阅读说明：本技术 超声波接合装置及超声波接合方法 (Ultrasonic bonding apparatus and ultrasonic bonding method ) 是由 须永诚寿郎 宫腰敏畅 牧田光悦 于 2019-06-06 设计创作，主要内容包括：本发明提供一种超声波接合装置及超声波接合方法,即使在配线间隔狭窄的情况下,也不会发生短路不良等,易于实现平面部件之间的电连接。超声波接合装置具有：供设置应接合的第一平面部件和第二平面部件的载置台；超声波变幅杆,其具有压靠第一平面部件和所述第二平面部件的叠层部分的按压部。载置台具有：供设置第一平面部件的低位侧表面；供设置第二平面部件的高位侧表面,其相对于低位侧表面以规定的台阶高度处于高的位置；和台阶壁面,其位于低位侧表面和高位侧表面的边界。(The invention provides an ultrasonic bonding apparatus and an ultrasonic bonding method, which can prevent short circuit failure and the like even in the case of narrow wiring intervals and can easily realize the electric connection between plane parts. The ultrasonic bonding apparatus includes: a mounting table on which a first planar member and a second planar member to be bonded are provided; and an ultrasonic horn having a pressing portion which presses against the laminated portion of the first planar member and the second planar member. The mounting table includes: a lower side surface on which the first planar member is provided; a high-level side surface on which the second planar member is provided, the high-level side surface being located at a high position by a prescribed step height with respect to the low-level side surface; and a step wall surface located at a boundary of the low-level side surface and the high-level side surface.)

1. An ultrasonic bonding apparatus, comprising:

A mounting table on which a first planar member and a second planar member to be bonded are provided; and

An ultrasonic horn having a pressing portion which presses against the laminated portion of the first planar member and the second planar member,

Wherein the mounting table includes:

A lower side surface on which the first planar member is provided;

a high-level side surface on which the second planar member is provided, the high-level side surface being located at a high position with respect to the low-level side surface by a prescribed step height; and

A step wall surface located at a boundary of the low-level side surface and the high-level side surface.

2. The ultrasonic bonding device according to claim 1,

The mounting table further includes:

A first fixing unit that detachably fixes the first planar member to the lower-level side surface such that an end of the first planar member is positioned in contact with the step wall surface; and

and a second fixing unit that detachably fixes the second planar member to the high-position side surface such that at least a part of the second planar member is stacked on the first planar member.

3. The ultrasonic joining apparatus according to claim 2, further comprising:

A moving mechanism for moving the ultrasonic horn relative to the mounting table; and

And a control unit that controls the moving mechanism so that the pressing portion of the ultrasonic horn is pressed against the laminated portion at a position corresponding to the step wall surface.

4. The ultrasonic bonding device according to any one of claims 1 to 3,

The step height is the same as or smaller than the thickness of the first planar member.

5. The ultrasonic joining apparatus according to claim 3 wherein said ultrasonic joining apparatus is characterized by

the control unit controls the moving mechanism so that the pressing portion of the ultrasonic horn presses the lamination portion located on the lower side surface within a predetermined range from the step wall surface.

6. the ultrasonic joining apparatus according to claim 4, wherein the joining apparatus is characterized in that

The control unit controls the moving mechanism so that the pressing portion of the ultrasonic horn presses the lamination portion located on the lower side surface within a predetermined range from the step wall surface.

7. An ultrasonic bonding method is characterized by comprising:

A step of preparing a mounting table having a lower-side surface, a higher-side surface located at a higher position by a predetermined step height with respect to the lower-side surface, and a step wall surface located at a boundary between the lower-side surface and the higher-side surface;

A step of providing a first planar member on the lower-level side surface so that an end of the first planar member is aligned with the step wall surface;

Providing a second planar member on the high-level side surface so as to form a laminated portion in which at least a part of the second planar member is laminated on the first planar member; and

And a step of pressing the pressing portion of the ultrasonic horn against the laminated portion at a position corresponding to the step wall surface.

8. The ultrasonic bonding method according to claim 7,

a first metal is formed on a surface of the first planar member laminated with the second planar member,

a second metal is formed on a surface of the second planar member laminated on the first planar member, and the first metal and the second metal are solid-phase bonded by ultrasonic waves at the laminated portion in contact with the pressing portion of the ultrasonic horn.

Technical Field

The present invention relates to an ultrasonic bonding apparatus and an ultrasonic bonding method.

Background

For example, as shown in patent document 1, a technique of connecting a wiring of a glass substrate serving as a display panel substrate to a Flexible Printed Circuit (FPC) or the like via an Anisotropic Conductive Film (hereinafter referred to as ACF) is known.

However, in recent years, pitch intervals of wiring patterns have become narrow, and when the wiring patterns are connected by ACF, short-circuit defects between wirings have become a problem.

Prior art reference

Patent document

Patent document 1: japanese patent laid-open publication No. 2016 & 186517

Disclosure of Invention

Technical problem to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic bonding apparatus and an ultrasonic bonding method which are capable of easily achieving electrical connection between planar members without causing short-circuit failure or the like even when wiring intervals are narrow.

Means for solving the problems

in order to achieve the above object, an ultrasonic bonding apparatus according to the present invention includes:

A mounting table on which a first planar member and a second planar member to be bonded are provided;

An ultrasonic horn having a pressing portion which presses against the laminated portion of the first planar member and the second planar member,

Wherein the mounting table includes:

A lower side surface on which the first planar member is provided;

a high-level side surface on which the second planar member is provided, the high-level side surface being located at a high position with respect to the low-level side surface by a prescribed step height; and

A step wall surface located at a boundary of the low-level side surface and the high-level side surface.

in order to ultrasonically bond the first planar member and the second planar member using the ultrasonic bonding apparatus of the present invention, first, the first planar member is provided on the lower-side surface so that an end portion of the first planar member is aligned with the step wall surface (position わ せ). Next, the second planar member is provided on the high-level side surface in such a manner as to form a laminated portion in which at least a part of the second planar member is laminated on the first planar member. Thereafter, if the pressing portion of the ultrasonic horn is pressed against the laminated portion at a position corresponding to the step wall surface, the ultrasonic joining is ended.

In the ultrasonic bonding apparatus of the present invention, since the step wall surface is provided on the surface of the mounting table, alignment of the first planar member and the second planar member is facilitated by the step wall surface, and ultrasonic bonding between the wiring patterns can be performed. Therefore, even when the wiring interval is narrowed to a level of several tens of μm or less, for example, short-circuit failure or the like does not occur, and electrical connection between the planar members is easily achieved.

Further, recently, a wide display close to the external size of the device is required as in a display of a smartphone or the like, and therefore, the bonding length between the wiring patterns has to be shortened, which causes a problem in connection reliability. According to the device of the present invention, solid-phase bonding between metals can be performed by ultrasonic bonding, and the reliability of connection is also improved.

In the ultrasonic bonding apparatus according to the present invention, since the mounting table has a stepped wall surface on the surface thereof, the wiring patterns can be bonded to each other reliably by ultrasonic bonding even when the width of the laminated portion of the first planar member and the second planar member is, for example, 60mm or more.

Preferably, the mounting table includes:

A first fixing unit that detachably fixes the first planar member to the lower-level side surface so that an end of the first planar member is positioned in contact with the step wall surface; and

And a second fixing unit that detachably fixes the second planar member to the high-position side surface such that at least a part of the second planar member is stacked on the first planar member.

The first fixing means is not particularly limited, and for example, a plurality of first suction holes formed in the lower surface of the mounting table are exemplified. The first plane member can be detachably fixed to the lower-level side surface by introducing negative pressure to the plurality of first suction holes. Similarly, the second fixing means is not particularly limited, and for example, a plurality of second suction holes formed in the upper surface of the mounting table are exemplified. By introducing negative pressure into the plurality of second suction holes, the second flat member can be detachably fixed to the high-position side surface.

preferably, the ultrasonic bonding apparatus of the present invention includes:

A moving mechanism for moving the ultrasonic horn relative to the mounting table;

And a control unit that controls the moving mechanism so that the pressing portion of the ultrasonic horn is pressed against the laminated portion at a position corresponding to the step wall surface.

The moving mechanism may be a mechanism for moving the ultrasonic horn relative to the mounting table, a mechanism for moving the mounting table relative to the ultrasonic horn, or both of these mechanisms. The moving mechanism includes at least a mechanism for moving the ultrasonic horn in a direction relatively close to the mounting table or in a direction opposite thereto. The moving mechanism preferably includes a mechanism for moving the ultrasonic horn relative to the mounting table in the planar direction.

preferably, the step height is the same as or smaller than the thickness of the first planar member. With this configuration, even if the mounting table has a manufacturing error, the upper surface of the first planar member does not become lower than the high-position side surface, and the upper surface of the first planar member is flush with the high-position side surface or slightly protrudes upward. Therefore, in the case where the second planar member is provided on the high-order side surface, the first planar member and the second planar member are surely brought into contact at their stacked portions (repeated portions). Therefore, ultrasonic bonding can be performed reliably, and the reliability of the connection portion is further improved.

Preferably, the moving mechanism is controlled by the control unit such that the pressing portion of the ultrasonic horn presses the stacked portion located on the lower side surface within a predetermined range from the step wall surface. The pressing portion of the ultrasonic horn preferably presses only the lamination portion without pressing the second planar member located on the high-order side surface, thereby performing ultrasonic bonding. With this configuration, disconnection of the wiring patterns and the like do not occur, and the reliability of ultrasonic bonding between the wiring patterns is further improved.

the ultrasonic bonding method of the present invention includes the steps of:

Preparing a mounting table having a lower-side surface, a higher-side surface located at a high position with respect to the lower-side surface by a predetermined step height, and a step wall surface located at a boundary between the lower-side surface and the higher-side surface;

a first planar member disposed on the lower side surface in such a manner that an end portion of the first planar member is aligned with the step wall surface;

Providing a second planar member on the high-level side surface in such a manner as to form a laminated portion in which at least a part of the second planar member is laminated on the first planar member;

The pressing portion of the ultrasonic horn is pressed against the laminated portion at a position corresponding to the step wall surface.

in the ultrasonic bonding method according to the present invention, since the step wall surface is formed on the surface of the mounting table, the step wall surface facilitates alignment of the first planar member and the second planar member, and ultrasonic bonding between the wiring patterns can be performed. Therefore, even when the wiring interval is narrowed to a level of several tens μm or less, for example, short-circuit failure or the like does not occur, and electrical connection between the planar members is easily achieved. Preferably, the direction of the ultrasonic wave is not the stacking direction of the stacked portion but a direction along the longitudinal direction of the bonded wiring patterns.

further, recently, a wide display close to the external size of the device is required as in a display of a smartphone or the like, and therefore, the bonding length between the wiring patterns has to be shortened, which causes a problem in connection reliability. According to the method of the present invention, solid-phase bonding between metals can be performed by ultrasonic bonding, and the reliability of connection is also improved.

In the ultrasonic bonding method according to the present invention, since the mounting table has a stepped wall surface on the surface thereof, the wiring patterns can be reliably ultrasonically bonded to each other even when the width of the laminated portion of the first planar member and the second planar member is as wide as, for example, 60mm or more.

Preferably, a first metal is formed on a surface of the first planar member in a stack with the second planar member,

A second metal is formed on a surface of the second planar member laminated on the first planar member, and the first metal and the second metal are solid-phase bonded by ultrasonic waves at the laminated portion in contact with the pressing portion of the ultrasonic horn.

Preferably, the connection portion of the wiring pattern formed on the first planar member is made of a first metal, and the connection portion of the wiring pattern formed on the second planar member is made of a second metal. They were solid-phase bonded by ultrasonic bonding. The metal is not particularly limited as long as it is a metal (including an alloy) capable of ultrasonic bonding, and examples thereof include silver, gold, aluminum, and an alloy containing these as a main component. Further, an oxidation-resistant film containing titanium or the like as a main component may be formed on the surface of these metals.

Drawings

Fig. 1 is a schematic configuration diagram of an ultrasonic bonding apparatus according to an embodiment of the present invention.

fig. 2 is a schematic view showing a step of an ultrasonic bonding method using the apparatus shown in fig. 1.

Fig. 3 is a schematic diagram showing the subsequent steps of fig. 2.

fig. 4 is a schematic diagram showing a subsequent stage of fig. 3.

fig. 5A is a schematic view showing a subsequent stage of fig. 4.

Fig. 5B is a schematic diagram showing the subsequent steps of fig. 5A.

Description of the symbols

2: ultrasonic bonding apparatus

4: electronic control base (first plane component)

4 a: wiring pattern

6: flexible substrate (second plane component)

6 a: wiring pattern

8: substrate assembly

10: platform (ス テ ー ジ)

10 a: lower side surface

10a 1: bonding position

10a 2: standby position

10 b: high side surface

10 c: step wall

11: standby adsorption hole

12: first adsorption hole

14: second adsorption hole

20: conveying head

30: cam (カ メ ラ)

50: ultrasonic amplitude transformer (ホ ー ン, amplitude transformer)

50 a: pressing part

Detailed Description

The present invention will be described below based on embodiments shown in the drawings.

a method of manufacturing the substrate assembly 8 shown in fig. 5B by performing the ultrasonic bonding method shown in fig. 2 to 5B using the ultrasonic bonding apparatus 2 shown in fig. 1 according to the embodiment of the present invention will be described.

as shown in fig. 5B, the substrate assembly 8 includes the electronic control substrate 4 as a first planar member and the flexible substrate 6 as a second planar member. The electronic control board 4 may be, for example, a liquid crystal display panel, an organic EL display panel, or another display panel, and may include, for example, a glass substrate.

The flexible substrate 6 is a substrate for supplying some signals and electric power to the electronic control substrate 4, and the wiring pattern 4a of the electronic control substrate 4 and the wiring pattern 6a of the flexible substrate 6 are electrically connected pattern by pattern.

In the substrate assembly 8 shown in fig. 5B, after the wiring pattern 4a and the wiring pattern 6a are ultrasonically bonded, the flexible substrate 6 is bent from the end portion of the electronic control substrate 4 on the wiring pattern 4a side toward the back side and is accommodated in, for example, the inside of the case of a smartphone. With this configuration, the entire surface close to the outer dimension of the housing can be used as the display screen of the electronic control board 4.

From this viewpoint, the overlapping width X1 (see fig. 5A) of the wiring patterns 4a and 6a in the X-axis direction is required to be set as small as possible, for example, 0.5mm or less, preferably 0.2mm or less. Further, the wiring intervals in the Y axis direction of the wiring patterns 4a and 6a are reduced to, for example, several tens μm or less, preferably 20 μm or less, while achieving high miniaturization of the screen display. In the figure, the thickness of the substrate 6 is drawn to be the same as that of the substrate 4, but in reality, the thickness of the substrate 6 is smaller than that of the substrate 4, but may be the same or the opposite.

In the present embodiment, the ultrasonic bonding apparatus 2 shown in fig. 1 is used to electrically connect the wiring pattern 4a of the electronic control board 4 and the wiring pattern 6a of the flexible board 6 for each pattern.

As shown in fig. 1, an ultrasonic bonding apparatus 2 of the present embodiment includes: a mounting table 10 on which the electronic control board 4 and the flexible board 6 to be bonded are provided; and an ultrasonic horn 50 having a pressing portion 50a that presses (contacts) the laminated portion of the electronic control substrate 4 and the front flexible substrate 6.

Further, the transfer head 20 is disposed above the mounting table 10 in the Z-axis direction so as to be movable relative to the mounting table 10 in the X-axis, Y-axis, and Z-axis directions. Further, at the upper portion of the mounting table 10 in the Z-axis direction, a camera 30 is disposed so as to be relatively movable in at least the X-axis and Y-axis directions with respect to the mounting table 10 so that the position in the Z-axis direction is shifted from the carrier head 20. The camera 30 may be disposed to be movable in the Z-axis direction relative to the mounting table 10, as in the case of the transfer head 20.

the ultrasonic horn 50 is disposed so as to be movable in the X-axis, Y-axis, and Z-axis directions relative to the mounting table 10 at a position not to collide with the carrier head 20 and the camera head 30. Relatively movable means that one can move relative to the other, the other can move relative to one, or one and the other can also move, the relative positions of one and the other being varied.

The relative movement mechanisms of the stage 10, the ultrasonic horn 50, the suction head 20, and the camera 30 are controlled by a control unit, not shown. The control unit may also serve as a control device of the apparatus 2, or may perform image processing of an image obtained by the camera 30 and negative pressure control of the suction holes 11, 12, and 14, which will be described later. The control unit may be a dedicated control circuit or may be constituted by a general-purpose computer having a control program.

In the drawing, the X axis, the Y axis, and the Z axis are substantially perpendicular to each other, the Z axis coincides with the height direction of the device 2, the X axis coincides with the longitudinal direction of the electronic control board 4 or the flexible board 6, and the Y axis coincides with the width direction of the electronic control board 4 or the flexible board 6. The X axis and the Y axis are substantially parallel to the display surface of the electronic control board 4.

At least a lower side surface 10a on which the electronic control board 4 is provided, a higher side surface 10b located at a higher position than the lower side surface 10a by a predetermined step height Z1, and a step wall surface 10c located at a boundary between the lower side surface 10a and the higher side surface 10b are formed on the Z-axis upper surface of the mounting table 10. The low-level side surface 10a and the high-level side surface 10b are substantially parallel to the X-Y axis plane, and the step wall surface 10c is substantially parallel to the Z-Y axis plane, respectively.

A bonding position 10a1 where the electronic control substrate 4 is disposed, and a standby position 10a2 where the flexible substrate 6 is temporarily disposed away in the X-axis direction (or the Y-axis direction) from the bonding position 10a1 are formed on the lower side surface 10 a. A plurality of first suction holes 12 formed in the mounting table 10 are opened in the lower side surface 10a located at the joining position 10a 1. Further, a plurality of standby suction holes 11 formed in the mounting table 10 are opened in the lower side surface 10a located at the standby position 10a 2.

By applying a negative pressure to the first suction holes 12, the electronic control board 4 placed at the joining position 10a1 can be detachably sucked at the joining position 10a1 and temporarily fixed to the lower side surface 10 a. At the bonding position 10a1, the electronic control board 4 is disposed such that the portion to be connected of the wiring pattern 4a formed on the board 4 faces upward in the Z-axis direction and the end portion of the wiring pattern 4a of the board 4 on the side to be connected touches (contacts) the step wall surface 10 c. As means for disposing the electronic control board 4 at the predetermined position on the lower surface 10a at the bonding position 10a1, for example, the suction head 20 shown in fig. 1 may be used, or a suction head different from this may be used.

by applying a negative pressure to the standby suction hole 11, the flexible substrate 6 placed at the standby position 10a2 can be detachably sucked at the standby position 10a2 and temporarily fixed to the lower surface 10 a. In the standby position 10a2, the flexible substrate 6 is disposed such that the portion to be connected of the wiring pattern 6a formed on the substrate 6 faces downward in the Z-axis direction and the end portion of the substrate 6 on the side to be connected of the wiring pattern 6a faces the opposite side in the X-axis direction opposite to the electronic control substrate 4. As means for disposing the flexible substrate 6 at the predetermined position on the lower surface 10a at the standby position 10a2, for example, the suction head 20 shown in fig. 1 is used.

In the present embodiment, the step height Z1 of the step wall surface 10c is equal to or smaller than the thickness t0 of the electronic control board 4, and the difference (t0-Z1) is preferably 0 to 20 μm, and more preferably 10 to 20 μm.

a plurality of second suction holes 14 formed in the mounting table 10 are opened in the vicinity of the step wall surface 10c in the high-level side surface 10b of the mounting table 10. As shown in fig. 4, when a negative pressure is applied to the second suction hole 14, the flexible substrate 6 placed on the high-position side surface 10b can be detachably sucked in the vicinity of the step wall surface 10c and temporarily fixed to the high-position side surface 10 b. As a means for disposing the flexible substrate 6 on the high-level side surface 10a in the vicinity of the step wall surface 10c, for example, the suction head 20 is used.

Next, an ultrasonic bonding method using the ultrasonic bonding apparatus 2 shown in fig. 1 will be described. As shown in fig. 2, first, the negative pressure in the standby suction hole 11 opened (side port) in the lower side surface 10a of the standby position 10a2 is released, and the flexible substrate 6 located in the standby position 10a2 is lifted up to the upper portion in the Z-axis direction by the suction head 20. The suction head 20 has a mechanism for holding the substrate 6 by suction on the head lower surface, for example, by suction force.

thereafter, as shown in fig. 3, the suction head 20 is moved in the X-axis direction together with the substrate 6 with respect to the mounting table 10. Further, the mounting table 10 may be moved in the X-axis direction. The suction head 20 is relatively moved in the X-axis direction with respect to the mounting table 10 so that the substrate 6 held by the suction head 20 is positioned on the high-level side surface 10b in the vicinity of the step wall surface 10 c. The movement of which is controlled by a control unit.

the camera 30 is inserted between the wiring pattern 4a and the wiring pattern 6a so that the portions to be connected of the wiring pattern 6a of the substrate 6 and the portions to be connected of the wiring pattern 4a of the substrate 4 are accurately aligned, and the positional relationship between the wiring patterns 4a and 6a is captured, and image processing thereof is performed in the control unit. Based on the image processing result, the control unit relatively moves the suction head 20 in the X-axis and Y-axis directions with respect to the stage 10 so that the portions to be connected to the wiring pattern 6a of the substrate 6 and the portions to be connected to the wiring pattern 4a of the substrate 4 are accurately aligned. Further, the control unit may control the moving mechanism to rotationally move the suction head 20 with respect to the mounting table 10 around the axis of the suction head, as necessary.

Next, the camera 30 moves in the X-axis direction from between the substrate 6 and the mounting table 10, and is retracted to a position where the movement of the suction head 20 in the Z-axis direction is not hindered. Thereafter, as shown in fig. 4, the suction head 20 approaches the high-position side surface 10b of the mounting table 10, and the suction holding of the substrate 6 is released, and the substrate 6 is mounted on the high-position side surface 10 b. At the same time, a negative pressure acts on the second suction hole 14, and the substrate 6 is sucked and held on the high-position side surface 10 b. In this state, the lower surface of the end portion of the substrate 6 in the X axis direction and the upper surface of the end portion of the substrate 4 in the X axis direction overlap each other, and a stacked portion is formed at a position corresponding to the step wall surface 10 c. In the laminated portion, the portions to be bonded of the wiring patterns 4a and the portions to be bonded of the wiring patterns 6a are opposed to each other.

Next, as shown in fig. 5A, the mounting table 10 is moved relative to the suction head 20 and the camera 30 in the X-axis direction, and the pressing portion 50a of the ultrasonic horn 50 is positioned directly above the Z-axis direction of the laminated portion between the wiring patterns 6a and 4 a. The relative movement of the mounting table 10 and the ultrasonic horn 50 in the X axis direction is controlled in advance so that the pressing portion 50a of the ultrasonic horn 50 is positioned on the lower side surface 10a within a predetermined range X3 in the X axis direction with respect to the step wall surface 10c of the mounting table 10.

That is, the moving mechanism is controlled by the control unit such that the pressing portion 50a of the ultrasonic horn 50 presses the stacked portion located on the lower side surface 10a within a predetermined range x3 from the step wall surface 10 c. The predetermined range X3 is preferably larger than 0 and smaller than the X-axis direction length X1 of the stacked portion. That is, the pressing portion 50a is controlled so as not to press the surface of the substrate 6 located on the high-side surface 10 b.

The length X1 in the X-axis direction of the laminated part is also required to be as small as possible, for example, 0.5mm or less, preferably 0.2mm or less, in accordance with the overlapping length of the portions to be connected of the wiring patterns 4a and 6 a. The length X2 in the X-axis direction of the pressing portion 50a pressing the overlapping portion (laminated portion) of the substrate 4 and the substrate 6 is preferably equal to or greater than the length X1 in the X-axis direction of the laminated portion, and the difference in length (X2-X1) is preferably 0.5mm or more, and more preferably 0.01 to 0.08 mm.

Next, as shown in fig. 5A to 5B, the ultrasonic horn 50 is relatively moved downward in the Z-axis direction with respect to the mounting table 10, the pressing portion 50a of the ultrasonic horn 50 is pressed against the laminated portion of the substrate 4 and the substrate 6, and a pressing force in the Z-axis direction and an ultrasonic vibration in the X-axis direction are applied to the laminated portion. As a result, the metals of the wiring patterns 4a and 6a of the laminated portion, which are arranged at a predetermined pitch interval in the Y-axis direction and are long in the X-axis direction, are solid-phase bonded by ultrasonic waves.

The metal constituting the wiring patterns 4a and 6a is not particularly limited as long as it is a metal (including an alloy) capable of ultrasonic bonding, and silver, gold, aluminum, an alloy containing these as a main component, or the like is exemplified. On the surface of these metals (particularly, on the surface of aluminum), an oxidation-resistant film containing titanium or the like as a main component is formed.

In the method of manufacturing the substrate assembly 8 according to the present embodiment (including the ultrasonic bonding method), since the step wall surface 10c is provided on the surface of the mounting table 10, the electronic control substrate 4 and the flexible substrate 6 can be easily aligned by the step wall surface 10c, and the wiring patterns 4a and 6a can be ultrasonically bonded to each other. Therefore, for example, even when the wiring interval (the interval of the line ピ ッ チ) in the Y axis direction is narrowed to a level of several tens μm or less, short-circuit failure or the like does not occur, and the electronic control board 4 and the flexible board 6 can be easily electrically connected to each other. It is preferable that the ultrasonic wave is oscillated in a direction along the longitudinal direction between the bonded wiring patterns 4a and 6a, not in the lamination direction (Z-axis direction) of the lamination portion.

Further, recently, a wide display close to the outer size of the housing of the device is required, such as a display of a smartphone or the like, and therefore, the bonding length x1 between the wiring patterns 4a and 6a has to be shortened, which causes a problem in connection reliability. According to the method of the present embodiment, solid-phase bonding between metals can be performed by ultrasonic bonding, and the reliability of connection is also improved.

In the method of manufacturing the substrate assembly according to the present embodiment, since the step wall surface 10c is provided on the surface of the mounting table 10, the wiring patterns can be reliably ultrasonically bonded to each other even when the width of the laminated portion of the electronic control substrate 4 and the flexible substrate 6 in the Y-axis direction is, for example, 60mm or more.

in the present embodiment, the control means controls the moving mechanism so that the pressing portion 50a of the ultrasonic horn 50 presses the lamination portion positioned on the lower side surface 10a within a predetermined range from the step wall surface 10 c. The pressing portion 50a of the ultrasonic horn 50 preferably presses only the lamination portion without pressing the flexible substrate 6 positioned on the high-position side surface 10b, and preferably performs ultrasonic bonding. With this configuration, the reliability of the ultrasonic bonding between the wiring patterns 4a and 6a is further improved without causing disconnection of the wiring patterns.

The present invention is not limited to the above-described embodiments, and various changes can be made within the scope of the present invention.

for example, the electronic control board 4 may be not only a rigid board including a glass board but also a flexible board having flexibility.

in the above embodiment, the flexible substrate 6 is used as the second planar member, but is not particularly limited.