductive connection portion between an IC-side terminal and a substrate-side terminal, where FIG. 3A is a plan view and FIG. 3B is a cross-sectional view thereof.

FIG. 4 is a perspective view showing an embodiment of a mobile phone which is an embodiment of the electronic apparatus according to the present invention.

FIG. 5 is a partially exploded perspective view showing an example of a conventional mounting structure of an IC chip.

6A and 6B are diagrams showing a conventional conductive connection between an IC terminal and a substrate terminal, FIG. 6A is a plan view thereof, and FIG.
Is a sectional view thereof.

[Explanation of symbols]

 Reference Signs List 1 liquid crystal device 2 liquid crystal panel 3 mounting structure of IC chip 4a, 4b substrate 4c substrate overhanging portion 8a, 8b electrode 16 liquid crystal 17 wiring pattern 18 FPC (substrate) 19 liquid crystal driving IC (IC chip) 19a active surface 21 base layer 22 Metal film pattern (substrate side terminal) 22a Tapered portion 22b Tapered cross section 23 Bump (IC side terminal) 24 ACF J IC mounting area L Bump length ΔL Extension length of substrate side terminal

Continued on the front page F-term (reference) 2H092 GA48 GA49 GA50 GA51 GA52 GA55 GA57 HA04 HA26 MA10 MA17 NA25 NA27 PA02 PA03 RA10 5E319 AC03 BB16 5F044 KK03 KK12 LL09 5G435 AA14 AA16 BB12 EE40 EE43 KK09 LL07

Claims (7)

[Claims] 1. A mounting structure of an IC chip comprising an IC chip having an IC terminal mounted on a substrate having a substrate terminal so that the IC terminal and the substrate terminal are conductively connected to each other. The mounting structure of an IC chip, wherein the substrate-side terminal is formed so as to extend toward the center of the IC chip beyond the IC-side terminal. 2. The mounting structure of an IC chip according to claim 1, wherein said substrate is formed by forming a metal film pattern as said substrate side terminal on a flexible base layer. 3. The mounting structure of an IC chip according to claim 1, wherein the substrate and the IC chip are conductively connected by an anisotropic conductive adhesive. 4. The device according to claim 1, wherein a length of the substrate-side terminal extending beyond the IC-side terminal is ΔL, and a length of the IC-side terminal is the length of the substrate-side terminal. Where L is the length corresponding to the vertical direction, and ΔL ≧ L / 5. 5. The device according to claim 1, wherein a plurality of types of the substrate-side terminals having different widths are formed, and the substrate-side terminals extend beyond the IC-side terminals. Is an IC chip mounting structure characterized by being inversely proportional to the width of these board-side terminals. 6. A pair of substrates facing each other, a liquid crystal sealed between the substrates, and a mounting structure of an IC chip connected to at least one of the pair of substrates,
A liquid crystal device, wherein the mounting structure of the IC chip is the mounting structure of the IC chip according to at least one of claims 1 to 5. 7. An electronic device comprising a liquid crystal device and a housing for accommodating the liquid crystal device, wherein the liquid crystal device is constituted by the liquid crystal device according to claim 6.