JP2010226020A - Device mounting method, droplet discharge head, and droplet discharge apparatus - Google Patents

Abstract

An anisotropic conductive paste is used to OLB-connect both substrates while concentrating conductive particles contributing to conduction in a pressure region between a device substrate and a connected substrate.
Using an anisotropic conductive paste W, a device substrate 21 on which a first wiring connection portion 61 is formed is mounted on a connected substrate 23 on which a second wiring connection portion 40 is formed. A method of electrically connecting the connecting portions, wherein the paste is applied to either the terminal portion 62a of the first wiring connecting portion or the terminal portion 40a of the second wiring connecting portion, and both terminal portions face each other. A step of positioning the device substrate on the substrate to be connected, and a step of pressing the device substrate against the substrate to be connected by the bonding tool 70 and electrically connecting both terminal portions via paste. Provided is a device mounting method in which a paste is applied so that a center N of a bonding tool rises after application and is spaced a certain distance H from the center axis C of the bonding tool during the process.
[Selection] Figure 8

Description

  The present invention relates to a device mounting method, a droplet discharge head, and a droplet discharge apparatus.

  A droplet discharge method (inkjet method) has been proposed as one method for manufacturing a microdevice. This droplet discharge method is a method in which a functional liquid containing a material for forming a device is formed into droplets and discharged from a droplet discharge head. Patent Document 1 discloses an example of a technique related to a droplet discharge head, and a technique for electrically connecting a terminal provided on an upper surface of a semiconductor chip and a terminal on a circuit board using wire bonding. Are listed. Patent Document 2 describes a droplet discharge head in which a driving element (piezoelectric element) is connected to a driving device (driver IC) by wire bonding.

  Particularly in recent years, when manufacturing microdevices based on the droplet discharge method, in order to meet the demand for further miniaturization of microdevices, outer leads are used by using a flexible substrate in which a wiring pattern that functions as outer leads is formed in advance. By performing bonding (OLB: Outer Lead Bonding) connection, it is considered to perform electrical connection between the drive element and the drive device without causing inconvenience such as short circuit between wires (Patent Literature). 3).

In general, in the case of OLB connection, an anisotropic conductive adhesive is often used to connect a flexible substrate and a connected substrate. In this method, after an anisotropic conductive adhesive is disposed between the flexible substrate and the connected substrate, the connection is performed by pressing the flexible substrate to the connected substrate while heating the adhesive.
In particular, this anisotropic conductive adhesive is suitable for OLB connection because it can easily form anisotropy between conductivity and insulation depending on the condition of the conductive particles mixed with the thermosetting resin. .

JP 2002-9235 A JP 2003-159800 A JP 2000-68989 A

  By the way, when using the anisotropic conductive adhesive, as described above, in order to achieve both conductivity and insulation, it is important to collect the conductive particles in a portion that efficiently contributes to conduction. However, when anisotropic conductive paste (ACP: Anisotropic Conductive Paste) is used as the anisotropic conductive adhesive, conductive particles that contribute to conduction are applied to the pressurization region between the flexible substrate and the connected substrate ( It was difficult to concentrate on the connection area.

More specifically, in the case of an anisotropic conductive paste, since the binder is in the form of a paste, the distribution of the conductive particles is likely to be in a non-uniform state already when applied on the substrate to be connected. This point will be described with reference to FIGS.
FIG. 11 is a view showing a state immediately before the flexible substrate 110 having the wiring pattern 111 is pressed by the bonding tool 120 after the anisotropic conductive paste W is applied on the wiring pattern 101 of the connected substrate 100. FIG. 12 is a view showing a state in which the flexible substrate 110 is pressed with the bonding tool 120 and the substrates 100 and 110 are OLB-connected using the anisotropic conductive paste W.

  As shown in FIG. 11, since the anisotropic conductive paste W has a paste-like binder, the shape after application becomes a semispherical cross-section like a candy. Therefore, there are many conductive particles R on the center line penetrating the application center (the center of the highest vertex rising after application) N of the anisotropic conductive paste W, and the number of the conductive particles R decreases toward the outer edge.

  Then, after the anisotropic conductive paste W is applied, the flexible substrate 110 is bonded (heated) by using the tool 120 while aligning the center axis C of the bonding tool 120 with the application center N of the anisotropic conductive paste W. Pressure). As a result, as shown in FIG. 12, the anisotropic conductive paste W spreads while flowing left and right between the flexible substrate 110 and the connected substrate 100 and then hardens. As a result, the flexible substrate 110 and the substrate to be connected 100 can be OLB-connected using the anisotropic conductive paste W.

  By the way, the main conductive particles R that contribute to the electrical connection are particles that exist in the pressurization region pressurized by the bonding tool 120, and the conductive particles R distributed around the conductive particles R do not contribute to the connection. . Therefore, it is necessary to efficiently capture (leave) the conductive particles R in the pressurized region. However, since bonding is performed in a state where the center axis C of the bonding tool 120 is aligned with the application center N of the anisotropic conductive paste W, the anisotropic conductive paste W present in a large amount on the center line passing through the application center N. Flows left and right and escapes. For this reason, the conductive particles R also flowed to the left and right in the same manner, and easily escaped from the pressure region. As a result, it has been difficult to concentrate the conductive particles R contributing to conduction in the pressure region between the flexible substrate 110 and the connected substrate 100.

  In particular, the height when the anisotropic conductive paste W is applied is about 100 to 500 μm, but the thickness after bonding (distance between both substrates) is about 1/10, which is about 10 to 50 μm. Therefore, the anisotropic conductive paste W present on the center line is crushed excessively and easily moves to the outside from the pressure region, and the above-described disadvantages are likely to occur.

The present invention has been made in view of such circumstances, and its main purpose is to use anisotropic conductive paste to transfer conductive particles contributing to conduction between the device substrate and the connected substrate. It is an object to provide a device mounting method capable of OLB connection of both substrates while being concentrated in a pressurizing region.
Another object is to provide a droplet discharge head and a droplet discharge apparatus having a device substrate and a connected substrate mounted by this method.

In addition, in order to leave conductive particles in the pressurized region as much as possible, if the ratio of the conductive particles contained in the anisotropic conductive paste is increased, the insulation performance will deteriorate, so it is desirable to maintain the insulation properties. It was inconvenient for the area. Further, when the amount of the anisotropic conductive paste applied itself is reduced, the anisotropic conductive paste may not be sufficiently filled between the flexible substrate and the connected substrate.
Therefore, it is desired to achieve the above-mentioned object without changing the amount of anisotropic conductive paste applied and the ratio of conductive particles.

The present invention provides the following means in order to solve the above problems.
(1) A device mounting method according to the present invention uses an anisotropic conductive paste to mount a device substrate on which a first wiring connection portion is formed on a connected substrate on which a second wiring connection portion is formed. A device mounting method for electrically connecting both wiring connecting portions, wherein the anisotropic conductive paste is applied to either the terminal portion of the first wiring connecting portion or the terminal portion of the second wiring connecting portion. On the substrate to be connected, the terminal part of the first wiring connection part and the terminal part of the second wiring connection part are opposed to each other with the application process and the applied anisotropic conductive paste interposed therebetween. A setting step of positioning the device substrate; heating the anisotropic conductive paste and pressing the device substrate against the connected substrate with a bonding tool; and pressing the terminal portion of the first wiring connection portion and the Second wiring connection A bonding step for electrically connecting the terminal portion of the portion via an anisotropic conductive paste, and the center of the highest vertex that rises after coating is spaced from the central axis of the bonding tool by a certain distance during the coating step. Thus, an anisotropic conductive paste is applied.

In the device mounting method according to the present invention, first, conductive particles are applied to the terminal portion of the first wiring connecting portion formed on the device substrate or the terminal portion of the second wiring connecting portion formed on the connected substrate. An application step of applying a predetermined amount of the included anisotropic conductive paste is performed. At this time, the anisotropic conductive paste is applied so that the center of the highest peak (coating center) that rises after application is spaced from the central axis of the bonding tool applied to a predetermined position on the device substrate in the subsequent bonding process. .
Next, the device substrate is positioned on the connected substrate so that the terminal portion of the first wiring connection portion and the terminal portion of the second wiring connection portion face each other with the applied anisotropic conductive paste interposed therebetween. Perform the process.

Next, a bonding process is performed in which the device substrate is mounted on the substrate to be connected using a bonding tool, and the first wiring connection and the second wiring connection portion are electrically connected.
First, after applying the bonding tool to a predetermined position of the device substrate, the anisotropic conductive paste is heated and the device substrate is pressed against the connected substrate while being pressed by the bonding tool. Then, the anisotropic conductive paste is crushed and spread while flowing between the device substrate and the connected substrate, and then cured. At this time, since the conductive particles contained in the anisotropic conductive paste come into contact with each other between the terminal part of the first wiring connection part and the terminal part of the second wiring connection part, both wiring connection parts are made conductive. As a result, the first wiring connection portion and the second wiring connection portion can be electrically connected.

  In particular, the anisotropic conductive paste is applied such that the center of the highest vertex is shifted laterally from the central axis of the bonding tool during the application process. Therefore, the region where the most conductive particles are present is shifted laterally from the central axis of the bonding tool. Therefore, when the anisotropic conductive paste is crushed between both substrates during the bonding process, a part of the region where the most conductive particles exist flows toward the central axis of the bonding tool. Therefore, unlike the prior art, as many conductive particles as possible can be concentrated (exist) in the pressurizing region pressed by the bonding tool. That is, as many conductive particles that contribute to conduction can be kept in the pressure region, that is, the connection region.

  Therefore, the OLB connection between the two substrates can be performed with much higher conductivity than in the past, and the connection reliability can be improved. Moreover, without changing the amount of anisotropic conductive paste and the ratio of conductive particles contained in the anisotropic conductive paste, it is possible to increase only the number of conductive particles that contribute to conduction, thereby improving conductivity. Can do.

(2) The device mounting method according to the present invention is the device mounting method according to the present invention, wherein a flow regulating portion that causes the anisotropic conductive paste to flow toward the central axis during the bonding step is provided on the connected substrate. It is characterized by being formed in advance.

  In the device mounting method according to the present invention, when the anisotropic conductive paste is crushed between the device substrate and the connected substrate during the bonding step, the anisotropic conductive paste is entirely center axis by the flow restricting portion. It flows toward. Accordingly, almost the entire region where the most conductive particles are present flows toward the central axis of the bonding tool. Therefore, a larger number of conductive particles can be intensively left in the pressurization region pressed by the bonding tool. Therefore, the continuity can be further improved and the connection reliability can be further improved.

(3) The liquid droplet ejection head according to the present invention includes the device substrate and the connected substrate obtained by the device mounting method of the present invention, and the electrical connection to the first wiring connection portion. A driving device mounted on the device substrate; a driving element mounted on the connected substrate in a state of being electrically connected to the second wiring connection portion; and displacing the substrate during operation; and a lower surface of the connected substrate Displacement of the connected substrate, which is disposed on the side and bonded to both substrates in a state of being sandwiched between the nozzle substrate and the connected substrate, in which a nozzle opening for discharging droplets is formed And a flow path forming substrate for forming a pressure generating chamber for generating a pressure for discharging the droplet between the two substrates.

In the droplet discharge head according to the present invention, the drive device mounted on the device substrate and the drive element mounted on the connected substrate are electrically connected by the connection of the first wiring connection portion and the second wiring connection portion. It is connected. When the drive element is activated based on an instruction from the drive device, the connected substrate is displaced. As a result, a pressure is generated for discharging the droplets into the pressure generating chamber. Thereby, a droplet can be discharged from a nozzle opening.
In particular, since the device substrate and the connected substrate having high conductivity and improved connection reliability are provided, a high-quality droplet discharge head with high operation reliability can be obtained.

(4) A droplet discharge apparatus according to the present invention includes the droplet discharge head according to the present invention.

  Since the droplet discharge device according to the present invention includes the droplet discharge head having high operation reliability and high quality, the operation reliability can be similarly improved and the quality can be improved.

According to the device mounting method of the present invention, the anisotropic conductive paste is used to concentrate both conductive particles contributing to conduction in the pressure region between the device substrate and the connected substrate while concentrating on both substrates. Can be OLB connected, and the continuity can be improved to improve the connection reliability.
Further, according to the droplet discharge head and the droplet discharge device according to the present invention, it is possible to improve the reliability of the operation and improve the quality.

1 is an external perspective view showing an embodiment of a droplet discharge head according to the present invention. It is a disassembled perspective view of the droplet discharge head shown in FIG. FIG. 2 is a partially cutaway perspective view of the droplet discharge head shown in FIG. 1 as viewed from the nozzle opening side. It is a cross-sectional arrow AA figure shown in FIG. FIG. 5 is an enlarged cross-sectional view of a portion where the flexible substrate and the diaphragm shown in FIG. 4 are OLB-connected. It is a top view of a flexible substrate. 3 is a flowchart for manufacturing the droplet discharge head shown in FIG. 1. FIG. 2 is a process diagram when manufacturing the droplet discharge head shown in FIG. 1, just after applying an anisotropic conductive paste on a terminal portion of a lead electrode of a diaphragm and immediately before pressing a flexible substrate with a bonding tool. It is a figure which shows a state. It is a perspective view showing one embodiment of a droplet discharge device concerning the present invention. FIG. 9 is a process diagram when manufacturing the droplet discharge head shown in FIG. 1, and shows a state where an anisotropic conductive paste is applied to a position different from FIG. 8. It is a figure which shows the conventional OLB connection, Comprising: After apply | coating anisotropic conductive paste on a to-be-connected board | substrate, it is a figure which shows the state just before pressurizing a device board | substrate with a bonding tool. It is a figure which shows the state which carried out OLB connection of both board | substrates with the anisotropic conductive paste after the state shown in FIG.

(Droplet ejection head)
Hereinafter, an embodiment of a droplet discharge head according to the present invention will be described with reference to FIGS. In the present embodiment, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. At this time, the transverse direction of the droplet discharge head (arrangement direction of the nozzles) is the X-axis direction, the longitudinal direction of the droplet discharge head (direction perpendicular to the X-axis direction) is the Y-axis direction, and the thickness of the droplet discharge head A direction (that is, a direction orthogonal to each of the X-axis direction and the Y-axis direction) is defined as a Z-axis direction.

  As shown in FIGS. 1 and 2, the droplet discharge head 1 of the present embodiment is mounted with a flexible substrate (device substrate) 21 on which a driver IC (drive device) 20 is mounted and a piezoelectric element (drive element) 22. A vibration plate (connected substrate) 23 that is displaced when the piezoelectric element 22 is operated, a reservoir forming substrate 24 bonded to the upper surface of the vibration plate 23, and a case member bonded to the upper surface of the reservoir forming substrate 24. 25 and a nozzle substrate 27 disposed on the lower surface side of the vibration plate 23 and formed with a nozzle opening 26 for discharging droplets, and bonded between the nozzle substrate 27 and the vibration plate 23. The main body 1A provided with the flow path forming substrate 28 is mainly configured.

  FIG. 1 is an external perspective view showing the droplet discharge head 1, and FIG. 2 is an exploded perspective view of the droplet discharge head 1. In this embodiment, the case where the droplet discharge head 1 is configured by one substrate 1A will be described as an example. However, the droplet discharge head may be configured by unitizing a plurality of substrates 1A. Absent.

Hereinafter, each of the above-described components will be described in detail.
First, the case member 25 is formed of a metal material such as stainless steel, and is used as an attachment member when the droplet discharge head 1 is mounted on, for example, a droplet discharge device.
The nozzle substrate 27 is a substrate made of, for example, stainless steel or glass ceramics. As shown in FIG. 3, the nozzle substrate 27 is a through-hole penetrating the substrate 27 and has a plurality of nozzle openings 26 for discharging functional liquid droplets. Is formed. FIG. 3 is a partially cutaway perspective view of the droplet discharge head 1 as viewed from the nozzle opening 26 side.

At this time, the first to fourth nozzle opening groups 26 </ b> A to 26 </ b> D are configured by a plurality of nozzle openings 26 formed side by side in the Y-axis direction.
The first nozzle opening group 26A and the second nozzle opening group 26B are arranged to face each other in the X axis direction, and the third nozzle opening group 26C and the fourth nozzle opening group 26D are arranged to face each other in the X axis direction. The third nozzle opening group 26C is formed so as to be adjacent to the first nozzle opening group 26A in the Y-axis direction, and the fourth nozzle opening group 26D is adjacent to the second nozzle opening group 26B in the Y-axis direction. It is formed to fit.

  In FIG. 3, the first to fourth nozzle opening groups 26 </ b> A to 26 </ b> D are illustrated as being configured by six nozzle openings 26, but actually, for example, about 720 nozzle openings 26. Is formed.

The flow path forming substrate 28 is a substrate formed of, for example, a rigid silicon single crystal, and a plurality of partition walls 30 anisotropically etch the silicon single crystal substrate that is the base material of the flow path forming substrate 28. Is formed.
The above-described nozzle substrate 27 is fixed to the lower surface of the flow path forming substrate 28 via, for example, an adhesive or a heat welding film. Similarly, the vibration plate 23 is fixed to the upper surface of the flow path forming substrate 28 via, for example, an adhesive or a heat welding film.

  In addition, in the space surrounded by the flow path forming substrate 28, the nozzle substrate 27, and the vibration plate 23, the functional liquid discharged from the nozzle opening 26 is arranged, and the liquid droplet of the functional liquid is generated as the vibration plate 23 is displaced. The pressure generating chamber 31 generates a pressure for discharging the water. A plurality of pressure generating chambers 31 are formed side by side in the Y-axis direction so as to correspond to the plurality of nozzle openings 26 constituting each of the first to fourth nozzle opening groups 26A to 26D.

The first pressure generating chamber group 31A is configured by the plurality of pressure generating chambers 31 formed corresponding to the first nozzle opening group 26A. Similarly, a second pressure generation chamber group 31B is configured by a plurality of pressure generation chambers 31 corresponding to the second nozzle opening group 26BD, and a third pressure generation is performed by the plurality of pressure generation chambers 31 corresponding to the third nozzle opening group 26C. The chamber group 31C is configured, and the fourth pressure generating chamber group 31D is configured by the plurality of pressure generating chambers 31 corresponding to the fourth nozzle opening group 26D.
The first pressure generation chamber group 31A and the second pressure generation chamber group 31B are arranged so as to face each other in the X-axis direction, and the third pressure generation chamber group 31C and the fourth pressure generation chamber group 31D are X-axis. It arrange | positions so that it may mutually oppose regarding a direction.

As shown in FIG. 4, one end of the plurality of pressure generating chambers 31 constituting the first pressure generating chamber group 31A communicates with each other by a communicating portion 35b via a supply path 35a constituting a part of the reservoir 35. Has been. FIG. 4 is a cross-sectional view taken along line AA shown in FIG.
The communication portion 35b is a through hole formed in the flow path forming substrate 28, and is connected to a reservoir portion 35c described later. Similarly, the end portions of the pressure generation chambers 31 constituting the second to fourth pressure generation chamber groups 31B to 31D are also connected to each other by the communication portion 35b via the supply path 35a.

The vibration plate 23 disposed between the flow path forming substrate 28 and the reservoir forming substrate 24 is provided on the upper surface of the elastic film 23a and an elastic film 23a provided to cover the upper surface of the flow path forming substrate 28. And a lower electrode film 23b.
The elastic film 23a is made of, for example, silicon dioxide having a thickness of about 1 to 2 μm, and the lower electrode film 23b is made of, for example, platinum having a thickness of about 0.2 μm. In the present embodiment, the lower electrode film 23 b is an electrode common to the plurality of piezoelectric elements 22.

  Incidentally, as shown in FIGS. 4 and 5, lead electrodes (second wiring connecting portions) 40 are formed on the upper surface of the diaphragm 23, specifically, the upper surface of the lower electrode film 23 b. 5 is an enlarged cross-sectional view of a portion where the flexible substrate 21 and the diaphragm 23 shown in FIG. 4 are OLB-connected. The lead electrode 40 is an electrode that is electrically connected to the piezoelectric element 22 and is connected to a wiring pattern 61 (first wiring connecting portion) to be described later of the flexible substrate 21 via an anisotropic conductive paste W. Electrically connected. In the present embodiment, the lead electrode 40 also functions as an electrode constituting the piezoelectric element 22.

The piezoelectric element 22 for displacing the diaphragm 23 includes a piezoelectric film 22a provided on the upper surface of the lower electrode film 23b, an upper electrode film 22b provided on the upper surface of the piezoelectric film 22a, and the upper electrode film. The lead electrode 40 is a lead wire 22b.
The piezoelectric film 22a is made of, for example, a metal oxide having a thickness of about 1 μm. The upper electrode film 22b is made of, for example, platinum having a thickness of about 0.1 μm. The lead electrode 40 is made of, for example, gold having a thickness of about 0.1 μm. An insulating film (not shown) is provided between the lead electrode 40 and the lower electrode film 23b.

  A plurality of piezoelectric elements 22 are provided so as to correspond to each of the plurality of nozzle openings 26 and the pressure generation chamber 31. That is, the piezoelectric element 22 is provided for each nozzle opening 26 (for each pressure generation chamber 31). As described above, the lower electrode film 23 b functions as a common electrode for the plurality of piezoelectric elements 22, and the upper electrode film 22 b and the lead electrode 40 function as individual electrodes for the plurality of piezoelectric elements 22.

In addition, a first piezoelectric element group 22A is formed by a plurality of piezoelectric elements 22 provided side by side in the Y-axis direction so as to correspond to each nozzle opening 26 constituting the first nozzle opening group 26A. Similarly, a second piezoelectric element group 22B corresponding to the second nozzle opening group 26B is formed, a third piezoelectric element group (not shown) corresponding to the third nozzle opening group 26C is formed, and a fourth nozzle opening group 26D. Corresponding to the fourth piezoelectric element group (not shown).
The first piezoelectric element group 22A and the second piezoelectric element group 22B are arranged so as to face each other in the X-axis direction. Further, the third piezoelectric element group and the fourth piezoelectric element group are arranged so as to face each other in the X-axis direction.

  The reservoir forming substrate 24 is, for example, a substrate formed by etching a silicon single crystal that is the same material as the flow path forming substrate 28. The reservoir forming substrate 24 is in a state where an insulating film is formed on the surface by, for example, thermal oxidation. The reservoir forming substrate 24 is preferably formed of a material having a thermal expansion coefficient substantially the same as the thermal expansion coefficient of the flow path forming substrate 28. For example, glass or a ceramic material may be used.

  As shown in FIG. 4, reservoir portions 35c corresponding to the respective communication portions 35b are formed on the reservoir forming substrate 24 so as to extend in the Y-axis direction. The reservoir 35 is configured by the reservoir 35c, the communication portion 35b, and the supply path 35a described above. In addition, the reservoir forming substrate 24 is formed with an introduction path 41 that is connected to the side wall of each communication portion 35b and introduces the functional liquid into each communication portion 35b.

A compliance substrate 42 is bonded to the upper surface of the reservoir forming substrate 24. The compliance substrate 42 includes a sealing film 43 and a fixing plate 44.
The sealing film 43 is formed of a material having low rigidity and flexibility, such as a polyphenylene sulfide film having a thickness of about 6 μm. The upper portion of the reservoir portion 35 c is sealed with the sealing film 43.

  The fixing plate 44 is made of a hard material such as a metal such as stainless steel having a thickness of about 30 μm. A region of the fixing plate 44 corresponding to the reservoir portion 35c is an opening 44a that is completely removed in the thickness direction. Therefore, the upper portion of the reservoir portion 35c is sealed only by the flexible sealing film 43. Thereby, it functions as a flexible portion 43a that can be deformed by a change in internal pressure. A case member 25 is provided on the compliance substrate 42.

  Further, the compliance substrate 42 and the case member 25 outside the reservoir portion 35c are formed with a functional liquid introduction port 45 that communicates with the introduction path 41 and supplies the functional liquid to the reservoir portion 35c. Normally, when the functional liquid is supplied from the functional liquid introduction port 45 to the reservoir section 35c, a pressure change occurs in the reservoir section 35c due to, for example, the flow of the functional liquid at the time of driving the piezoelectric element 22 or ambient heat. However, as described above, since the upper portion of the reservoir portion 35c is the flexible portion 43a sealed only by the sealing film 43, the flexible portion 43a is bent and deformed to absorb the pressure change. Therefore, the inside of the reservoir portion 35c is held at a constant pressure. The other portions are held at a sufficient strength by the fixing plate 44. The case member 25 is provided in a non-contact state with the flexible portion 43a so as not to impair the deformation state of the flexible portion 43a.

Two groove-shaped openings 46 extending in the Y-axis direction are formed in the central portion of the reservoir forming substrate 24 in the X-axis direction, as shown in FIG. Further, as shown in FIG. 4, in the region outside the X-axis direction in the opening 46, the first and second piezoelectric elements that seal the first to fourth piezoelectric element groups between the first piezoelectric element group 22 </ b> A and the diaphragm 23. Sealing portions 50A and 50B and third and fourth sealing portions are formed.
More specifically, the first sealing portion 50A seals the first piezoelectric element group 22A corresponding to the first pressure generating chamber group 31A with the diaphragm 23, and the second sealing portion 50B is the second piezoelectric member. The element group 22B is sealed. Although the third sealing portion and the fourth sealing portion are not shown in FIG. 4, they seal the third and fourth piezoelectric element groups.

  In the reservoir forming substrate 24, a space that does not hinder the movement of the piezoelectric element 22 is secured in a region facing the piezoelectric element 22, and a piezoelectric element holding portion 51 that can seal this space is formed. . The piezoelectric element holding portion 51 is formed in each of the first and second sealing portions 50A and 50B and the third and fourth sealing portions, and the first piezoelectric element group 22A to the fourth piezoelectric element group. It is formed with the size which covers. Of the piezoelectric elements 22, at least the piezoelectric film 22 a is sealed in the piezoelectric element holding portion 51.

As described above, the reservoir forming substrate 24 functions as a sealing member for blocking the piezoelectric element 22 from the external environment and sealing the piezoelectric element 22. By sealing the piezoelectric element 22 with the reservoir forming substrate 24, it is possible to prevent the piezoelectric element 22 from being damaged by an external environment such as moisture.
In the present embodiment, the inside of the piezoelectric element holding part 51 is only sealed, but for example, the space in the piezoelectric element holding part 51 is maintained in a vacuum, nitrogen or argon atmosphere, etc. The inside of the part 51 can be kept at a low humidity, and the destruction of the piezoelectric element 22 can be more reliably prevented.

  By the way, the inner peripheral wall 24a of the opening 46 of the reservoir forming substrate 24 is bonded to the anisotropic conductive paste W, which will be described later, when the flexible substrate 21 is mounted on the diaphragm 23 using the anisotropic conductive paste W. It functions as a flow restricting portion that flows toward the central axis C of the tool 70. This point will be described in detail later.

Of the piezoelectric elements 22 sealed by the piezoelectric element holding part 51 of the first sealing part 50A, one end of the lead electrode 40 is a terminal part connected to the terminal part 62a on the flexible substrate 21 side. This is a portion that functions as 40 a, extends to the outside of the first sealing portion 50 A, and is disposed on the flow path forming substrate 28 exposed by the opening 46.
Similarly, in the piezoelectric element 22 sealed by the piezoelectric element holding part 51 of the second sealing part 50B, one end part of the lead electrode 40 is on the flexible substrate 21 side as shown in FIGS. It is a part that functions as the terminal part 40 a connected to the terminal part 62 a, extends to the outside of the second sealing part 50 B, and is disposed on the flow path forming substrate 28 exposed by the opening 46.
The same applies to the piezoelectric element 22 sealed by the piezoelectric element holding part 51 of the third and fourth sealing parts.

  As shown in FIGS. 1 and 2, an opening 55 formed along the Y-axis direction is formed at the center of the case member 25 in the X-axis direction. The opening 55 is sized to include at least the opening region of the opening 46 formed in the reservoir forming substrate 24, and the holding region 56 of the driver IC 20 is formed in a notch shape.

  The driver IC 20 is a driver IC having, for example, a semiconductor integrated circuit (IC) including a circuit board and a driving circuit, and four driver ICs 20 are provided according to the first to fourth nozzle opening groups 26A to 26D. Each driver IC 20 is flip-chip mounted on a predetermined region (mounting region) on one surface of each of the four flexible substrates 21A to 21D. At this time, a resin (adhesive) W1 for increasing the connection strength is provided between the driver IC 20 and the flexible substrate 21 as shown in FIG.

As shown in FIGS. 1 and 5, the driver IC 20 is molded with a heat-dissipating resin W <b> 2 on the side wall surface 56 a of the holding region 56 of the opening 55 formed in the case member 25. Accordingly, the driver IC 20 is held on the side wall surface 56 a of the holding region 56 of the case member 25 in a state perpendicular to the surface direction (XY plane) of the reservoir forming substrate 24.
In particular, since the driver IC 20 is fixed to the case member 25 via the heat-dissipating resin W2, the heat generated by the driver IC 20 when the droplet discharge head 1 is driven is dissipated via the heat-dissipating resin W2 and the case member 25. Can be made. Accordingly, high heat dissipation characteristics can be obtained, and the driver IC 20 can be stably operated.

Each flexible board 21 is made of a flexible circuit board having flexibility. As shown in FIG. 6, a film base 60 and a wiring pattern 61 formed on the lower surface of the film base 60 are provided. I have. FIG. 6 is a plan view of the flexible substrates 21A and 21D.
Each flexible substrate 21 is formed in a substantially L shape in plan view, and has an end portion on one end side that is a connection portion 60 a bent by about 90 degrees along a one-dot chain line O. Each flexible substrate 21 is connected to the terminal portion 40a of the lead electrode 40 through the connection portion 60a.
In FIG. 6, the flexible boards 21 </ b> A and 21 </ b> D are illustrated, but the flexible boards 21 </ b> B and 21 </ b> C are different except that the extension direction of the external signal input unit 65 described later is opposite. The same applies to.

  The film base 60 is an insulating film made of polyimide having a thickness of about 25 μm, for example. The wiring pattern 61 is made of a conductive material such as copper, and is formed on the film substrate 60 by a technique such as electrolytic plating or etching by a printing method. The wiring pattern 61 includes a first wiring pattern 62, a second wiring pattern 63, and a ground wiring 64 that are electrically connected to the mounted driver IC 20, respectively.

The first wiring pattern 62 is a pattern extending toward the connection portion 60 a, and one end side of the connection portion 60 a functions as a terminal portion 62 a that is electrically connected to the terminal portion 40 a of the lead electrode 40.
Further, the first wiring pattern 62 of the present embodiment includes a dummy pattern 62 b that does not contribute to electrical connection to the piezoelectric element 22. The dummy pattern 62b is used for driving inspection of the driver IC 20 mounted on the flexible substrate 21 and is not electrically connected to the lead electrode 40. The dummy pattern 62b is connected to the lead electrode 40 that forms a dummy pattern for inspection for performing a driving inspection on the piezoelectric element 22 and the like. Such a dummy pattern 62b is formed on one end side of the connection portion 60a in the arrangement direction of the first wiring patterns 62, for example.

  On the other hand, the second wiring pattern 63 and the ground wiring 64 function as an external signal input unit 65 that is electrically connected to the external controller CT. An external signal input from the external signal input unit 65 is input to the driver IC 20 via the second wiring pattern 61.

  The flexible substrate 21 configured as described above is inserted into the opening 46 formed in the reservoir forming substrate 24 and the opening 55 formed in the case member 25 as shown in FIGS. 4 and 5. Has been. Thereby, the connection portion 60 a of the flexible substrate 21 is OLB-connected to the lead electrode 40 disposed in the opening 46 via the anisotropic conductive paste W. As a result, the terminal portion 62a of the first wiring pattern 62 constituting the wiring pattern 61 on the flexible substrate 21 side and the terminal portion 40a of the lead electrode 40 are in an electrically connected state.

(Manufacturing method of the droplet discharge head 1)
Next, a method for manufacturing the droplet discharge head 1 having the above-described configuration will be described with reference to the flowchart shown in FIG. In the following description, a device mounting method for mounting the flexible substrate 21 on the diaphragm 23 will be mainly described. Among the droplet discharge heads 1, the nozzle substrate 27, the flow path forming substrate 28, and the reservoir forming substrate 24. It is assumed that the manufacturing, connection, and arrangement of the case member 25, the piezoelectric element 22, and the like have already been completed.

First, a preparation step (S1) for preparing the flexible substrate 21 is performed.
As shown in FIG. 6, the wiring pattern 61 such as the first wiring pattern 62, the second wiring pattern 63, and the ground wiring 64 including the terminal portion 62 a and the dummy pattern 62 b is formed on the surface of the film base 60. These are formed on the film substrate 60 using a technique such as electrolytic plating or etching using a printing method. Here, the first wiring pattern 62 including the terminal portion 62 a is formed with high accuracy according to the interval between the nozzle openings 26 (nozzle pitch), that is, the interval between the piezoelectric elements 22.

Then, the first to fourth driver ICs 20A to 20D are mounted on the first to fourth flexible boards 21A to 21D, respectively. This flips the first to fourth driver ICs 20A to 20D to the mounting region (predetermined region) on one surface of the film base 60 of the first to fourth flexible substrates 21A to 21D (the lower surface of the flexible substrate 21). Mount the chip. Thereby, each driver IC 20 is electrically connected to the wiring pattern 61. Thereafter, the first to fourth flexible boards 21A to 21D and the first to fourth driver ICs 20A to 20D are fixed by the resin W1, respectively. Then, each flexible substrate 21 is subjected to a bending process (for example, a pressing process) along a one-dot chain line O.
At this point, the preparation process (S1) is completed.

  Next, as shown in FIG. 8, the conductive particles R are placed on either the terminal portion 62 a of the wiring pattern 61 formed on the flexible substrate 21 or the terminal portion 40 a of the lead electrode 40 formed on the diaphragm 23. An application step (S2) of applying a predetermined amount of the anisotropic conductive paste W containing slag is performed. In the present embodiment, the case where the anisotropic conductive paste W is applied onto the terminal portion 40a of the lead electrode 40 will be described as an example. FIG. 8 is a view showing a state in which the flexible substrate 21 is disposed oppositely on the lead electrode 40 after the anisotropic conductive paste W is applied on the terminal portion 40a of the lead electrode 40.

  By the way, when applying, the highest vertex center (application center) N that rises after application is separated from the center axis C of the bonding tool 70 applied to a predetermined position on the flexible substrate 21 side in the subsequent bonding step by a certain distance H. Then, an anisotropic conductive paste W is applied. In the present embodiment, the anisotropic conductive paste W is applied so as to approach the inner peripheral wall 24 a side of the reservoir forming substrate 24.

  Next, the terminal portion 62a side of the flexible substrate 21 is inserted into the opening 55 formed in the case member 25 and the opening 46 formed in the reservoir forming substrate 24, and the applied anisotropic conductive paste W is interposed therebetween. A setting step (S3) is performed in which the flexible substrate 21 is positioned on the vibration plate 23 so as to face the terminal portion 40a of the lead electrode 40 on the vibration plate 23 side.

  Next, a bonding step (S4) is performed in which the flexible substrate 21 is mounted on the diaphragm 23 by using the bonding tool 70, and the first wiring pattern 62 and the lead electrode 40 constituting the wiring pattern 61 are electrically connected. . This process will be described in detail.

  First, the bonding tool 70 having a flat tip is applied to a predetermined position of the flexible substrate 21 [the upper surface of the film base 60 functioning as the connection portion 60a (the surface on which the wiring pattern 61 is not formed)]. Then, the anisotropic conductive paste W is heated to a predetermined temperature, and the bonding tool 70 is pushed down in the direction of the arrow B to press the flexible substrate 21 against the diaphragm 23 while pressing it. Then, the anisotropic conductive paste W is crushed and spreads while flowing between the flexible substrate 21 and the diaphragm 23, and then hardened as shown in FIG. At this time, the conductive particles R contained in the anisotropic conductive paste W come into contact with each other between the terminal portion 62a on the flexible substrate 21 side and the terminal portion 40a of the lead electrode 40 on the diaphragm 23 side. The parts 40a and 62a are made conductive. As a result, the first wiring pattern 62 and the lead electrode 40 can be electrically connected.

In particular, the anisotropic conductive paste W is applied such that the center of the highest vertex N is shifted laterally (on the inner peripheral wall 24a side) by a certain distance H from the central axis C of the bonding tool 70 during the application step (S1). Therefore, the region where the most conductive particles R are present is shifted laterally from the central axis C of the bonding tool 70. Therefore, when the anisotropic conductive paste W is crushed during the bonding process, the region where the conductive particles R are most present flows toward the central axis C of the bonding tool 70. In addition, in the present embodiment, since the anisotropic conductive paste W is applied at a position shifted toward the inner peripheral wall 24a, the anisotropic conductive paste W is entirely removed from the central axis by the inner peripheral wall 24a when crushed. It flows toward C.
Accordingly, almost the entire region where the most conductive particles R are present flows toward the central axis C of the bonding tool 70.
However, a slight amount of the anisotropic conductive paste W enters a slight gap between the flexible substrate 21 and the inner peripheral wall 24a due to a capillary phenomenon or the like.

  Therefore, unlike the prior art, as many conductive particles R as possible can be concentrated (exist) in the region pressed by the bonding tool 70. That is, it is possible to keep as many conductive particles R that contribute to conduction as possible in the pressure region, that is, the connection region. Therefore, the flexible substrate 21 and the diaphragm 23 can be OLB-connected with much better conductivity than the conventional one, and the connection reliability can be improved. Moreover, without changing the amount of the anisotropic conductive paste W and the ratio of the conductive particles R contained in the anisotropic conductive paste W, only the number of conductive particles R contributing to conduction can be increased. Can increase the sex.

  As described above, according to the device mounting method of the present embodiment, using the anisotropic conductive paste W, the conductive particles R that contribute to conduction are applied to the pressure region between the flexible substrate 21 and the diaphragm 23. OLB connection can be performed while concentrating, and the continuity can be improved to improve the connection reliability.

In the present embodiment, the driver IC 20 is fixed to the case member 25 at the same time as the terminal portion 62a of the flexible substrate 21 and the terminal portion 40a of the lead electrode 40 are electrically connected. Specifically, the heat-dissipating resin W2 is applied to the side wall surface 56a of the case member 25 in advance. Thereby, simultaneously with the OLB connection described above, the driver IC 20 can be fixed to the case member 25 using the heat radiating resin W2, and the heat dissipation of the driver IC 20 can be improved.
The heat-dissipating resin W2 is not allowed to cure until the terminal portion 62a of the flexible substrate 21 is securely connected to the terminal portion 40a of the lead electrode 40. Thereby, the terminal part 62a of the flexible substrate 21 and the terminal part 40a of the lead electrode 40 can be satisfactorily connected.

As described above, the droplet discharge head 1 can be manufactured.
Next, the case where the liquid droplet ejection head 1 is operated to eject functional liquid droplets will be briefly described. In this case, first, an external signal is input from the external controller CT to the driver IC 20 via the external signal input unit 65. Then, the driver IC 20 operates each piezoelectric element 22. When the piezoelectric element 22 is actuated, the diaphragm 23 is displaced, and a pressure is generated for ejecting droplets into the pressure generating chamber 31. As a result, functional liquid droplets can be ejected from the nozzle openings 26.
In particular, according to the droplet discharge head 1 of the present embodiment, since the flexible substrate 21 and the diaphragm 23 having high conductivity and improved connection reliability are provided, the droplets have high operation reliability and high quality. The ejection head 1 can be obtained.

(Droplet discharge device)
Next, an embodiment of a droplet discharge apparatus according to the present invention provided with the above-described droplet discharge head 1 will be described with reference to FIG. FIG. 9 is a perspective view showing a schematic configuration of the droplet discharge device.

As shown in FIG. 9, the droplet discharge device IJ of this embodiment includes a droplet discharge head 1, a drive shaft 4, a guide shaft 5, an external controller CT, a stage 7, a cleaning mechanism 8, and a basic mechanism. The base 9 and the heater 6 are mainly configured.
The droplet discharge head 1 is attached to the droplet discharge device IJ by fixing a case member 25 to a carriage (not shown). The stage 7 supports the substrate P from which the functional liquid is discharged by the droplet discharge head 1 and includes a fixing mechanism (not shown) that fixes the substrate P at a reference position. The functional liquid is discharged from the nozzle opening 26 of the droplet discharge head 1 to the substrate P supported by the stage 7.

  A drive motor 2 is connected to the drive shaft 4. The drive motor 2 is a stepping motor or the like, and rotates the drive shaft 4 when a drive signal in the Y-axis direction is supplied from the external controller CT. When the drive shaft 4 rotates, the droplet discharge head 1 moves in the Y-axis direction. The guide shaft 5 is fixed so as not to move with respect to the base 9. The stage 7 includes a drive motor 3. The drive motor 3 is composed of a stepping motor or the like. When a drive signal in the X-axis direction is supplied from the external controller CT, the stage 7 is moved in the X-axis direction.

  The external controller CT supplies a voltage for controlling droplet ejection to the droplet ejection head 1. Further, the external controller CT supplies a drive pulse signal for controlling the movement of the droplet discharge head 1 in the Y-axis direction to the drive motor 2 and also the drive motor 3 in the X-axis direction of the stage 7. A drive pulse signal for controlling the movement of is supplied.

The cleaning mechanism 8 cleans the droplet discharge head 1 and includes a drive motor (not shown). By driving the drive motor, the cleaning mechanism 8 moves in the X-axis direction along the guide shaft 5. The movement of the cleaning mechanism 8 is also controlled by the external controller CT. Here, the heater 6 is means for heat-treating the substrate P by lamp annealing, and evaporates and dries the solvent contained in the functional liquid applied on the substrate P. The power on and off of the heater 6 is also controlled by the external controller CT.
The droplet discharge device IJ discharges droplets onto the substrate P while relatively scanning the droplet discharge head 1 and the stage 7 supporting the substrate P.

According to the droplet discharge device IJ configured as described above, since the high-quality droplet discharge head 1 with high operation reliability is provided, the operation reliability can be similarly improved to improve the quality. Can do.
In this embodiment, the functional liquid discharged from the droplet discharge head 1 includes a liquid crystal display device forming material for forming a liquid crystal display device and an organic EL forming material for forming an organic EL display device. And a wiring pattern forming material for forming a wiring pattern of an electronic circuit. Thereby, the droplet discharge apparatus IJ can manufacture each of the devices with the functional liquid discharged based on the droplet discharge method.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, the case where the droplet discharge head 1 is taken as an example and the device substrate and the connected substrate obtained by the device mounting method are applied to the flexible substrate 21 and the diaphragm 23 has been described. The present invention is not limited to the ejection head 1.
If the anisotropic conductive paste W is used to mount the device substrate on which the first wiring connection portion is formed on the connected substrate on which the second wiring connection portion is formed, the device mounting according to the present invention will be described. It is possible to apply the method.

Further, in the above embodiment, when the anisotropic conductive paste W is applied, it is applied to the terminal portion 40 a side of the lead electrode 40, but may be applied to the terminal portion 62 a side of the flexible substrate 21. Even in this case, the same effects can be achieved.
Further, when the anisotropic conductive paste W is applied laterally shifted from the central axis C of the bonding tool 70 by a certain distance H, it is applied to a position close to the inner peripheral wall 24a side of the reservoir forming substrate 24. FIG. As shown in FIG. 4, it may be applied to the side away from the inner peripheral wall 24a. Even in this case, it is possible to leave as many conductive particles R that contribute to conduction in the pressurized region as possible, and high conductivity can be ensured.

C ... Center axis of bonding tool N ... Center of top of anisotropic conductive paste W ... Anisotropic conductive paste IJ ... Droplet ejection device 1 ... Droplet ejection head 20 ... IC device (drive device)
21 ... Flexible substrate (device substrate)
23 ... Diaphragm (Substrate to be connected)
22 ... Piezoelectric element (drive element)
24a ... Inner wall (flow regulation part)
26 ... Nozzle opening 27 ... Nozzle substrate 28 ... Flow path forming substrate 31 ... Pressure generating chamber 40 ... Lead electrode (second wiring connection portion)
40a ... Terminal portion of second wiring connection portion 61 ... Wiring pattern (first wiring connection portion)
62a ... Terminal part of the first wiring connection part 70 ... Bonding tool

Claims (4)

A device in which an anisotropic conductive paste is used to mount a device substrate on which a first wiring connection portion is formed on a connected substrate on which a second wiring connection portion is formed, and to electrically connect both wiring connection portions An implementation method,
An application step of applying the anisotropic conductive paste to either the terminal portion of the first wiring connection portion or the terminal portion of the second wiring connection portion;
The device substrate is placed on the to-be-connected substrate so that the terminal portion of the first wiring connection portion and the terminal portion of the second wiring connection portion face each other with the applied anisotropic conductive paste interposed therebetween. A set process to be positioned;
While heating the anisotropic conductive paste and pressing the device substrate against the connected substrate with a bonding tool, the terminal portion of the first wiring connection portion and the terminal portion of the second wiring connection portion are A bonding step of electrically connecting through an anisotropic conductive paste,
In the coating step, the anisotropic conductive paste is coated such that the center of the highest vertex that rises after coating is spaced from the central axis of the bonding tool by a certain distance. The device mounting method according to claim 1,
A device mounting method, wherein a flow restricting portion that causes the anisotropic conductive paste to flow toward the central axis during the bonding step is formed in advance on the connected substrate. The device substrate and the connected substrate obtained by the device mounting method according to claim 1 or 2,
A driving device mounted on the device substrate in a state of being electrically connected to the first wiring connecting portion;
A drive element mounted on the connected substrate in a state of being electrically connected to the second wiring connection portion, and displacing the substrate during operation;
A nozzle substrate disposed on the lower surface side of the connected substrate and having a nozzle opening for discharging droplets;
A pressure generating chamber that is bonded to both substrates in a state of being sandwiched between the nozzle substrate and the connected substrate and generates pressure for discharging the liquid droplets in accordance with the displacement of the connected substrate. And a flow path forming substrate formed between the two.   A droplet discharge apparatus comprising the droplet discharge head according to claim 3.

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