JP3363924B2 - IC mounting method for liquid crystal display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a semiconductor integrated circuit device (hereinafter referred to as a driving IC) for driving a liquid crystal panel, which is face down bonded by a conductive adhesive on a substrate constituting the liquid crystal panel. The present invention relates to a method of mounting a drive IC on a liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, as one of liquid crystal display panels in which a drive IC is face-down bonded to a liquid crystal panel, for example, a substrate forming a liquid crystal display panel, one having a structure shown in FIGS. 3 and 4 is known. There is. 3 is a plan view showing the liquid crystal display panel, and FIG. 4 is a sectional view showing a section taken along line BB in FIG. A conventional mounting method will be described below by alternately using FIG. 3 and FIG.

In the conventional liquid crystal display panel, a pattern electrode 203 corresponding to the electrode of the driving IC 206 is formed of a conductive thin film on the first glass substrate 201 in the same step as the pixel pattern 204. Then, the pattern electrode 203 formed on the first glass substrate 201 and the protruding electrode 2 previously formed on the electrode portion of the drive IC 206.
07 is electrically and mechanically connected by a conductive adhesive 208.

A pixel pattern 205 is formed on the second glass substrate 202.

In this liquid crystal display panel, a first glass substrate 201 and a second glass substrate 202 are separated by a predetermined distance,
The surfaces on which the pixel pattern 204 and the pixel pattern 205 are formed face each other and the periphery is sealed with a sealant 210.

A liquid crystal (not shown) is sealed in a region where the first glass substrate 201 and the second glass substrate 202 overlap each other and inside the sealant 210.

A pattern electrode 203 formed on the first glass substrate 201 in the same process as the pixel pattern 204.
And a connection electrode, which is formed in advance on the electrode portion of the drive IC 206, for example, a protruding electrode 207, is mounted with the conductive adhesive 208 with the element formation surface of the drive IC 206 facing down to perform electrical connection. , Mechanical connection. Further, the surface of the glass substrate including the drive IC 206 is resin-sealed with resin 209.

[0008]

The above-mentioned mounting method is a simple mounting means and is effective in achieving a compact and inexpensive liquid crystal panel capable of high-density multi-terminal connection.

However, a drive IC for forming the protruding electrode 207
206 and the driving IC 206 on the first glass substrate 201.
Pattern electrode 20 formed corresponding to the electrode part pattern of
In the liquid crystal display panel in which 3 and 3 are face-down bonded, the electrical connection between the pattern electrode 203 and the protruding electrode 207 cannot be stably established, and there is an incomplete product, which poses a problem in mass production.

The present invention pays attention to such a point, and an object of the present invention is to provide a liquid crystal panel in which pattern electrodes formed on a glass substrate of a liquid crystal panel using a conductive adhesive and a driving IC are face down bonded. It is an object of the present invention to provide a method of mounting a drive IC on a liquid crystal panel capable of ensuring electrical connection and a liquid crystal panel using the same.

[0011]

In order to achieve the above object, the present invention provides a liquid crystal display panel for connecting a connecting electrode provided on an IC and a pattern electrode provided on a substrate of the liquid crystal display panel. In the method of mounting an IC, the connection electrode and the pattern electrode are electrically connected by face-down bonding via a conductive adhesive containing conductive particles mixed in a resin, and further from the back surface of the substrate. Conductivity
The resin remaining between the surface of the grain and the pattern electrode is locally
It burned in, and wherein the stabilizing <br/> connection between the conductive particle and the pattern electrode by the conductive grains are irradiated with laser light in an amount not dissolve.

Further , prior to the irradiation of the laser beam,
Curing the conductive adhesive to make adhesion and electrical connection
Is characterized by .

Further, the face-down bonding
At least later, prior to irradiation with the laser light, at least
The IC is sealed with a sealing resin .

Further, the conductive particles are made of a powder in which silver and palladium are mixed.

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a method of mounting a drive IC on a liquid crystal display panel of the present invention, and FIG. 2 is a sectional view showing a section taken along line AA of FIG. Hereinafter, the mounting method of the present invention will be described by alternately using FIG. 1 and FIG.

A pixel pattern 10 is formed on the first substrate 101.
4 is formed. Further, a pixel pattern 105 is formed on the second substrate 102.

In this liquid crystal display panel, the first substrate 101 and the second substrate 102 made of glass are separated by a predetermined distance, the surfaces on which the pixel patterns 104 and 105 are formed are opposed to each other, and the periphery is a sealant 103. Seal with.

The first substrate 101 and the second substrate 102
Liquid crystal (not shown) is sealed in the area where the and are overlapped with each other and inside the sealant 103.

A pixel pattern 10 is formed on the first substrate 101.
In the same step as 4, the pattern electrode 106 corresponding to the electrode portion of the drive IC 107 is formed.

Then, the pattern electrode 106 formed on the first substrate 101 and the protruding electrode 111 formed in advance on the electrode portion of the driving IC 107 are connected to the conductive adhesive 108.
Face down bonding at. After that, the laser light 107 is applied to the connection portion between the drive IC 107 and the pattern electrode 106 to establish electrical connection and mechanical connection.

In this embodiment, as the conductive adhesive 108, an Ag / Pd paste in which fine particles of Ag / Pd which are conductive particles are mixed in an epoxy resin is used.

A conductive adhesive 108 made of this Ag / Pd paste was spread with a squeegee on a glass substrate, and then,
A stamp method in which the protruding electrode 111 of the driving IC 107 is brought into contact with the Ag / Pd paste and the conductive adhesive 108 is transferred to the protruding electrode 111 formed on the driving IC 107.
A conductive adhesive 108 is formed on the protruding electrodes 111.

In this stamp method, a uniform amount of the conductive adhesive 108 is applied to the protruding electrodes 111 formed on the driving IC 107.
Can be transferred.

Projection electrode 11 to which conductive adhesive 108 is transferred
The drive IC 107 having No. 1 is face-down bonded to a predetermined position of the pattern electrode 106 formed on the first substrate 101, and lightly pressed from the opposite side of the projecting electrode 111 of the drive IC 107.

After that, the first substrate 101 is transmitted from the opposite side of the surface of the first substrate 101 on which the pattern electrode 106 is formed, and further, the pattern electrode 106 formed of a transparent conductive film such as indium oxide is transmitted. Conductive adhesive 108
The laser beam 109 is irradiated on the surface. After that, the conductive adhesive 108 is fully cured.

In this embodiment, YAG having a wavelength that allows transmission through the first substrate 101 and the pattern electrode 106.
A laser was used as the laser light 109. Note that Y
Other than the AG laser, it is also possible to use, as the laser beam 109, a laser beam having another wavelength that transmits the first substrate 101 and the pattern electrode 106 and gives thermal energy to the conductive adhesive 108. .

As a result of investigating the cause of the connection failure in the liquid crystal panel in the mounting method described in the conventional example, the conductive adhesive 10 made of Ag / Pd paste transferred onto the protruding electrodes was investigated.
8 and the pattern electrode 106, the epoxy resin layer is interposed on the Ag / Pd grain surface of the conductive adhesive 108,
It was found that electrical connection instability occurs because the Ag / Pd grains do not contact the pattern electrode 106.

By the irradiation of the laser beam 109 of the present invention, the epoxy resin on the surface of the Ag / Pd grains at the connecting portion is burned down by local heating, and the epoxy resin in the periphery is hardened, so that Ag / Pd
Since the Pd particles are in direct contact with the pattern electrode 106, stable electrical connection can be achieved.

Further, the drive IC 107 having the protruding electrodes 111 to which the conductive adhesive 108 is transferred is face-down bonded to a predetermined position of the pattern electrode 106 formed on the first substrate 101 to cure the conductive adhesive 108. After that, the above-mentioned YA is applied to the unstable part of the electrical connection.
By irradiating the laser beam 109 of G laser,
A stable electrical connection can also be made.

Furthermore, the pattern electrode 10 formed on the first substrate 101 in the same process as the pixel pattern 104.
6 and the protruding electrode 111 previously formed on the electrode portion of the driving IC 107 are face-down bonded with a conductive adhesive 108 to make electrical connection and mechanical connection, and the glass substrate surface including the driving IC 206 is covered with the resin 209. The same effect can be obtained by irradiating the laser beam 109 after resin sealing with.

By the above method of irradiating the connecting portion of the driving IC 107 with the laser beam 109, a liquid crystal display panel having stable electrical and mechanical connection can be stably obtained in mass production.

In this embodiment, the first substrate 101 and the second substrate 101
Although the liquid crystal display panel using the glass substrate as the substrate 102 has been described, it can be used for the liquid crystal display panel using the plastic substrate.

[0041]

As is apparent from the above description, according to the present invention, by irradiating the connecting portion of the driving IC with a laser beam, electrical and mechanical can be made more stable and reliable, so that reliability can be improved. The effect of improving is obtained.

Furthermore, since the present invention can be performed while making the most of the conventional manufacturing process, unnecessary equipment investment is unnecessary.

In recent years, there has been a demand for a higher density liquid crystal display panel, which has led to a demand for a mounting method that enables higher density mounting. The present invention can meet this demand.

When a laser beam was irradiated as in the present invention to the connection failure in the mounting method described in the conventional example, stable electrical connection was obtained. Therefore, the present invention is effective for correcting a defective product to a good product. The product yield is improved, and as a result, the cost of the product can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing a method of mounting a drive IC of a liquid crystal display panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a method for mounting a drive IC of a liquid crystal display panel according to an embodiment of the present invention.

FIG. 3 is a plan view showing a method of mounting a drive IC of a conventional liquid crystal display panel.

FIG. 4 is a cross-sectional view showing a method of mounting a drive IC for a conventional liquid crystal display panel.

[Explanation of symbols]

101 first substrate 102 second substrate 106 pattern electrode 107 drive IC 108 Conductive adhesive 109 laser light 110 sealing resin 111 protruding electrode

Claims (4)

(57) [Claims] 1. A method for mounting an IC of a liquid crystal display panel, comprising connecting a connection electrode provided on the IC and a pattern electrode provided on a substrate of the liquid crystal display panel, wherein the connection electrode and the pattern are provided. The electrodes are electrically connected by face-down bonding via a conductive adhesive in which conductive particles are mixed in resin, and the electrodes are left from the back surface of the substrate between the surface of the conductive particles and the pattern electrode.
Resin is locally burned out and the conductive particles do not dissolve
A method for mounting an IC on a liquid crystal display panel, which comprises stabilizing the connection between the conductive particles and the pattern electrode by irradiating a quantity of laser light. 2. Prior to the irradiation of the laser beam, the light guide
2. The method for mounting an IC on a liquid crystal display panel according to claim 1, wherein the electroadhesive is cured to perform adhesion and electrical connection . 3. After the face down bonding
Yes, at least IC prior to the irradiation of the laser light.
Claim 1 or characterized in that is sealed with a sealing resin
The method for mounting an IC of the liquid crystal display panel according to claim 2 . 4. The method for mounting an IC on a liquid crystal display panel according to claim 1, wherein the conductive particles are made of a powder in which silver and palladium are mixed.