JPH1152405A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element which enables the observation of a juncture between a base chip and a glass substrate at the packaging of the base chip, such as LSI, to the liquid crystal display element and/or after packaging thereof and making the resistance lower on wirings for a power source and grounding to the base chip, such as LSI, and boosting. SOLUTION: The wiring parts on the cell of the liquid crystal display element of a COG(chip on glass) type for driving the LSI 18 installed on the outside part of the cell are covered with metallic plating 9 or/and vapor deposition. In addition, the electrical junction to the LSI 18 is not subjected to the metallic plating 9 and/or vapor deposition and, therefore, the observation of the connections to the glass substrate 1 is made possible. Since only the power source wiring and grounding wiring to the LSI 18 and the wiring for boosting are subjected to the metallic plating and/or vapor deposition, the resistance to the wiring is made lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of mounting an LSI chip on a glass substrate having a wiring portion covered with metal by metal plating or / and vapor deposition by installing an LSI around a cell of a liquid crystal display element. The present invention relates to a liquid crystal display element that realizes reliable electrical contact between an LSI chip and a wiring portion when mounted by face-down bonding.

[0002]

2. Description of the Related Art In recent years, cost,
LSI for driving liquid crystal on a glass substrate due to the number of processes and reliability
COG type (Chip On Glass) for mounting a chip
The liquid crystal display element of s) is often used. FIG. 1 shows a basic configuration of a liquid crystal display element. FIG. 1 shows an alignment of two glass substrates 1 above and below, a gap is provided between the two glass substrates, a liquid crystal 4 is sealed in the gap, and the periphery is sealed with a seal 5 such as a resin. Are formed with transparent conductive patterns 2 and 3 such as a Nesa film and an ITO film.

Further, on the surface of the cell of the liquid crystal display element,
A polarizing filter 7 is attached. LS for driving liquid crystal
I8 is provided in the external wiring section, and takes in a power supply and a display command signal from the external electrode 6, and supplies a signal for the liquid crystal display element to the display section. The portions outside the cell formed simultaneously with the formation of the pattern 3 and the like are referred to as external electrodes and wiring portions.

FIG. 9 is a sectional view showing the vicinity of an LSI installed on a cell of a conventional COG type liquid crystal display device. FIG. 9 shows that the metal plating 9 applied to the external electrode 6 provided on the glass substrate 1 covers the connection portion immediately below the driving LSI 8. In addition, there is a type in which the metal plating 9 is applied to the entire outer electrode 6 for the purpose of lowering the electric resistance, for example, as disclosed in JP-A-4-170524.

Further, a driving L provided at the periphery of the cell
The conductive particles 11 (filler) having electrical conductivity are pressed between the bumps 10 of the external conductive portion of the SI 8 and the external electrode 6 face down by using a resin in which the conductive particles 11 are dispersed.

Next, in order to confirm that the conductive particles 11 are crushed by a predetermined amount and to confirm that the connection is complete, the driving LSI 8 is connected to the metal of the external electrode 6 in order to confirm the conduction through the conductive particles 11. After mounting on the plating 9 film, the crimped portion is observed from the glass side by an optical microscope. In addition, a display inspection is performed by connecting a driving power supply or the like.

[0007]

If the conductive particles are insufficiently crushed by the face-down pressure bonding and are weakly in contact with each other, the contact may be broken with time.
Observe the crimping part for setting the crimping condition of the SI and inspecting the processed product. At this time, if there is a metal plating film,
Since it cannot be visually observed or optically observed because of being blocked by the metal plating film, there are the following problems.

If a metal plating film is present up to the LSI crimping portion on the glass substrate, the collapse of the conductive particles (filler) due to the crimping is determined by a visual or optical observation from the glass side (back side) of the cell. There is a problem that inspection cannot be performed.

Further, if a metal plating film is provided up to the LSI crimping portion on the glass substrate, the bump portion of the LSI is crimped to the filler at a uniform pressure on the LSI crimping portion on the glass substrate or the cell side ( There is a problem that visual observation, optical observation, inspection and the like cannot be performed from the back).

Further, if a metal plating film is provided up to the LSI crimping portion on the glass substrate, the positional deviation between the LSI bump portion and the LSI crimping portion on the glass substrate can be visually or optically determined from the glass side (back side) of the cell. There is a problem that it is not possible to perform a specific observation and inspection.

[0011]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: an external electrode provided at a cell end; a display electrode in a liquid crystal sealed space; and a wiring portion connected to the display electrode. Each is characterized by being formed of a transparent conductive film, and the wiring portion and the external electrode are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with each LSI.

In the liquid crystal display element according to the present invention, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film. Section and external electrodes are each LSI
Except for the junction with, the cell is covered with a metal layer formed by metal plating or vapor deposition.
Observation and inspection by visual and optical methods to determine whether a predetermined amount of conductive particles (fillers) are crushed by misalignment between the bump portion of I and the LSI crimping portion on the glass substrate or by uniform crimping. Can be.

Further, in the liquid crystal display element according to the present invention, the external electrode provided at the end of the cell, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film, and Only the electrodes for the power supply, the ground wiring, and the boosting wiring among the external electrodes are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with the LSI.

According to a second aspect of the present invention, in the liquid crystal display device, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film. Only the electrodes for the power supply, the ground wiring, and the boost wiring among the electrodes, except for the junction with the LSI,
Since it is covered with a metal layer formed by metal plating or vapor deposition, conductive particles (fillers) are crushed by misalignment of the bump portion of the LSI and the LSI crimping portion on the glass substrate from the glass side (back) of the cell or uniform crimping. Can be observed and inspected as to whether the amount is a predetermined amount or not, a large current can flow, and the mechanical strength and the solder wettability of the connection of the lead wire and the like can be improved.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention relates to COG
In the liquid crystal display element of the type, the wiring portion on the cell is covered with metal by metal plating or / and vapor deposition, and the crimping portion of the LSI is not subjected to metal plating or / and vapor deposition, and the glass side of the cell (back) The present invention provides a liquid crystal display device capable of inspecting and observing a pressure-bonded portion from the same.

FIG. 2 shows the L of the liquid crystal display device according to the present invention.
FIG. 3 shows a cross-sectional view of an SI mounting portion. FIG. 2 shows a method of vacuum deposition, sputtering, ion plating, chemical vapor deposition (CVD), etc., followed by etching (wet, dry) on a glass substrate 1 using a compound such as tin oxide, indium oxide, and indium tin oxide. The display pattern and external electrode 6 made of the formed transparent conductive film such as a Nesa film or an ITO film.
Are formed at the same time, metal plating 9 is applied to portions other than the portions where the bumps 10 of the driving LSI 8 are pressed, and conductive particles 11 (fillers) having electrical conductivity are dispersed between the bumps 10 and the external electrodes 6. This is a configuration in which the pressure bonding is performed face down using a.

The glass substrate 1 is composed mainly of soda lime glass containing no alkali as a glass component, has good thermal stability and a high strain point, and has a thermal expansion coefficient of 3 from normal temperature.
At 50 ° C., the temperature is about 46 to 47 (× 10 ⁻⁷ / ° C.), and the melting temperature is as high as 1600 to 1650 ° C. Further, with respect to the flatness, the glass is made of high-quality glass with little unevenness, warpage, undulation, surface roughness, and the like, and has high quality in terms of scratches, pits, dirt, and the like.

The display pattern and the external electrode 6 are mainly composed of tin oxide or indium oxide, and are composed of indium tin oxide (IT).
O) A transparent conductive film is formed by vacuum evaporation or chemical vapor deposition of a compound made of cadmium tin oxide or the like, and then etched to form a transparent electrode having a predetermined shape.

In the metal plating 9, nickel is applied to the transparent conductive film by selective plating to a thickness of, for example, about 500 nm, and gold plating is applied to the surface thereof, for example, to a thickness of about 50 nm. Also, 10 parts of the bump for mounting the bare chip,
The transparent conductive film remains as it is without applying the metal plating 9.

The area where the metal plating 9 is to be applied should basically not be applied to the bump 10 serving as a conductive portion of the LSI 8, but the area where the metal plating 9 is applied should be bumped so that the metal plating 9 is not applied. A part separated from 10 parts by 30 μm or more and 0.5 mm or less is defined as a boundary of metal plating.

The conductive particles 11 (filler) are formed by adding 5-1 to resin.
This is a dispersion of conductive particles composed of silver (Ag) particles of about 5 μm. The conductive particles 11 are connected to the external electrode 6 by LS.
I8 is installed on the 10 bumps facing each other.

Further, the LSI 8 is mounted on the bump 10 at a predetermined position.
And press-fit by face down with uniform pressure. As a result, the filler in the resin is crushed, and the fillers come into surface contact with each other, thereby obtaining conductivity.

Next, in order to confirm conduction through the conductive particles 11, whether the conductive particles 11 are crushed by a predetermined amount is inspected and observed from the glass side (back side) of the crimped portion by a visual and optical method. In this configuration, it is checked whether the crushing of the conductive particles is a predetermined amount or not, and furthermore, whether the position of the bump portion between the LSI 8 and the pressure-bonding portion is misaligned or whether the conductive particles are crushed uniformly.

FIG. 3 shows a main processing step diagram of the liquid crystal display device of the present invention. FIG. 3A shows a state of the patterned substrate with the ITO film. A flat glass substrate 1 made of soda lime glass or the like and having a thickness of about 1.1 mm is formed by etching or the like using tin oxide, indium oxide, or the like to form a display pattern region, a wiring to a display portion, and a pattern such as an external electrode 6 having a resistance of 30Ω / A transparent conductive film of about □ of the ITO film 3 is formed. However, the bump portion 10 is a part of the pattern of the wiring portion to the display portion and the pattern of the external electrode 6, and a space where liquid crystal is sealed is formed in the display region.

FIG. 3B shows the state of photoresist coating. This state is for metal plating (for nickel)
This is 9-a mask patterning. In order to cover (coat) a portion that does not require metal plating (a liquid crystal display region or a bump portion) with a photoresist, a photoresist is applied to the glass substrate 1 by about 2 μm using a spinner or the like (eg, a negative type photoresist in this case). .

Further, a pattern of a portion that does not require metal plating is exposed to ultraviolet rays by a stepper or the like (for example, here, the integrated light amount is 100 mJ / cm ² ).
Then, the exposed portion becomes insoluble. Furthermore, dirt is removed by showering with pure water or ultrasonic cleaning in a photo process cleaning device or the like, and is dried by air blow such as an air knife method or a hot air drying method, so that the photoresist remains on the liquid crystal display area and the bump portion. Let it.

FIG. 3C shows a metal plating (nickel) 9-.
The state where a is applied is shown. According to FIG. 3B, in order to apply metal plating to portions other than the liquid crystal display pattern and the bump portion having no photoresist, first, cleaning is performed with an alkaline solution for the purpose of removing dirt on the surface or degreasing, and then hydrochloric acid or the like. Neutralize alkalinity with acid.

Further, a catalytic treatment is performed. First, as a catalyst, a catalyzed treatment solution containing simultaneously a metal chloride composed of stannous chloride and palladium chloride and hydrochloric acid is immersed at room temperature to about 40 ° C. for about 2 to 3 minutes.

Next, the catalyst nuclei forming the protective colloid and complex ions by the catalyst are treated with an accelerator solution to be activated. As the accelerator solution, 5-1
Using an acid such as hydrochloric acid or sulfuric acid of about 0%,
The treatment is performed at a temperature of about ゜ C for about 2 to 5 minutes.

Further, the substrate is immersed in a chemical nickel plating solution such as a nickel chloride solution or a nickel sulfate solution containing nickel ions at a temperature of room temperature to about 30 ° C. for about 3 to 5 minutes to form electroless nickel plating. To form a nickel plating layer 9-a.

FIG. 3D shows a state in which the photoresist has been removed. The photoresist is removed from the mask pattern for electroless nickel plating formed in FIG. 3C by a roll brush, a disk brush, an ultrasonic cleaning, or the like using a detergent, a release agent, or the like.

FIG. 3E shows metal plating (gold plating) 9-.
b shows a state where nickel is selectively applied on the nickel plating 9-a. Similar to the treatment step of FIG. 3C, first, the surface is cleaned with an alkaline solution for removing stains and degreasing, and then neutralized with an acid such as sulfuric acid to activate the nickel surface. To

Further, gold plating is performed using flash gold to form a thin plating layer having a thickness of about 50 nm. Immerse in a chemical gold plating solution composed of a metal salt such as a chloride solution or a sulfate solution containing gold ions at about room temperature, and further reduce with formaldehyde or Rochelle salt as a metal ion reducing agent to generate electroless gold plating, A gold plating layer 9-b is formed on the underlying nickel plating layer 9-a. The metal plating 9 is formed on the whole of the nickel plating layer 9-a and the gold plating layer 9-b.

FIGS. 4 and 5 show a transparent conductive film pattern and a metal plating pattern region on the glass substrate 1 of the cell 20 according to the first and second embodiments of the present invention according to the production process described with reference to FIG. . FIG. 4 is a region diagram of the metal plating 9 according to claim 1 of the present invention. FIG. 5 shows a second embodiment of the present invention.
FIG. 3 is a region diagram of metal plating 9 according to the first embodiment.

In FIG. 4, 1 is a glass substrate, 7 is a polarizing filter, 9 is a metal plated portion, 12 is a region corresponding to a bump of an LSI, and a region corresponding to the bump is a transparent conductive film such as an ITO film. Therefore, the bare chip LSI is L
Whether the conductive particles (filler) are uniformly crushed with a uniform pressing force on the crimping portion, and whether the crushing of the conductive particles (filler) has reached a predetermined amount, is determined by checking the cell position. Observation and inspection can be performed from the glass side (back).

Further, in FIG. 5, together with the functions in FIG. 4, 1 is a glass substrate, 7 is a polarizing filter, and 12 is LS.
A region corresponding to the bump I, 13 is a power line, 14 is a ground line, and metal plating 9 is applied only to 13 and 14,
Able to flow current without generating heat even with large current,
Mechanical strength was obtained for connection of lead wires and the like, and solder wettability was improved.

FIG. 6 is a flowchart showing the main part of an embodiment of the COG shown in FIG. In state 1, a transparent conductive film of the patterned ITO film 3 is formed on the glass substrate 1 by etching using indium tin oxide and a wiring to the display unit and the external electrode 6.

Next, in state 2, the mask pattern of the nickel plating 9-a, which is the lower layer (ground plating) of the metal plating, is masked with a photoresist. The portions that do not require metal plating (the liquid crystal display area and bumps) are covered (coated) with photoresist.

Further, in the state 3, the metal ion in the solution is reduced and precipitated by the nickel plating, which is the lower layer (ground plating) of the metal plating, without passing an electric current from the outside, and the plating layer is deposited on the surface of the body to be plated. Nickel plating by an electroless method. Nickel plating breaks out where there is no photoresist.

In state 4, the photoresist is peeled off the mask pattern for electroless nickel plating formed in state 2 using a detergent or a stripping agent.

In state 5, the photoresist debris in state 4 is further removed by heat, and at the temperature of 250 ° C. in order to eliminate the distortion and the like of the glass substrate 1 and strengthen the adhesion of the nickel plating layer. Age for 30 minutes.

Further, in the state 6, the gold plating 9-b is again applied to the underlying nickel plating layer 9 by electroless plating.
-A, a nickel plating layer 9-a and a gold plating layer 9
-B to form the metal plating 9 as a whole.

The state 7 is a two-layer structure of the transparent electrode film 3 for segment side display for liquid crystal display of the glass substrate 1 up to the state 6 and the glass substrate 2 on which the corresponding transparent electrode film for common side display is formed. Are aligned, a gap is provided between the two glass substrates, and the periphery is sealed with a seal 5 made of resin or the like (however, an injection port for injecting liquid crystal is not sealed).

Further, a glass substrate is put into a chamber by a liquid crystal injection device or the like, and the chamber is evacuated by a vacuum pump. Let it.

Further, when the liquid crystal is injected into the cells of the glass substrate, the injection port is sealed with a resin or the like. In addition, a polarization filter for limiting the polarization direction of incident light to one direction (depending on the liquid crystal display method, reflection type or transmission type for light, or twisting method of the liquid crystal itself for polarization direction) is attached to the upper part of the cell. Put on.

In the state 8, the bumps of the completed liquid crystal display element are face-down bonded by using a resin in which conductive particles 11 made of silver particles (fillers) having good electric conductivity are dispersed.

At this time, the LSI which is a bare chip is
The conductive particles 1 are flattened from the top of the LSI with a flat plate-shaped crimping machine (for example, a bonder) so as not to displace the crimping portion.
A uniform pressure is applied so that 1 (filler) is crushed by a certain amount. Various bonding such as cold pressing, hot pressing (room temperature 150 ° C.), pressing force (0.1 to 1 kg), pressing time (0.1 to 60 sec), and the like can be changed depending on the pressing force and the resin. At the same time, the glass substrate and the LSI are bonded with a resin.

FIG. 7 shows the flow of the electroless nickel plating section in the flowchart of the main part of FIG. In the state 3a, in order to apply the metal plating 9, cleaning is performed with an alkaline solution for removing stains and degreasing the surface.

Further, in the state 3b, the alkalinity of the treatment performed in the state 3a is neutralized with an acid such as hydrochloric acid.

In the state 3c, as a first step of the catalyzing treatment, the catalyst treatment is carried out with a metal chloride composed of stannous chloride and palladium chloride and hydrochloric acid at room temperature to about 40 ° C. for 2 to 3 times. Soak for about a minute.

Further, in the state 3d, the catalyst nucleus forming the protective colloid or the complex ion by the catalyst treatment is reduced to 5%.
Activate by treating with an accelerator solution consisting of about 10 to 10% of an acid such as hydrochloric acid or sulfuric acid at a temperature of about 30 to 50 ° C. for about 2 to 5 minutes.

In state 3e, in order to generate electroless nickel plating, a chemical nickel plating solution such as a nickel chloride solution or a nickel sulfate solution containing nickel ions is applied at room temperature to about 30 ° C. for about 3 to 5 minutes. Soak. Thus, the nickel plating which is the base of the metal plating 9 is formed by the electroless nickel plating.

FIG. 8 shows a flow chart of the electroless gold part in the main part flowchart of FIG. In the state 6a, first, cleaning with an alkaline solution such as nickel plating or the like is performed to remove dirt or degrease the surface in order to apply gold plating.

In the state 6b, an acid such as sulfuric acid is used to change the state 6b.
a. Neutralize the alkalinity in a and activate the nickel surface.

The state 6c is obtained by immersing in a chemical gold plating solution comprising a metal salt such as a chloride solution or a sulfate solution containing a gold ion at about room temperature, and further reducing it with formaldehyde or Rochelle salt as a reducing agent of the metal ion. Produces electroless gold plating.

As described above, the upper layer of nickel plating is formed by gold plating by electroless gold plating. The metal plating 9 is formed as a whole by the gold plating layer formed in FIG. 8 on the nickel plating layer of the base formed in FIG.

As described above, in the liquid crystal display element of the present invention, since the regions corresponding to the bumps are formed of the transparent conductive film such as the ITO film, misalignment or conductive particles are not generated with respect to the bump portion of the bare chip. It is possible to observe and inspect whether the (filler) is uniformly crushed and whether the crushing of the conductive particles (filler) has reached a predetermined amount from the glass side (back side) of the cell. In addition, since metal plating is applied to the power supply wiring, the ground wiring, and the boosting wiring to the LSI, a large current can flow without generating heat, mechanical strength can be increased for connection of lead wires and the like, and solder wettability can be improved. . Further, the present invention may use not only a glass substrate but also a resin film as long as it is transparent.

[0060]

As described above, in the liquid crystal display device according to the first aspect, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all transparent conductive films. In addition, the wiring portion and the external electrode are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with each LSI. Therefore, the bump portion of the LSI is formed from the glass side (back side) of the cell. After the mounting, it is possible to check the positional deviation between the substrate and the LSI crimping part on the glass substrate, and to observe and inspect whether the crushing of the conductive particles is uniform or a predetermined amount. And the repair amount and the repair process can be reduced, and the cost and reliability can be improved.

Further, in the liquid crystal display element according to the present invention, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film, and Since only the electrodes for the power supply, the ground wiring, and the boost wiring among the external electrodes are covered with the metal layer formed by metal plating or vapor deposition except for the joint portion with the LSI, the glass side of the cell (the back side) ) Can observe and inspect whether or not the conductive particles are crushed by a predetermined amount by misalignment between the bump portion of the LSI and the LSI crimping portion on the glass substrate or by uniform crimping. As a result, a large current can flow without generating heat, mechanical strength can be increased for connection of lead wires and the like, and improvement in solder wettability can be obtained, thereby improving work operability and reliability. .

Therefore, it is possible to observe the connection between the bare chip and the glass substrate during and / or after mounting the bare chip such as an LSI on the liquid crystal display element, and to supply power, ground and boost to the bare chip such as the LSI. It is possible to reduce the resistance of wiring such as.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a liquid crystal display element.

FIG. 2 is a sectional view of an LSI mounting portion of the liquid crystal display element according to the invention.

FIG. 3 is a view showing main processing steps of the liquid crystal display element of the present invention.

FIG. 4 is a region diagram of the metal plating 9 according to claim 1.

FIG. 5 is a region diagram of the metal plating 9 according to claim 2;

FIG. 6 is a flowchart of a main part in one embodiment of the COG according to FIG. 3;

FIG. 7 is a flowchart of a main part of nickel plating in one embodiment of the COG according to FIG. 3;

FIG. 8 is a flowchart of a main part of gold plating in one embodiment of the COG according to FIG. 3;

FIG. 9 is a cross-sectional view around an LSI installed on a cell of a conventional COG type liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Transparent electrode film (common side), 3 ... Transparent electrode film (display side), 4 ... Liquid crystal, 5 ... Seal, 6 ... External electrode, 7 ... Deflection filter, 8 ... Driving LSI, 9 ... metal plating, 9a ... nickel plating (electroless nickel plating), 9b ... gold plating (electroless gold plating), 10 ... bumps, 11 ... conductive particles (silver particles), 12 ... photoresist, 13 ... power supply line, 14 ... grounding Line, 20 ... cell.

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[Procedure amendment]

[Submission date] July 31, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Liquid crystal display device

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of mounting an LSI chip on a glass substrate having a wiring portion covered with metal by metal plating or / and vapor deposition by installing an LSI around a cell of a liquid crystal display element. The present invention relates to a liquid crystal display element that realizes reliable electrical contact between an LSI chip and a wiring portion when mounted by face-down bonding.

[0002]

2. Description of the Related Art In recent years, cost,
LSI for driving liquid crystal on a glass substrate due to the number of processes and reliability
COG type (Chip On Glass) for mounting a chip
The liquid crystal display element of s) is often used. FIG. 1 shows a basic configuration of a liquid crystal display element. FIG. 1 shows an alignment of two glass substrates 1 above and below, a gap is provided between the two glass substrates, a liquid crystal 4 is sealed in the gap, and the periphery is sealed with a seal 5 such as a resin. Are formed with transparent conductive patterns 2 and 3 such as a Nesa film and an ITO film.

Further, on the surface of the cell of the liquid crystal display element,
A polarizing filter 7 is attached. LS for driving liquid crystal
I8 is provided in the external wiring section, and takes in a power supply and a display command signal from the external electrode 6, and supplies a signal for the liquid crystal display element to the display section. The portions outside the cell formed simultaneously with the formation of the pattern 3 and the like are referred to as external electrodes and wiring portions.

FIG. 9 is a sectional view showing the vicinity of an LSI installed on a cell of a conventional COG type liquid crystal display device. FIG. 9 shows that the metal plating 9 applied to the external electrode 6 provided on the glass substrate 1 covers the connection portion immediately below the driving LSI 8. In addition, there is a type in which the metal plating 9 is applied to the entire outer electrode 6 for the purpose of lowering the electric resistance, for example, as disclosed in JP-A-4-170524.

Further, a driving L provided at the periphery of the cell
The conductive particles 11 (filler) having electrical conductivity are pressed between the bumps 10 of the external conductive portion of the SI 8 and the external electrode 6 face down by using a resin in which the conductive particles 11 are dispersed.

Next, in order to confirm that the conductive particles 11 are crushed by a predetermined amount and to confirm that the connection is complete, the driving LSI 8 is connected to the metal of the external electrode 6 in order to confirm the conduction through the conductive particles 11. After mounting on the plating 9 film, the crimped portion is observed from the glass side by an optical microscope. In addition, a display inspection is performed by connecting a driving power supply or the like.

[0007]

If the conductive particles are insufficiently crushed by the face-down pressure bonding and are weakly in contact with each other, the contact may be broken with time.
Observe the crimping part for setting the crimping condition of the SI and inspecting the processed product. At this time, if there is a metal plating film,
Since it cannot be visually observed or optically observed because of being blocked by the metal plating film, there are the following problems.

If a metal plating film is present up to the LSI crimping portion on the glass substrate, the collapse of the conductive particles (filler) due to the crimping is determined by a visual or optical observation from the glass side (back side) of the cell. There is a problem that inspection cannot be performed.

Further, if a metal plating film is provided up to the LSI crimping portion on the glass substrate, the bump portion of the LSI is crimped to the filler at a uniform pressure on the LSI crimping portion on the glass substrate or the cell side ( There is a problem that visual observation, optical observation, inspection and the like cannot be performed from the back).

Further, if a metal plating film is provided up to the LSI crimping portion on the glass substrate, the positional deviation between the LSI bump portion and the LSI crimping portion on the glass substrate can be visually or optically determined from the glass side (back side) of the cell. There is a problem that it is not possible to perform a specific observation and inspection.

[0011]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: an external electrode provided at a cell end; a display electrode in a liquid crystal sealed space; and a wiring portion connected to the display electrode. Each is characterized by being formed of a transparent conductive film, and the wiring portion and the external electrode are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with each LSI.

In the liquid crystal display element according to the present invention, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film. Section and external electrodes are each LSI
Except for the junction with, the cell is covered with a metal layer formed by metal plating or vapor deposition.
Observation and inspection by visual and optical methods to determine whether a predetermined amount of conductive particles (fillers) are crushed by misalignment between the bump portion of I and the LSI crimping portion on the glass substrate or by uniform crimping. Can be.

Further, in the liquid crystal display element according to the present invention, the external electrode provided at the end of the cell, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film, and Only the electrodes for the power supply, the ground wiring, and the boosting wiring among the external electrodes are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with the LSI.

According to a second aspect of the present invention, in the liquid crystal display device, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film. Only the electrodes for the power supply, the ground wiring, and the boost wiring among the electrodes, except for the junction with the LSI,
Since it is covered with a metal layer formed by metal plating or vapor deposition, conductive particles (fillers) are crushed by misalignment of the bump portion of the LSI and the LSI crimping portion on the glass substrate from the glass side (back) of the cell or uniform crimping. Can be observed and inspected as to whether the amount is a predetermined amount or not, a large current can flow, and the mechanical strength and the solder wettability of the connection of the lead wire and the like can be improved.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention relates to COG
In the liquid crystal display element of the type, the wiring portion on the cell is covered with metal by metal plating or / and vapor deposition, and the crimping portion of the LSI is not subjected to metal plating or / and vapor deposition, and the glass side of the cell (back) The present invention provides a liquid crystal display device capable of inspecting and observing a pressure-bonded portion from the same.

FIG. 2 shows the L of the liquid crystal display device according to the present invention.
FIG. 3 shows a cross-sectional view of an SI mounting portion. FIG. 2 shows a method of vacuum deposition, sputtering, ion plating, chemical vapor deposition (CVD), etc., followed by etching (wet, dry) on a glass substrate 1 using a compound such as tin oxide, indium oxide, and indium tin oxide. The display pattern and external electrode 6 made of the formed transparent conductive film such as a Nesa film or an ITO film.
Are formed at the same time, metal plating 9 is applied to portions other than the portions where the bumps 10 of the driving LSI 8 are pressed, and conductive particles 11 (fillers) having electrical conductivity are dispersed between the bumps 10 and the external electrodes 6. This is a configuration in which the pressure bonding is performed face down using a.

The glass substrate 1 is composed mainly of soda lime glass containing no alkali as a glass component, has good thermal stability and a high strain point, and has a thermal expansion coefficient of 3 from normal temperature.
At 50 ° C., the temperature is about 46 to 47 (× 10 ⁻⁷ / ° C.), and the melting temperature is as high as 1600 to 1650 ° C. Further, with respect to the flatness, the glass is made of high-quality glass with little unevenness, warpage, undulation, surface roughness, and the like, and has high quality in terms of scratches, pits, dirt, and the like.

The display pattern and the external electrode 6 are mainly composed of tin oxide or indium oxide, and are composed of indium tin oxide (IT).
O) A transparent conductive film is formed by vacuum evaporation or chemical vapor deposition of a compound made of cadmium tin oxide or the like, and then etched to form a transparent electrode having a predetermined shape.

In the metal plating 9, nickel is applied to the transparent conductive film by selective plating to a thickness of, for example, about 500 nm, and gold plating is applied to the surface thereof, for example, to a thickness of about 50 nm. Also, 10 parts of the bump for mounting the bare chip,
The transparent conductive film remains as it is without applying the metal plating 9.

The area where the metal plating 9 is to be applied should basically not be applied to the bump 10 serving as a conductive portion of the LSI 8, but the area where the metal plating 9 is applied should be bumped so that the metal plating 9 is not applied. A part separated from 10 parts by 30 μm or more and 0.5 mm or less is defined as a boundary of metal plating.

The conductive particles 11 (filler) are formed by adding 5-1 to resin.
This is a dispersion of conductive particles composed of silver (Ag) particles of about 5 μm. The conductive particles 11 are connected to the external electrode 6 by LS.
I8 is installed on the 10 bumps facing each other.

Further, the LSI 8 is mounted on the bump 10 at a predetermined position.
And press-fit by face down with uniform pressure. As a result, the filler in the resin is crushed, and the fillers come into surface contact with each other, thereby obtaining conductivity.

Next, in order to confirm conduction through the conductive particles 11, whether the conductive particles 11 are crushed by a predetermined amount is inspected and observed from the glass side (back side) of the crimped portion by a visual and optical method. In this configuration, it is checked whether the crushing of the conductive particles is a predetermined amount or not, and furthermore, whether the position of the bump portion between the LSI 8 and the pressure-bonding portion is misaligned or whether the conductive particles are crushed uniformly.

FIG. 3 shows a main processing step diagram of the liquid crystal display device of the present invention. FIG. 3A shows a state of the patterned substrate with the ITO film. A flat glass substrate 1 made of soda lime glass or the like and having a thickness of about 1.1 mm is formed by etching or the like using tin oxide, indium oxide, or the like to form a display pattern region, a wiring to a display portion, and a pattern such as an external electrode 6 having a resistance of 30Ω / A transparent conductive film of about □ of the ITO film 3 is formed. However, the bump portion 10 is a part of the pattern of the wiring portion to the display portion and the pattern of the external electrode 6, and a space where liquid crystal is sealed is formed in the display region.

FIG. 3B shows the state of photoresist coating. This state is for metal plating (for nickel)
This is 9-a mask patterning. In order to cover (coat) a portion that does not require metal plating (a liquid crystal display region or a bump portion) with a photoresist, a photoresist is applied to the glass substrate 1 by about 2 μm using a spinner or the like (eg, a negative type photoresist in this case). .

Further, a pattern of a portion that does not require metal plating is exposed to ultraviolet rays by a stepper or the like (for example, here, the integrated light amount is 100 mJ / cm ² ).
Then, the exposed portion becomes insoluble. Furthermore, dirt is removed by showering with pure water or ultrasonic cleaning in a photo process cleaning device or the like, and is dried by air blow such as an air knife method or a hot air drying method, so that the photoresist remains on the liquid crystal display area and the bump portion. Let it.

FIG. 3C shows a metal plating (nickel) 9-.
The state where a is applied is shown. According to FIG. 3B, in order to apply metal plating to portions other than the liquid crystal display pattern and the bump portion having no photoresist, first, cleaning is performed with an alkaline solution for the purpose of removing dirt on the surface or degreasing, and then hydrochloric acid or the like. Neutralize alkalinity with acid.

Further, a catalytic treatment is performed. First, as a catalyst, a catalyzed treatment solution containing simultaneously a metal chloride composed of stannous chloride and palladium chloride and hydrochloric acid is immersed at room temperature to about 40 ° C. for about 2 to 3 minutes.

Next, the catalyst nuclei forming the protective colloid and complex ions by the catalyst are treated with an accelerator solution to be activated. As the accelerator solution, 5-1
Using an acid such as hydrochloric acid or sulfuric acid of about 0%,
The treatment is performed at a temperature of about ゜ C for about 2 to 5 minutes.

Further, the substrate is immersed in a chemical nickel plating solution such as a nickel chloride solution or a nickel sulfate solution containing nickel ions at a temperature of room temperature to about 30 ° C. for about 3 to 5 minutes to form electroless nickel plating. To form a nickel plating layer 9-a.

FIG. 3D shows a state in which the photoresist has been removed. The photoresist is removed from the mask pattern for electroless nickel plating formed in FIG. 3C by a roll brush, a disk brush, an ultrasonic cleaning, or the like using a detergent, a release agent, or the like.

FIG. 3E shows a metal plating (gold plating) 9-.
b shows a state where nickel is selectively applied on the nickel plating 9-a. Similar to the treatment step of FIG. 3C, first, the surface is cleaned with an alkaline solution for removing stains and degreasing, and then neutralized with an acid such as sulfuric acid to activate the nickel surface. To

Further, gold plating is performed using flash gold to form a thin plating layer having a thickness of about 50 nm. Immerse in a chemical gold plating solution composed of a metal salt such as a chloride solution or a sulfate solution containing gold ions at about room temperature, and further reduce with formaldehyde or Rochelle salt as a metal ion reducing agent to generate electroless gold plating, A gold plating layer 9-b is formed on the underlying nickel plating layer 9-a. The metal plating 9 is formed on the whole of the nickel plating layer 9-a and the gold plating layer 9-b.

FIGS. 4 and 5 show a transparent conductive film pattern and a metal plating pattern region on the glass substrate 1 of the cell 20 according to the first and second aspects of the present invention according to the production process described with reference to FIG. . FIG. 4 is a region diagram of the metal plating 9 according to claim 1 of the present invention. FIG. 5 shows a second embodiment of the present invention.
FIG. 3 is a region diagram of metal plating 9 according to the first embodiment.

In FIG. 4, 1 is a glass substrate, 7 is a polarizing filter, 9 is a metal plated portion, 12 is a region corresponding to a bump of an LSI, and a region corresponding to the bump is a transparent conductive film such as an ITO film. Therefore, the bare chip LSI is L
Whether the conductive particles (filler) are uniformly crushed with a uniform pressing force on the crimping portion, and whether the crushing of the conductive particles (filler) has reached a predetermined amount, is determined by checking the cell position. Observation and inspection can be performed from the glass side (back).

Further, in FIG. 5, together with the functions in FIG. 4, 1 is a glass substrate, 7 is a polarizing filter, and 12 is LS.
A region corresponding to the bump I, 13 is a power line, 14 is a ground line, and metal plating 9 is applied only to 13 and 14,
Able to flow current without generating heat even with large current,
Mechanical strength was obtained for connection of lead wires and the like, and solder wettability was improved.

FIG. 6 is a flowchart showing the main part of an embodiment of the COG shown in FIG. In state 1, a transparent conductive film of the patterned ITO film 3 is formed on the glass substrate 1 by etching using indium tin oxide and a wiring to the display unit and the external electrode 6.

Next, in state 2, the mask pattern of 9-a for nickel plating, which is the lower layer (ground plating) of the metal plating, is masked with a photoresist. The portions that do not require metal plating (the liquid crystal display area and bumps) are covered (coated) with photoresist.

Further, in the state 3, the metal ions in the solution are reduced and precipitated by the nickel plating, which is the lower layer (ground plating) of the metal plating, without passing an electric current from the outside, and the plating layer is deposited on the surface of the body to be plated. Nickel plating by an electroless method. Nickel plating breaks out where there is no photoresist.

In state 4, the photoresist is peeled off the mask pattern for electroless nickel plating formed in state 2 using a detergent or a stripping agent.

In state 5, the photoresist debris in state 4 is further removed by heat, and at the temperature of 250 ° C. in order to eliminate the distortion and the like of the glass substrate 1 and strengthen the adhesion of the nickel plating layer. Age for 30 minutes.

Further, in the state 6, the gold plating 9-b is again applied to the underlying nickel plating layer 9 by the electroless plating method.
-A, a nickel plating layer 9-a and a gold plating layer 9
-B to form the metal plating 9 as a whole.

The state 7 is a two-layer structure of the transparent electrode film 3 of the segment side for liquid crystal display of the glass substrate 1 up to the state 6 and the glass substrate 2 on which the corresponding transparent electrode film of the common side display is formed. Are aligned, a gap is provided between the two glass substrates, and the periphery is sealed with a seal 5 made of resin or the like (however, an injection port for injecting liquid crystal is not sealed).

Further, a glass substrate is put into a chamber by a liquid crystal injection device or the like, evacuated by a vacuum pump, and after evacuating, the glass substrate is immersed in a dedicated liquid crystal dish containing liquid crystal, and the liquid crystal is injected into the cell. Let it.

Further, when the liquid crystal is injected into the cells of the glass substrate, the injection port is sealed with a resin or the like. In addition, a polarization filter for limiting the polarization direction of incident light to one direction (depending on the liquid crystal display method, reflection type or transmission type for light, or twisting method of the liquid crystal itself for polarization direction) is attached to the upper part of the cell. Put on.

In state 8, the bumps of the completed liquid crystal display element are face-down pressed using a resin in which conductive particles 11 made of silver particles (fillers) having good electrical conductivity are dispersed.

At this time, the LSI which is a bare chip is
The conductive particles 1 are flattened from the top of the LSI with a flat plate-shaped crimping machine (for example, a bonder) so as not to displace the crimping portion.
A uniform pressure is applied so that 1 (filler) is crushed by a certain amount. Various bonding such as cold pressing, hot pressing (room temperature 150 ° C.), pressing force (0.1 to 1 kg), pressing time (0.1 to 60 sec), and the like can be changed depending on the pressing force and the resin. At the same time, the glass substrate and the LSI are bonded with a resin.

FIG. 7 shows the flow of the electroless nickel plating section in the flowchart of the main part of FIG. In the state 3a, in order to apply the metal plating 9, cleaning is performed with an alkaline solution for removing stains and degreasing the surface.

Further, in the state 3b, the alkalinity of the treatment performed in the state 3a is neutralized with an acid such as hydrochloric acid.

In the state 3c, as a first step of the catalyzing treatment, the catalyst treatment is carried out with a metal chloride composed of stannous chloride and palladium chloride and hydrochloric acid at a temperature of about room temperature to about 40 ° C. for 2 to 3 hours. Soak for about a minute.

Further, in the state 3d, the catalyst nuclei forming the protective colloid and the complex ion by the catalyst treatment are removed by 5%.
Activate by treating with an accelerator solution consisting of about 10 to 10% of an acid such as hydrochloric acid or sulfuric acid at a temperature of about 30 to 50 ° C for about 2 to 5 minutes.

In state 3e, a chemical nickel plating solution such as a nickel chloride solution or a nickel sulfate solution containing nickel ions is formed at room temperature to about 30 ° C. for about 3 to 5 minutes in order to generate electroless nickel plating. Soak. Thus, the nickel plating which is the base of the metal plating 9 is formed by the electroless nickel plating.

FIG. 8 shows a flow chart of the electroless gold part in the flowchart of the main part of FIG. In the state 6a, first, cleaning with an alkaline solution such as nickel plating or the like is performed to remove dirt or degrease the surface in order to apply gold plating.

In the state 6b, the acid in the state 6
a. Neutralize the alkalinity in a and activate the nickel surface.

The state 6c is obtained by immersing in a chemical gold plating solution composed of a metal salt such as a chloride solution or a sulfate solution containing gold ions at about room temperature, and further reducing with formaldehyde or Rochelle salt as a metal ion reducing agent. Produces electroless gold plating.

As described above, the upper layer of nickel plating is formed by gold plating by electroless gold plating. The metal plating 9 is formed as a whole by the gold plating layer formed in FIG. 8 on the nickel plating layer of the base formed in FIG.

As described above, in the liquid crystal display element of the present invention, since the region corresponding to the bump is formed of the transparent conductive film such as the ITO film, the position shift and the conductive particles are not performed with respect to the bump portion of the bare chip. It is possible to observe and inspect whether the (filler) is uniformly crushed and whether the crushing of the conductive particles (filler) has reached a predetermined amount from the glass side (back side) of the cell.

Further, since metal plating is applied to the power supply wiring, the ground wiring, and the boosting wiring to the LSI, a large current can be passed without generating heat, the mechanical strength for connecting lead wires and the like can be increased, and solder wettability can be improved. Can be improved. Further, the present invention provides
In addition to the glass substrate, a resin film may be used if it is transparent.

[0059]

As described above, in the liquid crystal display device according to the first aspect, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all transparent conductive films. In addition, the wiring portion and the external electrode are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with each LSI. Therefore, the bump portion of the LSI is formed from the glass side (back side) of the cell. After the mounting, it is possible to check the positional deviation between the substrate and the LSI crimping part on the glass substrate, and to observe and inspect whether the crushing of the conductive particles is uniform or a predetermined amount. And the repair amount and the repair process can be reduced, and the cost and reliability can be improved.

Further, in the liquid crystal display element according to the present invention, the external electrode provided at the cell end, the display electrode in the liquid crystal sealed space, and the wiring portion connected to the display electrode are all formed of a transparent conductive film, and Since only the electrodes for the power supply, the ground wiring, and the boost wiring among the external electrodes are covered with the metal layer formed by metal plating or vapor deposition except for the joint portion with the LSI, the glass side of the cell (the back side) ) Can observe and inspect whether or not the conductive particles are crushed by a predetermined amount by misalignment between the bump portion of the LSI and the LSI crimping portion on the glass substrate or by uniform crimping. As a result, a large current can flow without generating heat, mechanical strength can be increased for connection of lead wires and the like, and improvement in solder wettability can be obtained, thereby improving work operability and reliability. .

Therefore, it is possible to observe the connection between the bare chip and the glass substrate during and / or after mounting the bare chip such as an LSI on the liquid crystal display element, and to supply power, ground and boost to the bare chip such as the LSI. It is possible to reduce the resistance of wiring such as.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a liquid crystal display element.

FIG. 2 is a sectional view of an LSI mounting portion of the liquid crystal display element according to the invention.

FIG. 3 is a view showing main processing steps of the liquid crystal display element of the present invention.

FIG. 4 is a region diagram of the metal plating 9 according to claim 1.

FIG. 5 is a region diagram of the metal plating 9 according to claim 2;

FIG. 6 is a flowchart of a main part in one embodiment of the COG according to FIG. 3;

FIG. 7 is a flowchart of a main part of nickel plating in one embodiment of the COG according to FIG. 3;

FIG. 8 is a flowchart of a main part of gold plating in one embodiment of the COG according to FIG. 3;

FIG. 9 is a cross-sectional view around an LSI installed on a cell of a conventional COG type liquid crystal display device.

[Description of References] 1 ... Glass substrate, 2 ... Transparent electrode film (common side), 3 ... Transparent electrode film (display side), 4 ... Liquid crystal, 5 ... Seal, 6 ... External electrode, 7 ... Deflection filter, 8 ... Driving LSI, 9: metal plating, 9a: nickel plating (electroless nickel plating), 9b: gold plating (electroless gold plating), 10: bump, 11: conductive particles (silver particles), 12: photoresist, 13: power supply Line, 14 ... ground line, 20 ... cell.

Claims (2)

[Claims] 1. A COG-type liquid crystal display element in which an LSI is installed and driven around a cell, an external electrode provided at an end of the cell, a display electrode in a liquid crystal sealed space, and a wiring connected to the display electrode. Each of the portions is formed of a transparent conductive film, and the wiring portion and the external electrode are covered with a metal layer formed by metal plating or vapor deposition except for a joint portion with each of the LSIs. Liquid crystal display element. 2. A COG-type liquid crystal display device in which an LSI is installed and driven around a cell, an external electrode provided at an end of the cell, a display electrode in a liquid crystal sealed space, and a wiring connected to the display electrode. Each part is formed of a transparent conductive film, and only the electrodes for the power supply, the ground wiring, and the boost wiring among the external electrodes, except for the junction with the LSI, are formed by metal plating or vapor deposition. A liquid crystal display device characterized by being covered with a liquid crystal display.