JPH11121893A - Method and structure for connecting circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance bondability of an anisotropic conductive adhesive being employed for bonding an electrode terminal formed on a board to a wiring board connected with a semiconductor device by setting the contact angle of the electrode terminal on the board to the water on the connecting surface at a specified value or below or setting the surface energy at a specified level or above. SOLUTION: The structure at the TCP connecting part of a liquid crystal is shown as an example of circuit connection structure. The liquid crystal 1 comprises a liquid crystal element P. Electrode terminals 4 are arranged on the inner surface at the end part of boards 2, 3 (only the board 2 is shown) and, a TCP 6 provided with a semiconductor device and a wiring circuit pattern 8 on a flexible basic material incorporating an IC circuit 5 is bonded through an anisotropic conductive adhesive 7. Since the contact angle θw on the surface of the electrode terminal 4 is set at 70 deg. or the surface energy θ is set at 37 dyne/cm, adhesion of the anisotropic conductive adhesive to the surface of the electrode terminal 4 can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit connection structure and a circuit connection method, and more particularly, to a wiring board having an electrode terminal formed on a substrate of an optical modulator or a liquid crystal device, and a wiring pattern connected to a semiconductor device. The present invention relates to a circuit connection structure and a circuit connection method in which the adhesiveness of an anisotropic conductive adhesive used for connection between the circuit connection structure is improved.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory view showing a general structure of a TCP connection portion of a liquid crystal device. In the figure, the liquid crystal device 1 includes a liquid crystal element P. The liquid crystal element P includes a pair of substrates 2 and 3 formed of a pair of glass plates arranged in parallel with a gap. Scan electrodes and information electrodes are formed on the inner surfaces of these substrates 2 and 3. (Not shown).
The substrates 2 and 3 are bonded together by a sealing material (not shown), and a liquid crystal (not shown) is injected and sealed in a gap between the substrates 2 and 3. Further, electrode terminals 4 are arranged on the inner surfaces of the ends of the substrates 2 and 3 (only the case of the substrate 2 is shown in the figure). A TCP (wiring substrate) 6 on which a semiconductor device and a wiring pattern 8 are provided is bonded via an anisotropic conductive adhesive 7.

In the method of manufacturing the liquid crystal element P, a pair of substrates 2 and 3 are attached to each other, a liquid crystal is injected into a gap between the substrates, and the electrode terminals 4 of the liquid crystal element are washed to remove contaminants on the surface of the electrode terminals. It has been manufactured by attaching an anisotropic conductive adhesive to the surface of the electrode terminal 4 and attaching TCP.

As described above, it is confirmed that a contaminant adheres to the surface of the electrode terminal 4 in a step before the anisotropic conductive adhesive is applied. It is not completely removed only by washing before applying the adhesive,
It has been confirmed that the adhesive remains on the surface of the electrode terminal 4 when the anisotropic conductive adhesive is applied.

[0005]

The anisotropic conductive adhesive is obtained by dispersing conductive particles 22 (particles having a diameter of 3 to 15 μm) in an adhesive film 21 having a thickness of 15 to 30 μm. . As shown in FIG. 2B, an electrode terminal 9 of the TCP 6 to which the anisotropic conductive adhesive 7 is to be connected.
And the upper and lower electrode terminals are positioned between the substrate and the electrode terminals 4 of the substrate, and heated and pressed (thermocompression bonding). As a result, the adhesive of the adhesive film 21 of the anisotropic conductive adhesive 7 is melted, and the space between the upper and lower electrode terminals is narrowed, so that the conductive particles 22 come into contact with the upper and lower electrode terminals 4 and 9 to conduct electricity. The conditions of thermocompression bonding are 150 to 200 ° C, 20 to 40 kg / cm ² ,
10-20 sec is desirable.

However, due to residual contaminants adhering to the surface of the electrode terminal of the substrate, the anisotropic conductive adhesive is peeled off from the electrode terminal immediately after the anisotropic conductive adhesive is applied. There was a problem that the conductive adhesive was poorly adhered and that it was easily peeled off from the electrode terminal surface of the liquid crystal element immediately after thermocompression bonding.

SUMMARY OF THE INVENTION The present invention has been made in order to improve such disadvantages of the prior art, and connects an electrode terminal formed on a substrate to a wiring substrate having a wiring pattern connected to a semiconductor device. It is an object of the present invention to provide a circuit connection structure and a circuit connection method in which the adhesiveness of the anisotropic conductive adhesive used in the above is improved.

[0008]

That is, the present invention relates to a wiring board provided with a semiconductor device and a wiring pattern connected at one end to the semiconductor device, wherein the wiring pattern is formed at the other end with an electrode terminal formed on the substrate. a circuit connection structure connected, contact angle theta _w to water at connection surfaces of the electrode terminals of the substrate is at 70 ° or less, or a circuit connected to the surface energy γ is equal to or is 37 dyne / cm or more Structure.

Further, the present invention provides an optical modulation panel having an electrode and having at least one of substrates on which a terminal of the electrode is formed on a peripheral portion, and an electrode of the optical modulation panel having an input electrode and an output electrode. What is claimed is: 1. An optical modulation device comprising: a semiconductor device for supplying a drive waveform; and a wiring substrate having a wiring pattern connected to the semiconductor device, wherein the wiring pattern of the wiring substrate is formed on a substrate of the optical modulation panel. is connected to the contact angle theta _w to water at connection surfaces of the electrode terminals of the optical modulation panel is not less 70 ° or less, or surface energy γ is an optical modulator, characterized in that it is 37 dyne / cm or more.

Further, the present invention comprises a liquid crystal panel having a liquid crystal sandwiched between a pair of substrates, electrodes provided on at least one of the substrates, and terminals of the electrodes formed on a peripheral portion, and input electrodes and output electrodes. A liquid crystal device comprising: a semiconductor device that supplies a drive waveform to an electrode of the liquid crystal panel; and a wiring substrate having a wiring pattern connected to the semiconductor device, wherein the wiring pattern of the wiring substrate is formed on at least one substrate of the liquid crystal panel. is connected to the electrodes formed terminal, or less contact angle theta _w is 70 ° to water in the connection surfaces of the electrode terminals of the liquid crystal panel, or the surface energy γ is 3
It is a liquid crystal device characterized by being 7 dyne / cm or more.

In the above circuit connection structure of the present invention, it is preferable that the wiring substrate is a TCP structure in which a semiconductor device and a wiring pattern are provided on a flexible base material. Further, it is preferable that the other end of the wiring pattern and the electrode terminal on the substrate are connected via an anisotropic conductive adhesive.

Further, the present invention relates to a circuit connecting method for connecting a wiring pattern of a wiring board having a semiconductor device and a wiring pattern connected to the semiconductor device at one end to an electrode terminal formed on the substrate at the other end. there are, contact angle theta _w to water at the connection surface of the electrode terminals of the substrate 70
° or less, or the surface energy γ is 37 dyne
/ Cm or more, and connecting the wiring pattern of the wiring board to the electrode terminal of the board.

[0013] In the above circuit connecting method of the present invention, with respect to the connecting surface of the electrode terminals of the substrate, and less contact angle theta _w 70 ° with respect to water subjected to UV irradiation and exposure of ozone or the surface energy γ is It is preferably at least 37 dyne / cm. Preferably, the treatment is performed by heating the substrate having the electrode terminals. Substrate heating temperature 120
It is preferable to carry out in the range of -200 ° C.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The circuit connection structure of the present invention is used for connection of electrode terminals, for example, in connection of electrode terminals on the periphery of an optical modulator, particularly connection between electrode terminals and the TCP structure on the periphery of a substrate of a liquid crystal device. It removes surface contaminants, optimizes the surface energy, and enhances the connection strength (adhesion).

That is, in the circuit connection structure of the present invention, the wiring pattern of a wiring board having a semiconductor device and a wiring pattern connected to the semiconductor device at one end is connected to an electrode terminal formed on the substrate at the other end. a circuit connection structure that the contact angle theta _w to water at the connection surface of the electrode terminal of the substrate is at 70 ° or less, or surface energy γ is equal to or is 37 dyne / cm or more.

FIG. 1 is an explanatory view showing the structure of a TCP connection portion of a liquid crystal device as an example of the circuit connection structure of the present invention.
In the figure, the liquid crystal device 1 includes a liquid crystal element P.
The liquid crystal element P includes a pair of substrates 2 and 3 formed of a pair of glass plates arranged in parallel with a gap. Scan electrodes and information electrodes are formed on the inner surfaces of these substrates 2 and 3. (Not shown). The substrates 2 and 3 are bonded together by a sealing material (not shown), and a liquid crystal (not shown) is injected and sealed in a gap between the substrates 2 and 3. Further, electrode terminals 4 are arranged on the inner surfaces of the ends of the substrates 2 and 3 (only the case of the substrate 2 is shown in the figure). In which a semiconductor device and a wiring pattern 8 are provided
P6 is bonded via an anisotropic conductive adhesive 7.
Or more electrode terminals 4 contact angle theta _w of water on the surface is not more 70 ° or less, or by the surface energy γ is 37 dyne / cm or more, the anisotropic conductive to be attached to the surface of the electrode terminal 4 The adhesive force of the adhesive 7 can be increased.

The method of measuring the surface energy γ in the present invention will be described. FIG. 3 is a schematic diagram for explaining a method of measuring a contact angle. The surface energy γ is an important amount for judging the properties of the interface and the degree of contamination. That is,
The wettability of the surface can be determined by measuring the contact angle. Droplet method, inclined plate method, capillary rise method and the like are widely used as contact angle measurement methods,
In the present invention, the droplet method was used. In this method, a droplet is placed on the surface of an electrode terminal 4 of a liquid crystal element P to be a sample, and the droplet 3
0 is an enlarged image. And the straight line 31 in the field of view
Is rotated about the contact point of the droplet 30, and the angle at the position of the tangent is read. In the present invention, the contact angles of three types of liquids (α-bromonaphthalene, methylene iodide, and water) were measured by a droplet method, and the surface energy γ was calculated. In addition, the code | symbol D in a figure shows an electrode terminal surface.

The surface energy γ was calculated by the following method. Formula (1) obtained by expanding Fowkes' formula

[0019]

(Equation 1)γ^d _L, Γ^p _L, Γ^h _LIs the dispersion term of the liquid and the polarity
Term, hydrogen bond term component γ^d _S, Γ^p _S, Γ^h _SIs the dispersion of the sample (solid)
Term, polar term, and hydrogen bond term component θ are calculated by using the contact angle of each liquid and _LBy substituting
From the three equations obtained, γ _SAnd the sum γ^d _S+
γ^p _S+ Γ^h _S= Γ.

[0020]

[Table 1]

In the present invention has a contact angle theta _w of water on the surface of the electrode terminal 4 is 70 ° or less, or as a method of surface energy γ is to 37 dyne / cm or more, the connection surfaces of the electrode terminals of the substrate It is preferable to perform UV irradiation and exposure to ozone.

Hereinafter, UV light irradiation and ozone exposure will be described. Before liquid crystal injection for a wider range of contact angle theta _w and the surface energy γ of the electrode terminal surfaces, performs exposure radiation and ozone of the UV light. Irradiation with UV light and exposure with ozone were performed using the cell surface treatment apparatus 40 shown in FIG. The device 40 includes a hot plate 41, on which the liquid crystal element P is mounted, and the mounted liquid crystal element P is heated.

The heating temperature is preferably higher from the viewpoint of removing dirt. However, since the effect of the alignment treatment of the alignment control film provided on the liquid crystal element may be affected, for example, the heating temperature is set to 120 ° C.
Temperatures of ~ 200 ° C are preferred. Above the hot plate 41, a quartz glass 42 as a shielding member is disposed so that the liquid crystal element P is surrounded by the quartz glass 42. Above the quartz glass 42, a UV lamp 43 is provided. Is placed. Further, an ozone supply nozzle 45 is opened in a space between the quartz glass 42 and the hot plate 41 so that ozone is supplied between the quartz glass 42 and the liquid crystal element P. The supply of ozone was performed at 50 g / cm ³ . The UV lamp 43 used was 500 W. By changing the irradiation time of the UV light was controlled to the value of the contact angle theta _w and the surface energy γ of the electrode terminal surface. After this treatment, liquid crystal was injected, and then the contact angle was measured.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples.

Reference Example 1 As a liquid crystal element, I was patterned into upper and lower stripes.
It has a TO electrode, and an inorganic insulating film (Ta
₂ O ₅ ), and using a device in which a polyimide alignment film was rubbed thereon, before injecting liquid crystal into the electrode terminal surface,
4, the substrate is heated at a temperature of 150 ° C., the supply amount of ozone is 50 g / cm ³ , and the UV lamp 43 is
UV light irradiation and ozone exposure were performed using a 00 W laser.

Immediately before attaching the electrode terminal and the anisotropic conductive adhesive, the contact angle of the electrode terminal surface was measured, and the surface energy γ
Was measured. Then, the attached anisotropic conductive adhesive was observed, and the presence or absence of peeling was examined. Table 2 summarizes the measured surface energy γ and the peeling state.
Summarizes the contact angle theta _w of the measured water, a situation peeling. This experiment was performed on 80 electrode terminals.

[0027]

[Table 2]

[0028]

[Table 3]

According to this experiment, 30 dyne / cm ≦ γ
At <35 dyne / cm, 80 ° ≦ θ _w ≦ 90 °, peeling of the anisotropic conductive adhesive was observed, and γ ≧ 35 dyne /
In cm and θ _w <80 °, no peeling was observed. That is, the condition of the surface D where the anisotropic conductive adhesive does not peel off from the electrode terminal surface D immediately after the application of the anisotropic conductive adhesive is γ
≧ 35 dyne / cm, θ _w <80 °.

Example 1 Next, with respect to the anisotropic conductive adhesive in which no peeling was observed in Reference Example 1, the state of peeling after thermocompression bonding was examined. Table 4 summarizes the measured surface energy γ and the peeling status, and Table 5 shows the measured water contact angle θ.
It is a summary of _w and the peeling status.

[0031]

[Table 4]

[0032]

[Table 5]

According to this experiment, 35 dyne / cm ≦ γ
In the case of <37 dyne / cm, 70 ° <θ _w <80 °, peeling of the anisotropic conductive adhesive was observed, and γ ≧ 37d
At yne / cm and θ _w ≦ 70 °, no peeling was observed. Note that 35 dyne / cm ≦ γ <37 dyne /
cm did not show peeling, but these were θ _w ≦ 70 °, and 6 did not show peeling even at 70 ° <θ _w <80 °. Is γ
≧ 37 dyne / cm.

That is, the conditions under which the anisotropic conductive adhesive does not peel off from the liquid crystal element electrode terminal surface even after thermocompression bonding are as follows:
γ ≧ 37 dyne / cm and θ _w ≦ 70 °. Θ _{w of the} electrode terminal surface is 70 ° or less or γ is 37 dyne / c
If m or more, the anisotropic conductive adhesive does not peel off from the electrode terminal surface of the liquid crystal element, and can fulfill the function of the original anisotropic conductive adhesive.

Example 2 Next, in Example 1, a drive evaluation was performed on a liquid crystal device having an element that was not peeled to determine whether proper display was possible.
The device used was one into which chiral smectic liquid crystal was injected. The evaluation was performed by sequentially applying the bipolar waveforms shown in FIG. 6, and all the devices showed good switching.

Although the above evaluation was performed on a device using a chiral smectic liquid crystal, good switching characteristics were similarly obtained when the same evaluation was performed on a device using a nematic liquid crystal.

[0037]

As described above, according to the present invention,
A circuit connection structure, particularly an anisotropic conductive adhesive used to connect an electrode terminal formed on a substrate such as an optical modulation device or a liquid crystal device with a wiring substrate having a wiring pattern connected to a semiconductor device, wherein is the contact angle theta _w of water in the electrode terminal surface 70 ° or less, or surface energy gamma 37Dyn
By setting it to e / cm or more, the adhesive strength of the anisotropic conductive adhesive stuck to the electrode terminal surface can be increased.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a structure of a TCP connection part of a liquid crystal device as an example of a circuit connection structure of the present invention.

FIG. 2 is an explanatory diagram showing a circuit connection structure using an anisotropic conductive adhesive.

FIG. 3 is a schematic diagram for explaining a method of measuring a contact angle.

FIG. 4 is an explanatory diagram showing UV light irradiation and ozone exposure.

FIG. 5 is an explanatory diagram showing a general structure of a TCP connection part of a liquid crystal device.

FIG. 6 is a diagram showing driving waveforms for evaluating driving of the liquid crystal device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal device 2,3 Substrate 4,9 Electrode terminal 5 IC circuit 6 TCP 7 Anisotropic conductive adhesive 8 Wiring pattern P Liquid crystal element 21 Adhesive film 22 Conductive particle 30 Droplet 31 Straight line (central part of visual field) 40 Cell surface treatment device 41 Hot plate 42 Quartz glass 43 UV lamp 44 UV light 45 Ozone supply nozzle 46 Ozone

Claims (13)

[Claims] 1. A circuit connection structure in which a wiring pattern of a wiring board provided with a semiconductor device and a wiring pattern connected to the semiconductor device at one end is connected to an electrode terminal formed on the substrate at the other end. A contact angle θ _w of water on the connection surface of the electrode terminal of the substrate to 70 ° or less;
Alternatively, the circuit connection structure, wherein the surface energy γ is 37 dyne / cm or more. 2. The circuit connection structure according to claim 1, wherein the wiring substrate is a TCP structure in which a semiconductor device and a wiring pattern are provided on a flexible base material. 3. The circuit connection structure according to claim 1, wherein the other end of the wiring pattern and an electrode terminal on the substrate are connected via an anisotropic conductive adhesive. 4. An optical modulation panel having electrodes and having at least one of substrates on which terminals of the electrodes are formed on a peripheral portion, and a drive waveform is provided to the electrodes of the optical modulation panel having input electrodes and output electrodes. An optical modulator having a semiconductor device and a wiring substrate having a wiring pattern connected to the semiconductor device, wherein the wiring pattern of the wiring substrate is connected to an electrode terminal formed on the substrate of the optical modulation panel, optical modulator, wherein the contact angle theta _w to water at the connection surface of the electrode terminals of the optical modulation panel is at 70 ° or less, or surface energy γ is 37 dyne / cm or more. 5. The optical modulation device according to claim 4, wherein the wiring substrate is a TCP structure in which a semiconductor device and a wiring pattern are provided on a flexible base material. 6. The optical modulation device according to claim 4, wherein the wiring pattern and an electrode terminal on the substrate of the optical modulation panel are connected via an anisotropic conductive adhesive. 7. A liquid crystal panel comprising a liquid crystal panel having a liquid crystal sandwiched between a pair of substrates, electrodes provided on at least one substrate, and terminals of the electrodes formed on a peripheral portion, and an input electrode and an output electrode. What is claimed is: 1. A liquid crystal device comprising: a semiconductor device for supplying a drive waveform to an electrode; and a wiring substrate having a wiring pattern connected to the semiconductor device, wherein the wiring pattern of the wiring substrate is formed on at least one substrate of the liquid crystal panel. is connected to the electrode terminal, the contact angle theta _w to water at connection surfaces of the electrode terminals of the liquid crystal panel is not less 70 ° or less, or surface energy γ is 37 dyne / c
m or more. 8. The liquid crystal device according to claim 7, wherein the wiring substrate is a TCP structure in which a semiconductor device and a wiring pattern are provided on a flexible base material. 9. The liquid crystal device according to claim 7, wherein the wiring pattern and an electrode terminal on the substrate of the liquid crystal panel are connected via an anisotropic conductive adhesive. 10. A circuit connection method in which a wiring pattern of a wiring board having a semiconductor device and a wiring pattern connected to the semiconductor device at one end is connected to an electrode terminal formed on the substrate at the other end. the contact angle theta _w to water at the connection surface of the substrate of the electrode terminals is not more 70 ° or less,
Alternatively, a circuit connection method comprising connecting a wiring pattern of a wiring board to an electrode terminal of the board by setting the surface energy γ to 37 dyne / cm or more. Respect 11. The connection surfaces of the electrode terminals of the substrate, and less contact angle theta _w 70 ° with respect to water subjected to UV irradiation and exposure of ozone or the surface energy γ of 37
The circuit connection method according to claim 10, wherein dyne / cm or more is set. 12. The circuit connection method according to claim 11, wherein the substrate having the electrode terminals is heated. 13. The circuit connection method according to claim 12, wherein the heating temperature of the substrate is in a range of 120 to 200 ° C.