JP2010069750A - Inkjet type recording head and its manufacturing method, inkjet type recording apparatus - Google Patents

Abstract

An ink jet recording head, a method of manufacturing the ink jet recording head, and an ink jet recording apparatus that can reduce the cost of the ink jet recording head are provided.
A substrate, a pressure generation chamber formed on the substrate, a vibration film formed on the surface side of the substrate to cover the pressure generation chamber, and a vibration film on the surface side of the substrate are formed. 20, a piezoelectric element 30 formed in a region facing the pressure generation chamber 10 across the substrate 20, wirings 34 and 35 formed on the surface side of the substrate 1 and connected to the piezoelectric element 30, and an IC element 50 (substrate 51, A driver circuit 52 formed on the surface of the substrate 51, a bump electrode 53 formed on the surface of the substrate 51 and connected to the driver circuit 52), and a sealing plate 40 having a recess 41a. Prepare. The bump electrode 53 is bonded to the wirings 34 and 35, and the sealing plate 40 is attached to the front surface side of the substrate 1 in a state where the IC element 50 and the piezoelectric element 30 are housed inside the recess 41a.
[Selection] Figure 1

Description

  The present invention relates to an ink jet recording head, a manufacturing method thereof, and an ink jet recording apparatus.

As this type of prior art, for example, there is one disclosed in Patent Document 1. That is, in Patent Document 1, a circuit (also referred to as a driver circuit or a drive circuit) for driving a piezoelectric element in an ink jet recording head is manufactured as an IC element on a separate substrate, and manufactured on this separate substrate. A structure is disclosed in which an IC element is mounted on a recording head, and each piezoelectric element and the IC element are connected by wire bonding.
However, the density of nozzle openings for discharging ink liquid is increasing, and the above-described connection by wire bonding is approaching the limit. To solve such a problem, the driver circuit is not formed on a separate substrate, but is directly formed on the flow path forming substrate constituting the recording head, as disclosed in, for example, Embodiment 1 of Patent Document 2. If this is performed, the driver circuit and the piezoelectric element can be electrically connected without relying on wire bonding, so that it is possible to cope with a higher density of nozzle openings.
JP 2002-254639 A JP 2001-205815 A

  By the way, the cost of the IC element is reduced by manufacturing as many as possible on one substrate (that is, as closely as possible). This is a general method for manufacturing an IC element. However, in Patent Document 2, since the pressure generation chamber, the reservoir, and the like are formed on the flow path forming substrate in addition to the IC elements, the IC elements cannot be densely arranged. For this reason, compared with a general manufacturing method, the yield of IC elements per substrate is small, and the manufacturing cost per IC element tends to be high.

  Further, on the flow path forming substrate, after the IC element is formed, a pressure generating chamber, a piezoelectric actuator, and a reservoir are formed. For this reason, even if the first IC element formed on the flow path forming substrate is a non-defective product that operates normally, if the actuator formed thereafter is a defective product that does not operate normally, the flow path formation The substrate is treated as a defective product. That is, the yield of the flow path forming substrate depends not only on the yield of the IC element but also on the yield of the actuator. The flow path forming substrate is recognized as a non-defective product only when the IC element and the actuator operate normally, and the pressure generation chamber and the reservoir are formed in conformity with the standard. Therefore, in particular, when defective products occur frequently in the second half of the manufacturing process (that is, including the steps of forming the IC element, the pressure generating chamber, the piezoelectric actuator, and the reservoir), the defective products are applied to the defective product. The first half of the manufacturing process is wasted, and the manufacturing cost of the flow path forming substrate may be significantly increased.

As described above, in Patent Document 2, since the IC elements cannot be densely arranged, the manufacturing cost of the IC elements tends to be high. In addition, since this IC element, piezoelectric actuator, pressure generation chamber, etc. are formed on the same substrate, especially when defective products occur frequently in the second half of the manufacturing process, the first half of the manufacturing process is wasted and the flow path is formed. There was a possibility that the manufacturing cost of the substrate would increase significantly. Therefore, there is a problem that it is difficult to reduce the cost of the ink jet recording head.
Accordingly, the present invention has been made paying attention to such problems, and an object thereof is to provide an ink jet recording head, a method for manufacturing the ink jet recording head, and an ink jet recording apparatus that can reduce the cost of the ink jet recording head. To do.

  [Invention 1] An ink jet recording head of Invention 1 includes a first substrate, a pressure generation chamber formed in the first substrate, and one surface side of the first substrate to cover the pressure generation chamber. A vibration film; a piezoelectric element formed on one surface side of the first substrate and facing the pressure generating chamber across the vibration film; and formed on one surface side of the first substrate. A wiring layer connected to the piezoelectric element, a second substrate, an integrated circuit formed on one surface of the second substrate, and formed on one surface side of the second substrate and connected to the integrated circuit And a third substrate having a recess, the bump electrode is bonded to the wiring layer, and the third substrate includes the integrated circuit and the second substrate on which the bump electrode is formed and the third substrate. With the piezoelectric element housed inside the recess, the first base And it is characterized in that mounted on one side of the. Here, the “integrated circuit” of the present invention is a driver circuit for driving an ink jet recording head, for example.

With such a configuration, since the integrated circuit and the piezoelectric element are electrically connected via the bump electrode, the nozzle openings can be densified compared to the case where the above connection is made by wire bonding. It is.
Further, since the integrated circuit and the pressure generating chamber are formed on different substrates, when manufacturing the integrated circuit, as many integrated circuits as possible are spread on one surface of the second substrate (that is, arranged as densely as possible). Can be manufactured). Thereby, the yield of the integrated circuit per substrate can be increased, and the cost of the integrated circuit can be reduced.

  Further, since the pressure generating chamber and the piezoelectric element are formed on the first substrate and the integrated circuit is formed on the second substrate, the first step of generating defective products is compared with the case where these are formed on the same substrate. The substrate can be dispersed on the substrate side and the second substrate side, and defective products can be screened as early as possible in the manufacturing process. Thereby, since an inkjet recording head can be manufactured by combining only good products, the cost of the inkjet recording head can be reduced.

[Invention 2] The inkjet recording head of Invention 2 is the inkjet recording head of Invention 1, further comprising a fourth substrate attached to the other surface side of the first substrate. A nozzle opening communicating with the pressure generating chamber is formed. Here, “the other surface” is a surface facing the opposite side to the one surface.
With such a configuration, the ink liquid can be discharged toward the other surface of the first substrate.
[Invention 3] The inkjet recording head of Invention 3 is the inkjet recording head of Invention 1 or Invention 2, further comprising a reservoir formed on the third substrate and communicating with the pressure generating chamber. Is.
With such a configuration, the ink liquid can be supplied from the reservoir to the pressure generating chamber.

[Invention 4] The ink jet recording head of Invention 4 is the ink jet recording head according to any one of Inventions 1 to 3, wherein the second substrate is disposed above the piezoelectric element, and the piezoelectric element and A gap is provided between the second substrate and the second substrate.
With such a configuration, the piezoelectric element can be protected using the second substrate, and a space for expanding and contracting the piezoelectric element can be secured between the second substrate and the piezoelectric element. it can.
[Invention 5] An ink jet recording apparatus according to Invention 5 includes the ink jet recording head according to any one of Inventions 1 to 4.
With such a configuration, since the ink jet recording heads of the inventions 1 to 4 are applied, the ink jet recording apparatus can be reduced in size and cost.

  [Invention 6] In the ink jet recording head manufacturing method of Invention 6, a step of forming a pressure generation chamber on a first substrate and a vibration film covering the pressure generation chamber on one surface side of the first substrate are formed. A step of forming a piezoelectric element in a region facing one side of the first substrate and the pressure generating chamber across the vibration film, and one side of the first substrate, Forming a wiring layer connected to the piezoelectric element; forming an integrated circuit on one surface of the second substrate; and bump electrodes connected to the integrated circuit on one surface side of the second substrate. Forming the integrated circuit and the bump electrode, forming the bump electrode on the wiring layer with one surface of the second substrate facing the one surface of the first substrate, and forming the integrated circuit and the bump electrode. The third substrate has the second substrate and the piezoelectric element. While housed inside parts and is characterized in that it comprises a step of attaching the third substrate on one surface side of the first substrate.

  With such a manufacturing method, the ink jet recording head of the invention 1 can be manufactured, so that the density of the nozzle openings can be increased. Further, when manufacturing an integrated circuit, as many integrated circuits as possible can be laid on one surface of the second substrate, so that the cost of the integrated circuit can be reduced. Furthermore, defective products can be screened as early as possible in the manufacturing process, and an ink jet recording head can be manufactured by combining only good products. Thereby, the cost of the ink jet recording head can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in each drawing described below, parts having the same configuration are denoted by the same reference numerals, and redundant description thereof is omitted.
(1) First Embodiment FIG. 1 is a cross-sectional view showing a configuration example of an ink jet recording head 100 according to an embodiment of the present invention. As shown in FIG. 1, the ink jet recording head 100 includes a substrate 1, a vibration film 20, a piezoelectric element (that is, a piezo element) 30, and a sealed portion having a recess 41 a in a region facing the piezoelectric element 30. A plate 40, an IC element 50, and a nozzle plate 60 are provided. Among these, the substrate 1 is, for example, a bulk silicon substrate having a plane orientation (100). The substrate 1 has a thickness of 50 μm to 500 μm, for example.

  FIG. 2 is a plan view showing a configuration example of the substrate 1. As shown in FIG. 2, the substrate 1 is formed with a plurality of individually divided ink flow paths 5. Here, the ink flow path is a path through which ink liquid flows. One ink flow path 5 includes an introduction portion 8, a constriction portion 9, and a pressure generation chamber 10. The introduction portion 8 is a space portion that receives supply of ink liquid from a reservoir described later. The narrowed portion 9 is a space portion narrowed and narrowed. Since the constricted portion 9 is between the introduction portion 8 and the pressure generation chamber 10, leakage of the pressure generated in the pressure generation chamber 10 to the introduction portion 8 side is suppressed. The cross section of the substrate 1 shown in FIG. 1 corresponds to the cross section when FIG. 2 is cut along the line X2-X′2.

  Further, as shown in FIG. 1, a nozzle plate 60 is bonded to the back surface of the substrate 1. The nozzle plate 60 is made of, for example, a bulk silicon substrate having a plane orientation (100), and through holes are provided from the front surface to the back surface. This through hole is the nozzle opening 62. The nozzle opening 62 communicates with the pressure generation chamber 10. The volume of the pressure generating chamber 10 that applies pressure to the ink liquid and the size of the nozzle opening 62 are optimized according to the discharge amount of the ink liquid, its discharge speed, discharge frequency, and the like.

  The vibration film 20 is an elastic film and is formed on the surface of the substrate 1 to cover the pressure generation chamber 10. The piezoelectric element 30 is formed directly above the pressure generating chamber 10 with the vibration film 20 interposed therebetween. The piezoelectric element 30 includes a lower electrode 31, a piezoelectric body 32 formed on the lower electrode 31, and an upper electrode 33 formed on the piezoelectric body 32. Here, the lower electrode 31 is, for example, a common electrode across a plurality of piezoelectric elements 30. The piezoelectric body 32 is a dielectric that expands, contracts, or is distorted when a voltage is applied, and is, for example, lead zirconate titanate (PZT). Further, unlike the lower electrode 31, the upper electrode 33 is not a common electrode but an individual electrode corresponding to each piezoelectric body in a 1: 1 ratio. The piezoelectric element 30 having such a configuration is provided directly above each pressure generation chamber 10. In addition, wirings 34 and 35 connected to the piezoelectric element 30 are formed on the surface of the substrate 1. The wiring 34 is a wiring for drawing out the lower electrode 31, and the wiring 35 is a wiring for drawing out the upper electrode 33.

On the other hand, the sealing plate 40 is made of, for example, a bulk silicon substrate. In the surface of the sealing plate 40 facing the piezoelectric element 30, there are a concave portion 41a for sealing (that is, sealing) the piezoelectric element 30 and the IC element 50, and a convex portion 41b surrounding the concave portion 41a. And are provided. As shown in FIG. 1, the convex part 41b of the sealing plate 40 is joined to the surface of the substrate 1 via an adhesive or the like. In addition, the recess 41a of the sealing plate 40 has a sufficient width so that the inner surface (that is, the side surface and the bottom surface) and the IC element 50 do not come into contact with each other.
Further, the sealing plate 40 is formed with a through hole formed from the front surface to the back surface. This through hole is a reservoir 45 that receives the supply of ink liquid from the outside. The reservoir 45 is formed large so as to have a volume sufficiently larger than the volumes of all the pressure generation chambers 10 described above.

The IC element 50 includes a substrate 51, a driver circuit 52 formed on the surface of the substrate 51, and a plurality of bump electrodes 53. Here, the substrate 51 is, for example, a bulk silicon substrate or an SOI substrate. An SOI substrate is a substrate in which single crystal silicon is formed over a supporting substrate with an insulating layer interposed therebetween. The support substrate is, for example, a bulk silicon substrate.
The driver circuit 52 is a circuit for driving the piezoelectric element 30. The bump electrode 53 is a terminal for exchanging power and signals from the outside to the driver circuit 52. These bump electrodes 53 are electrically connected to the wirings 34 and 35, respectively. As shown in FIG. 1, the IC element 50 is attached on the surface of the substrate 1 so as to cover the piezoelectric element 30. A certain gap is secured between the surface of the driver circuit 52 and the piezoelectric element 30 depending on the thickness of the bump electrode 53.

  FIG. 3 is a cross-sectional view illustrating a configuration example of the bump electrode 53. As shown in FIG. 3, a pad electrode 81 made of aluminum (Al) or the like is formed on the surface of the driver circuit 52, and a passivation made of an insulating material such as a silicon nitride film (SiN) is formed around the pad electrode 81. A film 83 is formed. That is, the passivation film 83 covers the surface of the driver circuit 52 with the pad electrode exposed.

An elastic internal resin (bump core) 53 a is formed so as to protrude at a position away from the pad electrode 81 on the passivation film 83. The internal resin 53a is formed, for example, by coating the surface of the passivation film 83 with an elastic resin film and then performing a patterning process such as etching. A conductive film 53 b is formed on the surface of the internal resin 53 a, and the conductive film 53 b is electrically connected to the pad electrode 81. The conductive film 53b is formed by depositing a conductive film such as Au, Cu, or Ni by vapor deposition or sputtering and performing a patterning process. Further, the conductive contact property of the conductive film 53b may be enhanced by covering the surface of the underlying conductive film made of copper (Cu), nickel (Ni), Al, or the like with Au plating or the like. The bump resin 53 is constituted by the internal resin 53a and the conductive film 53b.
The configuration of the bump electrode 53 is not limited to the above. For example, the entire hemispherical bump electrode 53 shown in FIG. 1 or 3 may be composed only of a conductive film such as Au, Cu, or Ni.

  FIG. 4 is a diagram illustrating an example of the positional relationship between the piezoelectric element 30, the sealing plate 40, and the IC element 50. FIG. 4 corresponds to a view in which the portion above the vibrating membrane 20 in FIG. 1 is viewed from below. As shown in FIG. 4, the piezoelectric element 30 is elongated in one direction (for example, the horizontal direction) in a plan view, and these are constant in another direction (for example, the vertical direction) orthogonal to the one direction in the plan view. Many are arranged at intervals. A plurality of IC elements 50 are arranged so as to overlap with these piezoelectric elements 30 in plan view, and one IC element 50 individually drives the plurality of piezoelectric elements 30.

  The ink jet recording head 100 having such a configuration takes ink liquid from an external ink supply means (not shown) into the reservoir 45 and, as indicated by an arrow in the figure, the ink extends from the reservoir 45 to the nozzle opening 62. Fill with liquid. Then, according to the recording signal from the IC element 50, a voltage is applied between the upper electrode 33 and the lower electrode 31 of the piezoelectric element 30 to expand and contract the piezoelectric body 32, or cause distortion. Accordingly, the vibration film 20 is deformed to increase the pressure in the pressure generating chamber 10, and the ink liquid is ejected from the nozzle opening 62.

Next, a method for manufacturing the ink jet recording head 100 will be described. 5 to 9 are cross-sectional views illustrating a method of manufacturing the ink jet recording head 100 according to the first embodiment of the present invention.
As shown in FIG. 5A, first, a substrate 1 made of, for example, bulk silicon is prepared. Next, the surface side of the substrate 1 is partially etched by photolithography and etching techniques to form a groove 61 in a region that becomes an ink flow path. Next, as shown in FIG. 5B, a sacrificial film 63 is formed on the entire surface of the substrate 1 to fill the groove 61. The thickness of the sacrificial film 63 is, for example, substantially the same as or deeper than the depth from the surface of the substrate 1 to the bottom surface of the groove 61. Next, the sacrificial film 63 is planarized by, for example, CMP (Chemical Mechanical Polish), and the sacrificial film 63 is removed from the region other than the groove 61. As a result, the sacrificial film 63 can be left only in the groove 61 as shown in FIG.

The sacrificial film 63 is removed in a later process. Therefore, it is preferable to use a film having high etching selectivity with respect to the substrate 1 (that is, a film that is more easily etched than the substrate 1 under predetermined etching conditions) as the sacrificial film 63. For example, when the substrate 1 is made of Si, a SiO ₂ film or a SiGe film can be used as the sacrificial film 63. The SiO ₂ film as the sacrificial film 63 may be a PSG film having a relatively high etching rate.
Further, the method for forming the sacrificial film 63 in the groove 61 is not limited to the above-described method (that is, a combination of a film formation process by CVD and a planarization process by CMP). For example, the sacrificial film 63 is formed by using a so-called gas deposition method or jet molding method in which ultra fine particles of 1 μm or less collide with the substrate 1 at a high speed by a gas pressure such as helium (He). It may be formed. According to such a method, it is possible to form (that is, fill) the sacrificial film 63 in the groove portion 61 without performing a planarization step by CMP.

Next, as shown in FIG. 6A, the vibration film 20 is formed on the surface of the substrate 1 and the sacrificial film 63. The vibration film 20 is an elastic film as described above, and is made of, for example, a SiO ₂ film, zirconium oxide (ZrO ₂ ), or a film in which these are laminated, and has a thickness of, for example, 1 to 2 μm. When ZrO ₂ is used for the vibration film 20, for example, ZrO ₂ is formed by sputtering (reactive sputtering film formation) of zirconium (Zr) with plasma containing O ₂ . Alternatively, ZrO ₂ may be formed by forming Zr on the surface of the substrate 1 and the sacrificial film 63 and then thermally oxidizing Zr in a diffusion furnace at 500 to 1200 ° C. The material of the vibration film 20 is not limited to the above type, but it is preferable to use a material that is not etched or hardly etched in the step of removing the sacrificial film 63.

  Next, as shown in FIG. 6B, piezoelectric elements 30 are formed on the vibration film 20 corresponding to the individual pressure generation chambers 10. Here, the lower electrode film is formed on the vibration film 20 by sputtering, for example. As a material for the lower electrode film, platinum (Pt), iridium (Ir), or the like is suitable. The reason is that a piezoelectric film described later formed by sputtering or sol-gel method needs to be crystallized by baking at a temperature of about 600 to 1000 ° C. in an air atmosphere or an oxygen atmosphere after the film formation. Because. For the material of the lower electrode film, it is necessary to select and use a material that can maintain conductivity under such high temperature and oxidizing atmosphere. In particular, when lead zirconate titanate (PZT) is used as the piezoelectric film, it is desirable to select and use a material that exhibits little change in conductivity due to diffusion of lead oxide. Pt, Ir, etc. are suitable as materials that satisfy such conditions. Next, the lower electrode film is partially etched by photolithography and etching techniques to form the lower electrode 31 having a shape as a common electrode.

  Then, a piezoelectric film is formed. Here, for example, a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst is applied, dried and gelled, and further sintered at a high temperature (that is, a sol-gel method) to form a piezoelectric film. As the material of the piezoelectric film, a PZT material is suitable, and the sintering temperature in that case is about 700 ° C., for example. The method for forming the piezoelectric film is not limited to the sol-gel method, and for example, the film may be formed by a spin coating method such as a sputtering method or a MOD method (organic metal thermal coating decomposition method). Alternatively, a PZT precursor film may be formed by a sol-gel method, a sputtering method, a MOD method, or the like, and then formed by a method of crystal growth at a low temperature by a high-pressure treatment method in an alkaline aqueous solution. The thickness of the piezoelectric film formed by such a method is, for example, 0.2 to 5 μm.

  Next, an upper electrode film is formed. The upper electrode film only needs to be a highly conductive material, and a metal film such as Al, gold (Au), nickel (Ni), or Pt, or a conductive oxide can be used. Next, the upper electrode film and the piezoelectric film are sequentially partially etched by photolithography and etching techniques to form the upper electrode 33 and the piezoelectric body 32 having a predetermined shape. Thereby, the piezoelectric element 30 including the lower electrode 31, the piezoelectric body 32, and the upper electrode 33 is completed on the vibration film 20. In the present embodiment, the case where the lower electrode 31 is the common electrode of the piezoelectric element 30 and the upper electrode 33 is the individual electrode of the piezoelectric element 30 has been described, but this is reversed for the convenience of the driver circuit 52 and wiring. Also good. That is, the lower electrode 31 may be an individual electrode and the upper electrode 33 may be a common electrode.

  Next, a conductive film is formed on the entire surface of the substrate 1. For example, a metal film such as Al, Au, Ni, or Pt can be used for the conductive film. Then, the conductive film is partially etched by photolithography and etching techniques. As a result, as shown in FIG. 6C, the wiring 34 for drawing out the lower electrode 31 that is a common electrode to the surface of the substrate 1 and the wiring 35 for drawing the upper electrode 33 of each piezoelectric element 30 to the surface of the substrate 1. And form.

In this embodiment, although not shown, a protective film may be formed so as to cover the piezoelectric element 30 before the wirings 34 and 35 are formed. The protective film is, for example, alumina (Al ₂ O ₃ ), and can be formed, for example, by sputtering, ALD (Atomic Layer Deposition), or MOCVD (Metal Organic CVD). Thus, when forming a protective film covering the piezoelectric element 30, the protective film is partially etched by photolithography and etching techniques to form contact holes on the lower electrode 31 and the upper electrode 33, respectively. Wirings 34 and 35 may be formed so as to fill the contact holes.

Next, the manufacturing process of the IC element 50 will be described.
As shown in FIG. 7A, first, a driver circuit 52 for driving the piezoelectric element 30 is formed on the surface of the substrate 51. Here, for example, as shown in FIG. 10, a plurality of drivers are formed on the surface of a semiconductor substrate (hereinafter also referred to as a wafer) 51 by using a semiconductor process (that is, a film forming process, a photolithography process, an etching process, etc.). The circuit 52 is spread and manufactured. Next, as shown in FIG. 7B, bump electrodes 53 are formed on the surface of the driver circuit 52. The bump electrode 53 is composed of, for example, an internal resin 53a and a conductive film 53b, and the formation method thereof is as described above. Thereafter, as shown in FIG. 10, the wafer 51 is diced (that is, cut) along the dicing line, and the plurality of IC elements 50 are separated into pieces. Such a manufacturing process of the IC element 50 can be performed before or after the manufacturing process of the substrate 1 or the sealing plate 40 or in parallel.

Next, the manufacturing process of the sealing plate 40 will be described.
As shown in FIG. 8A, first, for example, a bulk silicon substrate is prepared as the sealing plate 40. Next, the surface of the sealing plate 40 is partially etched by photolithography and etching techniques to form a recess 41a for sealing the piezoelectric element and the IC element. Here, for example, as shown in FIG. 4, the width of the recess 41 a is larger than the occupied area of the piezoelectric element 30 and the IC element 50 (to be sealed), and the depth is the piezoelectric element 30. The recess 41 a is formed so as to be larger than the thickness of the IC element 50. Thereby, the recessed part 41a which can seal the piezoelectric element 30 and the IC element 50 collectively can be formed.

Next, as shown in FIG. 8B, the sealing plate 40 is partially etched and penetrated by photolithography and etching techniques to form a reservoir 45 including a through hole. Here, for example, the reservoir 45 is formed by wet etching using a potassium hydroxide (KOH) aqueous solution or dry etching.
Next, a process of combining the substrate 1 shown in FIG. 6C, the IC element 50 shown in FIG. 7B, the sealing plate 40 shown in FIG. 8B, and the like will be described.

  As shown in FIG. 9, first, the separated IC element 50 is attached (that is, mounted) to the surface side of the substrate 1. Here, the IC element 50 and the substrate 1 are aligned so that the surface of the IC element 50 faces the surface of the substrate 1 and the plurality of bump electrodes 53 correctly overlap the wirings 34 and 35 in this state. Then, the bump electrode 53 is bonded to the wirings 34 and 35 in such a state of alignment. Next, the sealing plate 40 on which the reservoir 45 is formed is attached to the surface side of the substrate 1 via an adhesive or the like. Here, the sealing plate 40 and the substrate 1 are aligned so that the piezoelectric element 30 and the IC element 50 are correctly accommodated inside the recess 41a. And the surface of the sealing board 40 is joined to the surface of the board | substrate 1 in the state aligned in this way. Thereby, the piezoelectric element 30 and the IC element 50 are sealed by the sealing plate 40. In addition, the reservoir 45 is disposed to face the region where the introduction portion 8 is formed.

Next, the back surface of the substrate 1 is ground to open the bottom surface of the groove 61 (for example, see FIG. 5). By this grinding, the sacrificial film 63 (see, for example, FIG. 5) is exposed from the back surface of the substrate 1. Before and after this grinding, the vibration film 20 is removed by etching using the sealing plate 40 as a mask, and a part of the sacrificial film 63 is exposed on the bottom surface of the reservoir 45. Then, the sacrificial film 63 is etched through the reservoir 45 and the bottom surface of the groove 61 opened on the back surface of the substrate 1. As a result, the sacrificial film 63 is completely removed, and the ink flow path 5 including the introduction portion 8, the narrowed portion 9 and the pressure generation chamber 10 is formed. Etching of the sacrificial film 63 may be performed by either dry etching or wet etching. Here, the sacrificial film 63 is etched by using an etching gas or an etching solution in which the etching speed of the sacrificial film 63 is higher than that of the substrate 1. The film 63 is etched. For example, when the substrate 1 and the sealing plate 40 are Si and the sacrificial film 63 is a SiO ₂ film, carbon tetrafluoride (CF ₄ ) can be used as an example of an etching gas that satisfies the above conditions. A hydrogen fluoride solution (HF) can be used as an example of an etching solution that satisfies the same conditions.

Thereafter, as shown in FIG. 9, the nozzle plate 60 in which the nozzle openings 62 are formed is bonded to the back surface of the substrate 1 with an adhesive or the like. Through the steps as described above, the ink jet recording head 100 shown in FIG. 1 is completed.
As described above, according to the first embodiment of the present invention, the driver circuit 52 and the piezoelectric element 30 are electrically connected via the bump electrode 53, so that this connection is compared with the case where such connection is performed by wire bonding. Thus, the density of the nozzle openings 62 can be increased.
Further, since the IC element 50 and the ink flow path 5 (including the introduction part 8, the constriction part 9, and the pressure generation chamber 10) are formed on different substrates, as many ICs as possible are produced when the IC element 50 is manufactured. The element 50 can be manufactured by being spread on the surface of a semiconductor substrate (wafer) 51. As a result, the yield of the IC elements 50 per substrate can be increased, and the cost of the IC elements 50 can be reduced.

Further, since the ink flow path 5 and the piezoelectric element 30 are formed on the substrate 1 and the driver circuit 52 is formed on the substrate 51, the generation process of defective products can be performed in comparison with the case where these are formed on the same substrate. And the substrate 51 can be dispersed, and defective products can be screened at the earliest possible stage of the manufacturing process. Thereby, since an inkjet recording head can be manufactured by combining only good products, the cost of the inkjet recording head can be reduced.
Further, according to the ink jet recording apparatus including the ink jet recording head 100, the cost of the ink jet recording apparatus can be reduced.

(2) Second Embodiment In the first embodiment described above, when the ink flow path 5 including the introduction portion 8, the narrowing portion 9 and the pressure generation chamber 10 is formed on the substrate 1, the groove portion 61 is formed on the substrate 1. The case where the sacrificial film 63 is embedded therein has been described (for example, see FIG. 5). However, in the present invention, the ink flow path 5 can be formed without using the sacrificial film 63. In the second embodiment, a method of forming the ink flow path 5 that does not require a sacrificial film will be described.

11 and 12 are cross-sectional views illustrating a method for manufacturing the ink jet recording head 100 according to the second embodiment of the present invention.
As shown in FIG. 11A, first, a substrate 1 is prepared. The substrate 1 is preferably a bulk silicon substrate having a plane orientation of (110). Next, the vibration film 20 is formed on the surface of the substrate 1. As described above, the vibration film 20 is an elastic film, and is made of, for example, a SiO ₂ film, ZrO ₂ , or a film in which these are laminated, and has a thickness of, for example, 1 to 2 μm.

  Next, as shown in FIG. 11B, the piezoelectric element 30 including the lower electrode 31, the piezoelectric body 32, and the upper electrode 33 is formed on the vibration film 20. The method for forming the piezoelectric element 30 is the same as in the first embodiment. That is, a lower electrode film is first formed on the vibration film 20, and the formed lower electrode film is patterned to form the lower electrode 31. Next, a piezoelectric film is formed by a sol-gel method or the like so as to cover the lower electrode 31, and further, an upper electrode film is formed on the piezoelectric film. Then, the upper electrode film and the piezoelectric film are patterned to form the upper electrode 33 and the piezoelectric body 32. Thereby, the piezoelectric element 30 is completed.

Next, in FIG. 11B, a protective film (not shown) is formed so as to cover the piezoelectric element 30. The protective film is, for example, Al ₂ O ₃ . Then, the protective film is partially etched to form an opening (not shown) reaching the upper electrode 33 and an opening (not shown) reaching the lower electrode 31. Next, a conductive film is formed on the entire surface of the substrate 1 so as to fill these openings. Then, this conductive film is partially etched. As a result, as shown in FIG. 11C, a wiring 34 for leading the lower electrode 31 to the surface of the substrate 1 and a wiring 35 for leading the upper electrode 33 of each piezoelectric element 30 to the surface of the substrate 1 are formed.

Next, as shown in FIG. 12A, the separated IC element 50 is attached (that is, mounted) to the surface side of the substrate 1. The formation method of the IC element 50 is the same as that of the first embodiment, and is as described with reference to FIGS. 7A and 7B and FIG. The IC element is attached in the same manner as in the first embodiment, and a plurality of bump electrodes 53 are joined to the wirings 34 and 35 in a state where the IC element 50 and the substrate 1 are correctly aligned.
Next, the sealing plate 40 on which the reservoir 45 is formed is attached to the surface side of the substrate 1 via an adhesive or the like. The formation method of the sealing plate 40 is the same as that of the first embodiment, and is as described with reference to FIGS. 11A and 11B, for example. Further, the mounting method of the sealing plate 40 is the same as that of the first embodiment, and the surface of the sealing plate 40 is bonded to the surface of the substrate 1 in a state where the sealing plate 40 and the substrate 1 are correctly aligned. Thereby, the piezoelectric element 30 and the IC element 50 are sealed by the sealing plate 40. In addition, the reservoir 45 is disposed to face the region where the introduction portion 8 is formed.

Next, as shown in FIG. 12B, the back surface of the substrate 1 is ground to a desired thickness. For example, the substrate 1 having a thickness of about 650 μm is ground until the thickness reaches about 50 μm. If such grinding is performed before the sealing plate 40 is joined, the substrate 1 is as thin as paper and easily broken, and handling becomes extremely difficult. Therefore, this grinding is preferably performed after the sealing plate 40 is joined. Thereby, the sealing board 40 functions also as a support substrate which supports the board | substrate 1, and can handle the board | substrate 1 stably.
Next, as shown in FIG. 12C, the back surface of the substrate 1 is partially etched by, for example, photolithography and etching techniques, and the ink flow path including the introduction portion 8, the narrowed portion 9, and the pressure generation chamber 10 is obtained. 5 is formed. This etching process can be performed by either wet etching or dry etching, but when the substrate 1 is a bulk silicon substrate having a plane orientation (110), it can be anisotropically etched with a KOH aqueous solution. The inner side surface of the ink flow path 5 can be formed perpendicular to the front and back surfaces of the substrate 1.

The subsequent steps are the same as those in the first embodiment. That is, as shown in FIG. 9, the nozzle plate 60 in which the nozzle openings 62 are formed is bonded to the back surface of the substrate 1 via an adhesive or the like. Thereby, the ink jet recording head 100 shown in FIG. 1 is completed.
As described above, according to the second embodiment of the present invention, the formation of the sacrificial film 63 is not required when forming the ink flow path 5. Therefore, the number of steps can be reduced as compared with the first embodiment. Can contribute to the reduction of the manufacturing cost.
In the first and second embodiments described above, the substrate 1 corresponds to the “first substrate” of the present invention, the substrate 51 corresponds to the “second substrate” of the present invention, and the sealing plate 40 corresponds to the “first substrate” of the present invention. Corresponding to the “third substrate”, the nozzle plate 60 corresponds to the “fourth substrate” of the present invention. The driver circuit 52 corresponds to the “integrated circuit” of the invention, and the wirings 34 and 35 correspond to the “wiring layer” of the invention.

1 is a diagram illustrating a configuration example of an ink jet recording head 100 according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration example of a substrate 1. The figure which shows the structural example of the bump electrode 53. FIG. The figure which shows an example of the positional relationship of the piezoelectric element 30, the sealing board 40, and the IC element 50. FIG. FIG. 3 is a view showing a method for manufacturing the ink jet recording head 100 according to the first embodiment. FIG. 3 is a view showing a method for manufacturing the ink jet recording head 100 according to the first embodiment. FIG. 3 is a view showing a method for manufacturing the ink jet recording head 100 according to the first embodiment. FIG. 3 is a view showing a method for manufacturing the ink jet recording head 100 according to the first embodiment. FIG. 3 is a view showing a method for manufacturing the ink jet recording head 100 according to the first embodiment. The figure which shows the structural example of the semiconductor substrate (wafer) 51 before dicing. FIG. 6 is a diagram illustrating a method for manufacturing an ink jet recording head 100 according to a second embodiment. FIG. 6 is a diagram illustrating a method for manufacturing an ink jet recording head 100 according to a second embodiment.

Explanation of symbols

  1, 51 substrate, 5 ink flow path, 8 introduction part, 9 constriction part, 10 pressure generation chamber, 20 vibration film, 30 piezoelectric element, 31 lower electrode, 32 piezoelectric body, 33 upper electrode, 34, 35 wiring, 40 sealing Stop plate, 41a concave portion, 41b convex portion, 45 reservoir, 50 IC element, 52 driver circuit, 53 bump electrode, 53a internal resin, 53b conductive film, 60 nozzle plate, 61 groove portion, 63 sacrificial film, 62 nozzle opening portion, 100 Inkjet recording head

Claims (6)

A first substrate;
A pressure generating chamber formed in the first substrate;
A vibrating membrane formed on one side of the first substrate and covering the pressure generating chamber;
A piezoelectric element formed in a region on one surface side of the first substrate and facing the pressure generating chamber across the vibration film;
A wiring layer formed on one surface side of the first substrate and connected to the piezoelectric element;
A second substrate;
An integrated circuit formed on one surface of the second substrate;
A bump electrode formed on one side of the second substrate and connected to the integrated circuit;
A third substrate having a recess,
The bump electrode is bonded to the wiring layer,
The third substrate is attached to one surface side of the first substrate in a state where the second substrate on which the integrated circuit and the bump electrode are formed and the piezoelectric element are housed inside the recess. An ink jet recording head characterized by comprising: A fourth substrate attached to the other surface side of the first substrate;
2. The ink jet recording head according to claim 1, wherein a nozzle opening communicating with the pressure generating chamber is formed in the fourth substrate.   The ink jet recording head according to claim 1, further comprising a reservoir formed on the third substrate and communicating with the pressure generating chamber.   4. The device according to claim 1, wherein the second substrate is disposed above the piezoelectric element, and a gap is provided between the piezoelectric element and the second substrate. 5. The ink jet recording head according to one item.   An ink jet recording apparatus comprising the ink jet recording head according to any one of claims 1 to 4. Forming a pressure generating chamber on the first substrate;
Forming a vibration film covering the pressure generating chamber on one surface side of the first substrate;
Forming a piezoelectric element in a region on one surface side of the first substrate and facing the pressure generating chamber across the vibration film;
Forming a wiring layer connected to the piezoelectric element on one surface side of the first substrate;
Forming an integrated circuit on one side of the second substrate;
Forming a bump electrode connected to the integrated circuit on one surface side of the second substrate;
Bonding the bump electrode to the wiring layer with one surface of the second substrate facing the one surface of the first substrate;
The third substrate is placed on one surface side of the first substrate in a state where the second substrate on which the integrated circuit and the bump electrode are formed and the piezoelectric element are housed inside a recess of the third substrate. A method of manufacturing an ink jet recording head.

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