KR20050076689A - Electronic module and electronic device with the same electronic module and compression bonding checking method in the electronic module - Google Patents

Abstract

The present invention provides an electronic module having a configuration capable of quantitatively evaluating and managing whether a wiring terminal between an IC or a flexible wiring board and a transparent substrate is reliably connected by thermocompression bonding, and an electronic device equipped with the electronic module. And it aims at providing the thermocompression connection confirmation method in an electronic module.

If the minimum number of effective conductive particles of the ACF crimped between the dummy terminal and the transparent substrate is equal to or greater than the required minimum number of effective conductive particles in the connection terminal crimped under the same conditions in the electronic module, the electronic module is connected to the ACF. The crimp connection condition by means of selection is good.

Description

ELECTRONIC MODULE AND ELECTRONIC DEVICE WITH THE SAME ELECTRONIC MODULE AND COMPRESSION BONDING CHECKING METHOD IN THE ELECTRONIC MODULE}

The present invention relates to a crimp connection of an electronic module, and more particularly, to an electronic module having a configuration capable of quantitatively evaluating and managing a connection state by thermocompression bonding between an IC, a flexible wiring board, and a wiring terminal with a transparent substrate. A module, an electronic device equipped with this electronic module, and a thermocompression connection confirmation method for an electronic module.

BACKGROUND ART With the spread of portable telephones and portable information terminals (PDAs), display panels with higher definition image display functions, thinner and lower power consumption are required.

As a display panel that satisfies the above requirements, conventionally, liquid crystal display panels have been employed in many products, but recently, organic EL (electroluminescent) display panels have characteristics as self-luminous display elements, so they are employed in some products. And attracting attention as a next-generation display panel.

In the display panel, an anisotropic conductive film (ACF) containing conductive particles is generally formed between the IC and the transparent substrate (glass substrate) or the wiring terminal between the flexible wiring substrate and the transparent substrate (glass substrate). It is connected by thermocompression through.

The ACF is formed by dispersing a plurality of conductive particles in a thermoplastic or thermosetting resin film, wherein conductive particles are connected between terminals or electrodes which are replaced by thermocompression in a condition in which a predetermined amount of the conductive particles is distorted, thereby conducting in a single direction. Thus, the terminals and the electrodes are electrically and mechanically connected.

For this reason, ACF is used suitably when connecting a large number of terminals and electrodes collectively simultaneously.

Fig. 2 shows the configuration of the connection terminal portion between the IC and the transparent substrate thermocompressed by ACF. In the connection terminal shown in FIG. 2, the transparent substrate 2 provided with the transparent electrode 4 and the metal wiring 8 is faced down through the connection terminal (bump) 3 of the IC 1 and the ACF 7. Is pressed.

In the connection terminal section configured as described above, since there is an opaque metal wiring 8 on the outside of the crimping portion, the crimping portion cannot be directly observed from the outside, and the number of conductive particles contained in the ACF 7 is measured. It was difficult to confirm whether thermocompression was performed reliably by the method.

In contrast, Japanese Patent Application Laid-Open No. 11-125837 (hereinafter referred to as Patent Document 1) discloses a liquid crystal device that can be viewed from a non-compression surface of a glass substrate.

FIG. 1 shows a rear view of a connection terminal portion of an electronic module such as the liquid crystal device disclosed in Patent Document 1. As shown in FIG. In FIG. 1, two dummy terminals (bumps) 5 are provided at both ends of the thermocompression-bonding portion A, and in this position, the metal film 6 is replaced by the metal wiring 8 around the dummy terminals 5. ) Is installed.

3 is a cross-sectional view of the dummy terminal portion in FIG. 1. As shown in FIG. 3 and as can be seen in comparison with FIG. 2, in the dummy terminal portion, the non-transparent metal wiring 8 is not present on the transparent substrate 2 side, whereby the non-compression bonding of the transparent substrate 2 is performed. From the surface, the thermally compressed portion can be viewed, and the crushed state of the conductive particles of the ACF 7 on the dummy terminal 5 can be directly observed and confirmed.

By the way, in the above display panel, since each pixel of the liquid crystal display panel is basically a voltage driving type, the connection resistance between electrodes on the transparent substrate side and the flexible wiring substrate side is not so much a problem. In other words, in the liquid crystal panel display, even if the connection resistance between the two electrodes is somewhat large or somewhat uneven, the degree of influence on the display of the image is relatively small.

On the other hand, in the organic EL display panel which is attracting attention recently, the display pixel is a current driving type and has a current dependent characteristic in which the light emission luminance of the pixel also changes in proportion to the driving current. In particular, in a passive driving type EL display panel, unlike a liquid crystal, a relatively large current flows in each element, so that the wiring resistance and the connection resistance on the cathode side are often problematic.

For this reason, in the above-mentioned thermocompression-bonding connection, electrical connection is fully required.

In recent years, the connection terminal when thermocompression bonding an IC or a flexible wiring board or the like with a transparent substrate is remarkably narrowed in pitch, and a more reliable thermocompression connection is required.

Therefore, the necessity of not only qualitative management but also quantitative evaluation and management of the connection crimping state of the connection terminal part has increased.

However, in the said patent document 1, management of the crimping | compression state according to the crushed state of electroconductive particle, etc. was limited only to the qualitative side through visual confirmation. That is, the reference document 1 does not describe anything about the area of the dummy terminal, and does not disclose a management criterion regarding the number of crushed conductive particles.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and in a manufacturing line or the like, a configuration capable of quantitatively evaluating and managing whether or not a wiring terminal between an IC or a flexible wiring board and a transparent board is reliably connected by thermocompression bonding. It is an object of the present invention to provide a thermocouple connection checking method for an electronic module equipped, an electronic device equipped with the electronic module, and an electronic module.

A preferred embodiment of the electronic module according to the present invention made to solve the above problems is an electronic module in which at least one of the plurality of connection terminals provided on each of the transparent substrate and the electronic member is electrically connected through an anisotropic conductive film. At least one of the dummy terminals that are visible from the non-connected surface of the transparent substrate is provided, and is selected by the number of conductive particles of the anisotropic conductive film compressed between the dummy terminal and the transparent substrate.

In addition, one of the preferred embodiments of the thermal crimp connection confirmation method in the electronic module according to the present invention made to solve the above problems is that at least one pair of the plurality of connection terminals provided on each of the transparent substrate and the electronic member is formed of an anisotropic conductive film. A conductive terminal of the anisotropic conductive film compressed between the dummy terminal and the transparent substrate is provided in the electronic module electrically connected via the dummy terminal, which is provided at at least one position of the electronic member through the non-connected surface of the transparent substrate. By criterion, the crimp connection status is checked.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The basic configuration of the electronic module according to the present invention is the same as that shown in the prior art of FIG. That is, the electronic module shown in FIG. 1 includes a metal wiring (not shown) provided in a predetermined pattern on the transparent electrode 4 on the transparent substrate 2 and bumps of a plurality of ICs 1 installed corresponding to the metal wiring. In connecting (3), dummy terminals 5 which are not connected with wirings in which metal films 6 are provided in place of the metal wirings are formed at both ends of the plurality of bumps 3.

As shown in FIG. 3, which is a cross-sectional view of the dummy terminal portion in FIG. 1, since there is no opaque metal wiring 8 in the dummy terminal portion, the non-connected surface of the transparent substrate 2 (non-compression surface). ) Can see through the ACF 7.

For this reason, in the electronic module according to the present invention, the crimping portion between the dummy terminal 5 and the transparent substrate 1 can be directly observed from the outside, and the electrical properties in the thermocompression bonding through the ACF 7 can be observed. Based on statistical techniques, the crimp connection can be managed quantitatively.

The IC may be replaced with a flexible wiring board to have the same configuration, and the electronic member used in the present invention is used as a generic term for IC, flexible wiring board, and the like.

Therefore, also in the crimp connection between the wiring terminal of the transparent substrate and the flexible wiring board, the crimp connection can be quantitatively managed by the same configuration as that of the IC.

In the connection by ACF, whether the connection state is good or not depends on the number of effective conductive particles in the conductive particles contained in the ACF. Effective conductive particles are conductive particles that can be confirmed by observing that they are crushed, as disclosed in Citation Document 1 above.

However, in practice, the effective crimp width W is reduced by the crimp shift between the wiring terminals, for example, the crimp shift between the connection terminal (bump) 3 and the transparent electrode 4 as shown in FIG. The number decreases due to various factors such as unevenness, unevenness of the width of the metal electrode, and unevenness of the surface irregularities of the bumps.

The measurement of the number of the conductive particles may be carried out by observation under a microscope as in the prior art, or may be used by a method such as automation using a CCD camera or the like.

In FIG. 5, the distribution curve of the measurement result of the effective conductive particle number which confirmed that it was distorted in the dummy terminal part of the electronic module of good quality is shown. This distribution curve is an example of data in the case where the bump is 40 µm in width x 90 µm in length and the transparent electrode is 40 µm in width in the electronic module as shown in FIG.

In the dummy terminal portion crimped in the almost ideal state according to the design value, various effective factors for reducing the effective number of conductive particles can be ignored, and the effective number of conductive particles becomes a distribution curve as shown in FIG. The average was 29.8, and the standard deviation σ was 2.10.

However, in practice, the number of conductive particles is small due to the above-described factors. 5 (b) and 5 (c) show distribution curves of actual values of the effective number of conductive particles. In the distribution curve shown in Fig. 5B, the effective number of conductive particles is 19.5 averages per bump, and in the distribution curve shown in (c), the effective number of conductive particles is 10.1 averages per bump. .

Here, the required number of conductive particles per bump is roughly calculated.

For example, if the anode requires a current of up to about 18 mA, a minimum current value of 10 mA per conductive particle in the product specification is sufficient if there are at least two effective conductive particles between the pair of connection terminals. .

Further, for example, from data such as an environmental acceleration test conducted for 500 hours at 80 ° C. and 80% humidity, deterioration of the current value of the conductive particles due to aging can be considered to be about 1/2 at most.

Therefore, in consideration of such secular variation, it is sufficient that at least four effective conductive particles exist between a pair of connection terminals during crimping.

In the dummy terminal section showing the distribution curve as shown in (c) of FIG. 5, the value of (average value −6σ) is 4.4 per bump, which is higher than four of the lowest effective conductive particles including the secular variation as described above. Is a value.

In addition, since the value of (average value + 6σ) is 15.8 per bump, if the number of effective conductive particles of any bump is 16 or more, it is possible to satisfy four of the effective conductive particles required between the pair of connection terminals described above. Can be said.

As mentioned above, in the bump of the said size, the minimum number of the effective electroconductive particle in a dummy terminal part is 16.

As described above, the minimum number of effective conductive particles (16 in this case) of the ACF crimped between the dummy terminal and the transparent substrate is the effective number of conductive particles in the connection terminal crimped under the same conditions in the electronic module. If the required minimum number of (4 in the above case) is greater than or equal to the crimp connection state by the ACF of the electronic module, the crimp connection state can be evaluated and managed statistically and quantitatively.

In addition, since the numerical value of the said statistical calculation example changes with terminal size, ACF type, crimping | compression-bonding condition, board | substrate type, etc., it is necessary to determine effective number of electrically-conductive particles for every model.

In the present invention, it is preferable to provide two or more dummy terminals per column of connection terminals. If even one of the effective conductive particles is less than the minimum required number, the connection crimp between the wiring terminals is not sufficient, and therefore, the electronic module is determined to be defective.

The electronic module may be fed back to the crimping process again, and the same process is repeated until the electronic module meets the selection criteria based on the number of effective conductive particles.

In addition, the dummy terminal having the same area (size) as the connection terminal is easier to handle in measurement and calculation, and is superior in convenience and reproducibility in evaluation and management. It is preferable that the dummy terminal is the same in at least one of the length and width of the connection terminal.

Further, even when the area of the dummy terminal is different due to the limitation of the layout of the connection terminal or the like, by obtaining a correlation in advance at the time of measurement, appropriate evaluation can be performed by the above-described method.

According to the present invention, it is possible to provide various electronic devices such as a display panel device which can improve the yield and the reliability by mounting the electronic module in which the connection crimp between the wiring terminals is confirmed as described above. .

1 is a rear view of a connection terminal unit of an electronic module;

Fig. 2 is a sectional view showing the structure of a connection terminal portion between an IC thermally compressed by an ACF and a transparent substrate.

3 is a cross-sectional view of the dummy terminal portion in FIG. 1.

4 is a view for explaining an effective crimp width between wiring terminals.

5 is a diagram showing a distribution curve of measurement results of an effective number of conductive particles.

<Description of the symbols for the main parts of the drawings>

1: IC

2: transparent substrate

3: Connection terminal (bump)

4: transparent electrode

5: Dummy terminal

6: metal film

7: Anisotropic conductive film (ACF)

8: metal wiring

Claims (14)

At least one of the plurality of connection terminals provided on each of the transparent substrate and the electronic member is an electronic module electrically connected through an anisotropic conductive film, At least one of the electronic member is provided with a dummy terminal that can be seen from the non-connection surface of the transparent substrate, characterized in that the electron is selected by the number of conductive particles of the anisotropic conductive film pressed between the dummy terminal and the transparent substrate module. The electronic module according to claim 1, wherein the electronic member is a semiconductor integrated circuit, and a connection terminal thereof is a bump. The electronic module of claim 1, wherein the electronic member is a flexible wiring board. The electronic module according to any one of claims 1 to 3, wherein the length and width of the dummy terminal are the same as at least one of the length and width of the connection terminal. 4. The connection terminal according to any one of claims 1 to 3, wherein the minimum number of effective conductive particles of the anisotropic conductive film crimped between the dummy terminal and the transparent substrate is crimped under the same conditions in the electronic module. An electronic module, wherein the electronic module is selected as being at least the required minimum number of the effective conductive particles. The effective number of conductive particles in the connection terminal crimped under the same conditions in the electronic module according to claim 4, wherein the minimum number of effective conductive particles in the anisotropic conductive film crimped between the dummy terminal and the transparent substrate is crimped. Electronic module characterized in that the screening is selected as the minimum number or more. At least one of the plurality of connection terminals provided on each of the transparent substrate and the electronic member is an electronic module electrically connected to each other through an anisotropic conductive film, and at least one dummy terminal can be seen from the non-connected surface of the transparent substrate. And an electronic module that is installed by the number of conductive particles of the anisotropic conductive film pressed between the dummy terminal and the transparent substrate. 8. The electronic device of claim 7, wherein the electronic member is a semiconductor integrated circuit, and the connection terminal is a bump. The electronic device of claim 7, wherein the electronic member is a flexible wiring board. The electronic device according to any one of claims 7 to 9, wherein the length and width of the dummy terminal are the same as at least one of the length and width of the connection terminal. 10. The connection terminal according to any one of claims 7 to 9, wherein the minimum number of effective conductive particles of the anisotropic conductive film crimped between the dummy terminal and the transparent substrate is crimped under the same conditions in the electronic module. An electronic device, wherein the electronic device is screened as being at least the required minimum number of effective conductive particles. 11. The method according to claim 10, wherein the minimum number of effective conductive particles of the anisotropic conductive film crimped between the dummy terminal and the transparent substrate is required for the effective number of conductive particles in the connection terminal crimped under the same conditions in the electronic module. An electronic device, characterized in that screened as having a minimum number or more. Regarding the electronic module in which at least one of the plurality of connection terminals provided on each of the transparent substrate and the electronic member is electrically connected through the anisotropic conductive film, At least one place of the electronic member is provided with a dummy terminal that is visible from the non-connected surface of the transparent substrate, and the crimped connection state is confirmed by the number of conductive particles of the anisotropic conductive film squeezed between the dummy terminal and the transparent substrate. A crimp connection confirmation method for an electronic module. The minimum number of conductive particles of the anisotropic conductive film crimped between the dummy terminal and the transparent substrate and the required minimum number of conductive particles in the connection terminal crimped under the same conditions in the electronic module. The crimp connection confirmation method for an electronic module, characterized by checking the crimp connection state by comparison.