JP2005223159A - Actuator apparatus, liquid injection head, and liquid injection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator apparatus wherein exfoliation of a terminal at the time of wire bonding can be prevented, and the terminal and a connection wiring can be connected comparatively easily and certainly, so that yield can be improved; and to provide a liquid injection head and a liquid injection apparatus. <P>SOLUTION: At least a piezoelectric element is covered with a first insulating film 100 which is composed of inorganic insulating material, and in which the terminals 90a is arranged on a surface and a step-different portion 120 whose height is relatively lower than the terminal 90a is formed at least in a part of periphery of the terminal portion 90a. In the step-different portion 120, metal layers (91, 92) which constitute the terminal portion 90a are continuously arranged from the terminal 90a to a wall surface 120a which crosses at least the surface of the terminal 90a in the step-differen portion 120. At least parts of edges 90b of the metal layers (91, 92) in the step-different portion 120 are covered with a second insulating film 110 composed of inorganic insulating material, and the surface of the terminal 90a is arranged at a position relatively higher than the end of the second insulating film 110 which covers the ends 90b of the metal layers (91, 92) in the step-different portion 120. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an actuator device, a liquid ejecting head, and a liquid ejecting apparatus that include a vibration plate provided on one surface side of a substrate on which a pressure generating chamber is formed, and a piezoelectric element provided via the vibration plate.

  An actuator device including a piezoelectric element that is displaced by applying a voltage is mounted on, for example, a liquid ejecting head that ejects droplets. As such a liquid ejecting head, for example, a part of a pressure generation chamber communicating with a nozzle opening is configured by a vibration plate, and the vibration plate is deformed by a piezoelectric element so as to pressurize ink in the pressure generation chamber and thereby the nozzle opening Inkjet recording heads that discharge ink droplets are known. Two types of ink jet recording heads have been put into practical use: those equipped with a piezoelectric actuator device in a longitudinal vibration mode that extends and contracts in the axial direction of the piezoelectric element, and those equipped with a piezoelectric actuator device in a flexural vibration mode. Yes.

  Here, as the latter ink jet type recording head, a drive IC is mounted on a substrate to be bonded to a flow path forming substrate in which a pressure generating chamber is formed, for example, a reservoir forming substrate, and a lead drawn from each piezoelectric element. A structure in which the electrode and the driving IC are connected by wire bonding is employed (see, for example, Patent Document 1). Wire bonding performed in the manufacture of such an ink jet recording head is performed by connecting one end of the connection wiring to the terminal portion of the drive IC using a capillary or the like and then connecting the other end of the connection wiring to the terminal portion of the lead electrode. In this case, there is a problem that the terminal portion on the lead electrode side is easily peeled off.

  Further, as a conventionally known bonding pad structure on the semiconductor side, for example, there is a structure in which a peripheral portion of a wiring layer constituting the bonding pad is covered with a protective oxide film (see, for example, Patent Document 2). By adopting such a structure for the terminal portion of the lead electrode, peeling of the terminal portion can be prevented. However, there is a problem in that the opening of the bonding pad needs to be larger than the outer diameter of the tip of the capillary, the terminal portion needs to be formed relatively large, and the terminal portions cannot be arranged with high density. In addition, if the peripheral edge of the terminal portion is covered with the protective oxide film in this way, there is a possibility that poor connection between the terminal portion and the connection wiring may occur when the tip of the capillary contacts the protective oxide film during wire bonding. .

  Further, as the bonding pad structure of the semiconductor device, the peripheral portion of the pad layer constituting the bonding pad is covered with an insulating cover film, and the surface of the pad layer and the cover film is polished to obtain the surface of the pad layer and the cover film. There is a structure that is flush with the surface (see, for example, Patent Document 3). By adopting such a structure for the terminal portion of the lead electrode, it is possible to prevent the terminal portion from peeling off. However, even in such a structure, the tip of the capillary sinks on the terminal portion during wire bonding, and hits the cover film, which may cause a connection failure between the terminal portion and the connection wiring. In addition, after wire bonding, the terminal portion and the connection wiring are usually molded (potted) with resin. At this time, if the terminal portion and the cover film are flush with each other, only the connection wiring receives a force from the mold resin, and the connection wiring may be peeled off from the terminal portion.

  The above-described problem exists not only in an actuator device mounted on a liquid ejecting head such as an ink jet recording head but also in an actuator device mounted on another device.

Japanese Patent Laid-Open No. 2002-160366 (page 3, FIG. 2) Japanese Patent Laid-Open No. 6-5653 (FIG. 4) JP 2000-58580 A (FIG. 1)

  In view of such circumstances, the present invention can prevent the terminal portion from being peeled off during wire bonding, and can relatively easily and reliably connect the terminal portion and the connection wiring, thereby improving the yield. It is an object to provide an actuator device, a liquid ejecting head, and a liquid ejecting apparatus that can be improved.

A first aspect of the present invention that solves the above problems includes a diaphragm provided on one side of a substrate on which a pressure generating chamber is formed, a lower electrode, a piezoelectric layer, and an upper electrode provided through the diaphragm. An actuator device comprising a plurality of piezoelectric elements comprising: a terminal portion electrically connected to the piezoelectric element and connected to a connection wiring by wire bonding; the terminal portion is provided on a surface made of an inorganic insulating material. And at least a portion of the periphery of the terminal portion is covered with a first insulating film provided with a step portion having a relatively lower height than the terminal portion. The metal layer constituting the terminal part is continuously provided from the terminal part to a wall surface intersecting at least the surface of the terminal part in the step part, and the metal layer in the step part is provided. At least a part of the portion is covered with a second insulating film made of an inorganic insulating material, and the surface of the terminal portion covers the edge of the metal layer in the stepped portion. In the actuator device, the actuator device is provided at a relatively higher position.
In the first aspect, since the edge portion of the metal layer in the step portion is covered with the second insulating film, it is possible to prevent the terminal portion from being peeled off during wire bonding. In addition, since the surface of the terminal portion is provided at a position relatively higher than the end portion of the second insulating film covering the edge portion of the metal layer in the stepped portion, for example, the outer diameter of the capillary tip is Even when the width is larger than the surface of the terminal portion, the capillary does not come into contact with the second insulating film at the time of wire bonding, and the terminal portion and the connection wiring can be reliably connected, and the yield can be improved.

According to a second aspect of the present invention, in the first aspect, the second aspect includes a lead electrode drawn from the piezoelectric element onto the first insulating film, and the terminal portion is provided at a tip portion of the lead electrode. The step portion is provided on at least the tip surface side of the lead electrode, and at least an edge portion of the metal layer extending in the step portion on the tip surface side of the lead electrode is covered with the second insulating film. It is in the actuator device characterized by the above.
In the second aspect, since the edge portion of the metal layer extending in the stepped portion on the front end surface side of the lead electrode is covered with the second insulating film, it is possible to prevent the terminal portion from peeling off during wire bonding. Can do.

According to a third aspect of the present invention, in the first aspect, the semiconductor device includes a lead electrode drawn from the piezoelectric element onto the first insulating film, and the terminal portion is provided at a tip portion of the lead electrode. The step portion is provided at least on both sides in the width direction of the lead electrode, and at least the edge portion of the metal layer extending in the step portion on both sides in the width direction of the lead electrode is covered with the second insulating film. It is in the actuator device characterized by the above.
In the third aspect, since the edge portion of the metal layer extending in the step portion on both sides in the width direction of the lead electrode is covered with the second insulating film, it is possible to prevent the terminal portion from peeling off during wire bonding. Can do.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the step portion is provided so as to surround the terminal portion, and the edge portion of the metal layer is extended in the step portion. Is covered with the second insulating film.
In the fourth aspect, since the peripheral portion of the metal layer extended in the stepped portion is covered with the second insulating film, the terminal portion can be more reliably prevented from peeling off.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the terminal portion includes a first metal layer provided on the first insulating film side, and the first metal layer. The actuator device includes a second metal layer that is provided and has a smaller outer shape than the first metal layer.
In the fifth aspect, the contact area between the first and second metal layers and the second insulating film is increased by making the outer shape of the second metal layer smaller than that of the first metal layer. Adhesion can be improved, and peeling of the terminal portion can be more reliably prevented.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the other end of the connection wiring having one end connected to the terminal portion of the drive IC is connected to the terminal portion. It is in the actuator device.
In the sixth aspect, it is possible to prevent peeling of the terminal portion on the so-called second bonding side, in which the bonding connection is performed while pressing the connection wiring against the terminal portion with the capillary.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the actuator device is characterized in that the first insulating film and the second insulating film are made of the same material.
In the seventh aspect, the adhesion between the first insulating film and the second insulating film can be improved.

An eighth aspect of the present invention is the actuator device according to the seventh aspect, wherein the first insulating film and the second insulating film are made of aluminum oxide.
In the eighth aspect, since the first insulating film and the second insulating film are made of aluminum oxide having an extremely low moisture permeability, the piezoelectric element (piezoelectric layer) is destroyed due to moisture over a long period of time. Can be prevented.

According to a ninth aspect of the present invention, a nozzle plate having a nozzle opening communicating with the pressure generating chamber is joined to the other surface side of the substrate of the actuator device according to any one of the first to eighth aspects. The liquid ejecting head is characterized.
In the ninth aspect, the terminal portion does not peel even when wire bonding is performed, and a liquid ejecting apparatus with improved yield can be realized relatively easily and reliably.

A tenth aspect of the present invention is a liquid ejecting apparatus including the liquid ejecting head according to the ninth aspect.
In the tenth aspect, a highly reliable liquid ejecting apparatus can be realized relatively easily and reliably.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. 1 and a cross-sectional view along AA ′. Further, FIG. 3 is a cross-sectional view taken along the line BB ′ of FIG. As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in the present embodiment, and one surface thereof is made of silicon dioxide previously formed by thermal oxidation. A 2 μm elastic film 50 is formed. A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. In addition, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14. The communication unit 13 constitutes a part of a reservoir that communicates with a reservoir unit 32 of the protective substrate 30 described later and serves as a common ink chamber for the pressure generation chambers 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13.

Further, on the opening surface side of the flow path forming substrate 10, a mask film 51 used as a mask when forming the pressure generating chamber 12 is interposed, and the pressure generating chamber 12 is opposite to the ink supply path 14. A nozzle plate 20 having a nozzle opening 21 communicating in the vicinity of the end is fixed through an adhesive, a heat-welded film, or the like. The nozzle plate 20 has a thickness of, for example, 0.01 to 1 mm, a linear expansion coefficient of 300 ° C. or less, for example, 2.5 to 4.5 [× 10 ⁻⁶ / ° C.], glass ceramics, silicon It consists of a single crystal substrate or non-rust steel.

  On the other hand, as described above, the elastic film 50 having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10. For example, an insulator film 55 having a thickness of about 0.4 μm is formed. Further, on the insulator film 55, a lower electrode film 60 having a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 1.0 μm, and a thickness of, for example, about 0 The upper electrode film 80 having a thickness of 0.05 μm is laminated by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In either case, a piezoelectric active part is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50, the insulator film 55, and the lower electrode film 60 serve as a diaphragm.

  For example, in the present embodiment, as shown in FIG. 2, the lower electrode film 60 is formed in a region facing the pressure generation chamber 12 in the longitudinal direction of the pressure generation chamber 12, and corresponds to the plurality of pressure generation chambers 12. It is provided continuously in the area. The piezoelectric layer 70 and the upper electrode film 80 are basically provided in a region facing the pressure generation chamber 12, but in the longitudinal direction of the pressure generation chamber 12, the piezoelectric layer 70 and the upper electrode film 80 are outside the end portion of the lower electrode film 60. The end surface of the lower electrode film 60 is covered with the piezoelectric layer 70. In the vicinity of the longitudinal end of the pressure generating chamber 12, a piezoelectric inactive portion 330 having the piezoelectric layer 70 but not substantially driven is formed.

As a material for forming the piezoelectric layer 70 constituting the piezoelectric element 300, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, nickel, magnesium, bismuth, or ytterbium is used. A relaxor ferroelectric or the like to which a metal such as the above is added is used. The composition may be appropriately selected in consideration of the characteristics, application, etc. of the piezoelectric element 300. For example, PbTiO ₃ (PT), PbZrO ₃ (PZ), Pb (Zr _x Ti _1-x ) O ₃ (PZT) ), Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), Pb (Zn _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PZN-PT), Pb (Ni ₁ ) _{/ 3 Nb 2/3) O 3 -PbTiO} 3 (PNN-PT), Pb (In 1/2 Nb 1/2) O 3 -PbTiO 3 (PIN-PT), Pb (Sc 1/3 Ta 1/2 _{) O 3 -PbTiO 3 (PST-} PT), Pb (Sc 1/3 Nb 1/2) O 3 -PbTiO 3 (PSN-PT), BiScO 3 -PbTiO 3 (BS-PT), BiYbO 3 -PbTiO 3 (BY PT), and the like.

  The surface of each layer constituting such a piezoelectric element 300 is covered with a first insulating film 100 made of an inorganic insulating material, except for a connection hole 100a with a lead electrode 90 described later. Specifically, as shown in FIGS. 2A and 2B, the first insulating film 100 is provided in the pattern region of each layer constituting the piezoelectric element 300, and the longitudinal direction of the upper electrode film 80. A connection hole 100 a serving as a connection portion between the lead electrode 90 and the upper electrode film 80 is provided in a region facing the vicinity of the end portion. That is, at least the pattern region of each layer constituting the piezoelectric element 300 is completely covered with the first insulating film 100 except for the connection hole 100a.

  Further, on the surface of the first insulating film 100, a lead electrode 90 connected to the upper electrode film 80 of each piezoelectric element 300 is extended through the connection hole 100a. Specifically, the lead electrode 90 is drawn out from the vicinity of one end in the longitudinal direction of each upper electrode film 80, in this embodiment, from the portion corresponding to the piezoelectric inactive portion 330 to the vicinity of the end of the flow path forming substrate 10. ing. In the present embodiment, the lead electrode 90 includes a first metal layer 91 formed on the first insulating film 100 side, and a second metal layer 92 formed on the first metal layer 91. Consists of. Examples of the material of the first metal layer 91 include nickel, titanium, copper, nickel chromium alloy, and titanium tungsten alloy. Examples of the material of the second metal layer 92 include gold and aluminum alloy. Etc. The leading end portion of the lead electrode 90 is connected to the other end of a connection wire 210 made of a bonding wire having one end connected to a terminal portion 200a of a driving IC 200 mounted on a protective substrate 30 described later. It is a terminal portion 90a on the bonding side.

  Further, as shown in FIG. 3, the first insulating film 100 is provided with a step 120 that is relatively lower in height than the terminal portion 90a, at least partly around the terminal portion 90a. First and second metal layers 91 and 92 constituting the terminal portion 90a are extended on at least the wall surface 120a intersecting the surface of the terminal portion 90a of the stepped portion 120. For example, in the present embodiment, the stepped portion 120 is continuously provided so as to surround the terminal portion 90a of the adjacent lead electrode 90 on the surface of the first insulating film 100, and the first and second portions constituting the terminal portion 90a. The second metal layers 91 and 92 are continuously extended from the wall surface 120a of the step portion 120 to a part of the bottom surface 120b.

  Further, a second insulating film 110 made of an inorganic insulating material is provided on the lead electrode 90 and the first insulating film 100. For example, in this embodiment, the pattern region of each layer constituting the lead electrode 90 and the piezoelectric element 300 is covered with the second insulating film 110 except for the region facing the terminal portion 90a. That is, the second insulating film 110 is provided so as to surround the terminal portion 90 a and covers the edge portions 90 b of the first and second metal layers 91 and 92 extending in the stepped portion 120. The second insulating film 110 also covers the first insulating film 100 exposed around the lead electrode 90. In the present invention, the surface of the terminal portion 90a is relatively higher than the end portion of the second insulating film 110 covering the edge portions 90b of the first and second metal layers 91 and 92 in the stepped portion 120. In the position.

  Thus, in the present invention, the first and second metal layers 91 and 92 constituting the terminal portion 90a are extended into the step portion 120, and the first and second metal layers in the step portion 120 are provided. Since the edge portion 90b of 91 and 92 is covered with the second insulating film 110, it is possible to prevent the terminal portion 90a from being peeled off during wire bonding. Specifically, by extending the first and second metal layers 91 and 92 into the stepped portion 120, the bonding area between the terminal portion 90a and the first insulating film 100 can be increased. Further, the edge 90b of the first and second metal layers 91 and 92 in the step 120 and the first insulating film 100 exposed on the bottom surface of the step 120 are continuously formed by the second insulating film 110. By covering, the rigidity around the terminal portion 90 is increased. Thereby, even if wire bonding (second bonding) is performed on the terminal portion 90a, the terminal portion 90a can be prevented from peeling off.

  In particular, as in the present embodiment, by extending the terminal portion 90a from the wall surface 120a of the stepped portion 120 to a part of the bottom surface 120b, a region covering the edge portion 90b of the terminal portion 90 with the second insulating film 110 is provided. This increases the rigidity around the terminal portion 90a, so that the terminal portion 90a can be more reliably prevented from peeling off.

  In the present invention, as described above, the second insulating film 110 covers the upper surface of the terminal portion 90a of the lead electrode 90 and the edge portions 90b of the first and second metal layers 91 and 92 in the stepped portion 120. Since the second insulating film 110 covering the edge portion 90b of the first and second metal layers 91 and 92 is located higher than the end portion of the terminal portion 90a, the second insulating film 110 covers the edge portion 90b of the first and second metal layers 91 and 92. It does not protrude high. For this reason, during wire bonding, for example, when the outer diameter of the tip of the capillary is larger than the width of the surface of the terminal portion 90a, when the relative position of the capillary and the terminal portion 90a is slightly shifted, or when the tip of the capillary is on the terminal portion 90a Even if it sinks in step 2, the tip of the capillary does not come into contact with the second insulating film 110, so that the terminal portion 90a and the connection wiring 210 can be connected relatively easily and reliably, and the yield is improved. can do.

  Furthermore, with such a structure, the pitch of the adjacent lead electrodes 90 can be narrowed while ensuring the connection region on the upper surface of the terminal portion 90a larger than the outer diameter of the tip of the capillary, and the piezoelectric element 300 can be reduced. It is possible to cope with higher density.

  In addition, since each layer which comprises the piezoelectric element 300 is covered with the 1st and 2nd insulating films 100 and 110, destruction resulting from the water | moisture content (humidity) of the piezoelectric material layer 70 can be prevented. Further, the second insulating film 110 covers the layers constituting the piezoelectric element 300 and the surface of the lead electrode 90 except for the terminal portion 90a of the lead electrode 90, so that the end of the second insulating film 110 is covered. Even when moisture enters from the part side, it is possible to prevent moisture from reaching the piezoelectric layer 70 and to more reliably prevent breakage of the piezoelectric layer 70 due to moisture.

Here, the material of the first and second insulating films 100 and 110 may be an inorganic insulating material. For example, aluminum oxide (AlO _x ), silicon oxide (SiO _x ), and tantalum oxide. It is preferable to use an inorganic insulating material such as (TaO _x ). For example, when aluminum oxide is used as one or both of the first and second insulating films 100 and 110, the first and second insulating films 100 and 110 are formed to be relatively thin. However, moisture permeation in a high humidity environment can be sufficiently prevented. In particular, when each of the first and second insulating films 100 and 110 is formed of aluminum oxide, it is possible to sufficiently prevent the permeation of moisture even if each film thickness is about 50 nm.

  In addition, the first insulating film 100 and the second insulating film 110 are preferably formed using the same material. This is because the adhesion between the first insulating film 100 and the second insulating film 110 can be improved, and the piezoelectric element 300 can be prevented from being damaged by moisture over a long period of time.

  A protective substrate 30 having a piezoelectric element holding portion 31 capable of ensuring a space that does not hinder the movement of the region facing the piezoelectric element 300 on the surface of the flow path forming substrate 10 on the piezoelectric element 300 side is an adhesive. 35 is joined. Since the piezoelectric element 300 is formed in the piezoelectric element holding part 31, it is protected in a state hardly affected by the external environment. As described above, each lead electrode 90 extends to the outside of the piezoelectric element holding portion 31 to form the terminal portion 90a, and one end is connected to the terminal portion 200a of the drive IC 200 mounted on the protective substrate 30. The other end of the connection wiring 210 is connected to the terminal portion 90 a of each lead electrode 90.

  Further, the protective substrate 30 is provided with a reservoir portion 32 in a region corresponding to the communication portion 13 of the flow path forming substrate 10. In this embodiment, the reservoir portion 32 is provided along the direction in which the pressure generating chambers 12 are arranged so as to penetrate the protective substrate 30 in the thickness direction, and as described above, the communication portion of the flow path forming substrate 10. 13, a reservoir 130 is formed which serves as a common ink chamber for each pressure generating chamber 12. Examples of the material of the protective substrate 30 include glass, ceramic material, metal, resin, and the like, but it is more preferable that the protective substrate 30 be formed of substantially the same material as the thermal expansion coefficient of the flow path forming substrate 10. In the embodiment, a single crystal silicon substrate made of the same material as the flow path forming substrate 10 is used.

  A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. The sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and one surface of the reservoir portion 32 is sealed by the sealing film 41. Yes. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 130 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 130 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of this embodiment, after taking ink from an external ink supply means (not shown) and filling the interior from the reservoir 130 to the nozzle opening 21, the pressure is applied according to the recording signal from the drive IC 200. By applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the generation chamber 12 to bend and deform the diaphragm and the piezoelectric element 300, the pressure in each pressure generation chamber 12 is increased. Ink droplets are ejected from the opening 21.

Here, a method of manufacturing such an ink jet recording head will be described with reference to FIGS. 4 to 7 are cross-sectional views of the pressure generation chamber 12 in the longitudinal direction. First, as shown in FIG. 4A, the flow path forming substrate 10 which is a silicon single crystal substrate is thermally oxidized in a diffusion furnace at about 1100 ° C., and the elastic film 50 and the mask film 51 are formed on the surface of the flow path forming substrate 10. A silicon dioxide film 52 is formed. Next, as shown in FIG. 4B, after a zirconium (Zr) layer is formed on the elastic film 50 (silicon dioxide film 52), it is thermally oxidized in, for example, a diffusion furnace at 500 to 1200 ° C. to form zirconium oxide. An insulator film 55 made of (ZrO _x ) is formed. Next, as shown in FIG. 4C, for example, after the lower electrode film 60 is formed by laminating platinum and iridium on the insulator film 55, the lower electrode film 60 is patterned into a predetermined shape.

  Next, as shown in FIG. 4D, for example, a piezoelectric layer 70 made of lead zirconate titanate (PZT) or the like and an upper electrode film 80 made of iridium, for example, are formed on the entire surface of the flow path forming substrate 10. To form. Next, as shown in FIG. 5A, the piezoelectric layer 300 is formed by patterning the piezoelectric layer 70 and the upper electrode film 80 in regions facing the pressure generation chambers 12.

Next, as shown in FIG. 5B, in this embodiment, the first insulating film 100 made of aluminum oxide (AlO _x ) is formed and patterned into a predetermined shape. That is, the first insulating film 100 is formed as a thick film on the entire surface of the flow path forming substrate 10 and is etched through a predetermined mask, whereby the terminal portion 90a of the lead electrode 90 formed in the process described later is performed. A step 120 is formed in a surrounding region, and a connection hole 100 a is formed in a region facing each upper electrode film 80.

  Next, as shown in FIG. 5C, lead electrodes 90 are formed. Specifically, for example, a first metal layer 91 made of titanium tungsten alloy is formed over the entire surface of the flow path forming substrate 10, and then a second metal layer 92 made of aluminum alloy is formed thereon. For example, the second metal layer 92 is selectively wet-etched with a predetermined etching solution through a mask pattern (not shown) made of a resist or the like and patterned into a predetermined shape. Next, the first metal layer 91 is used for etching the second metal layer 92 through the mask pattern used in the patterning of the second metal layer 92 and the second metal layer 92. Are selectively wet-etched with different predetermined etchants and patterned into a predetermined shape. Thereby, a lead electrode 90 composed of the first metal layer 91 and the second metal layer 92 is formed.

Next, as shown in FIG. 5D, for example, a second insulating film 110 made of aluminum oxide (AlO _x ) is formed and patterned into a predetermined shape. That is, the second insulating film 110 is formed on the entire surface of the flow path forming substrate 10, and then the second insulating film 110 in a region facing the terminal portion 90 a of the lead electrode 90 is removed. At this time, the second insulating film 110 is patterned so that the second insulating film 110 existing around the terminal portion 90a is relatively lower than the surface of the terminal portion 90a.

  Next, as shown in FIG. 6A, a protective substrate 30 is bonded to the piezoelectric element 300 side of the flow path forming substrate 10 with an adhesive 35, and a mask patterned into a predetermined shape as shown in FIG. 6B. The pressure generating chamber 12 and the like are formed by anisotropically etching the flow path forming substrate 10 through the film 51.

  In practice, a large number of chips are simultaneously formed on a single wafer by the above-described series of film formation and anisotropic etching, and after the process is completed, a single chip-sized flow path is formed as shown in FIG. Divide each substrate 10. After that, the nozzle plate 20 is bonded to the flow path forming substrate 10 through the mask film 51, and the drive IC 200 is mounted on the protective substrate 30 and the compliance substrate 40 is bonded as shown in FIG. 6C.

  Next, the lead electrode 90 drawn from each piezoelectric element 300 and the drive IC 200 are connected by wire bonding. Specifically, as shown in FIG. 7A, one end of the connection wiring 210 is connected to the terminal portion 200 a of the drive IC 200 using the capillary 250. Next, as shown in FIG. 7B, the capillary 250 is moved and the connection wiring 210 is extended, and the connection wiring 210 is connected to the terminal portion 90 a (connection surface) of the lead electrode 90 at the tip of the capillary 250. The other end of the connection wiring 210 is connected to the terminal portion 90a.

  Thus, when the connection wiring 210 is wire-bonded to the terminal portion 90a of each lead electrode 90 using the capillary 250, the end portion of the second insulating film 110 is relative to the surface of the terminal portion 90a. In a low position. Therefore, at the time of wire bonding, for example, when the tip outer diameter of the capillary is larger than the width of the surface of the terminal portion 90a, when the capillary position is slightly shifted, or when the capillary tip sinks on the terminal portion 90a, The tip of the capillary 250 does not contact the second insulating film 110, and the connection wiring 210 and the terminal portion 90a can be reliably connected. Therefore, the yield can be improved. Moreover, since the edge part 90b of the 1st and 2nd metal layers 91 and 92 in the level | step-difference part 120 is covered with the 2nd insulating film 110, it can prevent that the terminal part 90a peels at the time of wire bonding. it can.

  Thereafter, although not shown, the ink jet recording head of this embodiment is manufactured by molding a region where the driving IC 200 and the lead electrode 90 are connected by the connection wiring 210 with resin. Here, since the upper surface of the end portion of the flow path forming substrate 10 including each terminal portion 90a of the lead electrode 90 is an uneven surface over the direction in which the piezoelectric elements 300 are arranged side by side, Since the force acts by being distributed between the connection wiring 210 and the terminal portion 90a, the possibility that the connection wiring 210 and the terminal portion 90a are separated after molding is reduced.

(Embodiment 2)
FIG. 8 is an enlarged plan view of a main part of an ink jet recording head according to Embodiment 2 of the present invention. In the first embodiment described above, the step portion 120 is continuously provided so as to surround the adjacent terminal portion 90a, and the edges of the first and second metal layers 91 and 92 extending into the step portion 120 are provided. The example in which the portion 90b is covered with the second insulating film 110 has been described, but in the present embodiment, the second insulating film 110 is not provided in the region between the adjacent terminal portions 90a. . Even in such a structure, since both end portions in the longitudinal direction of the lead electrode 90 are covered with the second insulating film 110, the terminal portion 90a can be prevented from being peeled off. Further, since the interval between the adjacent lead electrodes 90, in particular, the terminal portions 90a can be narrowed, it is possible to cope with the increase in the density of the piezoelectric elements while preventing the terminal portions 90a from being peeled off.

(Embodiment 3)
FIG. 9 is an enlarged cross-sectional view of a main part of an ink jet recording head according to Embodiment 3 of the present invention. In Embodiment 1 described above, the example in which the step portion 120 is formed by etching the first insulating film 100 has been described. However, in the present embodiment, the wiring 400 is provided on the insulating film 55, and the wiring 400 is formed on the wiring 400. In this example, the step portion 120A is provided around the terminal portion 90a of the first insulating film 100B by providing the first insulating film 100B with a uniform thickness. Thus, by providing the wiring 400 at a predetermined portion on the insulating film 55 and forming the first insulating film 100B from the wiring 400, the stepped portion 120A can be relatively easily formed in the first insulating film 100B. be able to.

  As shown in FIG. 10, the first lead electrode 95A is drawn on the insulator film 55 from one longitudinal end portion of the piezoelectric element 300, and the tip portion of the first lead electrode 95A is used as the wiring 400 described above. You may make it do. Specifically, the first lead electrode 95A is drawn out on the insulating film 55, and the first insulating film 100B is provided with a substantially uniform thickness on the first lead electrode 95A. In such a structure, the first insulating film 100B is connected to the second lead electrode 95B through the connection hole 100a, and the second insulating film 110B except for the terminal portion 90a from above is connected by the second insulating film 110B. Covered.

(Other embodiments)
Although the embodiments of the present invention have been described above, the basic configuration of the ink jet recording head is not limited to the above-described one. For example, in each of the embodiments described above, the terminal portion 90a is electrically connected to the piezoelectric element 300 by providing the terminal portion 90a at the tip of the lead electrodes 90 and 95B. However, the present invention is not limited to this. The terminal portion and the piezoelectric element may be connected by other wiring or the like.

  In the first embodiment described above, the step portion 120 is provided so as to surround the terminal portion 90a, and the edge portions 90b of the first and second metal layers 91 and 92 in the step portion 120 are formed as the second insulating film. However, the present invention is not limited to this, and is not limited thereto. At least a step portion is provided on the leading end surface side of the lead electrode or on both sides in the width direction of the lead electrode, and the metal constituting the terminal portion on at least the wall surface of these step portions. While extending a layer, you may make it cover the edge part of the metal layer in a level | step-difference part with a 2nd insulating film. Even with such a structure, it is possible to prevent the terminal portion from being peeled off during wire bonding.

  Further, in the above-described first embodiment, the case where the present invention is applied to the lead electrode 90 (upper electrode lead electrode) drawn from the surface of the upper electrode film 80 has been described. You may make it apply this invention to the lead electrode (lead electrode for lower electrodes) pulled out from the film | membrane.

  In the first embodiment described above, the example in which the second metal layer 92 is provided in substantially the same shape on the first metal layer 91 constituting the lead electrode 90 (terminal portion 90a) has been described. For example, the second metal layer may be smaller than the outer shape of the first metal layer. This increases the contact area between the edge of the first and second metal layers and the second insulating film, thereby improving the adhesion and more reliably preventing the terminal portion from being peeled off during wire bonding. be able to.

  Further, for example, in the above-described first embodiment, a thin film type ink jet recording head manufactured by applying a film forming and lithography process is taken as an example. However, the present invention is not limited to this example. The present invention can also be applied to a thick film type ink jet recording head formed by a method such as affixing.

  Furthermore, the ink jet recording head of each of these embodiments constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 11 is a schematic view showing an example of the ink jet recording apparatus.

  As shown in FIG. 11, in the recording head units 1A and 1B having the ink jet recording head, cartridges 2A and 2B constituting ink supply means are detachably provided, and a carriage 3 on which the recording head units 1A and 1B are mounted. Is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is conveyed on the platen 8. It is like that.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head of the present invention. However, the basic configuration of the liquid ejecting head is not limited to the above-described configuration. The present invention covers a wide range of liquid ejecting heads, and can naturally be applied to those ejecting liquids other than ink. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (surface emitting displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like. Further, it goes without saying that the present invention can be applied not only to an actuator device mounted on a liquid jet head (inkjet recording head) but also to an actuator device mounted on any device.

FIG. 3 is an exploded perspective view of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the recording head according to the first embodiment. FIG. 6 is an enlarged plan view of a main part of a recording head according to a second embodiment. FIG. 4 is an enlarged cross-sectional view of a main part of a recording head according to a third embodiment. FIG. 4 is an enlarged cross-sectional view of a main part of a recording head according to a third embodiment. 1 is a schematic diagram of a recording apparatus according to an embodiment.

Explanation of symbols

  10 flow path forming substrate, 12 pressure generating chamber, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 40 compliance substrate, 60 lower electrode film, 70 piezoelectric layer, 80 upper electrode film, 90 lead electrode, 100 first electrode Insulating film 110 Second insulating film 120 Stepped portion 130 Reservoir 200 Drive IC 210 Connection wiring 250 Capillary 300 Piezoelectric element 400 Wiring

Claims (10)

A vibration plate provided on one side of the substrate on which the pressure generating chamber is formed, a plurality of piezoelectric elements including a lower electrode, a piezoelectric layer, and an upper electrode provided through the vibration plate, and electrically connecting the piezoelectric element And an actuator device having a terminal portion to which connection wiring is connected by wire bonding.
At least the piezoelectric element is formed by a first insulating film made of an inorganic insulating material, the terminal part being provided on the surface, and a step part having a relatively lower height than the terminal part provided at least around the terminal part. The element is covered, and in the stepped portion, a metal layer constituting the terminal portion is continuously provided from the terminal portion to a wall surface intersecting at least the surface of the terminal portion in the stepped portion, The edge part of the metal layer in the step part is covered with a second insulating film made of an inorganic insulating material, and the surface of the terminal part covers the edge part of the metal layer in the step part. An actuator device, wherein the actuator device is provided at a position relatively higher than an end portion of the second insulating film. 2. The lead electrode according to claim 1, further comprising a lead electrode led out from the piezoelectric element onto the first insulating film, wherein the terminal portion is provided at a tip portion of the lead electrode, and the step portion is formed on the lead electrode. An actuator device comprising: an edge portion of the metal layer which is provided at least on the tip surface side and extends at least in the stepped portion on the tip surface side of the lead electrode is covered with the second insulating film. . 2. The lead electrode according to claim 1, further comprising a lead electrode led out from the piezoelectric element onto the first insulating film, wherein the terminal portion is provided at a tip portion of the lead electrode, and the step portion is formed on the lead electrode. Actuator device provided at least on both sides in the width direction, and at least edges of the metal layer extending in the stepped portions on both sides in the width direction of the lead electrode are covered with the second insulating film. . 4. The step portion according to claim 1, wherein the step portion is provided so as to surround the terminal portion, and an edge portion of the metal layer extending in the step portion is covered with the second insulating film. An actuator device characterized by comprising: 5. The terminal portion according to claim 1, wherein the terminal portion includes a first metal layer provided on the first insulating film side, and the first metal layer provided on the first metal layer. And the second metal layer having a small outer shape. The actuator device according to claim 1, wherein the other end of the connection wiring having one end connected to the terminal portion of the drive IC is connected to the terminal portion. 7. The actuator device according to claim 1, wherein the first insulating film and the second insulating film are made of the same material. 8. The actuator device according to claim 7, wherein the first insulating film and the second insulating film are made of aluminum oxide. A liquid ejecting head, comprising: a nozzle plate having a nozzle opening communicating with the pressure generating chamber is bonded to the other surface side of the substrate of the actuator device according to claim 1. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 9.

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