KR20070019559A - Junction method - Google Patents

Abstract

assignment

Provided is a bonding method that enables high speed and high precision mounting without using a thin film bonding material such as ACF.

Resolution

The bumps of TCP and the array wiring of the LCD are held in close proximity or contact. Laser light is irradiated to the array wiring. At that time, the laser beam is irradiated until the array wiring (metal electrode) exceeds the melting temperature. Then, the metal electrode of the array wiring is heated by the energy from the laser light, and the vicinity of the surface of the metal electrode of the array wiring melts, and the contact with the upper metal electrode is brought into contact. And when it comes to a contact state, what is called an atomic diffusion phenomenon in which the metal atom which comprises each metal electrode moves to the metal electrode which became a contact state in mutual metal electrodes occurs. When this atomic diffusion phenomenon occurs, metal atoms are mixed with each other to form an alloy, and the bumps of TCP and the array wiring of the LCD are joined.

Junction Devices, Liquid Crystal Display Panels, Drive Circuit Boards

Description

Joining method {JUNCTION METHOD}

1 is a schematic block diagram illustrating a liquid crystal display device according to an embodiment of the present invention.

2 is a conceptual diagram illustrating TCP (2) according to an embodiment of the present invention.

3 is a conceptual diagram illustrating a bonding apparatus 100 according to an embodiment of the present invention.

4 is a schematic block diagram illustrating a laser irradiation part 15 according to an embodiment of the present invention.

5 is a schematic block diagram illustrating a laser irradiation part 15 # according to an embodiment of the present invention.

It is a figure explaining bonding of an array substrate (glass substrate) and TCP by the bonding apparatus which concerns on embodiment of this invention.

FIG. 7 is a view for explaining a bonding method between a bump (metal electrode) of TCP (2) according to an embodiment of the present invention and an array wiring (metal electrode) of LCD.

FIG. 8 is a diagram illustrating bonding in the case where an oxide film is formed on the surfaces of the bumps of TCP (2) and the array wiring of LCD.

FIG. 9 is a diagram for explaining a method of joining both when the bump of TCP 2 and the array wiring of the LCD 1 are all formed of the same metal. FIG.

FIG. 10 is a view for explaining another bonding method between bumps (metal electrodes) of TCP (2) and array wiring (metal electrodes) of LCD according to the embodiment of the present invention. FIG.

(Explanation of symbols for the main parts of the drawing)

1: LCD 2: TCP

3: printed circuit board 4: interface

5: driver IC 6: FPC

15: laser irradiation unit 16: support

20: cylinder 30: pressurized head

55: backup glass 70: control unit

75 vacuum suction unit 80 inert gas supply unit

100: bonding device

Field of technology

The present invention relates to a bonding method suitable for bonding a liquid crystal display panel and a driving circuit board.

Conventional technology

In recent years, liquid crystal display devices are rapidly spreading as image display devices for personal computers and other various monitors.

In this type of liquid crystal display, an image formed on the liquid crystal surface by irradiating the liquid crystal surface having a predetermined spread with uniform brightness as a whole by disposing a backlight which is a planar light source for illumination on the back of the liquid crystal display panel. It is configured to visualize.

A liquid crystal display device supports a liquid crystal display panel formed by enclosing a liquid crystal material between two glass substrates, a printed circuit board for driving a liquid crystal material mounted on the liquid crystal display panel, and a liquid crystal display panel support on the back of the liquid crystal display panel. And a backlight unit arranged through the frame, and an outer edge frame covering them.

Among the liquid crystal displays, in the case of TFT (Thin Film Transistor) liquid crystal displays, one of the glass substrates constituting the liquid crystal display panel constitutes an array substrate, and the other glass substrate constitutes a color filter substrate. do.

The array substrate is also referred to as an array substrate because TFTs, display electrodes, drive lines made of liquid crystal materials, drawing electrodes for electrically connecting to a printed circuit board, and the like are formed, and TFTs are regularly arranged on a glass substrate. have.

In addition to the color filter, a common electrode, a black matrix, an alignment film, and the like are formed on the color filter substrate.

The printed circuit board is generally connected (mounted) through the lead electrode formed on the array substrate through a Tape Automated Bonding (TAB) tape carrier (hereinafter also referred to simply as TAB). Alternatively, a package (that is, a tape carrier package (hereinafter also referred to as TCP)) in which an LSI chip is connected to a tape film by TAB technology is also mounted. In addition, a chip on film / FPC (COF) or a system on film (SOF) may be mentioned as the same package technology, without being limited to the TAB technology.

The input lead conductor of the TAB is connected to the conductor to which the printed circuit board is corresponding. On the other hand, the output lead conductor of TAB is connected to the corresponding lead electrode of an array substrate. At the time of the connection, that is, the connection between the input lead conductor of TAB and the corresponding conductor of the printed circuit board, for example, solder, anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) Bonding material of a thin film is used. Alternatively, a method or material such as NCP (Non Conductive Particle / Paste) is used. In addition, hereinafter, ACF, ACP, NCP, etc. will be referred to simply as ACF.

ACF disperse | distributes the particle | grains which consist of a conductive material in resin as an adhesive agent, and there exist two types of thermosetting ACF which uses a thermoplastic resin as an adhesive agent, and a thermosetting type ACF which uses a thermosetting resin as an adhesive agent. The method of joining by a thermoplastic type ACF and a thermosetting type ACF is consistent with the point which performs the thermal pressurization with heating and pressurization, and Unexamined-Japanese-Patent No. 2002-249751 uses a heater tool and a near-infrared lamp. Disclosed is a method of irradiation and thermocompression bonding.

As another method, Japanese Patent Application Laid-Open No. 2000-26127 discloses a method in which two objects are welded by irradiating a laser beam on a thin film provided therebetween in connection with bonding of a glass plate and an adhesive partner.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-249751

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-26127

However, since the conventional bonding method based on thermocompression bonding using ACF is not a method that takes into account thermal expansion and contraction of materials, thermal expansion and shrinkage in particular in large liquid crystal display panels requiring a narrow pitch or narrow frame. This increases, resulting in various problems.

Specifically, in the case of mounting a package formed of TAB, silicon chip or the like formed on the basis of polyimide or the like, mounting unevenness is caused by a difference in shrinkage amount after thermal expansion of an array substrate in contact with ACF as an adhesive and TAB or silicon chip. It may occur.

This mounting stain has a high degree of occurrence as the bonding strength of ACF is strong. In particular, in the mounting of a silicon chip, since the rigidity of the chip is higher than that of TAB, it appears as a certain unevenness. This is a major factor in that mounting of a silicon chip is not widespread as a mounting technique of a large high-precision liquid crystal display panel.

In addition, in the case of bonding using other thin film bonding materials, not only the ACF but also a large liquid crystal display panel in which the same thermal expansion and contraction need to be taken into consideration and these narrow pitches and narrow picture frames are required. It is necessary to perform alignment adjustment of the thin film at the time of joining with high precision, and the process becomes complicated and the cost of the joining material itself becomes high.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a bonding method that enables high speed and high precision mounting without using a bonding material of a thin film such as ACF.

Means to solve the problem

The joining method according to the present invention has a melting point or the same melting point as the melting point of the first metal electrode of the first member and the first metal electrode of the second member as a joined object in order to form an electrical path. As a joining method for joining a high second metal electrode, the first metal electrode is irradiated with a laser while the first metal electrode and the second metal electrode are in contact with each other. Pressing means is pressed against the first metal electrode of the first member and the second metal electrode of the second member and brought into close contact with each other, until the temperature of the first metal electrode approaches the melting point by laser irradiation. The metal atom of the 1st metal electrode is heated, and it joins by the atomic diffusion phenomenon of the metal electrode of a 2nd metal electrode.

Preferably, after joining a 1st metal electrode and a 2nd metal electrode, irradiation of a laser is stopped and support of a 1st member is released.

Preferably, the first metal electrode is a wiring electrode formed on the surface of the first member, respectively. The first member transmits the laser, and the first metal electrode absorbs the laser. The laser beam passes through the first member and is irradiated to the first metal electrode. A plurality of sets of tanks of the first and second metal electrodes are provided by the first and second members. In the first and second members, pattern positions are formed such that the corresponding first and second metal electrodes of each pair are joined in a state of being in close or in contact with each other. In each of the plurality of sets, the laser is irradiated in a state where the pattern positions of the corresponding first and second metal electrodes approximately coincide.

Here, "the 1st member transmits a laser" means that the 1st member transmits a laser and since the absorption at that time is weak, the thermal deformation produced by absorption does not occur. I shall do it.

In addition, "the 1st metal electrode absorbs a laser" means that the first metal electrode absorbs the laser beam transmitted through the first member and the temperature rises to the extent that the first and second metal electrodes are joined. It means the absorption which can be done.

In addition, "approximately coincidence" shall mean that the position is aligned so that corresponding metal electrodes may be electrically connected to each other without shifting or straddling a plurality of metal electrodes adjacent to each other.

Preferably, an oxide film is formed on the surface of the first metal electrode as a surface coating, the first metal electrode is at a temperature close to the melting point by laser irradiation, and at least part of the oxide film is laser irradiated. It is controlled so as to become the temperature which diffuses to the inside of a 1st metal electrode in the time which has existed, As a result, it joins by the atomic diffusion phenomenon of the metal atom of a 1st metal electrode, and the metal atom of a 2nd metal electrode.

Preferably, temperature control is performed by flowing an inert gas at a temperature lower than either of the first metal electrode or the second metal electrode irradiated with a laser to cool the at least one metal electrode.

Preferably, the first member corresponds to a glass substrate, and the second member corresponds to an integrated circuit or an IC package product.

Preferably, melting | fusing point of a 2nd metal electrode is higher than melting | fusing point of a 1st metal electrode, and when an integrated circuit or IC package product arrange | positions mutually mutual metal electrodes on a glass substrate, and at the time of laser irradiation, Not supported

In particular, laser irradiation is performed over a glass substrate.

Preferably, the laser is converged on the second metal electrode over the first metal electrode to melt the second metal electrode.

The bonding method which concerns on this invention irradiates a laser and bonds a metal electrode by the atomic diffusion phenomenon of metal electrodes. Therefore, it is possible to realize high speed and high precision mounting without bonding metal electrodes using a bonding material of a thin film such as ACF.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail, referring drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent part in drawing, and the description is not repeated.

1 is a schematic block diagram illustrating a liquid crystal display device according to an embodiment of the present invention.

Referring to FIG. 1, in the liquid crystal display device according to the embodiment of the present invention, a connection wiring between a liquid crystal display panel (hereinafter also referred to as LCD) 1 and a peripheral circuit disposed around the LCD 1 is provided. The interface part 4 provided, the printed circuit board 3 for driving the liquid crystal material mounted on the LCD, and the printed circuit board 3 and the LCD 1 are provided to provide a component of the liquid crystal display panel. TCP (2) including a driver IC (5) for driving, and a flexible substrate (hereinafter referred to as FPC) 6 for electrically connecting the printed circuit board 3 and the interface unit 4 is provided. .

2 is a conceptual diagram illustrating TCP (2) according to an embodiment of the present invention.

Referring to FIG. 2, the TCP 2 according to the embodiment of the present invention includes a driver IC 5, and a plurality of input and output lead conductors are provided from the driver IC 5.

In the following, the bonding apparatus according to the embodiment of the present invention mainly relates to the bonding method of the TCP 2 including the drive IC 5 used for the connection of the LCD 1 and the printed circuit board 3. Explain. Specifically, the bonding method of joining the lead conductor of the TCP (2) and the LCD (1), that is, the bump (metal electrode) of the TCP (2), and the array wiring (metal electrode) of the LCD by laser irradiation. Explain about.

3 is a conceptual diagram illustrating the bonding apparatus 100 according to the embodiment of the present invention.

3, the bonding apparatus 100 which concerns on embodiment of this invention is the support part for supporting the laser part 15 which irradiates the laser which is monochromatic light, and the array substrate (glass substrate) 1 which is LCD. 16, the pressurizing head 30, the cylinder 20, the laser unit 15, the backup glass 55, the control unit 70 for controlling the whole bonding apparatus 100, and the object vacuum A vacuum suction unit 75 for adsorption and an inert gas supply unit 80 capable of supplying an inert gas are provided. And TCP2 is inserted between the pressurizing head 30 and the array board | substrate 1 which slide up and down.

The laser unit 15 irradiates laser light of a predetermined wavelength.

The cylinder 20 is for pressurizing at the joining of the TCP 2 and the array substrate 1 via the pressurizing head 30 based on the instruction of the controller 70, or pressurized based on the instruction of the controller 70. It is assumed that the position of the head is adjusted to control the position of the pressurized head.

In addition, as a pressurizing head, what is called an optical flat and an optical window which are workpieces with high plane precision can be used.

The vacuum suction part 75 vacuum-chucks TCP2 in this example which is an object from the suction hole provided in the pressurizing head based on the instruction | indication of the control part 70. Thereby, the alignment misalignment which may arise by the pressurization at the time of adhesion | attachment with an ACF is prevented, and the alignment with high precision is attained. Moreover, when joining metal electrodes mentioned later by a vacuum chuck, it becomes possible to support the position of the metal electrode of TCP (2).

In addition, in FIG. 3, although the case where one suction hole and the vacuum suction part 75 are connected through the pressurization head as an example is shown, it is not limited to this, A vacuum chuck is performed using a some suction hole. Of course it is possible.

In addition, although mentioned later, the inert gas supply part 80 injects inert gas, such as nitrogen gas or carbon dioxide, with respect to a target object from the supply hole provided in the pressurizing head based on the instruction | indication of the control part 70. FIG.

4 is a schematic block diagram illustrating a laser irradiation part 15 according to an embodiment of the present invention.

Referring to FIG. 4, the laser irradiation unit 15 according to the embodiment of the present invention includes a laser transmitter 200, a beam expander 105, a dichroic 110, a slit 115, Beam samplers 120 and 121, laser mirror 125, condenser lenses 130 and 155, laser line generator 135, alignment laser pointer 140, power meter 145, CCD ( 150).

As an example, the laser oscillator 200 can use a solid-state laser, such as a YAG laser, which emits laser light in the vicinity of wavelength lambda = 1064 nm. The laser light emitted from the laser oscillator 200 is deflected by the beam expander 105 into parallel rays of a predetermined width. Then, after passing through the dichroic 110, the slit 115 is ligated by the light beam of the slit width. After passing through the slit 115, a portion of light rays are reflected by the sampler 120 and incident on the power meter 145. The power meter 145 detects the received light intensity of the incident light beam, determines whether or not the laser light of the desired light intensity is emitted from the laser oscillator 200, and determines the laser oscillator 200 and the like not shown. The output of the laser oscillator 200 is adjusted through the controlling unit 70 for controlling. The laser light passing through the slit 115 is reflected by the laser mirror 125 and is incident on the condensing lens 130. The condenser lens 130 condenses the incident laser light at a previously designed focal position.

The alignment laser pointer 140 is a laser oscillator which oscillates a laser beam for alignment adjustment, for example, a wavelength which is visible light is selected. For example, in this example, a 690 nm laser is used. The laser light emitted from the alignment laser pointer 140 is shaped by the laser line generator 135 and irradiated to the object in the same manner as the laser light emitted from the laser oscillator 200 through the dichroic 110. This laser light is laser for alignment adjustment, ie alignment, and positioning control is performed using this laser light.

On the other hand, the reflected light when the laser beam is irradiated to the object is reflected by the condenser lens 130, the laser mirror 125, the sampler 120, and the dichroic 110, and is also reflected by the sampler 121. The light is condensed on the CCD by the condenser lens 155. That is, the CCD can monitor the object to which the laser beam is irradiated by the reflected light by image processing.

In addition, although the case where the laser mirror 125 was used as the laser reflection element in the said laser irradiation part 15 was demonstrated, it is not limited to this, For example, instead of the laser mirror 125, the reflection angle of a laser is shown. Of course, it is also possible to use a so-called galvano mirror or polygon mirror that can be finely adjusted.

5 is a schematic block diagram illustrating a laser irradiation part 15 # according to an embodiment of the present invention.

Referring to Fig. 5, a laser irradiation part 15 # using a galvano mirror is shown here. Specifically, the laser irradiation unit 15 # is a galvanometer scanner 93 which turns the laser oscillator 100, the galvano mirrors 91 and 92, and the galvano mirrors 91 and 92 in the direction of the arrow. 94) and an f? Lens that converges the laser light coming from the galvano mirror 91 and irradiates the object with a predetermined spot diameter. The galvano mirror 91 directs the laser light coming from the galvano mirror 92 in the X direction in response to the turning of the galvanometer scanner 93. The galvano mirror 92 directs the laser light coming from the laser oscillator 100 in the Y direction in response to the turning of the galvanometer scanner 94. In addition, although the structure of the alignment laser pointer 140, the power meter 145, and the CCD 150 which were demonstrated in FIG. 4 is not shown here, similarly to FIG. 4, a dichroic or a sampler is attached to the optical path of a laser beam. It is naturally possible to make it the same structure by arrange | positioning.

It is a figure explaining bonding of an array substrate (glass substrate) and TCP by the bonding apparatus which concerns on embodiment of this invention.

As shown in FIG. 6, by the irradiation from the laser oscillator 100, it is reflected by the laser mirror 125, passes through the array substrate (glass substrate) 1 through the backup glass 55, and directly lasers. Will be irradiated to the pin point. This laser irradiation part 15 is what is called a laser marker, and can irradiate a laser beam with arbitrary traces to the predetermined position located on the support 16 which is a sample mounting table as laser irradiation.

In general, conventional laser markers can be irradiated at predetermined positions using CAD data. Therefore, for example, positioning control of an irradiation point can be performed using the CAD data of LCD as it is. As the irradiation path of the laser light, it is preferable that the energy can be locally concentrated so as to sufficiently heat the object. In addition, it is possible to appropriately adjust the amount of energy supply to the object by appropriately controlling the amount of irradiation light and / or the irradiation trajectory of the laser light, and for example, a so-called wobbling method or a method of painting seamlessly can be adopted. Do. The irradiation trajectory by the wobbling method proceeds while turning the center of the irradiation spot. On the other hand, the method of painting seamlessly fills all the area to be irradiated by a plurality of parallel lines. Since this technique is general, the detailed description is abbreviate | omitted in this specification.

In the laser oscillator 100, by using a so-called Q switch 210, it is possible to oscillate a pulse beam having a very high Q value. That is, it becomes possible to heat an object for a short time by irradiating a laser of high energy density. In this example, a case of performing laser irradiation using a pulse beam as an example will be described. However, the present invention is not limited to this, but for example, continuous wave beam (CW beam) continuously irradiating a predetermined amount of energy is continuously irradiated. Of course it is possible.

Moreover, as a laser oscillator, a semiconductor laser, a YAG laser, or YVO ₄ It is also possible to irradiate with a predetermined | prescribed spot diameter and predetermined | prescribed operation trajectory using the solid-state laser or fiber laser which used crystals, such as these. In addition, as selection of a wavelength, it is necessary to select corresponding to the absorption band variation of the chemical bond of the OH group (hydroxyl group) of glass. For example, it is known that the transmittance near the wavelength of 2.7 µm falls to almost zero. In general, the transmittance of electromagnetic waves of about 4 μm or more and about 10 μm is remarkably bad and damages to glass. Therefore, it is possible to select an appropriate wavelength in consideration of absorption bands or the like based on materials.

Hereinafter, the bonding method of the bump (metal electrode) of TCP2 and the array wiring (metal electrode) of LCD which concerns on embodiment of this invention is demonstrated.

First, as a 1st system, the system (melt diffusion system) which melts and joins a part of metal electrode by laser irradiation is demonstrated.

It is a figure explaining the joining method of the bump (metal electrode) of TCP2 and the array wiring (metal electrode) of LCD which concerns on embodiment of this invention. In addition, although one set of bonding is demonstrated about the bump of TCP2 and the array wiring of LCD hereafter, as shown in FIG. 6, bump and array wiring are respectively provided to TCP2 and LCD1, respectively. It is assumed that a plurality of sets are provided and the pattern positions are formed so as to be joined in a state where the corresponding bumps and the array wiring are adjacent to or in contact with each other. In addition, in each group, it is assumed that laser irradiation is performed in a state where the pattern positions of the corresponding bumps and array wirings approximately coincide.

Referring to Fig. 7A, bumps (metal electrodes) of convex TCP 2 are shown on the upper side, and convex array wirings (metal electrodes) are shown on the lower side. In addition, gold (Au), aluminum (Al), etc. are used here as a metal which forms bump or array wiring. The melting point of gold (Au) and aluminum (Al) is about 900 degrees and about 660 degrees, and the melting point of gold (Au) is higher than that of aluminum (Al). First, as a 1st system, the system (melt diffusion system) which melts and joins a part of metal electrode by laser irradiation is demonstrated.

Here, the bump of the TCP 2 and the array wiring of the LCD 1 are supported in a state of being in close proximity or contact. In this case, it is assumed that the metal forming the bump of the TCP 2 has a higher melting point than the metal forming the array wiring of the LCD 1. For example, a case where bumps are formed of gold (Au) and array wiring is formed of aluminum (Al) as described above will be described.

As shown in FIG. 6, the array substrate (glass substrate) 1 is transmitted through the backup glass 55 to irradiate the array wiring with laser light. At that time, the laser beam is irradiated until the array wiring (metal electrode) exceeds the melting temperature. Then, the metal electrode of the array wiring is heated by the energy from the laser light, and the vicinity of the surface of the metal electrode of the array wiring is melted, and even when the metal electrodes are in close proximity, the metal electrodes on the upper side are affected by the surface tension or the like. It becomes a contact state. In the contact state, a so-called atomic diffusion phenomenon occurs in which the metal atoms constituting each of the metal electrodes move to the metal electrode in the contact state.

When this atomic diffusion phenomenon occurs, alloys are formed by mixing metal atoms with each other, and the bumps of TCP 2 and the array wiring of the LCD are bonded as shown in Fig. 7B. In this system, the bonding between the metal electrodes is performed while the bump position of the TCP 2 and the position of the array wiring of the LCD are supported. For example, when pressurized by a cylinder, the shape of the molten array wiring (metal electrode) may change physically remarkably. This may cause short circuits or short circuits of electrical paths in contact with adjacent array wirings. In this method, by supporting the bump position of the TCP (2) adjacent to the array wirings without applying excessive pressurization, The shape is not significantly deformed. Moreover, after joining, laser irradiation is stopped and support of the bump position of TCP2 is released. In addition, when excessive pressurization is not carried out, it is also possible to make self weight apply between the said metal electrodes, without performing support of the bump position of the said TCP2.

In addition, the laser beam is irradiated in a state in which the array wiring and the bump are in close proximity or contact by applying only an auxiliary pressure without melting and pressurizing only the surface of the bump (metal electrode) or by supporting only with the TCP's own weight or without supporting it. When overheated, they are bonded to each other by the diffusion phenomenon of metal atoms, are optimally positioned by self-alignment, and the corresponding electrodes are joined to each other, and excessive pressure is not applied, so that shorting of adjacent electrodes can be avoided. Become. In addition, since the stress to the array substrate (glass substrate) 1 or TCP 2 can be avoided, it becomes possible to avoid the damage of the board | substrate etc. by pressurization.

In addition, when the array wiring is melted and brought into contact with the upper metal electrode under the influence of surface tension or the like, when a plurality of array wiring and a plurality of bumps are arranged and bonded, the gap between the array wirings or the bumps is different. It is also possible to absorb and bond. In addition, since excessive pressurization is not applied, a plurality of metal electrodes can be joined without being shorted with other metal electrodes as described above. In addition, when a plurality of array wirings and a plurality of bumps are arranged, it is also possible to pressurize to indent the distance of the deviation degree of the gap in consideration of the deviation between the array wirings or the bumps.

Moreover, although the laser beam which permeate | transmitted the array substrate (glass substrate) 1 is slightly absorbed by an array substrate, it transmits to such an extent that a thermal deformation does not produce. On the other hand, the array wiring receives and absorbs the transmitted laser light, and the temperature rises to the extent that the bump and the array wiring are joined. In addition, since the array wiring to be bonded is sandwiched between the array substrate 1 and the TCP 2, the laser beam can be irradiated to the portion to be bonded effectively by irradiating through the array substrate that transmits the laser light. In addition, since the bump side of TCP 2 is supplied with energy from the array wiring side and joined, that is, it is not directly melted by a laser beam, it is also possible to set it as a metal electrode with a thickness. In this system, the laser beam transmitted from the array substrate side is irradiated to the array wiring, and the array wiring is melted and bonded to the bump. For example, the TCP (2) does not transmit the laser beam. It is also possible to form the light-shielding material.

Moreover, as temperature to heat, although irradiation of an array wiring (metal electrode) is more than melting temperature, it is necessary to control irradiation of a laser beam so that it may not reach to melting temperature of a bump (metal electrode). For example, as described above, when the array wiring is aluminum (Al) and the bump is gold (Au), for example, if heating to the melting temperature of gold (Au), the array wiring (metal electrode) formed of aluminum (Al) The change in shape is remarkable, and as described above, for example, there is a possibility that it may be shorted in contact with an adjacent array wiring, so that the laser beam is irradiated within a range capable of maintaining the convex shape of the array wiring (metal electrode). It is possible to heat.

In this regard, a metal formed of aluminum (Al) so as not to rise too much to the melting temperature of gold (Au), for example, by using the inert gas supply unit 80 as described in FIG. 3 to control the temperature of the metal electrode. In order to cool an electrode, temperature control can be performed by injecting inert gas lower than the melting temperature of one metal electrode from a supply hole, etc. to a junction part. The same applies to the following method.

In the above description, the method of joining the bumps by irradiating the laser beam to the array wiring has been described. However, since the array wiring is a wiring electrode, the laser wiring is simply irradiated, and when the temperature continues to rise, it is evaporated and lost, and the disconnection of the electrical path is caused. There is a possibility that the metal electrode melts and shorts by melting and spreading,

On the other hand, since an oxide film is formed into a metal electrode in the vicinity of the surface, it is known that this oxide film becomes a factor which inhibits the conduction of metal electrodes.

FIG. 8 is a diagram illustrating bonding in the case where an oxide film is formed on the surfaces of the bumps of the TCP 2 and the array wiring of the LCD.

Referring to Fig. 8, a case where an oxide film is formed on the surface of the bump 2 of the upper TCP 2 and the array wiring of the opposing LCD is shown here. Usually, in order to remove the oxide film formed on the surface of a metal electrode, the shaving method or the method of removing by a chemical reaction is used, but array wiring is heated because array wiring is heated until it becomes more than melting temperature like this method. The oxide film formed on the surface of the film causes a reverse diffusion phenomenon that melts into the array wiring.

Therefore, the bumps and the array wiring are combined as shown in Fig. 7B described above by welding each other by the atomic diffusion phenomenon of the metal electrode at a simple and high speed, without using a special method of removing the oxide film.

In the above, the material of the metal forming the bumps of the TCP 2 and the metal forming the array wiring of the LCD 1 are different, and the melting temperature of the metal forming the bumps is different from that of the metal forming the array wiring of the LCD. The case where it is higher than temperature was demonstrated.

On the other hand, when the metal forming the bumps of the TCP 2 and the metal forming the array wiring of the LCD 1 are the same, that is, the melting temperature of the metal forming the bumps and the metal forming the array wiring of the LCD are the same. The same method as described above can also be adopted in the case where the melting temperatures of the same are the same, but in the case of the same material, not only one metal electrode but also both metal electrodes can be irradiated with the laser.

FIG. 9 is a diagram for explaining a method of joining both when the bump of TCP 2 and the array wiring of the LCD 1 are all formed of the same metal.

As shown in FIG. 9, for example, the position of the convergence point of laser irradiation is set so that it may become a bump side. In Fig. 7, the position of the convergence point of the laser irradiation is set to heat the array wiring of the LCD 1, but in this example, the convergence point of the laser irradiation so that the laser is irradiated to the bumps of the TCP 2 over the array wiring. The position is set on the bump side, and laser light is irradiated to the bump of TCP 2 and the array wiring of LCD 1. Specifically, the laser beam is irradiated over the array wiring of the LCD 1 until the bump of the TCP 2 exceeds the melting temperature.

Then, the metal electrode of the array wiring and the bump is heated by the energy from the laser light, and the vicinity of the surface of the metal electrode of the array wiring and the bump is melted and brought into a contact state. And when it comes to a contact state, what is called an atomic diffusion phenomenon in which the metal atom which comprises each metal electrode moves to the metal electrode which became a contact state in mutual metal electrodes occurs. When this atomic diffusion phenomenon occurs, the metal atoms of each other are mixed to form an alloy and are joined.

In the above description, a method of melting and bonding a part of the metal electrode by laser irradiation (melt diffusion method) has been described. Next, a method of bonding a part of the metal electrode without melting (solid state diffusion method) will be described. do.

It is a figure explaining the other bonding system of the bump (metal electrode) of TCP2 and the array wiring (metal electrode) of LCD which concerns on embodiment of this invention.

Referring to Fig. 10A, bumps (metal electrodes) of convex TCP (2) are shown on the upper side, and convex array wirings (metal electrodes) on the lower side, with the oxide films interposed therebetween as described above. It is assumed that it is in contact. Therefore, it is assumed that the bumps and the array wiring of the TCP 2 are not in a conductive state by the oxide film.

In this example, the bumps of the TCP 2 are pressed while the array wiring (metal electrode) is irradiated.

First, as shown in FIG. 6, a laser beam is irradiated to array wiring through the backup glass 55. FIG. At that time, the laser beam is irradiated to near the melting temperature at which the array wiring (metal electrode) does not exceed the melting temperature. Then, the array wiring (metal electrode) is heated by the energy from the laser beam, but since the laser beam is irradiated so as not to reach the melting temperature, the metal electrode of the array wiring does not melt. On the other hand, as described above, a portion of the oxide film attached to the surface of the metal electrode is heated to the vicinity of the melting temperature, so that the diffusion of the oxide film into the array wiring (metal electrode) occurs. Further, since the bump of the TCP 2 is pressed, the film thickness of the oxide film attached to the surface of the array wiring and the bump becomes thin, resulting in direct contact between the bump and at least a part of the metals of the array wiring. Then, the metal atoms with increased energy inside the array wiring (metal electrode) cause an atom diffusion phenomenon with the metal atoms of the bump (metal electrode) through the portions in which the metals directly contact each other. As a result, as shown in FIG. 10 (b), as described above, the metal atoms are mixed with each other to form an alloy, and the bump and the array wiring are joined. Further, in the case of the solid state diffusion method, since the metal electrode is not a method of melting and joining, for example, as described above, there is no possibility that the metal electrode will come into contact with an adjacent array wiring or be short-circuited or disconnection of the electrical path. It is possible to safely join each other. In addition, depending on the relationship between the material of the array wiring and the heating temperature, a case in which the back diffusion phenomenon does not occur with respect to the oxide film described above is considered. In this case, the array wiring (metal It is also possible to mechanically break down the oxide film attached to the surface of the electrode to expose the metal so that the above-described atomic diffusion phenomenon of the metal atoms can be caused through the portions in which the metals are in direct contact with each other.

As described above, in the bonding method according to the present invention, by irradiating a metal electrode with a laser of a predetermined wavelength, the metal atoms of the metal electrodes are reacted with each other at a pin point by an atomic diffusion phenomenon to join the metal electrodes. Therefore, it is not necessary to join metal electrodes using thin film materials, such as ACF, and the joining time of metal electrodes can be shortened and high speed and high precision mounting are attained.

In the embodiment of the present invention, since the metal electrodes are bonded to each other by an efficient laser irradiation as necessary when necessary, sufficient effects can be expected in terms of effective power consumption.

In addition, in the use of laser irradiation, the mounting energy can be extremely localized, and the precision mounting can be performed with good energy concentration efficiency and position accuracy by using the feature of monochromatic light.

Moreover, in the conventional system, since TCP, driver IC, array substrate (glass substrate), etc. expand due to endothermic at the time of mounting, it is necessary to design a part by reducing correction beforehand, but according to the embodiment of the present invention In this case, since the processing is extremely short, ideally, the reduction correction is unnecessary, and it is possible to realize an extremely high precision alignment.

In addition, in the above, although the bonding apparatus which mounts an array board | substrate (glass board | substrate) and TCP was mainly demonstrated, it is not limited to this, An IC silicon chip (hereinafter, a silicon chip) is mounted on another mounting board | substrate, for example. The same can be applied to a technology for mounting a chip on glass (COG) to be bonded or a part manufacturing technology such as TAB / COF.

In the above description, the case where the bumps of TCP and the metal electrodes of the array wiring of the LCD are bonded to each other by laser irradiation has been mainly described. However, the bonding or bonding between the TCP and the LCD is not limited to conduction. It is also possible to reinforce the bonding or bonding strength of the TCP and LCD by providing the bumps of the dummy and the array wiring of the dummy for the purpose of reinforcing the strength, and bonding the metal electrodes to each other by laser irradiation.

It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown by above-described not description but Claim, and it is intended that the meaning of a claim and equality and all the changes within a range are included.

The bonding method which concerns on this invention irradiates a laser and bonds a metal electrode by the atomic diffusion phenomenon of metal electrodes. Therefore, it is possible to realize high speed and high precision mounting without bonding metal electrodes using a bonding material of a thin film such as ACF.

Claims (9)

In order to form an electrical path, the first metal electrode of the first member and the second metal electrode having the same or higher melting point of the first metal electrode of the second member as the joined body are formed. As a joining method to join, In a state where the first metal electrode and the second metal electrode are in contact with each other, the first metal electrode is irradiated with a laser, Pressurizes the first metal electrode of the first member and the second metal electrode of the second member by pressing means to make close contact; The metal atoms of the first metal electrode are heated until the temperature of the first metal electrode by laser irradiation is close to the melting point, and bonded by the atomic diffusion phenomenon between the metal electrodes of the second metal electrode. Bonding method characterized in that. The method of claim 1, And after the bonding of the first metal electrode and the second metal electrode, irradiation of the laser is stopped to release the support of the first member. The method of claim 1, The first metal electrode is a wiring electrode formed on the surface of the first member, respectively, the first member transmits the laser, and the first metal electrode absorbs the laser, The laser penetrates through the first member and is irradiated to the first metal electrode, A plurality of sets of the first and second metal electrodes are provided in the first and second members, In the first and second members, pattern positions are formed such that the corresponding first and second metal electrodes of each of the pairs are joined in a state of being in close proximity or contact with each other, In each of said plurality of sets, said laser beam is irradiated in the state in which the pattern position of the said corresponding 1st and 2nd metal electrode corresponded substantially. The method of claim 1, On the surface of the first metal electrode, an oxide film is formed as a surface film. By the laser irradiation, the first metal electrode is controlled to be at a temperature close to the melting point, and at least a part of the oxide film is at a temperature diffused into the first metal electrode within the time of the laser irradiation, As a result, it joins by the atomic diffusion phenomenon of the metal atom of the said 1st metal electrode, and the metal atom of the said 2nd metal electrode, The joining method characterized by the above-mentioned. The method of claim 1, Temperature control is performed by flowing an inert gas at a temperature lower than either the first metal electrode or the second metal electrode irradiated with the laser to cool the at least one metal electrode. Bonding method. The method of claim 1, The said 1st member is corresponded to a glass substrate, The second member corresponds to an integrated circuit or an IC package product. The method of claim 6, The melting point of the second metal electrode is higher than the melting point of the first metal electrode, and the integrated circuit or IC package product is placed on the glass substrate so that the metal electrodes are aligned with each other. Joining method characterized in that not. The method of claim 7, wherein Bonding method characterized in that to perform the laser irradiation over the glass substrate. The method of claim 1, And joining the laser to the second metal electrode over the first metal electrode to melt the second metal electrode.

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