JP4102384B2 - Conductive material with laminated structure - Google Patents

Description

  The present invention relates to a conductive material having a laminated structure, and more particularly to a conductive material having a laminated structure in which conductive particles are dispersed on the surface.

  As shown in FIGS. 1A to 1C, spherical conductive particles are generally used to provide electrical continuity between a glass substrate terminal and a driving component terminal of a conventional liquid crystal display. Yes. The conductive material 3 is applied or adhered to the surface of the glass substrate 1 on which the terminals 2 are formed. And the terminal 5 formed in the surface of the drive component 4 and the terminal 2 formed in the surface of the glass substrate 1 are joined via the electrically-conductive material 3 so that the position of terminals may match. Between the terminals 2 and 5, electrical conduction occurs in the Z-axis direction, and electrical insulation occurs in the direction of the XY plane.

  As shown in FIG. 2A, the conductive material 3 is formed of a thermoplastic layer or a thermosetting layer in which spherical conductive particles 31 are uniformly dispersed. However, in order to prevent the conductive particles 31 from being clustered and to distribute the conductive particles 31 uniformly in the conductive material 3, it is necessary to apply an external electric field and an external magnetic field to the conductive material 3. In addition, it is necessary to use equipment for precise control. Therefore, the manufacturing cost increases.

  Further, when the terminal 5 of the drive component 4 is crimped to the terminal 2 of the glass substrate 1 of the liquid crystal display by the conductive material 3, as shown in FIG. 2B, between the terminals 2 and 5 via the conductive particles 31. Electrical conduction in the Z-axis direction is established. Since the conductive particles 31 are pressed between the glass substrate 1 and the driving component 4, there is a possibility that the conductive particles 31 in a portion other than the joint portion of the terminals 2 and 5 may be short-circuited. That is, as shown in part A of FIG. 2B, undesired electrical conduction is established in the direction of the XY plane.

  With respect to the liquid crystal display, it is required to further shorten the pitch interval between the terminal 2 of the glass substrate 1 and the terminal 5 of the driving component 4 in a demand for high resolution and a smaller size. As a result, the junction impedance between the terminals 2 and 5 increases due to the reduction of the junction area. In order to satisfy the demand for fine pitch, it is necessary to reduce the size of the conductive particles 31. As a result, the difficulty of manufacturing the conductive particles 31 and the manufacturing cost increase. Further, the surface roughness of the terminals 2 and 5 restricts further reduction in the size of the conductive particles 31. If the size of the conductive particles 31 is made smaller than the size allowed by the surface roughness of the terminals 2 and 5, an electrical conduction failure will occur. When the density of the conductive particles 31 increases, the junction impedance can be reduced, but the demand for fine pitch bonding is not satisfied. Due to the above circumstances, conventional conductive materials are used for bonding when the pitch interval is larger than 50 microns.

  Therefore, it is desired to provide a conductive material that can solve the above-described drawbacks and that is suitable for fine pitch bonding between the terminals of the liquid crystal display and the terminals of the driving component.

  One of the objects of the present invention is a conductive material including at least one polymer plastic layer in which conductive particles are dispersed on the surface, and the density of the conductive particles per unit surface area is reduced. It is to provide a conductive material that can satisfy the requirements of micro-pitch joining.

  Another object of the present invention is a conductive material comprising at least one polymer plastic layer having conductive particles dispersed on the surface, wherein the density of the conductive particles dispersed on the surface of the polymer plastic layer is determined by an external electric field and an external magnetic field. It is an object of the present invention to provide a conductive material that can be easily controlled without application of. Thereby, manufacturing cost can be reduced.

In order to achieve the above-described object, the present invention provides a conductive material that can be used for joining a terminal of a driving component and a terminal of a glass substrate. The conductive material according to the present invention includes at least one polymer plastic layer having conductive particles dispersed on the surface. The density of the conductive particles at the unit surface area of each polymer plastic layer can be reduced by dispersing the conductive particles on the surface of the polymer plastic layer. Further, the conductive particles are separated from each other by the polymer plastic layer in a portion other than the terminal joint portion in the conductive material. Therefore, the short phenomenon which may occur between the conductive particles in portions other than the terminal joint portion in the conductive material is avoided. In addition, the laminated conductive material of the present invention provides the following three mechanisms in order to achieve the object of fine pitch bonding. (1) Increase the number of conductive material layers while keeping the number of conductive particles per unit volume constant. As a result, the number of conductive particles per unit surface area can be reduced, and the probability of short-circuiting between conductive particles in portions other than the joint portion is reduced. And since the pitch space | interval between terminals can be shortened, fine pitch joining will be implement | achieved. (2) The conductive material of the present invention uses fibrous conductive particles. The junction impedance between the terminals can be lower. As a result, the pitch interval between terminals is shortened, and the object of fine pitch bonding is achieved. (3) The conductive material of the present invention uses fibrous conductive particles. Fibrous conductive particles are not easily washed away at the time of terminal bonding as compared with conventional spherical conductive particles. Therefore, the fibrous conductive particles can provide a clustering effect, which is advantageous for shortening the pitch interval between terminals. This achieves the purpose of fine pitch bonding. The conductive material of the present invention is suitable for use in an ultrafine pitch liquid crystal display.

1A to 1C are cross-sectional views illustrating a flow of a bonding process between a terminal of a glass substrate and a terminal of a driving component using a conventional conductive material. FIG. 2A to FIG. 2B are cross-sectional views illustrating a flow of a bonding process between a terminal of a glass substrate and a terminal of a driving component using a known conductive material in which conductive particles are dispersed. FIG. 3A to FIG. 3C are cross-sectional views corresponding to the respective stages of the joining process flow between the terminals of the glass substrate and the terminals of the driving component using the conductive material according to the first embodiment of the present invention. FIG. 4A to FIG. 4C are cross-sectional views corresponding to the respective stages of the joining process flow between the terminals of the glass substrate and the terminals of the driving component using the conductive material according to the second embodiment of the present invention.

  The objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

  The present invention provides a conductive material comprising at least one polymer plastic layer having conductive particles dispersed on the surface thereof. The polymer plastic layer is made of a thermoplastic resin or a thermosetting resin. When the conductive material of the present invention is used to crimp the drive component terminals and the glass substrate terminals, the junction impedance between these terminals is reduced. And the objective of obtaining a super fine pitch is achieved.

  More specifically, the conductive material of the present invention comprises a thermoplastic resin layer or a thermosetting resin layer having conductive particles dispersed on the surface. The density and uniformity of the conductive particle distribution on the surface of such a polymer plastic layer can be easily controlled. Since the conductive particles are distributed on the surface of the polymer plastic layer, the number of conductive particles per unit surface area of the single surface of the polymer plastic layer (the density of the conductive particles) is compared with the conventional conductive material in which the conductive particles are dispersed. And become smaller. However, after crimping the terminal of the driving component and the terminal of the glass substrate with the conductive material of the present invention, the number of conductive particles at the joint between these terminals is the number of conductive particles in the entire surface of the polymer plastic layer at the joint. Is the same as the sum of For this reason, the electrically conductive material of this invention can provide electrical continuity between terminals similarly to the conventional electrically conductive material.

  In addition, the density of the conductive particles on the unit surface area of the single surface of the polymer plastic layer is reduced, and the conductive particles are separated by the polymer plastic layer of the conductive material other than the terminal joint portion. For this reason, the short phenomenon which may arise between the electrically-conductive particles in parts other than a terminal junction part among electrically conductive materials as shown by A part of FIG. 2B can be avoided.

  The conductive material of the present invention can have a single layer structure or a multilayer structure. When the conductive material of the present invention is formed as a multilayer structure, the number of conductive particles per unit surface area of the single layer (that is, the density of the conductive particles) is reduced by dispersing the conductive particles on the surface of each polymer plastic layer. be able to. As a result, the pitch interval between the terminal of the driving component and the terminal of the glass substrate can be further shortened. If the number of conductive particles per unit volume is made constant while increasing the number of laminated layers, the number of conductive particles per unit surface area of a single polymer plastic layer will be decreased. Thereby, the pitch interval between terminals can be further shortened. The relationship between the pitch width and the number of layers can be expressed by the following formula.

P = T + S
A = T + S / (n + 1)
n = Th / (2 × B)
A <P
In the formula, P represents the pitch width, T represents the terminal width (lead width), S represents the spacing between the terminals, and A represents the expected pitch width in the conductive material having a laminated structure. , N represents the number of stacked layers, Th represents the thickness of the conductive material, and B represents the diameter of the conductive particles.

  Even if the number of laminated conductive materials of the present invention increases, the pitch interval between the terminals can be shortened. However, since the distance between the glass substrate and the driving component is constant, the number of layers is larger, and the thickness of each layer is smaller. As a result, the insulation impedance between the layers becomes insufficient. And the probability of short-circuiting increases. Therefore, the number of stacked conductive materials of the present invention is 1 to 20 layers, preferably 1 to 10 layers, and more preferably 1 to 5 layers.

  When the conductive material of the present invention includes at least two laminated polymer plastic layers, conductive particles may be dispersed on the surface of at least one of the two laminated polymer plastic layers between the interfaces.

  Furthermore, the conductive particles may be irregularly dispersed on the surface of the polymer plastic layer of the conductive material of the present invention. It is not necessary to define the orientation distribution of the conductive particles. The irregular distribution of conductive particles on the surface of the polymer plastic layer allows further fine pitch bonding.

  The conductive material of the present invention can reduce the density of conductive particles per unit surface area. Therefore, the conductive material of the present invention can be used for an ultrafine pitch liquid crystal display having a size of less than 25 microns.

Examples of the conductive particles of the conductive material of the present invention include a metal material having low resistance selected from the group consisting of gold, silver, copper, aluminum, nickel, stainless steel and carbon, and combinations thereof. The shape of the conductive particles is fibrous.

  In the case where the shape of the conductive particles is fibrous, a terminal is crimped via the conductive material of the present invention, so that a linear contact is established between the conductive particles and the terminal. Accordingly, the junction impedance is lower than that of conductive particles of other shapes.

  In the case of forming the fibrous conductive particles with metal, first, the metal is formed into a foil shape, and then finished into a fiber shape by a predetermined cutting technique. In addition, the fibrous conductive particles are a fiber process using a high-pressure steam jet, a molten fiber spinning process, or the name of the invention of US Pat. METAL FIBER AGGLOMERATE AND PROCESS FOR MANUFACTURING THE SAME) ”can also be produced by the metal fiber forming method proposed by the specification of Taiwanese Patent Publication No. 511406 or nanometer fiber technology. .

  The size of the conductive particles can be in units of micrometers, and thus in nanometers. The ratio between the height and width of the conductive particles can be in the range of about 0.2-1. When the ratio between the height and the width is less than 0.2, the diameter of the conductive particles becomes smaller than the size allowed by the surface roughness of the terminal, which may cause poor bonding. Then, the signal is not transmitted effectively. When the ratio between the height and the width is equal to 1, the spherical conductive particles dispersed on the surface of the polymer plastic layer may move as the softened polymer plastic layer flows. As a result, the distribution of the conductive particles on the terminal becomes non-uniform. However, the above problems can be avoided by using a polymer plastic layer having some viscosity. In order to satisfy the requirements of fine pitch and low impedance, it is preferable to use non-spherical conductive particles in which the ratio of height to width is not equal to 1 in the conductive material of the present invention. It is more preferable to use fibrous conductive particles for the conductive material of the present invention. This is because even when the softened polymer plastic layer flows, the fibrous conductive particles dispersed on the surface of the polymer plastic layer are merely deformed and do not flow out. There will be no shortage of conductive particles on the terminal.

  When the conductive material of the present invention is used to join a terminal of a glass substrate and a terminal of a liquid crystal display, the electrical impedance is constructed by a kind of linear adhesion after crimping, so that the junction impedance is reduced. It will be. Furthermore, the relationship between the pitch interval and the density of the conductive particles is a linear relationship. The number of conductive particles per unit surface area of the conductive material of the present invention can be set to 1/5 to 1/2 of the number of conductive particles of the conventional conductive material. Therefore, the requirements for fine pitch bonding can be satisfied.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
3A to 3C are cross-sectional views corresponding to the respective stages of the bonding process flow between the terminals of the glass substrate and the terminals of the liquid crystal display using the conductive material according to the first embodiment of the present invention. Referring to FIG. 3A, the conductive material 3 having a laminated structure in the first embodiment includes a polymer plastic layer 32 having fibrous conductive particles 33 dispersed on the surface. The fibrous conductive particles 33 are uniformly distributed on the two surfaces of the polymer plastic layer 32. This conductive material 3 is applied on the glass substrate 1 on which the terminals 2 are formed. Subsequently, the drive component 4 is pressure-bonded to the glass substrate 1 so that the positions of the terminals are aligned. Since the conductive particles 33 come into contact with the terminals 2 and 5 after the crimping, an electrical connection (electric connection in the Z-axis direction) is formed between the terminals 2 and 5. On the other hand, as shown in FIG. 3B, the conductive particles 33 other than the joints of the terminals 2 and 5 are separated by the polymer plastic layer 32, respectively, and no electrical connection is established there (ie, X There is no electrical connection in the direction and Y direction).

  FIG. 3C is a schematic plan view of FIG. 3B. From FIG. 3C, the distribution of the conductive particles 33 of the conductive material 3 can be seen. The total number of conductive particles 33 in the conductive material 3 is equal to the sum of the number of conductive particles 33 dispersed on the two surfaces of the polymer plastic layer 32. Therefore, when it is intended to make the density of the conductive particles 33 equal to that of the conventional conductive material, the conductive material 3 has a lower density of the conductive particles 33 per unit surface area on the two surfaces of the polymer plastic layer 32. Become. Therefore, the surface portion of the conductive material 3 other than the joint portion of the terminals 2 and 5 has a lower density of the conductive particles 33 per unit surface area. If the particle density per unit surface area is low, the probability of an electrical short circuit at a portion other than the joint portion is low. This means that fine pitch bonding is achieved. Further, the fibrous conductive particles 33 are linearly connected to the terminals 2 and 5 after being crimped. Thus, a low junction impedance is achieved.

  FIGS. 4A to 4C are cross-sectional views corresponding to respective stages of a bonding process flow of a glass substrate terminal and a liquid crystal display terminal using a conductive material according to the second embodiment of the present invention. Referring to FIG. 4A, the conductive material 3 having a laminated structure in the second embodiment includes three laminated polymer plastic layers 32 having fibrous conductive particles 33 dispersed on the surface. The conductive particles 33 are uniformly distributed on the respective surfaces of the three polymer plastic layers 32. However, the conductive particles 33 are one of the two polymer plastic layers 32 between the interfaces of the laminated polymer plastic layers. It is only dispersed on the surface. The conductive material 3 is applied to the surface of the glass substrate 1 on which the terminals 2 are formed, and then the driving component 4 is pressure-bonded to the glass substrate 1 so that the terminals are aligned with each other. Since the conductive particles 33 come into contact with the terminals 2 and 5 after the crimping, an electrical connection (electric connection in the Z-axis direction) is formed between the terminals 2 and 5. On the other hand, as shown in FIG. 4B, the conductive particles 33 other than the joint portions of the terminals 2 and 5 are separated from each other by the laminated polymer plastic layer 32, and no electrical connection is established there (ie, , There are no electrical connections in the X and Y directions).

  FIG. 4C is a schematic plan view of FIG. 4B. From FIG. 4C, the distribution of the conductive particles 33 of the conductive material 3 can be seen. The total number of conductive particles 33 of the conductive material 3 is equal to the total number of conductive particles 33 dispersed on each of the surfaces of each polymer plastic layer 32. According to the three-layer laminated structure of the conductive material 3 in the second embodiment, when the density of the conductive particles 33 is set to be equal to that of the conventional conductive material, the conductive material 3 is provided with the conductive particles 33 per unit surface area. Is lower than that of the first embodiment. In addition, no electrical connection is established in any part other than the joints of the terminals 2 and 5. When the particle density per unit surface area decreases, fine pitch bonding is achieved.

  The conductive material having the laminated structure of the present invention is formed by distributing conductive particles in the form of a layered distribution. For example, the conductive particles 33 are dispersed on the two surfaces of the polymer plastic layer 32 as shown in FIG. For this reason, the density of the conductive particles per unit surface area can be reduced. Furthermore, since the conductive particles are dispersed on the surface of the polymer plastic layer, it is not necessary to apply an electric field and a magnetic field in order to uniformly control the distribution of the conductive particles, and the density of the conductive particles can be easily controlled. . Therefore, the manufacturing cost can be reduced.

  In addition, the density of the conductive particles per unit surface area in the conductive material of the present invention is reduced, and the conductive particles are separated from each other by the laminated polymer plastic layer in a portion other than the terminal joint portion. Therefore, it is possible to avoid a short-circuit phenomenon that may occur between conductive particles in a portion of the conductive material other than the terminal joint. Since the density of the conductive particles per unit surface area is further reduced, the pitch interval can be shortened.

  In summary, the laminated conductive material of the present invention provides the following three mechanisms to achieve the purpose of fine pitch bonding. (1) The number of conductive materials is increased while the number of conductive particles per unit volume is kept constant. Thereby, the number of conductive particles per unit surface area can be reduced, and the probability of short-circuiting between conductive particles other than the joint portion is reduced. And since the pitch interval between terminals can be shortened, fine pitch joining can be achieved. (2) The conductive material of the present invention uses non-spherical conductive particles. Thereby, the junction impedance between terminals can be lower. As a result, the pitch interval between terminals is shortened, and the object of fine pitch bonding is achieved. (3) The conductive material of the present invention uses non-spherical conductive particles. Compared to conventional spherical conductive particles, non-spherical conductive particles are not easily washed away when the terminals are joined. Therefore, the non-spherical conductive particles can provide a clustering effect, which is advantageous for shortening the pitch interval between terminals. Therefore, the purpose of fine pitch bonding is achieved.

The above-described embodiments are merely used to explain the present invention, and are not intended to limit the scope of the present invention. Modifications can be made to the above-described embodiments in accordance with the spirit of the invention.

Claims (8)

Consisting of at least one polymer plastic layer with conductive particles dispersed on the surface,
A conductive material in which the shape of the conductive particles is fibrous .   The conductive material according to claim 1, wherein the polymer plastic layer is made of a thermoplastic resin.   The conductive material according to claim 1, wherein the polymer plastic layer is made of a thermosetting resin. The conductive material includes a plurality of laminated polymer plastic layers,
The conductive material according to claim 1, wherein the conductive particles are dispersed on the surface of at least one of two laminated polymer plastic layers between the interfaces.   The conductive material according to claim 4, wherein the polymer plastic layer is made of a thermoplastic resin.   The conductive material according to claim 4, wherein the polymer plastic layer is made of a thermosetting resin.   The conductive material according to claim 1, wherein the conductive particles are formed from a material selected from the group consisting of gold, silver, copper, aluminum, nickel, stainless steel and carbon, and combinations thereof.   The conductive material according to claim 4, wherein the conductive particles are formed from a material selected from the group consisting of gold, silver, copper, aluminum, nickel, stainless steel, carbon, and combinations thereof.

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