JP6552229B2 - Coating treatment method, connection method, and joined body - Google Patents

Description

  The present invention relates to a film processing method for processing at least one of an oxide film and a rust preventive film on a terminal, and a connection method using the film processing method.

  Conventionally, as a means for connecting an electronic component to a substrate, a tape-like connection material in which a thermosetting resin in which conductive particles are dispersed is applied to a release film (for example, anisotropic conductive film (ACF)) Is used.

  This anisotropic conductive film is used, for example, for connection (FOB: Flex on Board) between a COF (Chip on Film) and a rigid substrate (for example, PWB (Printed Wiring Board)).

In order to improve the solderability of components such as IC chips and capacitors to be mounted on the rigid substrate, a rust preventive film with a rust preventive agent called preflux (OSP: Organic Solderability Preservative) may be formed. is there. As the preflux, for example, imidazole preflux is known.
However, if the substrate on which the rust preventive film is formed on the terminal is connected to another circuit member using an anisotropic conductive film, there is a problem that connection reliability is lowered.

Further, if the terminal is not plated with gold or the like in the rigid substrate, the terminal surface is oxidized to form an oxide film.
When the substrate having the oxide film formed on the terminals is also connected to other circuit members using an anisotropic conductive film, there is a problem that connection reliability is lowered.

  As a method for removing the oxide film, for example, a metal oxide film that burns off the oxide film by injecting a heated inert gas onto the metal with the oxide film formed on the surface and simultaneously irradiating the laser beam. A removal method has been proposed (see, for example, Patent Document 1).

JP 2001-158985 A

  However, in the above-described proposed technology, no mention is made of the irradiation range of the laser light, and no consideration is given to the adverse effect when the laser light is irradiated to a place other than the metal.

  An object of the present invention is to solve the above-mentioned problems in the prior art and to achieve the following objects. That is, an object of the present invention is to provide a film processing method capable of preventing adverse effects when laser light is irradiated to a portion other than a terminal, and a connection method using the film processing method.

The means for solving the problems are as follows. That is,
A laser beam is irradiated only to the said terminal of the circuit member which has a terminal which has an at least one film | membrane of an oxide film and a rust preventive film on the surface, and the said film is processed, The film processing method characterized by the above-mentioned is there.
<2> The film treatment method according to <1>, wherein the circuit member is a circuit member connected to another circuit member via an anisotropic conductive film in contact with the terminal.
<3> The film treatment method according to any one of <1> to <2>, wherein the irradiation of the laser beam onto the terminal is performed using a laser beam having a spot diameter equal to or less than a width of the terminal. .
<4> The film treatment according to any one of <1> to <2>, wherein the irradiation of the laser beam to the terminal is performed by passing through the opening of the laser beam irradiation auxiliary member having at least one opening. Is the method.
<5> The film processing method according to <4>, wherein the opening is an opening in the same area as the irradiation area of the laser light in the terminal.
<6> The film processing method according to <4>, wherein the opening is an opening having a width less than a width of the terminal.
<7> A connection method for connecting the terminal of a first circuit member having a terminal having a film of at least one of an oxide film and an antirust film on the surface and a terminal of a second circuit member,
A film treatment step of treating the film by irradiating only the terminal of the first circuit member with a laser beam;
A first disposing step of disposing an anisotropic conductive film on the terminal of the first circuit member;
A second disposing step of disposing the second circuit member on the anisotropic conductive film;
Heating and pressing the second circuit member with a heating pressing member,
It is the connection method characterized by this.
<8> The connection method according to <7>, wherein the irradiation of the laser beam to the terminal of the first circuit member is performed using a laser beam having a spot diameter equal to or smaller than the width of the terminal.
<9> The above <7> to <8>, wherein the laser light irradiation to the terminal of the first circuit member is performed through the opening of the laser light irradiation auxiliary member having at least one opening. Any one of the connection methods.
<10> The connection method according to <9>, wherein the opening is an opening in the same area as the irradiation area of the laser light in the terminal.
<11> The connection method according to <9>, wherein the opening is an opening having a width smaller than the width of the terminal.

  According to the present invention, the above-mentioned problems in the prior art can be solved, the above-mentioned object can be achieved, and a coating treatment method that can prevent adverse effects when laser light is irradiated to a portion other than the terminal, and the coating It is possible to provide a connection method using the processing method.

FIG. 1A is a schematic top view for explaining one aspect of the film processing method of the present invention. FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A. FIG. 1C is a schematic cross-sectional view for explaining one aspect of the film processing method of the present invention. FIG. 1D is a schematic cross-sectional view (enlarged view) for explaining one aspect of the film processing method of the present invention. FIG. 1E is a schematic top view for explaining one aspect of the film processing method of the present invention. FIG. 1F is a cross-sectional view taken along line AA of FIG. 1E. FIG. 2A is a schematic top view for explaining another aspect of the film processing method of the present invention. FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A. FIG. 2C is a schematic top view for explaining another aspect of the film processing method of the present invention. FIG. 2D is a cross-sectional view taken along line A-A of FIG. 2C. FIG. 2E is a schematic top view for explaining another aspect of the film processing method of the present invention. FIG. 2F is a cross-sectional view taken along line AA of FIG. 2E. FIG. 3 is a schematic top view for explaining an example of the laser beam irradiation assisting member. FIG. 4A is a schematic top view for explaining another aspect of the film processing method of the present invention. FIG. 4B is a cross-sectional view taken along line A-A of FIG. 4A. FIG. 4C is a schematic top view for explaining another aspect of the film processing method of the present invention. FIG. 4D is a cross-sectional view taken along line A-A of FIG. 4C. FIG. 4E is a schematic top view for explaining another aspect of the film processing method of the present invention. FIG. 4F is a cross-sectional view taken along line AA of FIG. 4E. FIG. 5 is a schematic top view for explaining an example of the laser beam irradiation assisting member. FIG. 6 is a schematic top view for explaining an example of the laser beam irradiation assisting member. FIG. 7A is a schematic top view for explaining an example of a laser beam irradiation assisting member. FIG. 7B is a cross-sectional view taken along line A-A of FIG. 7A.

(Film treatment method)
The film treatment method of the present invention is a method of treating the film by irradiating a laser beam only to the terminal of the circuit member having a terminal having an oxide film and / or an anticorrosive film on the surface.

The oxide film and rust preventive film on the terminal surface affect the electrical connection. In particular, when an anisotropic conductive film is used to connect a terminal having an oxide film or a rust preventive film on the surface and a terminal of another circuit member, connection reliability is lowered.
Then, this inventor examined having irradiated the laser beam and processed the oxide film or rust preventive film of the terminal surface. At that time, it was found that when the circuit member other than the terminal was irradiated with the laser light, an adverse effect occurred. For example, when the substrate exposed between the terminals is irradiated with laser light, the substrate is damaged, and the material of the substrate is scattered as dust. For example, when the substrate is a glass epoxy substrate, glass fibers are scattered. If the connection is made as it is, a connection failure due to the scattered matter occurs, so that cleaning for removing the scattered matter is required.
Therefore, as a result of further examination, the present inventor irradiates the circuit with the laser beam by irradiating the circuit member other than the terminal with the laser beam, although the terminal is irradiated with the laser beam. The inventors have found that it is possible to prevent damage to members other than the terminals of the members and to prevent adverse effects when laser light is irradiated to locations other than the terminals, and to complete the present invention.

<Circuit member>
The circuit member is not particularly limited as long as it is a circuit member having a terminal, and can be appropriately selected according to the purpose. For example, a plastic substrate having a terminal, Flex-on-Board (flex on board, FOB And Flex-on-Flex (FOF).

The circuit member is preferably a circuit member to be subjected to anisotropic conductive connection using an anisotropic conductive film.
That is, it is preferable that the said circuit member is a circuit member connected with another circuit member via the anisotropic conductive film which contact | connects the said terminal.

  The material of the terminal is not particularly limited and can be appropriately selected depending on the purpose. For example, Cu, Ni plated with Cu, Au, and Cu, Sn plated with Au are used. The plated Cu may, for example, be mentioned.

  There is no restriction | limiting in particular as a material and structure of the plastic substrate which has the said terminal, According to the objective, it can select suitably, For example, the rigid board | substrate which has a terminal, the flexible substrate which has a terminal, etc. are mentioned. As a rigid board | substrate which has the said terminal, the glass epoxy board | substrate etc. which have a copper wiring are mentioned, for example. Examples of the flexible substrate having the terminal include a polyimide substrate having a copper wiring.

  There is no restriction | limiting in particular as a shape of the said terminal, According to the objective, it can select suitably, For example, a rectangle etc. are mentioned.

<< Oxide film >>
There is no restriction | limiting in particular as said oxide film, According to the objective, it can select suitably, For example, the oxide film etc. which the surface of the said terminal oxidized naturally are mentioned.
The oxide film may cover the entire surface of the terminal or may partially cover it.

<< Rust prevention film >>
The said rust preventive film is formed by the rust prevention process by a rust preventive agent, for example.

There is no restriction | limiting in particular as said rust preventive agent, According to the objective, it can select suitably. The antirust agent is generally called preflux or OSP (Organic Solderability Preservative).
The rust inhibitor contains, for example, at least an imidazole compound, copper ions, and an organic acid. Examples of the imidazole compound include benzimidazole. The benzimidazole may have a substituent.

There is no restriction | limiting in particular as the method of the said rust prevention process, According to the objective, it can select suitably, For example, the circuit member processed is obtained by diluting the said rust inhibitor or the said rust inhibitor. Examples include a method of immersing in an aqueous solution.
By performing the antirust treatment, the terminals on the circuit member and the circuit portion are protected.

  There is no restriction | limiting in particular as thickness of the said rustproof film, According to the objective, it can select suitably.

  The anticorrosion coating may cover the entire surface of the terminal or may partially cover it.

It can be confirmed, for example, by the following method that the film (at least one of the oxide film and the rust preventive film) is formed on the terminal.
A carbon layer for surface protection is formed on the rustproof film of the terminal on which the rustproof film is formed.
Subsequently, a focused ion beam (FIB, Focused Ion Beam) is irradiated to the terminal, and a part of the terminal is dug.
The presence and thickness of the anticorrosive film can be confirmed by tilting the excavated portion of the terminal a little and observing it using structured illumination microscopy (SIM).

  There is no restriction | limiting in particular as a wavelength of the said laser beam, According to the objective, it can select suitably.

Examples of the laser used for the irradiation of the laser light include semiconductor lasers (AlGaAs, InGaAsP, GaN etc.), Nd: YAG lasers, excimer lasers (ArF, KrF, XeCl etc.), dye lasers, solid state lasers (ruby laser etc.) ), Gas laser (He—Ne, He—Xe, He—Cd, CO ₂ , Ar, etc.) and the like. Among these, a CO ₂ laser is preferable in terms of energy efficiency.

  There is no restriction | limiting in particular as irradiation intensity of the said laser beam, According to the objective, it can select suitably.

  There is no restriction | limiting in particular as irradiation time of the said laser beam, According to the objective, it can select suitably.

The irradiation of the laser beam to the terminal is preferably performed using a laser beam having a spot diameter equal to or smaller than the width of the terminal.
Here, the spot diameter is the diameter of the laser beam on the surface of the irradiation object when the laser object is irradiated on the irradiation object separated by the focal distance, and for example, the size of the damage mark of the irradiation object Can be measured from

Further, it is preferable that the irradiation of the laser beam to the terminal is performed through the opening of the laser beam irradiation auxiliary member having at least one opening.
Furthermore, it is preferable that the opening is an opening of the same area as the irradiation area of the laser light in the terminal. Alternatively, the opening is preferably an opening having a width less than the width of the terminal.
The width of the opening is the diameter when the opening is circular, and when the opening is a shape other than circular, the terminal of the terminal when the laser beam irradiation auxiliary member is disposed on the terminal It is the width of the opening in the width direction.

  Here, one aspect of the film processing method of the present invention will be described with reference to the drawings.

<First aspect>
A 1st aspect is an aspect by which irradiation of the said laser beam to the said terminal is performed using the laser beam which has a spot diameter below the width | variety of the said terminal.

  First, a circuit member 1 as shown in FIGS. 1A and 1B is prepared. The circuit member 1 has a substrate 1A and a terminal 1B on the substrate 1A. An anticorrosive film 1C is formed on the terminal 1B. The terminal 1B is connected to the wiring 1D. The shape of the terminal 1B is rectangular.

Next, the laser light irradiation apparatus 10 is used to irradiate the entire surface of the terminal 1B with laser light. At this time, the substrate 1A is not irradiated with the laser beam. Here, since the spot diameter S of the laser beam is equal to or less than the width of the terminal 1B as shown in FIGS. 1C and 1D, even if the entire terminal 1B is irradiated with the laser beam, the laser beam is transmitted to the substrate 1A. It can adjust so that it may not be irradiated.
The spot diameter is preferably 1/2 or less of the width of the terminal, and more preferably 1/2 to 1/3. When the spot diameter is too small, the time for scanning the laser beam becomes long.

The irradiation of the laser beam may be performed by moving the laser beam irradiation device 10 or may be performed by moving the circuit member 1.
The laser light irradiation is preferably performed by scanning the longitudinal direction of the terminal. By doing so, the number of times the straight line is scanned can be reduced, and the scanning time can be shortened.

  Through the above steps, the rust preventive film 1C on the terminal 1B can be removed, and the surface of the terminal 1B is exposed as shown in FIGS. 1E and 1F.

  In the first aspect, since the spot diameter of the laser beam is equal to or less than the width of the terminal, the laser is applied to the terminal without requiring an auxiliary member as used in the second aspect and the third aspect described later. When light is irradiated, it is possible to prevent the laser light from being irradiated to the members of the circuit member other than the terminals.

<Second aspect>
The second aspect is an aspect in which the laser light irradiation to the terminal is performed through the opening of the laser light irradiation auxiliary member having at least one opening, and the opening is in the terminal. It is an aspect which is an opening of the same field as an irradiation field of the laser beam.

  First, a circuit member 1 as shown in FIGS. 2A and 2B is prepared. The circuit member 1 has a substrate 1A and a terminal 1B on the substrate 1A. An anticorrosive film 1C is formed on the terminal 1B. The terminal 1B is connected to the wiring 1D. The shape of the terminal 1B is rectangular.

  Next, the laser light irradiation apparatus 10 is used to irradiate the entire surface of the terminal 1B with laser light. At this time, the laser light is irradiated from a direction perpendicular to the substrate 1A. Further, as shown in FIGS. 2C and 2D, the substrate 1A is prevented from being irradiated with the laser light. Here, in order to prevent the substrate 1A from being irradiated with laser light, the laser light irradiation auxiliary member 5A having an opening having the same shape as the terminal is used so that the laser light is irradiated to the terminal 1B through the opening. To do. And in the irradiation direction of a laser beam, the said opening and terminal 1B are arrange | positioned so that those shapes may overlap. 2D indicates the outer edge of the laser beam.

  There is no restriction | limiting in particular as a material of the laser beam irradiation assistance member 5A, if it is a member which does not permeate | transmit the said laser beam, According to the objective, it can select suitably, For example, a metal etc. are mentioned.

The irradiation of the laser beam may be performed by moving the laser beam irradiation device 10 or may be performed by moving the circuit member 1.
When moving the laser beam irradiation apparatus 10, the circuit member 1 and the laser beam irradiation auxiliary member 5A are both fixed (not moved) while the laser beam is being irradiated.
When moving the circuit member 1, the laser beam irradiation auxiliary member 5A is also moved in the same direction at the same time. That is, the circuit member 1 and the laser beam irradiation auxiliary member 5A are relatively fixed.
The laser light irradiation is preferably performed by scanning the longitudinal direction of the terminal. By doing so, the number of times the straight line is scanned can be reduced, and the scanning time can be shortened.

  Through the above steps, the rust preventive film 1C on the terminal 1B can be removed, and the surface of the terminal 1B is exposed as shown in FIGS. 2E and 2F.

In the second aspect, since the laser beam irradiation assisting member 5A is used, even if the spot diameter of the laser beam is larger than the width of the terminal 1B, the laser beam is not irradiated to the members of the circuit member 1 other than the terminal 1B. It is possible to prevent the members from being damaged.
Therefore, in this aspect, when the terminal width is narrow (for example, the terminal width is 50 μm to 150 μm), when the terminal pitch is narrow [for example, the line and space (L / S) is 50 μm to 150 μm / 50 μm to 150 μm. ] Is particularly effective.

  In addition, the laser beam irradiation assistance member used by the said 2nd aspect is not restricted to what is shown to FIG. 2C. For example, it may be as shown in FIG. That is, as shown in FIG. 3, the laser beam irradiation auxiliary member 5B may have a plurality of openings corresponding to the positions of the plurality of terminals 1B. By providing a plurality of openings corresponding to the positions of the plurality of terminals 1B as the laser beam irradiation assisting member 5B, the number of times of moving the laser beam irradiation assisting member 5B can be reduced. Therefore, it is advantageous that the laser beam irradiation assisting member has a plurality of openings corresponding to the positions of the plurality of terminals in terms of improving the accuracy of laser beam irradiation and shortening the time for carrying out the film processing method. .

<Third Aspect>
A third aspect is an aspect in which the laser light irradiation to the terminal is performed through the opening of the laser light irradiation auxiliary member having at least one opening, and the opening has a width of the terminal. This is an embodiment in which the opening is less than a width.

  First, a circuit member 1 as shown in FIGS. 4A and 4B is prepared. The circuit member 1 has a substrate 1A and a terminal 1B on the substrate 1A. An anticorrosive film 1C is formed on the terminal 1B. The terminal 1B is connected to the wiring 1D. The shape of the terminal 1B is rectangular.

  Next, using the laser beam irradiation device 10, the entire surface of the terminal 1B is irradiated with laser light. At this time, the laser light is irradiated from the direction perpendicular to the substrate 1A. Further, as shown in FIGS. 4C and 4D, the substrate 1A is prevented from being irradiated with the laser light. Here, in order to prevent the substrate 1A from being irradiated with the laser beam, the laser beam irradiation assisting member 5C having a circular opening having a diameter of 1/2 of the width of the terminal 1B is used. The terminal 1B is irradiated. The broken line in FIG. 4D indicates the outer edge of the laser beam.

The irradiation of the laser beam may be performed by moving the laser beam irradiation device 10 or may be performed by moving the circuit member 1.
When moving the laser beam irradiation apparatus 10, the laser beam irradiation auxiliary member 5C is also moved in the same direction at the same time. That is, the laser beam irradiation device 10 and the laser beam irradiation auxiliary member 5C are relatively fixed.
When the circuit member 1 is moved, the laser light irradiation device 10 and the laser light irradiation auxiliary member 5C are fixed.
The laser light irradiation is preferably performed by scanning the longitudinal direction of the terminal. By doing so, the number of times of scanning the straight line is reduced, and the scanning time can be shortened.

  Through the above steps, the rust preventive film 1C on the terminal 1B can be removed, and the surface of the terminal 1B is exposed as shown in FIGS. 4E and 4F.

  The laser beam irradiation assisting member is not limited to the above-described mode, and may be in an open state (having an open end) in the longitudinal direction of the terminal 1B as in the laser beam irradiation assisting member 5D shown in FIG. . Further, as in the laser beam irradiation assisting member 5E shown in FIG. 6, it may be a laser beam irradiation assisting member having an opening longer than the length in the longitudinal direction of the terminal 1B in the longitudinal direction. Further, it may be a laser light irradiation auxiliary member having an opening like the laser light irradiation auxiliary member 5F shown in FIGS. 7A and 7B.

  In the film treatment method of the present invention, the oxide film or the rustproof film on the terminal may not be completely removed if it can be made thin to some extent. For example, after the film treatment method of the present invention, even if the oxide film or the rust preventive film remains on the terminal, a negative effect due to the oxide film or the rust preventive film remaining (for example, It is acceptable if it is a level that does not cause a decrease in connection reliability in connection using an anisotropic conductive film.

  There is no restriction | limiting in particular as an average thickness of the said film | membrane on the said terminal after processed by the film | membrane processing method of this invention, Although it can select suitably according to the objective, 0.4 micrometer or less is preferable, 0.. 3 micrometers or less are more preferable. In other words, in the film processing method, the terminal is irradiated with the laser beam to make the average thickness of the film on the terminal preferably 0.4 μm or less, more preferably 0.3 μm or less .

(Connection method)
The connection method of the present invention includes at least a film treatment process, a first arrangement process, a second arrangement process, and a heating and pressing process, and further includes other processes as necessary.
The connection method is a connection method for connecting the terminal of the first circuit member and the terminal of the second circuit member.

<Film treatment process>
There is no particular limitation on the film treatment process, as long as the film treatment process is performed by irradiating the laser light only to the terminal of the first circuit member, and can be appropriately selected according to the purpose. For example, the film treatment method of the present invention can be mentioned. The preferred embodiment is also the same.

  The terminal in the first circuit member has a film of at least one of an oxide film and an anticorrosion film on the surface.

<< first circuit member >>
As said 1st circuit member, the said circuit member illustrated in the said film processing method of this invention is mentioned, for example.

<< second circuit member >>
The second circuit member is not particularly limited as long as it is a circuit member that has a terminal and is an object of anisotropic conductive connection using the anisotropic conductive film, and is appropriately selected according to the purpose. For example, a plastic substrate having a terminal, Flex-on-Board (flex on board, FOB), Flex-on-Flex (flex on flex, FOF) and the like can be mentioned.

  The material of the terminal is not particularly limited and can be appropriately selected depending on the purpose. For example, Cu, Ni plated with Cu, Au, and Cu, Sn plated with Au are used. The plated Cu may, for example, be mentioned.

  There is no restriction | limiting in particular as a material and structure of the plastic substrate which has the said terminal, According to the objective, it can select suitably, For example, the rigid board | substrate which has a terminal, the flexible substrate which has a terminal, etc. are mentioned. As a rigid board which has the above-mentioned terminal, a glass epoxy board etc. which have copper wiring are mentioned, for example. As a flexible substrate which has the said terminal, the polyimide substrate etc. which have copper wiring are mentioned, for example.

  There is no restriction | limiting in particular as a shape of the said 2nd circuit member, and a magnitude | size, According to the objective, it can select suitably.

  It is preferable that the oxide film and the rustproof film are not formed on the terminal of the second circuit member. In the case where an oxide film or a rust preventive film is formed on the terminal of the second circuit member, it is preferable to carry out the film treatment method of the present invention.

<First arrangement step>
If it is a process of arranging an anisotropic conductive film on the said terminal of the said 1st circuit member as said 1st arrangement | positioning process, there will be no restriction | limiting in particular, According to the objective, it can select suitably.

<< anisotropic conductive film >>
There is no restriction | limiting in particular as said anisotropic conductive film, According to the objective, it can select suitably, For example, an electroconductive particle, curable resin, and a hardening agent are contained at least, and also if needed And other components such as a film-forming resin.

  There is no restriction | limiting in particular as average thickness of the said anisotropic conductive film, According to the objective, it can select suitably.

<Second arrangement step>
The second disposing step is not particularly limited as long as it is a step of disposing the second circuit member on the anisotropic conductive film, and can be appropriately selected according to the purpose.

<Heat pressing process>
The heating and pressing step is not particularly limited as long as it is a step of heating and pressing the second circuit member with the heating and pressing member, and can be appropriately selected according to the purpose. For example, heating by the heating and pressing member And can be pressed.
Examples of the heating and pressing member include a pressing member having a heating mechanism. Examples of the pressing member having the heating mechanism include a heat tool.
There is no restriction | limiting in particular as temperature of the said heating, Although it can select suitably according to the objective, 140 to 200 degreeC is preferable.
There is no restriction | limiting in particular as a pressure of the said press, Although it can select suitably according to the objective, 0.1 MPa-80 MPa are preferable.
There is no restriction | limiting in particular as the time of the said heating and press, According to the objective, it can select suitably, For example, 0.5 second-120 second etc. are mentioned.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Preparation of anisotropic conductive film>
Phenoxy resin (product name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.) 40 parts by mass, bifunctional acrylic monomer (polyethylene glycol # 200 diacrylate, product name: A-200, manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 parts by mass, urethane 20 parts by mass of acrylate (product name: U-2PPA, manufactured by Shin-Nakamura Chemical Co., Ltd.), 2 parts by mass of phosphate ester acrylate (product name: PM-2, manufactured by Nippon Kayaku Co., Ltd.), organic peroxide (dilauroyl) 3 parts by mass of peroxide) and 5 parts by mass of conductive particles (Cu particles, average particle size 10 μm) were uniformly mixed using a stirrer (rotation and revolution mixer, Aritori Nertaro, manufactured by Shinky Corporation). The blended mixture was applied on silicone-treated PET (polyethylene terephthalate) so that the average thickness after drying was 20 μm, and dried at 70 ° C. for 5 minutes to prepare an anisotropic conductive film.

<Manufacture of joined body>
Flex-on-Board (flex on board, FOB) mounting was performed by the following method.
A PWB (printed wiring board) was used as the first circuit member. As the PWB substrate, an FR4 glass epoxy substrate having a thickness of 1.0 mm was used. A Cu foil having a thickness of 35 μm was used for the terminal and wiring of the PWB. The terminal pitch was 400 μm (L / S = 200 μm / 200 μm). The PWB is subjected to a rust prevention treatment using a heat-resistant preflux made of an imidazole compound (Tough Ace E3, manufactured by Shikoku Kasei Kogyo Co., Ltd.). The average thickness of the anticorrosive film by the anticorrosive treatment was determined from the arithmetic average value of the results obtained by measuring the thickness of the anticorrosive film at 30 points by the above-described method using FIB and SIM.
As the second circuit member, an FPC (flexible printed wiring board) was used. A 25 μm thick polyimide film was used as the FPC substrate. A Cu foil having a thickness of 18 μm was used for the terminals and wiring of the FPC. The pitch of the FPC terminals is the same as the pitch of the PWB terminals.

<< Film treatment process >>
The rustproof film was treated as shown in FIGS. 1A to 1F.
First, the first circuit member was irradiated with laser light (spot diameter: 100 μm to 200 μm) having a spot diameter smaller than the terminal width (200 μm). At this time, the terminal is irradiated with the laser beam, but the substrate (in particular, the substrate between the terminals) is not irradiated with the laser beam. When irradiating the laser beam, the laser beam trajectory was scanned in the longitudinal direction of the terminal, and moved back in the longitudinal direction of the terminal after being slightly moved in the width direction of the terminal.
By the above, the antirust film on the said terminal was processed. The average thickness of the antirust film before and after the treatment was measured by the method described above using FIB and SIM.
As a laser beam irradiation apparatus, a CO ₂ laser (LC-2G) manufactured by Hitachi Via Mechanics Co., Ltd. was used.
The intensity of the laser beam was 50W.

<< First placement step, second placement step, and heating and pressing step >>
Then, the anisotropic conductive film was arrange | positioned on the terminal of the said 1st circuit member after a film processing process. Subsequently, the second circuit member was disposed on the anisotropic conductive film. Subsequently, using a Teflon (registered trademark) sheet having an average thickness of 250 μm as a buffer material, the second circuit member is heated and pressed by a heating tool under the conditions of 130 ° C., 3 MPa, and 10 seconds, and connected. A joined body was obtained.

<Evaluation>
It used for the following evaluation. The results are shown in Table 1.

<< Connection reliability (conducting resistance) >>
The initial resistance value of the obtained bonded body and the resistance value after being left for 1,000 hours at 85 ° C. and 85% RH were measured by the following methods.
Specifically, the resistance value was measured when a current of 1 mA was applied by a four-terminal method using a digital multimeter (part number: digital melt meter 7555, manufactured by Yokogawa Electric Corporation). The resistance value was measured for 30 channels, and the maximum resistance value was taken as the measured value. The measurement results were evaluated according to the following evaluation criteria. The rate of increase in resistance was determined using the following equation.
Resistance increase rate (%) = [(resistance after initial standing for 1,000 hours / initial resistance)-1] × 100
〔Evaluation criteria〕
◎: Resistance increase rate is less than 5% ○: Resistance increase rate is 5% or more and less than 8% △: Resistance increase rate is 8% or more and less than 10% ×: Resistance increase rate is less than 10%

(Example 2)
<Manufacture of joined body>
In Example 1, the pitch of the terminals was changed to 200 μm (L / S = 100 μm / 100 μm). In Example 1, the film treatment process was replaced with the following film treatment process. A bonded body was manufactured in the same manner as Example 1 except for the above.
The obtained joined body was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<< Film treatment process >>
The rustproof film was treated as shown in FIGS. 2A to 2F.
First, a laser beam irradiation auxiliary member was disposed on the first circuit member. The laser light irradiation auxiliary member is made of SUS having a thickness of 1 mm, and has an opening (length 2.0 mm × width 100 μm) having the same shape as the terminal (length 2.0 mm × width 100 μm). The laser beam irradiation auxiliary member was disposed so that the opening overlapped with the terminal.
And the laser beam (spot diameter 100 micrometers-200 micrometers) was irradiated to the said terminal using the laser beam irradiation apparatus so that the said opening of the said laser beam irradiation auxiliary member may be passed. At that time, the first circuit member and the laser beam irradiation auxiliary member were relatively fixed. Moreover, the laser beam was not irradiated to locations other than the said terminal in the said 1st circuit member by the said laser beam irradiation assistance member. When the laser beam was irradiated, the locus of the laser beam was scanned in the longitudinal direction of the terminal.
By the above, the antirust film on the said terminal was processed. The average thickness of the antirust film before and after the treatment was measured by the method described above using FIB and SIM.

(Example 3)
<Manufacture of joined body>
In Example 1, the pitch of the terminals was changed to 200 μm (L / S = 100 μm / 100 μm). In Example 1, the film treatment process was replaced with the following film treatment process. A bonded body was manufactured in the same manner as Example 1 except for the above.
The obtained joined body was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<< Film treatment process >>
As shown in FIGS. 4A to 4F, the antirust coating was processed.
First, a laser beam irradiation auxiliary member was disposed on the first circuit member. The laser beam irradiation assisting member is made of SUS having a thickness of 1 mm, and has a circular opening having a diameter of 50 μm. The size of the terminal of the first circuit member is 2.0 mm long × 100 μm wide.
And the laser beam (spot diameter 100 micrometers-200 micrometers) was irradiated to the said terminal using the laser beam irradiation apparatus so that the said opening of the said laser beam irradiation auxiliary member may be passed. At that time, the laser beam irradiation apparatus and the laser beam irradiation assisting member are relatively fixed. Further, the laser light irradiation assisting member did not irradiate the first circuit member other than the terminal with the laser light. When irradiating the laser beam, the laser beam trajectory was scanned in the longitudinal direction of the terminal, and moved back in the longitudinal direction of the terminal after being slightly moved in the width direction of the terminal.
By the above, the antirust film on the said terminal was processed. The average thickness of the antirust film before and after the treatment was measured by the method described above using FIB and SIM.

(Comparative example 1)
<Manufacture of joined body>
In Example 1, the pitch of the terminals was changed to 200 μm (L / S = 100 μm / 100 μm). Also, in Example 1, the film treatment step was not performed. A bonded body was manufactured in the same manner as Example 1 except for the above.
In addition, the average thickness of the antirust film was measured by the above-mentioned method using FIB and SIM.
The obtained joined body was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative example 2)
<Manufacture of joined body>
A joined body was manufactured in the same manner as in Example 1, except that the terminal pitch was changed to 200 μm (L / S = 100 μm / 100 μm).
In the film processing step, since the substrate was also irradiated with the laser light, the substrate was damaged. And the glass epoxy dust was generated because the glass epoxy substrate was damaged.

(Reference Example 1)
<Manufacture of joined body>
In Example 1, no rust preventive film was formed on the first circuit member. Also, in Example 1, the film treatment step was not performed. A bonded body was manufactured in the same manner as Example 1 except for the above.
The obtained joined body was evaluated in the same manner as in Example 1. The results are shown in Table 1.

In Examples 1 to 3, the rust preventive film on the terminal was treated (thinned) by the film treatment process, so that in the connection reliability test, the conduction resistance was compared with Comparative Example 1 in which the film treatment process was not performed. There was almost no increase in value. This result was equivalent to the case where the rust preventive film was not formed on the terminal (Reference Example 1).
Moreover, when a laser beam was irradiated to locations (substrates) other than the terminals in the film processing step, damage to the substrate occurred (Comparative Example 1).

  If there is a thick oxide film or rust preventive film on the terminal, the conduction resistance value increases in the durability test even if the conduction resistance at the initial stage of connection is good. This is presumably because the contact between the terminal and the conductive particles deteriorates when the connection portion repeatedly contracts and expands during the durability test due to the presence of the thick oxide film or rust preventive film. Therefore, in the present embodiment, the evaluation is performed based on the connection reliability.

  The film treatment method of the present invention can be suitably used for treatment of a film on a terminal of a circuit member connected using an anisotropic conductive film.

DESCRIPTION OF SYMBOLS 1 Circuit member 1A Board | substrate 1B Terminal 1C Rust prevention film 5A Laser beam irradiation auxiliary member 5B Laser beam irradiation auxiliary member 5C Laser beam irradiation auxiliary member 5D Laser beam irradiation auxiliary member 5E Laser beam irradiation auxiliary member 5F Laser beam irradiation auxiliary member 10 Laser beam Irradiation device S Spot diameter

Claims (11)

Irradiating laser light only to the terminal of the circuit member having a terminal having at least one of an oxide film and a rust preventive film on the surface, and processing the film ,
Irradiating the laser beam onto the terminal is performed through the opening of a laser beam irradiation auxiliary member having at least one opening .   The film processing method according to claim 1, wherein the circuit member is a circuit member connected to another circuit member via an anisotropic conductive film in contact with the terminal.   3. The film treatment method according to claim 1, wherein the laser beam is irradiated to the terminal using a laser beam having a spot diameter equal to or smaller than the width of the terminal. The film processing method according to claim 1, wherein the opening is an opening in the same region as an irradiation region of the laser beam in the terminal. The film processing method according to any one of claims 1 to 3, wherein the opening is an opening having a width smaller than the width of the terminal. A connection method for connecting the terminal of the first circuit member having a terminal having at least one of an oxide film and a rust preventive film on the surface, and the terminal of the second circuit member,
A film processing step of processing the film by irradiating a laser beam only to the terminal of the first circuit member;
A first disposing step of disposing an anisotropic conductive film on the terminal of the first circuit member;
A second disposing step of disposing the second circuit member on the anisotropic conductive film;
Heating and pressing the second circuit member with a heating pressing member,
The connection method , wherein the laser light irradiation to the terminal of the first circuit member is performed through the opening of a laser light irradiation auxiliary member having at least one opening . The connection method according to claim 6, wherein the irradiation of the laser beam to the terminal of the first circuit member is performed using a laser beam having a spot diameter equal to or smaller than the width of the terminal. The connection method according to claim 6, wherein the opening is an opening in the same region as the irradiation region of the laser beam in the terminal. The connection method according to any one of claims 6 to 7, wherein the opening is an opening having a width smaller than the width of the terminal. A joined body in which the terminal of the first circuit member and the terminal of the second circuit member are anisotropically conductively connected via the cured product of the anisotropic conductive film,
A joined body, wherein the terminal of the first circuit member has a film of at least one of an oxide film and an anticorrosion film, and a part of the film is removed with a width smaller than the width of the terminal . The joined body according to claim 10, wherein an average thickness of the film of the terminal of the first circuit member is 0.4 μm or less.