JP2006318686A - Heat seal connector and its connection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat seal connector capable of stabilizing electrical connection and resistance by suppressing or preventing migration regardless of generation of droplets due to dew condensation; and to provide its connection method. <P>SOLUTION: This heat seal connector is provided with: an insulating film 1 having flexibility; a plurality of silver lines 2 arranged side by side on a surface of the film 1; and a resist layer 10 stacked on the surface of the film 1 for forming connection terminals 3 by respectively exposing both ends of the respective silver lines 2. A part of each connection terminal 3 is covered with a carbon coating 20; a remaining part 6 of the connection terminal 3 is exposed; the carbon coating 20 and the remaining part 6 of the connection terminal 3 are stuck to a glass body 40 through an anisotropic conductive adhesive 30 to connect them by thermocompression bonding by using a tool bar 50. Since the hardly-ionized carbon coating 20 is stuck or subjected to thermocompression bonding by the anisotropic conductive adhesive 30, droplets are prevented from adhering to a tip part 4 and an end part 5 of the connection terminal 3 even when dew condensation occurs, and elution of silver ions can be suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat seal connector used for circuit connection of various electric devices and electronic devices and a connection method thereof.

  Although not shown in the drawings, the conventional heat seal connector has a flexible insulating film, a plurality of silver lines juxtaposed on the surface of the film, and both ends of each silver line laminated on the surface of the film. And a resist layer that is used as a connection terminal by exposing each of the plurality of electronic devices, and a plurality of connection terminals are connected to a plurality of electronic devices such as a personal computer, a mobile phone, a liquid crystal panel, and a circuit board such as a circuit board.

  By the way, since the heat seal connector is also an industrial product, it may break down due to long-term use. Migration may be cited as a cause of this failure. This migration is also called electromigration, and is a phenomenon in which a metal component moves across the top or inside of a nonmetallic medium due to the influence of an electric field. Such migration occurs when a voltage is applied to the silver line of the heat seal connector during high humidity or condensation, and the silver ions in the silver line are eluted, which may cause a short circuit accident or system breakdown. It is done.

As a means for preventing short-circuit accidents and system destruction associated with such migration, conventionally, a method of suppressing elution of silver ions by adding metal powder such as zinc powder to silver paste forming a silver line has been proposed. (See Patent Document 1).
JP-A-8-222839

  However, when adding metal powder to the silver paste forming the silver line, it is possible to suppress the elution of silver ions to some extent, but when the water droplets adhere due to condensation, a great problem that the effect can hardly be obtained. There is.

  The present invention has been made in view of the above, and it is intended to provide a heat seal connector that can prevent migration and stabilize electrical connection and resistance regardless of the generation of water droplets due to condensation, and a connection method thereof. It is aimed.

In the present invention, in order to solve the above-mentioned problems, a conductive line formed on a flexible insulating substrate, and an insulating layer formed on the substrate and exposing both ends of the conductive line to serve as connection terminals With
A part of the connection terminal is covered with a migration-preventing layer to expose the remaining part of the connection terminal, and the migration-preventing layer and the remaining part of the connection terminal are stacked on the adherend with an anisotropic conductive adhesive, It is characterized by being connected by thermocompression bonding.

Note that a part of the connection terminal is a terminal part that is exposed and located near the boundary between the front end of the connection terminal and the insulating layer, and the connection terminal is connected between the front end and the terminal part. The rest,
The migration prevention layer can be a first prevention layer that covers the tip of the connection terminal and a second prevention layer that covers the end of the connection terminal.

Further, the migration preventing layer can be a carbon film.
Further, when the length of the first prevention layer is A, the length of the second prevention layer is B, the length of the remaining portion of the connection terminal is C, and the length L of the thermocompression bonding portion in the thermocompression bonding tool is A + B + C And can be connected so as to satisfy the following expressions (1) and (2).
A, B ≧ L × 0.1 Formula (1)
L × 0.2 ≦ A + B ≦ L × 0.5 Formula (2)

In the present invention, in order to solve the above-mentioned problem, a conductive line formed on a flexible insulating substrate and a connection terminal formed on the substrate and exposing both ends of the conductive line are used. An insulating layer, and a portion of the connection terminal is covered with a migration prevention layer to expose the remainder of the connection terminal, and the migration prevention layer and the remainder of the connection terminal are attached to the adherend via an anisotropic conductive adhesive. It is a connecting method for connecting by thermocompression bonding with a thermocompression bonding tool,
A part of the connection terminal is a terminal part that is exposed near the boundary between the tip of the connection terminal and the insulating layer, and the remaining part of the connection terminal is between the terminal part and the terminal part of the connection terminal. ,
The migration prevention layer is a first prevention layer that covers the tip of the connection terminal, and a second prevention layer that covers the end of the connection terminal,
When the length of the first prevention layer is A, the length of the second prevention layer is B, the length of the remaining portion of the connection terminal is C, and the length L of the thermocompression bonding portion in the thermocompression bonding tool is A + B + C, The connection is made to satisfy the expressions (1) and (2).
A, B ≧ L × 0.1 Formula (1)
L × 0.2 ≦ A + B ≦ L × 0.5 Formula (2)

  Here, the base material in the claims is not particularly required to be transparent or opaque, and the material, thickness, and size can be changed as necessary. Examples of the base material include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polybutylene naphthalate, polyarylate, and the like. The conductive line is made of a gold, silver, copper, or nickel line formed by drying and curing the conductive ink, and is formed by, for example, a screen printing method or a gravure printing method.

  Any one or a plurality of migration prevention layers may be used. The vicinity of the boundary includes both the boundary and the vicinity of the boundary. The adherend includes at least various types of glass and circuit boards. Furthermore, the conductive particles of the anisotropic conductive adhesive are, for example, carbon particles, metal particles, plastic particles whose surfaces are plated with gold or silver, ceramic particles, and the like.

  According to the present invention, since a part of the connection terminal protected by the migration prevention layer is thermocompression bonded to the adherend together with the remaining part, it is possible to suppress water droplets from adhering to a part of the connection terminal. In addition, since the anisotropic conductive adhesive is applied to the remaining part of the connection terminal and a migration prevention layer made of a material having a high resistance value is not overlapped, the connection stability is maintained while maintaining a low resistance value. Can be improved.

According to the present invention, there is an effect that, regardless of the generation of water droplets due to condensation, migration can be suppressed and electrical connection and resistance can be stabilized.
In addition, a part of the connection terminal is a terminal part that is exposed near the boundary between the connection terminal where the migration is likely to occur and the insulating layer, and the migration prevention layer is the first part that covers the front part of the connection terminal. If the first prevention layer and the second prevention layer covering the end portion of the connection terminal are used, migration can be effectively suppressed.

Further, if the migration preventing layer is made of a carbon film that is excellent in insulation, surface modification, and adhesion, a part of the connection terminal is difficult to ionize.
Further, when the length of the first prevention layer is A, the length of the second prevention layer is B, the length of the remaining portion of the connection terminal is C, and the length L of the thermocompression bonding portion in the thermocompression bonding tool is A + B + C If the connections are made so as to satisfy the expressions (1) and (2), the ratio of the migration prevention layer in the total thermocompression bonding area can be set to less than 50%, and an increase in the electric resistance value can be prevented.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. A heat seal connector and a connection method thereof according to the present embodiment include an insulating film 1 and the film as shown in FIGS. A plurality of silver lines 2 arranged side by side on the surface of the film 1 and a resist layer 10 laminated on the surface of the film 1 to expose both ends of each silver line 2 to be connection terminals 3. 3 is covered with a carbon film 20 which is a migration preventing layer to expose the remaining part 6 of the connection terminal 3, and the carbon film 20 and the remaining part 6 of the connection terminal 3 are attached to the glass body 40 with the anisotropic conductive adhesive 30. To connect through.

  The film 1 is formed into a flexible flat rectangular thin plate using a predetermined synthetic resin, for example, polyester having excellent heat resistance, chemical resistance, electrical characteristics, and the like. For example, the film 1 is 10 to 80 μm, preferably 20 to 20 μm. The thickness is 50 μm.

  The plurality of silver lines 2 are patterned in parallel at a predetermined pitch in the surface width direction of the film 1 by screen-printing a silver resin-based ink that has been previously vibrated and agitated and drying and curing. The silver resin-based ink is prepared, for example, as a paste by mixing 70 parts by mass of scale-like metal plating particles with 10 parts by mass of a polyester-based synthetic resin, or a heat mainly composed of bisphenol A type epoxy resin. 10 parts by mass of curable resin, 70 parts by mass of flaky silver powder, 3 parts by mass of amine-based curing accelerator, 1 part by mass of leveling agent, dispersion stabilizer, antifoaming agent, thixotropic agent are each toluene: methyl ethyl ketone = 7 : Prepared by dissolving in a mixed solvent of 3.

  Each silver line 2 is formed in a strip shape having a thickness of 5 to 35 μm and a width of 100 to 500 μm, for example, and is linearly directed in the vertical direction of the surface of the film 1. It is set as the connection terminal 3 for electrode parts. A part of each connection terminal 3 is laminated and covered with a carbon film 20, and a part of this connection terminal 3 is generally composed of a tip 4 of the connection terminal 3 that is likely to cause migration and a resist layer 10. It consists of the terminal part 5 exposed from the vicinity of the boundary, and the space between the tip part 4 and the terminal part 5 of these connection terminals 3 is the remaining part 6 of the connection terminal 3.

  The resist layer 10 is printed and formed in a planar rectangle using, for example, polymethyl methacrylate, and is laminated on the center of the surface of the film 1 to cover the center of the plurality of silver lines 2.

  The carbon film 20 is formed into a band having the same width as or slightly wider than the silver line 2 by screen-printing a carbon-based conductive paste that has been vibrated and agitated in advance and drying and curing. The surface to be laminated is completely covered and conductively connected to the electrode part of the electronic device as a connection part. The carbon film 20 includes a first prevention layer 21 laminated on the tip portion 4 of the connection terminal 3 and a second prevention layer 22 laminated on the end portion 5 of the connection terminal 3. It is characterized by excellent quality, insulation and adhesion.

  The anisotropic conductive adhesive 30 is obtained by mixing and dispersing conductive particles 32 such as metal powder in an insulating resin adhesive 31 and bonding them by applying a certain pressure so that the anisotropic conductive adhesive 30 is perpendicular to the bonding surface ( It functions to exhibit conductivity in the connection direction) and insulation in the horizontal direction. Examples of the conductive particles 32 of the anisotropic conductive adhesive 30 include Ag, Cu, and graphite, and the average particle diameter is adjusted in a range of 1.2 to 3 times the thickness of the carbon film 20. The reason why the average particle diameter of the conductive particles 32 is in the range of 1.2 to 3 times the thickness of the carbon film is that the conductive particles 32 are not completely covered by the carbon film 20 or have an obstacle to conduction within this range. .

  In the above, when the heat seal connector is connected to the glass body 40 via the anisotropic conductive adhesive 30, the anisotropic conductive adhesive 30 is attached to the carbon film 20 and the remaining portion 6 of the connection terminal 3 as shown in FIG. If the carbon film 20 and the remaining portion 6 of the connection terminal 3 are adhered to the glass body 40 via the anisotropic conductive adhesive 30, and pressed by the tool bar 50 from above the film 1 and thermocompression bonded, the heat seal is achieved. The connector can be connected to the glass body 40.

At this time, the length of the first prevention layer 21 is A, the length of the second prevention layer 22 is B, the length of the remaining portion 6 of the connection terminal 3 is C, and the length L of the thermocompression bonding portion 51 in the tool bar 50 is. Is A + B + C, it is preferable to connect so as to satisfy the following expressions (1) and (2).
A, B ≧ L × 0.1 Formula (1)
L × 0.2 ≦ A + B ≦ L × 0.5 Formula (2)
If the connection is made so as to satisfy the expressions (1) and (2) and the occupation area of the carbon film 20 having a high resistance value is 20 to 50% of the total thermocompression bonding area, an increase in the resistance value is effectively prevented. Because it can.

  According to the above, the anisotropic conductive adhesive is not simply bonded to the glass body 40 via the anisotropic conductive adhesive 30 but via the carbon film 20 which is difficult to ionize a part of the connection terminal 3. 30 is bonded and thermocompression bonded, so even if condensation occurs, water droplets do not adhere to the tip 4 and terminal 5 of the connection terminal 3 that are susceptible to adverse effects, and the elution of silver ions is extremely effectively suppressed. can do. Therefore, the occurrence of migration can be prevented, and system destruction due to a short circuit accident can be effectively prevented.

  Furthermore, since only the anisotropic conductive adhesive 30 is applied to the remaining part 6 of the connection terminal 3 and there is no carbon film 20 having a high resistance value, the resistance value of conduction is higher than necessary when the electronic device is connected. Never become. Therefore, it is possible to improve the connection stability while maintaining a low resistance value.

Hereinafter, examples of the heat seal connector and the connection method thereof according to the present invention will be described together with comparative examples.
Examples First, 10 parts by mass of thermosetting resin mainly composed of bisphenol A type epoxy resin, 70 parts by mass of scale-like silver powder, 3 parts by mass of amine-based curing accelerator, leveling agent, dispersion stabilizer, antifoaming 1 part by mass of each of the agent and thixotropic agent was dissolved in a mixed solvent of toluene: methyl ethyl ketone = 7: 3 to prepare a silver ink.

  Further, 100 parts by mass of a polyester resin and 5 parts by mass of an isocyanate curing agent were dissolved in methyl ethyl ketone, and 40 parts by mass of carbon black and 27 parts by mass of graphite were added thereto and kneaded with three rolls to prepare a carbon paste. .

  In addition, 200 parts by mass of bisphenol A type epoxy resin having an epoxy equivalent of 900 to 1200, 50 parts by mass of NBR, 100 parts by mass of t-butylphenol having a weight average molecular weight of 750, and 110 parts by mass of 2-methylimidazole are dissolved in cyclohexane. An anisotropic conductive adhesive was prepared by adding 20 parts by mass of gold-plated carbon particles having a radius of 16 μm.

  When silver ink, carbon paste, and anisotropic conductive adhesive are prepared in this way, the prepared silver ink is screen-printed on a polyester film having a thickness of 25 μm to produce 40 silver lines having a pitch of 0.5 mm and a line width of 0.25 mm. In this arrangement, a resist layer was laminated on the center of the surface of the film to form connection terminals in which both ends of each silver line were exposed.

  Next, carbon paste was screen printed on a part of each connection terminal, and the carbon paste was dried to laminate a carbon film having a line width of 0.35 mm. Regarding the carbon film, the thickness after drying after removing the solvent is 10 μm, the length A of the first prevention layer is 0.25 mm, the length B of the second prevention layer is 0.25 mm, and the remaining part of the connection terminal Lamination was performed such that the length C was 1.5 mm. Then, an anisotropic conductive adhesive was applied to the carbon film and the remainder of the connection terminal with a bar coater so that the thickness after removal of the solvent was 20 μm, and a heat seal connector was manufactured.

  Once the heat seal connector is manufactured, the heat seal connector is heated between an ITO substrate with a sheet resistivity of 30Ω and a gold-plated copper foil glass epoxy substrate using a tool bar with a crimping width of 2.0 mm under the conditions of 170 ° C., 40 kg, 12 seconds. Crimped and put in a 60 °, 95%, RH environment for 500 hours with a voltage of 30V between adjacent terminals applied, and confirmed the change in resistance between connecting terminals and the presence or absence of abnormal appearance of connecting terminals. Summarized in 1.

In the thermocompression bonding, the length of the first prevention layer is A, the length of the second prevention layer is B, the length of the remaining connection terminal is C, and the length L of the thermocompression bonding portion in the tool bar is A + B + C. In this case, the expressions (1) and (2) were satisfied.
A, B ≧ L × 0.1 Formula (1)
L × 0.2 ≦ A + B ≦ L × 0.5 Formula (2)

Comparative Example 1
Basically, it is the same as the embodiment, but the length A of the first prevention layer is 0.1 mm, the length B of the second prevention layer is 0.1 mm, and the length C of the remaining part of the connection terminal is 1. The heat seal connector was manufactured by changing to 8 mm.
When the heat seal connector was manufactured, the same test as in the example was performed and the results are summarized in Table 1.

Comparative Example 2
Basically, it is the same as the embodiment, but the length A of the first prevention layer is 0.75 mm, the length B of the second prevention layer is 0.5 mm, and the length C of the remaining portion of the connection terminal is 0. The heat seal connector was manufactured by changing to .75 mm.
When the heat seal connector was manufactured, the same test as in the example was performed and the results are summarized in Table 1.

According to the heat seal connector of the example, extremely good results were obtained with respect to the resistance value and the presence / absence of abnormal appearance of the connection terminals.
On the other hand, in the case of the heat seal connector of Comparative Example 1, the expressions (1) and (2) were not satisfied and the appearance of the connection terminals was abnormal. Further, in the case of the heat seal connector of Comparative Example 2, the formula (2) was not satisfied and the resistance value increased after 500 hours.

It is a plane explanatory view showing an embodiment of a heat seal connector concerning the present invention. It is sectional explanatory drawing which shows embodiment of the heat seal connector which concerns on this invention, and its connection method. It is explanatory drawing which shows the connection state in embodiment of the heat seal connector which concerns on this invention, and its connection method.

Explanation of symbols

1 Film (base material)
2 Silver line (conductive line)
3 connection terminal 4 tip part 5 terminal part 6 remaining part 10 resist layer (insulating layer)
20 Carbon film (migration prevention layer)
21 1st prevention layer 22 2nd prevention layer 30 Anisotropic conductive adhesive 32 Conductive particle 40 Glass body (adhered body)
50 Toolbar (Thermo-compression tool)
51 Thermocompression bonding part

Claims (5)

A heat seal connector provided with a conductive line formed on an insulating base material having flexibility, and an insulating layer formed on the base material and exposing both ends of the conductive line as connection terminals,
A part of the connection terminal is covered with a migration-preventing layer to expose the remaining part of the connection terminal, and the migration-preventing layer and the remaining part of the connection terminal are stacked on the adherend with an anisotropic conductive adhesive, A heat seal connector characterized by being connected by thermocompression bonding. A part of the connection terminal is a terminal part that is exposed near the boundary between the tip of the connection terminal and the insulating layer, and the remaining part of the connection terminal is between the terminal part and the terminal part of the connection terminal. ,
The heat seal connector according to claim 1, wherein the migration prevention layer is a first prevention layer that covers a tip portion of the connection terminal and a second prevention layer that covers a terminal portion of the connection terminal.   The heat seal connector according to claim 1 or 2, wherein the migration preventing layer is a carbon film. When the length of the first prevention layer is A, the length of the second prevention layer is B, the length of the remaining portion of the connection terminal is C, and the length L of the thermocompression bonding portion in the thermocompression bonding tool is A + B + C, The heat seal connector according to claim 2 or 3 connected so as to satisfy the formulas (1) and (2).
A, B ≧ L × 0.1 Formula (1)
L × 0.2 ≦ A + B ≦ L × 0.5 Formula (2) Equipped with a conductive line formed on a flexible insulating substrate and an insulating layer formed on the substrate to expose both ends of the conductive line to be a connection terminal, and part of the connection terminal is migrated Heat which is covered with a prevention layer to expose the remainder of the connection terminal, and the migration prevention layer and the remainder of the connection terminal are stacked on the adherend via an anisotropic conductive adhesive and thermocompression-bonded by a thermocompression bonding tool. A method of connecting a seal connector,
A part of the connection terminal is a terminal part that is exposed near the boundary between the tip of the connection terminal and the insulating layer, and the remaining part of the connection terminal is between the terminal part and the terminal part of the connection terminal. ,
The migration prevention layer is a first prevention layer that covers the tip of the connection terminal, and a second prevention layer that covers the end of the connection terminal,
When the length of the first prevention layer is A, the length of the second prevention layer is B, the length of the remaining portion of the connection terminal is C, and the length L of the thermocompression bonding portion in the thermocompression bonding tool is A + B + C, A connection method of a heat seal connector, wherein the connection is performed so as to satisfy the formulas (1) and (2).
A, B ≧ L × 0.1 Formula (1)
L × 0.2 ≦ A + B ≦ L × 0.5 Formula (2)

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