JP2009252882A - Electronic device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device that uniformizes the crushing condition of a bump electrode, and to provide a method of manufacturing the same. <P>SOLUTION: The electronic device is provided with a sealing board 40, a bump electrode 43 formed on the surface of the sealing board 40 and a protrusion 41b formed on the sealing board 40, and the protrusion 41b is brought into contact with a substrate 1 when the bump electrode 43 is joined with wiring 35, thus determining the condition of crushing of the bump electrode 43. Owing to such a structure, the condition of crushing condition of a plurality of the bump electrodes can be uniformized in an area surrounded by the protrusion 41b, and a variance of a contact area between the bump electrode and wiring be also suppressed. Contact resistance between the bump electrode and the wiring as well as an adhesive force working therebetween can be uniformized, respectively, so that electrical connection therebetween can be made firmer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device and a method for manufacturing the same, and more particularly, to a technique that can uniformize the degree of collapse of bump electrodes.

Conventionally, in an ink jet recording head, a circuit for driving a piezoelectric element (hereinafter referred to as a driver circuit) is manufactured on a separate substrate as an IC element and mounted on the recording head. Is 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.
For such a problem, if the driver circuit is not formed on a separate substrate, but directly formed on the flow path forming substrate constituting the recording head, for example, as disclosed in Patent Document 1, a wire is obtained. Since it is possible to electrically connect the driver circuit and the piezoelectric element without depending on the bonding, it is possible to cope with an increase in the density of the nozzle openings.

Further, as a method for forming a terminal for electrically connecting the driver circuit and the piezoelectric element, there is a method as disclosed in Patent Document 2, for example. According to such a method, the driver circuit and the piezoelectric element can be electrically connected via the bump electrode. Since the above connection can be realized with a narrower pitch than wire bonding and with a reduced thickness, it is possible to increase the density of the nozzle openings and further reduce the size of the ink jet recording head. be able to.
JP 2001-205815 A JP 2005-101527 A

By the way, in the method disclosed in Patent Document 2, for example, when the bump electrode is bonded to the wiring or the like, the degree of collapse of the bump electrode changes depending on the bonding pressure. For this reason, if the variation in bonding pressure is large, bump electrode crushing is uneven within the substrate surface or between batches, and the yield of the ink jet recording head and the reliability of electrical connection may be reduced. .
Therefore, the present invention has been made in view of such circumstances, and an object of the present invention is to provide an electronic device and a method for manufacturing the same that can uniformize the degree of collapse of the bump electrodes.

[Invention 1-5] The electronic device of the invention 1 includes a first substrate, and the first substrate is formed on the first substrate and a bump electrode formed on one surface of the first substrate. A contact portion, wherein the contact portion contacts the other substrate when the bump electrode is bonded to a predetermined region of the other substrate, and determines the collapse state of the bump electrode. It is what.
An electronic device according to a second aspect of the present invention is the electronic device according to the first aspect, comprising a plurality of the bump electrodes, and the contact portion is disposed so as to surround the plurality of bump electrodes within one surface of the first substrate. It is characterized by that.

The electronic device according to a third aspect of the invention is the electronic device according to the first or second aspect, further comprising an integrated circuit formed on one surface of the first substrate, wherein the bump electrode is connected to the integrated circuit. It is a feature. Here, the integrated circuit is, for example, a driver circuit for driving an ink jet recording head.
The electronic device according to a fourth aspect of the present invention is the electronic device according to any one of the first to third aspects of the present invention, including a second substrate as the other substrate, and the second substrate is formed on one surface of the second substrate. And the bump electrode is bonded to the wiring in a state where one surface of the first substrate faces one surface of the second substrate and the contact portion is in contact with the second substrate. It is characterized by being.

An electronic device according to a fifth aspect of the present invention includes a second substrate, and the second substrate includes a wiring formed on one surface of the second substrate and a contact portion formed on the second substrate. The contact portion is configured to contact the other substrate when the bump electrode formed on one surface of the other substrate is bonded to the wiring and determine the degree of collapse of the bump electrode. To do.
According to the electronic devices of the inventions 1 to 5, for example, when bonding the plurality of bump electrodes formed on one surface of the first substrate to the wiring formed on one surface of the second substrate, respectively, These bump electrodes can be uniformly crushed, and variations in contact area between the bump electrodes and the wiring can be reduced. As a result, the contact resistance generated between the bump electrode and the wiring and the adhesive force acting between the bump electrode and the wiring can be made uniform, so that the electrical connection between them can be made more reliable. can do. Therefore, it is possible to contribute to improvement in yield and reliability of the electronic device.

[Invention 6 to 10] The electronic device of Invention 6 is the electronic device of Invention 4 or Invention 5, in which the pressure generating chamber formed in the second substrate and one of the second substrates so as to cover the pressure generating chamber. And a piezoelectric element formed on the vibration film.
The electronic device according to a seventh aspect of the present invention is the electronic device according to the sixth aspect, further comprising a third substrate bonded to the other surface facing the one surface of the second substrate, wherein the third substrate has the pressure generation A nozzle opening communicating with the chamber is formed.

The electronic device according to an eighth aspect of the invention is the electronic device according to the sixth or seventh aspect, wherein the bump electrode is formed on a bottom surface of a concave portion formed on one surface of the first substrate, and the convex portion surrounding the concave portion is the It is a contact part, It is characterized by the above-mentioned.
An electronic device according to a ninth aspect is characterized in that, in the electronic device according to the eighth aspect, the piezoelectric element is sealed in the recess.
An electronic device according to a tenth aspect of the present invention is the electronic device according to any one of the sixth to ninth aspects, further comprising a reservoir that communicates with the pressure generating chamber and receives an ink liquid from the outside, wherein the reservoir is the first reservoir. It is formed on a substrate.
According to the electronic devices of the inventions 6 to 10, it is possible to provide an ink jet recording head with high yield and reliability, and an ink jet recording device including the recording head.

[Invention 11] In the method of manufacturing an electronic device according to Invention 11, the bump electrode formed on one surface of the first substrate is bonded to one of the first substrate and the second substrate when the bump electrode is bonded to a predetermined region of the second substrate. A contact portion that contacts and determines the degree of crushing of the bump electrode is provided in advance on the other of the first substrate and the second substrate.
According to such a method, for example, the degree of collapse of the bump electrode can be made uniform, and variations in the contact area between the bump electrode and the wiring can be reduced. As a result, the contact resistance generated between the bump electrode and the wiring and the adhesive force acting between the bump electrode and the wiring can be made uniform, so that the electrical connection between them can be made more reliable. can do. Therefore, it is possible to contribute to improvement in yield and reliability of the electronic device.

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 a first 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 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, and is formed with a plurality of individually divided ink flow paths. Here, the ink flow path is a path through which the ink liquid flows, and includes the pressure generation chamber 10.
A nozzle plate 60 is bonded to the back surface of the substrate 1 via an adhesive (not shown). 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. Note that the volume of the pressure generation chamber 10 that applies pressure to the ink liquid and the size of the nozzle opening 62 are optimized in accordance with the discharge amount of the ink liquid, the discharge speed, the 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 a common electrode across a plurality of piezoelectric elements 30, for example. 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. A concave portion 41 a for sealing the piezoelectric element 30 and a convex portion 41 b surrounding the concave portion 41 a are provided on the surface of the sealing plate 40 facing the piezoelectric element 30. As shown in FIG. 1, the convex portion 41b of the sealing plate 40 is bonded to the surface of the substrate 1 via an adhesive or the like (not shown), and the piezoelectric element 30 has a space that does not hinder its movement. In the state, it is sealed (that is, sealed) in the recess 41a.
A driver circuit 42 for driving the piezoelectric element 30 is integrally formed on the bottom surface of the recess 41a. A plurality of bump electrodes 43 are formed on the active surface (that is, the circuit forming surface) of the driver circuit 42, and these bump electrodes 43 are electrically connected to the wirings 34 and 35, respectively.

FIG. 2 is a cross-sectional view showing a configuration example of the bump electrode 43. As shown in FIG. 2, a pad electrode 81 made of aluminum (Al) or the like is formed on the active surface of the driver circuit 42, and is made of an insulating material such as a silicon oxide (SiO ₂ ) film around it. A passivation film 83 is formed. That is, the passivation film 83 covers the active surface with the pad electrode exposed, so that an elastic internal resin (bump core) 43a protrudes at a position away from the pad electrode 81 on the passivation film 83. Is formed. The internal resin 43a 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 43 b is formed on the surface of the internal resin 43 a, and the conductive film 43 b is electrically connected to the pad electrode 81. The conductive film 43b 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 43b may be enhanced by further covering the surface of the underlying conductive film made of copper (Cu), nickel (Ni), Al, or the like with Au plating or the like. A bump electrode 43 is constituted by the internal resin 43a and the conductive film 43b.

The configuration of the bump electrode 43 is not limited to the above. For example, the entire hemispherical bump electrode 43 shown in FIGS. 1 and 2 may be composed of only a conductive film such as Au, Cu, or Ni.
Moreover, the sealing plate 40 shown in FIG. 1 has 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 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 a recording signal from the driver circuit 42, 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 generation chamber 10, and the ink liquid is discharged from the nozzle opening 62.

  By the way, in this ink jet recording head 100, the convex portion 41b provided on the surface of the sealing plate 40 comes into contact with the surface of the substrate 1, and a certain separation distance is provided between the surface of the sealing plate 40 and the surface of the substrate 1. Thus, the degree of collapse of the bump electrode 43 is automatically determined. That is, when the height of the convex portion 41b is large when viewed from the bottom surface of the concave portion 41a, the degree of collapse of the bump electrode 43 is small, and the contact area between the bump electrode 43 and the wiring 35 is small. Further, when the height of the convex portion 41 b is small, the degree of collapse of the bump electrode 43 is large, and the contact area between the bump electrode 43 and the wiring 35 is large. Thus, there is a correlation between the height of the convex portion 41 b and the degree of collapse of the bump electrode 43. For this reason, when designing the ink jet recording head 100, the above correlation is obtained by experiment or simulation, and the height of the convex portion 41b is set to a predetermined value so that the collapse state of the bump electrode 43 becomes a desired shape. It is preferable to set.

Next, a method for manufacturing the ink jet recording head 100 will be described. 3 to 6 are cross-sectional views illustrating a method for manufacturing the ink jet recording head 100 according to the first embodiment of the present invention.
As shown in FIG. 3A, 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 51 in a region that becomes an ink flow path. Next, as shown in FIG. 3B, a sacrificial film 53 is formed on the entire surface of the substrate 1 to fill the groove 51. The thickness of the sacrificial film 53 is, for example, substantially the same thickness as the depth from the surface of the substrate 1 to the bottom surface of the groove 51 or a thickness greater than that. Next, the sacrificial film 53 is planarized by, for example, CMP (Chemical Mechanical Polish) to remove the sacrificial film 53 from regions other than the groove 51. As a result, the sacrificial film 53 can be left only in the groove 51 as shown in FIG.

The sacrificial film 53 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 53. 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 53. The SiO ₂ film as the sacrificial film 53 may be a PSG film having a relatively high etching rate.

  Further, the method for forming the sacrificial film 53 in the groove 51 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 53 is formed by using a so-called gas deposition method or jet molding method, in which ultrafine 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 53 in the groove 51 without performing a planarization step by CMP.

Next, as shown in FIG. 4A, the vibration film 20 is formed on the surface of the substrate 1 and the sacrificial film 53. 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 53 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 53.

  Next, as shown in FIG. 4B, 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 of the lower electrode film, platinum (Pt), iridium (Ir), or the like is preferable. 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 lower electrode 31 is a common electrode of the piezoelectric element 30 and the upper electrode 33 is an individual electrode of the piezoelectric element 30, but this may be reversed for the convenience of the driver circuit 42 and wiring. 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. 4C, a wiring 34 for drawing out the lower electrode 31 that is a common electrode to the substrate surface 1 and a wiring 35 for drawing the upper electrode 33 of each piezoelectric element 30 to the substrate surface 1 are formed. 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, as shown in FIG. 5A, a sealing plate 40 made of, for example, bulk silicon 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. Here, for example, the concave portion 41a is formed so that the shape of the concave portion 41a in plan view is similar to that of the piezoelectric element and has a large area, and the depth of the concave portion 41a is larger than the thickness of the piezoelectric element. Thereby, the recessed part 41a which can seal a piezoelectric element can be formed in the state which ensured the space of the grade which does not inhibit the motion of a piezoelectric element.

In the present invention, the piezoelectric elements are not individually sealed, but a plurality of piezoelectric elements are arranged in one recess 41a, whereby the plurality of piezoelectric elements are collectively sealed by one recess 41a. You may make it stop. In this case, the recess 41a may be formed wide so that a plurality of piezoelectric elements can be sealed together.
In addition, the convex part 41b will be formed in the outer periphery of a recessed part simultaneously with formation of the recessed part 41a. As described above, since there is a correlation between the height of the convex portion 41b viewed from the bottom surface of the concave portion 41a and the degree of collapse of the bump electrode 43, the degree of collapse of the bump electrode 43 becomes a desired shape in a later step. Thus, the recessed part 41a is formed in the predetermined depth here.

Next, as shown in FIG. 5B, a driver circuit 42 for driving the piezoelectric element 30 is formed on the bottom surface of the recess 41a. The driver circuit 42 is formed by a semiconductor process (that is, a film forming process, a photolithography process, an etching process, etc.). Then, as shown in FIG. 5C, a bump electrode 43 is formed on the active surface of the driver circuit. The bump electrode 43 is composed of, for example, an internal resin 43a and a conductive film 43b, and the formation method thereof is as described above.
Next, as shown in FIG. 5C, 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, as shown in FIG. 6, the sealing plate 40 on which the reservoir 45 is formed is bonded to the surface of the substrate 1 via an adhesive or the like. Here, the sealing plate 40 and the substrate 1 are aligned so that the recess 41a correctly overlaps with the piezoelectric element 30 and the plurality of bump electrodes 43 correctly overlap with the wirings 34 and 35, respectively. And the surface of the sealing board 40 is joined to the board | substrate 1 surface in the state aligned in this way. Accordingly, the piezoelectric element 30 is disposed and sealed in the recess 41a, and the bump electrode 43 and the wirings 34 and 35 are electrically connected to each other. A reservoir 45 is disposed to face the ink flow path.

  In the bonding process shown in FIG. 6, the bump 41 b contacts the surface of the substrate 1 after the bump electrode 43 contacts the surface of the wirings 34 and 35. Then, when the convex portion 41b contacts the surface of the substrate 1, a certain separation distance is secured between the sealing plate 40 and the substrate 1, and the plurality of bump electrodes 43 formed on the bottom surface of the concave portion 41a are crushed. The condition is automatically determined. Therefore, the degree of crushing of the bump electrode 43 can be made uniform on the bottom surface of the recess 41a, and variations in the contact area between the bump electrode 43 and the wirings 34 and 35 can be reduced.

Next, the back surface of the substrate 1 is ground to open the bottom surface of the groove 51. By this grinding, the sacrificial film 53 (see, for example, FIG. 4) is exposed from the back surface of the substrate 1. Further, before and after this grinding, the vibration film 20 is removed by etching using the sealing plate 40 as a mask, and an opening 46 exposing a part of the sacrificial film 53 is formed. Then, the sacrificial film 53 is etched through the reservoir 45 and the opening 46 and the bottom surface of the groove 51 opened on the back surface of the substrate 1. Thereby, the sacrificial film 53 is completely removed, and the pressure generating chamber 10 is formed. Etching of the sacrificial film 53 may be performed by either dry etching or wet etching. Here, the sacrificial film 53 is etched by using an etching gas or an etching solution in which the etching speed of the sacrificial film 53 is higher than that of the substrate 1. The film 53 is etched. For example, when the substrate 1 and the sealing plate 40 are Si and the sacrificial film 53 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. 6, the nozzle plate 60 in which the nozzle openings 62 are formed is bonded to the back surface of the substrate 1 through 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, when the plurality of bump electrodes 43 formed on the surface of the sealing plate 40 are joined to the wirings 34 and 35 formed on the surface of the substrate 1, respectively. In the region surrounded by the convex portion 41b (that is, the bottom surface of the concave portion 41a), the degree of collapse of the bump electrode 43 can be made uniform, and the variation in the contact area between the bump electrode 43 and the wirings 34 and 35 is reduced. be able to. As a result, the contact resistance generated between the bump electrode 43 and the wirings 34 and 35 and the adhesive force acting between the bump electrode 43 and the wirings 34 and 35 can be made uniform. Connection can be made more reliable. Therefore, it is possible to contribute to improvement in yield and reliability of the electronic device.

  In the first embodiment, the sealing plate 40 corresponds to the “first substrate” of the present invention, and the surface of the sealing plate 40 corresponds to “one surface of the first substrate” of the present invention. The convex portion 41b corresponds to the “contact portion” of the present invention, and the driver circuit 42 corresponds to the “integrated circuit” of the present invention. Further, the substrate 1 corresponds to the “second substrate” of the present invention, the front surface of the substrate 1 corresponds to “one surface of the second substrate” of the present invention, and the back surface of the substrate 1 corresponds to the “second substrate” of the present invention. Corresponds to “the other side of”. The nozzle plate 60 corresponds to the “third substrate” of the present invention. The ink jet recording head 100 and the ink jet recording apparatus including the head 100 correspond to the “electronic device” of the present invention.

(2) Second Embodiment In the above-described first embodiment, when the pressure generating chamber 10 is formed on the substrate 1, the concave portion 51 is formed in the substrate 1, and the sacrificial film 53 is embedded therein (FIG. 3). However, in the present invention, the pressure generating chamber 10 can be formed without using the sacrificial film 53. In the second embodiment, a method of forming the pressure generation chamber 10 that does not require a sacrificial film will be described.

8 and 9 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. 8A, 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 illustrated in FIG. 8B, 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 body 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 body 32 are formed by patterning the upper electrode film and the piezoelectric body film. Thereby, the piezoelectric element 30 is completed.

Next, in FIG. 8B, 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. 8C, a wiring 34 for leading the lower electrode 31 to the substrate surface 1 and a wiring 35 for leading the upper electrode 33 of each piezoelectric element 30 to the substrate surface 1 are formed.

  Next, as shown in FIG. 9A, the sealing plate 40 on which the reservoir 45 is formed is bonded to the surface of the substrate 1 via an adhesive or the like. The formation method of the sealing plate 40 is as having demonstrated, for example with reference to Fig.5 (a)-(d). As in the first embodiment, in this bonding step, the sealing plate 40 and the substrate 1 are arranged so that the concave portion 41a correctly overlaps the piezoelectric element 30 and the plurality of bump electrodes 43 correctly overlap the wirings 34 and 35, respectively. Are aligned, and the surface of the sealing plate 40 is bonded to the surface of the substrate 1. Accordingly, the piezoelectric element 30 is disposed and sealed in the recess 41a, and the bump electrode 43 and the wirings 34 and 35 are electrically connected to each other. A reservoir 45 is disposed to face the ink flow path.

  Next, as shown in FIG. 9B, 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 illustrated in FIG. 9C, the pressure generation chamber 10 is formed by partially etching the back surface of the substrate 1 using, for example, photolithography and etching techniques. 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 wall of the pressure generation chamber 10 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. 6, 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 third embodiment of the present invention, the formation of the sacrificial film 53 is not required when forming the pressure generating chamber 10, so that the number of steps can be reduced as compared with the first embodiment. Can contribute to the reduction of the manufacturing cost.

(3) Third Embodiment In the first embodiment described above, the case where the “contact portion” of the present invention is the convex portion 41 b and the convex portion 41 b is provided on the surface of the sealing plate 40 has been described. With such a configuration, as shown in FIGS. 7A and 7B, the convex portion 41 b comes into contact with the surface of the substrate 1, so that a constant amount is provided between the surface of the sealing plate 40 and the surface of the substrate 1. The separation distance d is secured, and the degree of collapse of the bump electrode 43 is automatically determined. However, the formation position of the “contact portion” of the present invention is not limited to the sealing plate 40, and may be the substrate 1, for example.

Specifically, as shown in FIGS. 10A and 10B, a convex portion 1b may be provided on the surface of the substrate 1 as the “contact portion” of the present invention. In this case, the piezoelectric element, the wiring 35 connected to the piezoelectric element, and the like are formed on the bottom surface of the concave portion 1a surrounded by the convex portion 1b. When the plurality of bump electrodes 43 formed on the sealing plate 40 are joined to the wiring 35 or the like, the convex portion 1b contacts the surface of the sealing plate 40, so that the surface of the sealing plate 40 and the substrate A certain distance d is ensured between the surface and one surface, and the degree of collapse of the bump electrode 43 is automatically determined. Therefore, in the region surrounded by the convex portion 1b, the degree of crushing of the plurality of bump electrodes 43 can be made uniform, and the same effect as in the first and second embodiments can be obtained.
In the third embodiment, the convex portion 1b corresponds to the “contact portion” of the present invention. Other correspondences are the same as those in the first embodiment.

(4) Fourth Embodiment In the first embodiment described above, the case where the “contact portion” of the present invention is the convex portion 41 b and the convex portion 41 b is provided on the surface of the sealing plate 40 has been described. In the third embodiment, the case where the “contact portion” of the present invention is the convex portion 1 b and the convex portion 1 b is provided on the surface of the substrate 1 has been described. However, the “contact portion” of the present invention may be provided on both of the sealing plate 40 and the substrate 1, but not both.

Specifically, as shown in FIGS. 11A and 11B, a convex portion 41b is provided on the surface of the sealing plate 40, and a convex portion 1b is provided on the surface of the substrate 1 in a region facing the convex portion 41b. May be. In this case, when the plurality of bump electrodes 43 are joined to the wiring 35 or the like, the convex portion 41b and the convex portion 1b come into contact with each other, and a certain distance is provided between the surface of the sealing plate 40 and the surface of the substrate 1. The distance d is secured, and the degree of collapse of the bump electrode 43 is automatically determined. Therefore, in the region surrounded by the convex portions 1b and 41b, the degree of crushing of the plurality of bump electrodes 43 can be made uniform, and the same effect as in the first to third embodiments can be obtained.
In the fourth embodiment, both the convex portion 41b and the convex portion 1b correspond to the “contact portion” of the present invention. Other correspondences are the same as those in the first embodiment.

(5) Fifth Embodiment In the fourth embodiment described above, both the convex portion 41b provided on the sealing plate 40 and the convex portion 1b provided on the substrate 1 are the “contact portion” of the present invention. Explained. However, the “contact portion” of the present invention is not limited to a convex portion, and may be a concave portion, for example.
Specifically, as shown in FIGS. 12A and 12B, a convex portion 41b is provided on the surface of the sealing plate 40, and a concave portion 1b ′ is provided on the surface of the substrate 1 in a region facing the convex portion 41b. The “contact portion” of the present invention may be configured by a combination of the convex portion 41b and the concave portion 1b ′. Alternatively, as shown in FIGS. 13A and 13B, a concave portion 41b ′ is provided on the surface of the sealing plate 40, and a convex portion 1b is provided on the surface of the substrate 1 in a region facing the concave portion 41b ′. You may comprise the "contact part" of this invention with the combination of 'and the convex part 1b. In either case, the convex portion comes into contact with the bottom surface of the concave portion, and a certain separation distance d is secured between the surface of the sealing plate 40 and the surface of the substrate 1, and the degree of collapse of the bump electrode 43 is automatically determined. The Therefore, in the region surrounded by the above-described concavo-convex portion, the degree of crushing of the plurality of bump electrodes 43 can be made uniform, and the same effect as in the first to fourth embodiments can be obtained.
In the fifth embodiment, a combination of the convex portion 41b and the concave portion 1b ′ or a combination of the concave portion 41b ′ and the convex portion 1b corresponds to the “contact portion” of the present invention. Other correspondences are the same as those in the first embodiment.

(6) Sixth Embodiment In the first to fifth embodiments described above, the case where the “contact portion” of the present invention is provided on the sealing plate 40 or the substrate 1 has been described. However, the “contact portion” of the present invention may be formed not only on the sealing plate 40 and the substrate 1 but also on the IC element.
For example, as shown in FIGS. 14A and 14B, a convex portion 71b is formed on the outer peripheral portion of the surface of the substrate 71 made of bulk silicon, and a driver circuit is formed on the bottom surface of the concave portion 71a surrounded by the convex portion 71b. The IC element 70 may be configured by forming 42 and a plurality of bump electrodes 43. With such a configuration, when the plurality of bump electrodes 43 formed on the substrate 71 are bonded to a predetermined region (for example, wiring) of another substrate (not shown), the convex portion 71b contacts the other substrate. By doing so, a certain separation distance is secured between the substrate 71 and another substrate, and the degree of collapse of the bump electrode 43 is automatically determined. The other substrate is a wiring substrate such as an interposer. Therefore, the crushing state of the plurality of bump electrodes 43 can be made uniform on the surface of the substrate 71, and the same effects as those of the first to fifth embodiments can be obtained.

In the sixth embodiment, as shown in FIGS. 15A and 15B, the convex portions 71 b may be disposed adjacent to both sides of each bump electrode 43. With such a configuration, the substrate 71 can be supported on both sides of each bump electrode 43 at the time of bonding, so that the degree of collapse of each bump electrode 43 can be determined with higher accuracy, and the degree of collapse. Can be made more uniform.
In the sixth embodiment, the substrate 71 corresponds to the “first substrate” of the present invention, the convex portion 71 b corresponds to the “contact portion” of the present invention, and the IC element 70 corresponds to the electronic device of the present invention. ing. Other correspondences are the same as those in the first embodiment.

(7) Seventh Embodiment In the first to sixth embodiments described above, the wirings 34 and 35 to be bonded to the bump electrode 43 are made of a metal film such as Al, Au, Ni, or Pt, for example. explained. However, the configuration of the wirings 34 and 35 is not limited to this. For example, as shown in FIGS. 16A and 16B, like the bump electrode 43, the wiring 35 is composed of an internal resin 35a and a conductive film 35b covering the internal resin 35a, and the conductive film 35b is a piezoelectric element (not shown). The upper electrode may be electrically connected. Although not shown, the same applies to the wiring 34 electrically connected to the lower electrode.

  Even in such a configuration, for example, when the convex portion 41 b provided on the sealing plate 40 contacts the surface of the substrate 1, a certain separation distance is provided between the surface of the sealing plate 40 and the surface of the substrate 1. d is secured, and the degree of collapse of the bump electrode 43 and the degree of collapse of the wirings 34 and 35 are automatically determined. Accordingly, it is possible to equalize the degree of crushing of the plurality of bump electrodes 43 and the degree of crushing of the plurality of wirings 34 and 35, respectively, and obtain the same effects as in the first to sixth embodiments.

1 is a diagram illustrating a configuration example of an ink jet recording head 100 according to a first embodiment. The figure which shows the structural example of the bump electrode 43. FIG. FIG. 2 is a diagram illustrating a method for manufacturing an ink jet recording head 100 (part 1). FIG. 2 is a diagram illustrating a method for manufacturing the ink jet recording head 100 (part 2). FIG. 3 is a diagram illustrating a method for manufacturing the ink jet recording head 100 (No. 3). FIG. 4 illustrates a method for manufacturing the ink jet recording head 100 (No. 4). The figure which shows an example of the "contact part" of this invention (1st Embodiment). The figure which shows the manufacturing method which concerns on 2nd Embodiment (the 1). The figure which shows the manufacturing method which concerns on 2nd Embodiment (the 2). The figure which shows an example of the "contact part" of this invention (3rd Embodiment). The figure which shows an example of the "contact part" of this invention (4th Embodiment). The figure which shows an example of the "contact part" of this invention (5th Embodiment). The figure which shows an example of the "contact part" of this invention (5th Embodiment). Sectional drawing and the bottom view which show the structural example of the IC element 70 which concerns on 6th Embodiment. Sectional drawing and the bottom view which show the other structural example of the IC element 70 which concerns on 6th Embodiment. The figure which shows the structural example of the wiring 35 which concerns on 7th Embodiment.

Explanation of symbols

  1 Substrate, 1a, 41a, 71a, 1b ′, 41b ′ Concavity, 1b, 41b, 71b Convex, 10 Pressure generating chamber, 20 Vibration film, 30 Piezoelectric element, 31 Lower electrode, 32 Piezoelectric body, 33 Upper electrode, 34 , 35 wiring, 35a, 43a internal resin, 35b, 43b conductive film, 40 sealing plate, 42 driver circuit, 43 bump electrode, 45 reservoir, 51 groove, 53 sacrificial film, 60 nozzle plate, 62 nozzle opening, 70 IC Element, 100 Inkjet recording head

Claims (11)

A first substrate,
The first substrate is
A bump electrode formed on one surface of the first substrate;
A contact portion formed on the first substrate,
The electronic device according to claim 1, wherein when the bump electrode is bonded to a predetermined region of another substrate, the contact portion is in contact with the other substrate to determine a degree of collapse of the bump electrode. A plurality of the bump electrodes are provided,
The electronic device according to claim 1, wherein the contact portion is disposed so as to surround the plurality of bump electrodes within one surface of the first substrate. An integrated circuit formed on one surface of the first substrate,
The electronic device according to claim 1, wherein the bump electrode is connected to the integrated circuit. A second substrate as the other substrate,
The second substrate is
Wiring formed on one surface of the second substrate,
The bump electrode is bonded to the wiring in a state where one surface of the first substrate faces one surface of the second substrate and the contact portion is in contact with the second substrate. The electronic device according to any one of claims 1 to 3. A second substrate,
The second substrate is
Wiring formed on one surface of the second substrate;
A contact portion formed on the second substrate,
The contact portion is configured to contact the other substrate and determine a degree of collapse of the bump electrode when a bump electrode formed on one surface of the other substrate is bonded to the wiring. Electronic equipment. A pressure generating chamber formed in the second substrate;
A vibrating membrane formed on one surface of the second substrate so as to cover the pressure generating chamber;
The electronic device according to claim 4, further comprising: a piezoelectric element formed on the vibration film. A third substrate bonded to the other surface opposite to the one surface of the second substrate;
The electronic device according to claim 6, wherein a nozzle opening communicating with the pressure generating chamber is formed in the third substrate. The bump electrode is formed on the bottom surface of the recess formed on one surface of the first substrate,
The electronic device according to claim 6, wherein a convex portion surrounding the concave portion is the contact portion.   The electronic device according to claim 8, wherein the piezoelectric element is sealed in the recess. A reservoir that communicates with the pressure generation chamber and receives an ink supply from the outside; and
The electronic device according to claim 6, wherein the reservoir is formed on the first substrate.   Abutting that determines whether the bump electrode is crushed by contacting one of the first substrate and the second substrate when a bump electrode formed on one surface of the first substrate is bonded to a predetermined region of the second substrate. A part is provided in advance on the other of the first substrate and the second substrate.

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