JP2002329958A - Method of joining circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of joining circuit boards which exactly conductively connects terminals by preventing the misregistration between terminal rows due to the difference of the thermal expansion coefficients of the two circuit boards to be joined together, thereby accurately opposing the corresponding terminals in both terminal rows to each other. SOLUTION: At a room temperature, the arrangement pitch P1 of the connector terminals 44 of a base film 43 is smaller by a specified quantity than the arrangement pitch P2. Then, in order to join them, first the base film 43 is elongated by preheating, and the arrangement pitch of the connector terminals 44 is made the same as the arrangement pitch of input terminals 35. Next, they are registered so that the corresponding connector terminals 44 of the base film 43 and the input terminal 35 of the glass board 33 oppose to each other. When joining them together through an anisotropic conductive adhesive 36 by regular pressurized heating after this, each terminal row of both the base film 43 and the glass board 33 is elongated by the same quantity. As a result, no matter where the origin of the elongation of the base film 43 and the glass board 33 at this regular pressurized heating are, the misregistration is not made to occur in the terminal rows.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining circuit boards, and more particularly, to a method for joining circuit boards which can prevent displacement of terminal rows due to a difference in thermal expansion coefficient between two circuit boards to be joined.

[0002]

2. Description of the Related Art In a method of manufacturing a liquid crystal display device, for example, a method of thermocompression bonding one circuit board of a liquid crystal display panel and a flexible circuit board therebetween through a connector member such as an anisotropic conductive adhesive is often used. Used.

FIG. 9 is a perspective view of a part of an example of a conventional circuit board bonding apparatus used in such a circuit board bonding method. This joining apparatus includes a fixed base 1 having a suction mechanism (not shown), and a movable base with a suction mechanism (not shown) arranged movably in the X and Y directions (horizontal direction) beside the fixed base 1. 2. A bonding tool 3 and the like are provided above the fixed base 1 so as to be vertically movable.

The liquid crystal display panel 4 is positioned on the fixed base 1 and is attracted and arranged. In the liquid crystal display panel 4, an upper glass substrate 5 and a lower glass substrate 6 are bonded together via a substantially rectangular frame-like sealing material (not shown), and a liquid crystal (between the two glass substrates 5 and 6 inside the sealing material). (Not shown) is sealed, the upper polarizing plate 7 is attached to the upper surface of the upper glass substrate 5, and the lower polarizing plate (not shown) is attached to the lower surface of the lower glass substrate 6. In this case, a predetermined side portion of the lower glass substrate 6 protrudes from the upper glass substrate 5, and a plurality of input terminals 8 (see FIG. 10) made of a transparent metal such as ITO are provided on the protruding portion 6a. And a strip-shaped anisotropic conductive adhesive 9 on the input terminal 8.
Are temporarily crimped and arranged. Anisotropic conductive adhesive 9
Is composed of a thermosetting resin 10 containing a large number of conductive particles 11, as shown in FIG.

[0005] A flexible circuit board 1 is mounted on a movable base 2.
2 are positioned and sucked and arranged.
In the flexible circuit board 12, a semiconductor chip 14 such as an LSI for driving a liquid crystal display panel is provided with a COF (chip on chip) at the center of the upper surface of a base film 13 made of polyimide or the like.
A plurality of connection terminals 15 (see FIG. 10) made of copper or the like are connected to the semiconductor chip 14 and provided on the lower surface of one end of the base film 13.

Next, the terminals arranged at one end of the flexible circuit board 12 are connected to the liquid crystal display panel 4 by this bonding apparatus.
The case of bonding to the terminal arrangement portion on the protruding portion 6a of the lower glass substrate 6 will be described. First, the liquid crystal display panel 4 is positioned and fixed at a predetermined position on the fixed base 1 by suction. In this case, a strip-shaped anisotropic conductive adhesive 9 is arranged on the protrusion 6 a of the lower glass substrate 6. Further, the flexible circuit board 12 is positioned at a predetermined position on the movable base 2 and is attracted and arranged. In this state, the flexible circuit board 1
One end of 2 protrudes from movable table 2 by a predetermined amount, and is positioned on anisotropic conductive adhesive 9.

Next, in this state, although not shown, the positions of one end of the flexible circuit board 12 and the protruding portion 6a of the lower glass substrate 6 in the X and Y directions are detected by an image processing position provided with a camera or the like. Detected by device. Then, based on the detection result, the movable base 2 is appropriately moved in the X and Y directions, and the end of the flexible circuit board 12 is aligned with the protruding portion 6 a of the lower glass substrate 6. Next, the bonding tool 3 is lowered, and the lower surface of one end of the flexible circuit board 12 is pressed against the upper surface of the anisotropic conductive adhesive 9 on the projecting portion 6a of the lower glass substrate 6 by the lower surface. Then, the lower surface of one end of the flexible circuit board 12 is joined to an appropriate position on the protruding portion 6a of the liquid crystal display panel 4 via an anisotropic conductive adhesive 9 by heating and pressing by the bonding tool 3, and each terminal Are electrically connected via conductive particles in the anisotropic conductive adhesive 9.

FIG. 10 shows this ideal bonding state. However, in FIG. 10, for convenience of illustration, only three out of a large number of connection terminals 15 and input terminals 8 are shown. This ideal bonding state is obtained when the coefficient of thermal expansion of the base film 13 is equal to the coefficient of thermal expansion of the lower glass substrate 6 of the liquid crystal display panel 4, and the arrangement pitch of the connection terminals 15 and the arrangement pitch of the input terminals 8 are provided. Are the same, and the connection terminal 15 and the input terminal 8 facing each other are conductively connected via the conductive particles 11 interposed therebetween and elastically deformed appropriately. Further, the lower surface of one end of the flexible circuit board 12 including the connection terminals 15 and the upper surface of the protruding portion 6 a of the lower glass substrate 6 including the input terminals 8 are bonded via a thermosetting resin 10.

Since the coefficient of thermal expansion of the base film 13 made of polyimide or the like of the flexible circuit board 12 is larger than the coefficient of thermal expansion of the lower glass substrate 6 of the liquid crystal display panel 4, the heating temperature of the bonding tool 3 at the time of joining is reduced. When the temperature is increased to about 200 to 300 ° C., the X of the portion of the base film 13 including the connection terminals 15 is reduced.
The amount of elongation in the direction (hereinafter, simply referred to as the amount of elongation) is larger than the amount of elongation in the X direction (hereinafter, simply referred to as the amount of elongation) of the portion of the lower glass substrate 6 including the input terminal 8 of the projection 6a. Would. That is, as shown in FIG. 11, the respective temperatures of the base film 13 and the lower glass substrate 6 are both at room temperature before the start of bonding, and rise substantially in the same manner even when the bonding is started and heated. At this point, the temperature of the base film 13 becomes the bonding temperature T1, and the temperature of the lower glass substrate 6 becomes the bonding temperature T2 slightly lower than the bonding temperature T1 of the base film 13. However, as shown in FIG. 12, at the end of the joining, the extension L1 of the base film 13 is considerably larger than the extension L2 of the lower glass substrate 6. The definitions of the elongation amounts L1 and L2 will be described later.

In consideration of the difference (L1−L2) between these elongation amounts L1 and L2, in the initial state before joining, as shown in FIG.
The arrangement pitch P1 of the connection terminals 15 is smaller than the arrangement pitch P2 of the input terminals 8 of the protruding portions 6a of the lower glass substrate 6 by a predetermined amount so as to offset the difference (L1-L2) in the amount of elongation. . Here, the elongation amounts L1 and L2 are the increasing amounts of the respective total values of the arrangement pitches P1 and P2 of the terminals 15 and 8, that is, the terminals 15a and 15b at the left and right ends shown in FIG. 8a and 8b is the amount of increase in the length between the centers in the width direction.

[0011]

In the above-mentioned conventional bonding method, the positioning of the one end of the flexible circuit board 12 with respect to the projection 6a of the lower glass substrate 6 is merely performed. It is difficult to control the base point of elongation due to heating during bonding of the glass substrate 6. The base point of the elongation slightly changes depending on the contact condition of the heater chip and the like, and the base point of the elongation due to heating at the time of bonding the base film 13 and the lower glass substrate 6 is indicated by line AA in FIG. When the center is in the left-right direction as described above, the base film 13 and the lower glass substrate 6 are evenly extended in the left-right direction, respectively, so that, as shown in FIG. The position can be almost the same. However, the base film 13 and the lower glass substrate 6
In the case where the base point of the elongation due to the heating at the time of bonding is, for example, the right end as shown by the line BB in FIG. 13, the base film 13 and the lower glass substrate 6 both extend almost only in the left direction. As shown in FIG. 14, the arrangement position of the connection terminal 15 and the arrangement position of the input terminal 8 are shifted. As a result, there is a problem that the facing area between the connection terminal 15 and the input terminal 8 decreases, the number of the conductive particles 11 interposed therebetween decreases, and the connection resistance increases. In particular, when the arrangement pitch of the connection terminals 15 and the input terminals 8 is reduced, this is a great obstacle. SUMMARY OF THE INVENTION It is an object of the present invention to prevent a position shift between terminal rows due to a difference in thermal expansion coefficient between two circuit boards to be joined, and to accurately oppose corresponding terminals of both terminal rows to ensure reliable conduction. An object of the present invention is to provide a method for joining circuit boards to be connected.

[0012]

According to a first aspect of the present invention, there is provided a method for bonding a circuit board, comprising: a first circuit board having a first terminal row in which a plurality of terminals are arranged; A second terminal in which a plurality of terminals corresponding to each terminal of one terminal row are arranged
And a second circuit board provided with a first terminal row and a second terminal row are connected to each other with a connector member so that the first terminal row and the second terminal row face each other, and the first terminal row and the second terminal are connected to each other. In the method of joining circuit boards, wherein the terminals corresponding to the rows are conductively connected to each other via the connector member, the first terminal row and the second terminal row may be formed so that the arrangement pitches thereof are different in advance. A preliminary step of pre-heating or pre-cooling at least one circuit board of the second circuit boards to a temperature at which the terminal arrangement pitches of the first terminal row and the second terminal row are the same; After the step, a positioning step of aligning the first circuit board and the second circuit board such that respective corresponding terminals of the first terminal row and the second terminal row face each other; After the positioning step, the first A joining step of joining the first terminal row and the second terminal row by applying pressure while heating the circuit board and the second circuit board with the connector member interposed therebetween. It is characterized by the following.
According to the first aspect of the present invention, at least one of the two circuit boards is pre-heated or pre-cooled to a preset pre-heating temperature or cooling temperature before joining by bonding. The terminal pitches were made equal and the corresponding terminals were aligned so that they faced each other, and the elongation of each pitch of both circuit boards due to heating in the subsequent joining process was made equal. The terminal row can be prevented from being displaced due to the difference in the coefficient of thermal expansion or the difference in the base point of elongation. In the present invention, as described in claim 2, each temperature of the first circuit board and the second circuit board at the time of completion of the preliminary step is equal to the first terminal row and the temperature in the joining step. The temperature is set so that the amounts of elongation of the second terminal row become equal. And as described in claim 3,
According to the present invention, the first circuit board has a larger coefficient of thermal expansion than the second circuit board, and
The second terminal row is more suitable for joining circuit boards having a larger terminal pitch than the terminal row of (1). In that case, only the first circuit board is used in the preliminary step as described in claim 4. Should be preheated. Further, as described in claim 5, as the connector member, it is preferable to use an anisotropic conductive adhesive in which conductive particles are contained in a thermosetting resin. As described, in the preliminary step, the anisotropic conductive adhesive is preferably heated to cure the thermosetting resin to such an extent that the flow of the conductive particles can be suppressed. Further, according to the present invention, the first circuit board is one circuit board of a liquid crystal display panel, and the second circuit board is a flexible circuit board. It is suitable for.
According to another aspect of the present invention, there is provided a circuit board bonding method, comprising: a plurality of first terminals forming a first terminal row of a first circuit board; and a second circuit board. The first
Are electrically connected to the second terminals which are arranged corresponding to the respective terminals by forming an array of second terminals via an anisotropic conductive adhesive comprising conductive particles contained in a thermosetting insulating resin. In the method of joining circuit boards, the anisotropic conductive adhesive is heated together with the first or second circuit board to harden the insulating resin to such an extent that the flow of the conductive particles is suppressed. Preliminary curing step, and after the preliminary step, pressurizing the first circuit board and the second circuit board while heating with the anisotropic conductive adhesive therebetween,
A joining step of further curing the insulating resin than the state cured in the preliminary step, and electrically connecting the first terminal row and the second terminal row via the conductive particles. It is characterized by the following.

[0013]

FIG. 1 is a perspective view of a main part of a circuit board bonding apparatus according to an embodiment of the present invention. This joining device includes a fixed base 21 with a suction mechanism (not shown). A bonding tool 22 is arranged above the fixed base 21. The bonding tool 22 includes a heater chip 23, and a suction mechanism (not shown).
It is attached to one side of the lower surface of the attached support plate 24. Bonding tool 22 including heater chip 23
Has a heating temperature control function that can instantaneously set a plurality of heating temperatures. At the four corners on the other side of the lower surface of the support plate 24, suction legs 25 are provided. The lower surface of the suction leg 25 has a pressure surface lower than the atmospheric pressure due to the operation of the suction mechanism. The height position of the lower surface of the suction leg 25 is substantially the same as the height position of the lower surface of the bonding tool 22. Then, the heater chip 23, the support plate 24, and the suction leg 25 are integrally moved in the X, Y, and Z directions (for positioning) and the rotation angle θ (for posture adjustment) in the XY plane. It has become.

The liquid crystal display panel 31 is positioned on the fixed base 21 in the X, Y, and θ directions and is attracted and arranged. The liquid crystal display panel 31 includes an upper glass substrate 32
The lower glass substrate 33 and the lower glass substrate 33 are bonded together via a substantially rectangular frame-shaped sealing material (not shown), and a liquid crystal (not shown) is sealed between the two glass substrates 32 and 33 inside the sealing material. An upper polarizer 34 is attached to the upper surface of the substrate 32, and a lower polarizer (not shown) is mounted on the lower surface of the lower glass substrate 33.
Consists of the ones that are pasted. In this case, a predetermined side of the lower glass substrate 33 protrudes from the upper glass substrate 32, and a plurality of input terminals 35 (see FIG. 2) made of a transparent metal such as ITO are provided on the protruding portion 33a. On the input terminal 35, a strip-shaped anisotropic conductive adhesive 36 is temporarily pressed and arranged. As shown in FIG. 2, the anisotropic conductive adhesive 36 is made of a thermosetting resin 37 containing a large number of conductive particles 38.

On the lower surfaces of the four suction legs 25, a flexible circuit board 41 is positioned by suction in the X, Y, and θ directions and is arranged by suction. Flexible circuit board 4
1, a semiconductor chip 43 made of an LSI or the like for driving a liquid crystal display panel is mounted on a central portion of an upper surface of a base film 42 made of polyimide or the like by a COF (chip on film) method,
A plurality of connection terminals 44 (see FIG. 2) made of copper or the like are provided on the lower surface of one end of the base film 42 so as to be connected to the semiconductor chip 43.

Next, one end of the flexible circuit board 41 is connected to the lower glass substrate 3 of the liquid crystal display panel 31 by this bonding apparatus.
A description will be given of a case in which the bonding is performed on the third protrusion 33a.
First, the liquid crystal display panel 31 is placed on the fixed base 21 by X, Y, θ.
The position and posture are determined in the direction, and the suction arrangement is performed. In this case, a strip-shaped anisotropic conductive adhesive 36 is temporarily pressed and arranged on the protruding portion 33a of the lower glass substrate 33. Further, the flexible circuit board 41 is attached to the lower surface of the four suction legs 25 by X,
It is positioned in the Y and θ directions and is arranged by suction. In this state, one end of the flexible circuit board 41 where the connection terminals 44 are juxtaposed is arranged so as to be in close contact with the front end surface of the heater chip 23 serving as a thermocompression bonding head. Note that the heater chip may be provided with a suction function also on the front end face, and one end of the flexible circuit board 41 may be sucked on the front end face.

Here, in FIG. 1, the bonding tool 2
2 is a liquid crystal display panel 3 adsorbed and arranged on a fixed base 21
Although shown as being located above the one protruding portion 33a, at this time, the bonding tool 22 is moved in the Y direction at the upper limit position and is located at the standby position where it does not face the fixed base 21. FIG. 2 shows the relationship between the connection terminals 44 of the base film 42 and the input terminals 35 of the lower glass substrate 33 in this state. However, in FIG. 2, for convenience of illustration, only three of the connection terminals 44 and the input terminals 35 are illustrated. In the state shown in FIG. 2, that is, in the initial state before the joining, the difference (L1) between the extension L1 of the base film 42 and the extension L2 of the lower glass substrate 33 at the end of the main heating and pressing shown in FIG.
In consideration of -L2), the arrangement pitch P1 of the connection terminals 44 is smaller than the arrangement pitch P2 of the input terminals 35 by a predetermined amount so as to offset the difference (L1-L2) in elongation.

Next, in a state where the bonding tool 22 is located at the standby position, one end of the base film 42 where the connection terminals 44 are juxtaposed is preset by preheating by the bonding tool 22 including the heater chip 23. Heat to preheat temperature. Then, as shown in FIG. 5, the temperature of the lower glass substrate 33 is kept at room temperature, but the temperature of the base film 42 rises to reach a preset preheating temperature T3. Thereby, as shown in FIG. 6, the lower glass substrate 33 does not extend, but the base film 42 extends by a predetermined amount L3. Here, the extension amount L3 of the base film 42 is set in advance so as to be the total value of the difference (P2−P1) between the arrangement pitch P2 of the input terminals 35 and the arrangement pitch P1 of the connection terminals 44 shown in FIG. In other words, as shown in FIG. 3, the arrangement pitch P3 of the connection terminals 44 is equal to the arrangement pitch P2 of the input terminals 35.

Next, in this state, although not shown, the positions of one end of the flexible circuit board 41 and the protruding portion 33a of the lower glass substrate 33 in the X and Y directions are detected by an image processing position provided with a camera or the like. Detected by device. Then, based on the detection result, the bonding tool 22 located at the standby position is appropriately moved in the X and Y directions, and the end of the flexible circuit board 41 is aligned with the protruding portion 33a of the lower glass substrate 33, The connection terminals 44 of the flexible circuit board 41 are accurately located at the matching positions above the corresponding input terminals 35.

Next, the bonding tool 22 is lowered by a predetermined amount in the Z direction, and the lower surface of one end of the flexible circuit board 41 is pressed against the upper surface of the anisotropic conductive adhesive 36 on the projection 33a of the lower glass substrate 33. . Then, the heater chip 23 generates heat, and the bonding tool 22 is heated to the main heating temperature to perform main heating and pressurization. As a result of this main heating and pressing, as shown in FIG. 5, the temperature of the base film 42 further rises from the preheating temperature T3 to reach the expected joining temperature T1 at the end of the main heating and pressing, and at the same time, the lower glass substrate 33 Rises from room temperature to reach the junction temperature T2 expected at the end of the main heating and pressurizing. As a result, as shown in FIG. 6, the base film 42 further extends by (L1-L3), the amount of elongation from the beginning becomes the desired amount of elongation L1, and the lower glass substrate 33 grows by the desired amount L2. Where L
Preheating temperature T3 so that 2 = (L1-L3)
Is set, the amount of extension at one end of the base film 42 and the amount of extension of the protruding portion 33a of the lower glass substrate 33 at the time of the main heating and pressing are the same.

As a result, even if the base point of the elongation of the base film 13 and the lower glass substrate 6 is at the center in the left-right direction as shown by the line AA in FIG. 3, it may be at the right end as shown by the line BB. 4, the arrangement pitch of the connection terminals 44 and the arrangement pitch of the input terminals 35 are enlarged equally, so that the connection terminals 44 exactly face the corresponding input terminals 35, as shown in FIG. And an overlapping arrangement.
In this state, the connection terminal 44 and the input terminal 35 opposed to each other are reliably and electrically connected to each other via the conductive particles 38 interposed therebetween and appropriately elastically deformed.
The lower surface of one end of the flexible circuit board 41 including the connection terminals 44 and the upper surface of the protruding portion 33 a of the lower glass substrate 33 including the input terminals 35 are bonded via a thermosetting resin 37.

As described above, in this bonding method, the flexible circuit board 41 is pre-heated before the main heating and pressurizing so that the pitch between the connection terminals is the same as the pitch between the input terminals to be bonded, and the alignment is performed. After performing the main heating and pressing, the flexible circuit board 41 in the main heating and pressing is performed.
Since the preheating temperature T3 at one end of the flexible circuit board 41 is set such that the extension (L1-L3) of one end of the flexible circuit board 41 is equal to the extension L2 of the protrusion 33a of the lower glass substrate 33, the base to be joined is formed. Film 42 and lower glass substrate 3
3, the terminal rows are prevented from being displaced due to the difference in the coefficient of thermal expansion and the difference in the base point of elongation, so that the terminal rows can be always electrically connected as expected.

In the above embodiment, the case where only the base film 42 is preheated has been described. However, the present invention is not limited thereto.
2, the lower glass substrate 33 may be pre-heated by the fixing table 21 provided with a heating means (not shown). Next, regarding each temperature change of the base film 42 and the lower glass substrate 33 and each elongation amount of the base film 42 and the lower glass substrate 33 in this case,
This will be described with reference to FIGS.

First, as shown in FIG. 7, the temperatures of the base film 42 and the lower glass substrate 33 are both room temperature in an initial state before bonding. And base film 4
2 and preheating of the lower glass substrate 33 are started separately,
The temperature of the base film 42 is set to a preset preheating temperature T
4 (T4> T3), and the temperature of the lower glass substrate 33 is increased to a preset preheating temperature T5. As a result, as shown in FIG. 8, the terminal array on the base film 42 extends by a predetermined amount L4 (L4> L3), and the terminal array on the lower glass substrate 33 only extends by a predetermined amount L5. extend. Here, T3 and L3 are the preheating temperature and the elongation due to the preheating temperature in the above-described embodiment. Here, when the respective preheating temperatures T4 and T5 are set in advance so that (L4−L5) = L3, the arrangement pitch of the connection terminals 44 and the arrangement pitch of the input terminals 35 after the preheating are equal. Become.

Next, the main heating and pressurizing is performed for a predetermined time, and the temperature of the base film 42 is further increased from the preheating temperature T4 to the bonding temperature T1 expected at the end of the main heating and pressurizing. The temperature is further increased from the preheating temperature T5 and the bonding temperature T2 scheduled at the end of the main heating and pressurizing.
And As a result, as shown in FIG. 8, the base film 42 further extends by (L1-L4), the amount of elongation from the beginning becomes the desired amount of elongation L1, and the lower glass substrate 33 further elongates by (L2-L5). Thus, the amount of growth from the beginning becomes the expected amount of growth L2. Here, (L1−L4) = (L2
−L5), the preheating temperatures T4 and T5 are set in advance so that the amount of elongation of the terminal arrangement portion of the base film 42 and the lower glass
Is the same as the amount of extension of the projection 33a. Therefore,
Also in this case, the positional displacement of the terminal rows due to the difference in the coefficient of thermal expansion between the base film 42 to be bonded and the lower glass substrate 33 and the difference in the base point of elongation is prevented, and the terminal rows are always reliably connected as expected. can do.

In the case of the base film 42 made of polyimide or the like, the preheating temperatures T3 and T4 are usually about 100
° C or higher. On the other hand, the dimensions of the base film 42 at room temperature may change due to moisture absorption. However, even in such a case, when the base film 42 is preheated and reaches the preheating temperatures T3 and T4, it is sufficiently dried,
The desired dimensions including the elongation amounts L3 and L4 due to the preheating are obtained, and at this time, the positioning is performed in the same manner as in the above-described embodiment, so that the influence of the dimensional change due to the moisture absorption of the base film 42 can be eliminated.

When the lower glass substrate 33 is preheated, the anisotropic conductive adhesive 36 disposed on the protruding portion 33a is also preheated. In this case, if the preheating temperature T5 of the lower glass substrate 33 is set to a temperature at which the thermosetting resin 37 is hardened by preheating to such a degree that the flow of the conductive particles 38 is suppressed, the heat is applied during the main heating and pressurizing. The curable resin 37 does not excessively flow, the movement of the conductive particles 38 is reduced, and the distribution of the conductive particles 38 after the main heating and pressing can be made uniform.

In the above embodiment, instead of the flexible circuit board 41, a TAB (tape automated board) is used.
nding), a TCP (tape carrier package), a semiconductor chip, or the like may be bonded to the projection 33a of the liquid crystal display panel 31. Further, when the coefficient of thermal expansion of one of the circuit boards adsorbed and arranged on the fixed base 21 is larger than the coefficient of thermal expansion of the other circuit board joined thereto, the one of the circuit boards is preheated in a predetermined manner. Preheating may be performed to a temperature, or the other circuit board may be precooled to a preset cooling temperature. in addition,
In the above embodiment, the base film 42 may be kept at room temperature, and the lower glass substrate 33 may be pre-cooled to a preset cooling temperature.

[0029]

As described above, according to the present invention, at least one of the two circuit boards is preheated or cooled to a preset preheating temperature or cooling temperature before joining. Since the pitch of each terminal of both circuit boards is made equal, the corresponding terminals are aligned so that they face each other, and the expansion of each pitch of both circuit boards due to heating in the subsequent bonding step is made equal, so that they should be bonded. It is possible to prevent the terminal rows from being displaced due to the difference in the coefficient of thermal expansion or the difference in the base point of elongation between the two circuit boards, and to make sure that the corresponding terminal rows always accurately correspond to the corresponding terminals, thereby securely connecting the terminals.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a circuit board joining apparatus as one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an initial state before a flexible circuit board is bonded on a lower glass substrate in the bonding apparatus shown in FIG. 1;

FIG. 3 is a sectional view showing a state in which the flexible circuit board is preheated from the state shown in FIG. 2;

FIG. 4 is a sectional view showing a state in which the flexible circuit board is joined to a lower glass substrate from the state shown in FIG. 3;

FIG. 5 is a diagram showing temperature changes of the flexible circuit board and the lower glass substrate in the cases shown in FIGS. 2 to 4;

FIG. 6 is a diagram showing the respective amounts of elongation of the flexible circuit board and the lower glass substrate in the case shown in FIG.

FIG. 7 is a view showing another example of each temperature change of the flexible circuit board and the lower glass substrate.

FIG. 8 is a view showing the respective amounts of elongation of the flexible circuit board and the lower glass substrate in the case shown in FIG. 7;

FIG. 9 is a perspective view showing a part of an example of a conventional circuit board joining apparatus.

FIG. 10 is a sectional view showing a state in which the flexible circuit board is joined to a lower glass substrate in the joining apparatus shown in FIG. 9;

FIG. 11 is a diagram showing temperature changes of a flexible circuit board and a lower glass substrate in the conventional example.

FIG. 12 is a diagram showing the amount of elongation of a flexible circuit board and a lower glass substrate in the case shown in FIG. 11;

FIG. 13 is a cross-sectional view showing an initial state before the flexible circuit board is bonded to the lower glass substrate in the bonding apparatus shown in FIG. 9;

FIG. 14 is a cross-sectional view for explaining a state after bonding when a base point of elongation of the base film and the lower glass substrate is the right end as indicated by line BB in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Fixing stand 22 Bonding tool 23 Heater chip 24 Support plate 25 Suction leg 31 Liquid crystal display panel 32 Upper glass substrate 33 Lower glass substrate 33a Projection 35 Input terminal 36 Anisotropic conductive adhesive 37 Thermosetting resin 38 Conductive particles 41 Flexible circuit board 42 Base film 43 Semiconductor chip 44 Connection terminal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA48 GA50 MA32 NA27 NA29 5E344 BB02 BB04 BB07 DD06 DD10 EE21 EE23 5F044 NN12 NN19

Claims (8)

[Claims] 1. A first circuit board having a first terminal row in which a plurality of terminals are arranged, and a second terminal row in which a plurality of terminals corresponding to each terminal of the first terminal row are arranged. A second circuit board provided, and the first terminal row and the second terminal row are joined to each other by a connector member,
In a circuit board joining method for electrically connecting the corresponding terminals of the first terminal row and the second terminal row via the connector member, the first terminal row and the second terminal row may be connected to each other. At least one of the first and second circuit boards formed with different arrangement pitches in advance is brought to a temperature at which the terminal arrangement pitches of the first terminal row and the second terminal row are the same. A pre-heating or pre-cooling pre-process; and after the pre-process, the first circuit board and the second circuit board are connected to the corresponding terminals of the first terminal row and the second terminal row, respectively. A positioning step of aligning the first circuit board and the second circuit board after the positioning step.
A circuit board, wherein the circuit board is heated and pressurized while heating with the connector member interposed therebetween to join the first terminal row and the second terminal row. Joining method. 2. The invention according to claim 1, wherein the first circuit board and the second circuit board at the time of completion of the preliminary process are provided.
Each temperature of the circuit board of the first embodiment is the first temperature in the bonding step.
A temperature at which respective amounts of elongation due to temperature rises of the terminal row and the second terminal row become equal to each other. 3. The invention according to claim 1, wherein
The first circuit board has a higher coefficient of thermal expansion than the second circuit board, and the terminal pitch of the second terminal row is larger than that of the first terminal row before the preliminary process. Characteristic method of joining circuit boards. 4. The method according to claim 3, wherein in the preliminary step, only the first circuit board is pre-heated. 5. The circuit board according to claim 1, wherein the connector member is an anisotropic conductive adhesive in which conductive particles are contained in a thermosetting resin. Method. 6. The invention according to claim 5, wherein in the preliminary step, the anisotropic conductive adhesive is heated to cure the thermosetting resin to such an extent that the flow of the conductive particles can be suppressed. Circuit board joining method. 7. The invention according to claim 1, wherein the first circuit board is one of a liquid crystal display panel, and the second circuit board is a flexible circuit board. Characteristic method of joining circuit boards. 8. A plurality of first terminals forming a first row of terminals on a first circuit board, and a second row of terminals arranged on the second circuit board so as to correspond to the first terminals, respectively. Second to form
A circuit board bonding method for electrically connecting the terminal and the terminal via an anisotropic conductive adhesive comprising conductive particles contained in a thermosetting insulating resin, wherein the anisotropic conductive adhesive A heating step of heating the insulating resin together with the first or second circuit board to harden the insulating resin to such a degree that the flow of the conductive particles is suppressed; The circuit board and the second circuit board are pressurized while being heated with the anisotropic conductive adhesive interposed therebetween, and the insulating resin is further hardened than the hardened state in the preliminary step. A bonding step of conductively connecting the first terminal row and the second terminal row via the conductive particles.