JP6587178B2 - Ink jet print head and manufacturing method thereof - Google Patents

Description

  The present invention relates to an ink jet print head and a method for manufacturing the same.

Patent Document 1 discloses an ink jet print head using a piezoelectric element. The ink jet print head disclosed in Patent Document 1 includes a semiconductor substrate, a movable film (vibration film) that is provided on the semiconductor substrate and is movable in a direction facing the semiconductor substrate, a piezoelectric element provided on the movable film, and a movable film. A pressure chamber formed on the semiconductor substrate side of the film so as to face the movable film and filled with ink. The movable film and the surface of the piezoelectric element are covered with a hydrogen barrier film made of Al ₂ O ₃ . An interlayer insulating film made of SiO ₂ is formed on the hydrogen barrier film. Wirings for piezoelectric elements are formed on the interlayer insulating film. The interlayer insulating film and the wiring are covered with a surface protective film made of SiN.

  The movable film is formed with a communication chamber that penetrates the movable film and communicates with the pressure chamber. Further, the hydrogen barrier film, the interlayer insulating film, and the surface protective film are formed so as to penetrate therethrough, and through holes (ink discharge holes) that communicate with the communication chamber are formed.

JP 2011-56939 A

The inventor tried to use polyimide as a surface protective film of an ink jet print head. When polyimide is used as the surface protective film, flexibility is improved as compared with the case where an oxide film or a nitride film is used as the surface protective film. For this reason, it is considered that the displacement amount of the movable film can be increased.
However, when polyimide is used as the surface protective film, there are the following problems when the ink discharge holes are formed in the surface protective film. For example, when the ink discharge hole is formed in the surface protective film by dry etching using the resist pattern as a mask, a part of the polyimide is removed in the resist removing process (ashing process).

  In addition, in the case where ink discharge holes are formed in the surface protective film by using photosensitive polyimide as a surface protective film, exposing the pattern corresponding to the ink discharge holes, and then developing the polyimide, ink discharge The side surface of the hole is not perpendicular to the surface of the movable film, and becomes an inclined surface (tapered surface). Even when ink discharge holes are formed in the surface protective film by wet etching, the side surfaces of the ink discharge holes are not perpendicular to the surface of the movable film, but become inclined surfaces.

When ink discharge holes are formed in the surface protective film by dry etching using a hard mask, the side surfaces of the ink discharge holes are substantially perpendicular to the surface of the movable film. Since this is necessary, the number of processes increases.
An object of the present invention is to provide an ink jet print head that can make the side surface of the ink ejection hole substantially perpendicular to the surface of the movable film without increasing the number of steps, and a method for manufacturing the same.

  An ink jet print head according to the present invention includes a substrate having a pressure chamber filled with ink, a movable film forming layer including a movable film disposed on the pressure chamber and defining a top surface portion of the pressure chamber, and the movable film And a piezoelectric element formed on a surface opposite to the pressure chamber. In the movable film, an ink discharge passage that penetrates the movable film in the thickness direction and communicates with the pressure chamber is formed in a region where the piezoelectric element is not formed. On the surface of the movable film opposite to the pressure chamber, a polyimide nozzle having an ink discharge hole communicating with the ink discharge passage is formed in a region near the ink discharge passage. The ink discharge passage and the ink discharge hole are aligned with each other when viewed from the pressure chamber side, and their cross-sectional shapes and sizes are substantially equal.

  In this configuration, since the ink discharge holes can be formed by dry etching using the movable film forming layer as a hard mask, a side surface (processed surface) with good perpendicularity can be obtained. Further, it is not necessary to remove the movable film forming layer. Therefore, according to this configuration, the side surface of the ink ejection hole can be made substantially perpendicular to the surface of the movable film without increasing the number of steps.

In one embodiment of the present invention, the side surface of the ink ejection hole is formed substantially perpendicular to the surface of the movable film. According to this configuration, a high-performance nozzle can be obtained.
In one embodiment of the present invention, the cross-sectional shape of the ink discharge passage and the ink discharge hole is circular.
In one embodiment of the present invention, the ink discharge hole is formed by dry etching from the pressure chamber side using the movable film having the ink discharge passage as a hard mask.

In one embodiment of the present invention, the nozzle is constituted by a part of a surface protective film made of polyimide. In this configuration, since it is not necessary to provide a member dedicated to the nozzle, the configuration is simplified.
In one embodiment of the present invention, the piezoelectric element is formed in an annular shape surrounding the ink discharge passage in a plan view viewed from the normal direction with respect to the main surface of the movable film.

In one embodiment of the present invention, the piezoelectric element includes a lower electrode formed on a surface of the movable film forming layer opposite to the pressure chamber, and the movable film forming layer is opposite to the lower electrode. An upper electrode disposed on the side, and a piezoelectric film provided between the upper electrode and the lower electrode.
In one embodiment of the present invention, a hydrogen barrier film formed on the movable film forming layer and covering the piezoelectric element and the movable film forming layer, an interlayer insulating film formed on the hydrogen barrier film, and the interlayer Formed on an insulating film and connected to the lower electrode; formed on the interlayer insulating film; connected to the upper electrode; formed on the movable film forming layer; An area surrounding the ink discharge passage on the film surface, a surface protection film made of polyimide covering the interlayer insulating film and the wiring, and the nozzle is constituted by a region near the ink discharge passage in the surface protection film Yes.

In one embodiment of the present invention, the circuit further includes a drive circuit that is formed on the substrate and applies a voltage to the piezoelectric element.
In one embodiment of the present invention, the movable film forming layer is made of a SiO ₂ film.
In one embodiment of the present invention, the piezoelectric film is a PZT film.
In one embodiment of the present invention, the upper electrode is formed of the piezoelectric body and Ir0 ₂ film formed on the film, laminated film of Ir film formed on the Ir0 ₂ film.

In one embodiment of the present invention, the lower electrode is a laminated film of a Ti film formed on the movable film side and a Pt film formed on the Ti film.
An ink jet print head manufacturing method according to the present invention includes a step of forming a movable film forming layer including a movable film forming region having an ink discharge passage forming region on a substrate, and formation of the ink discharge passage on the movable film forming region. Forming a piezoelectric element in a region excluding the region, forming a hydrogen barrier film and an insulating film covering the piezoelectric element and the lower electrode in order on the movable film forming layer, the hydrogen barrier film and the Patterning an insulating film to form an opening in the laminated film of the hydrogen barrier film and the insulating film to expose the ink discharge passage forming region and its peripheral portion on the surface of the movable film forming region; Forming a wiring connected to the piezoelectric element, and passing through the movable film forming layer in the thickness direction in the ink discharge passage forming region. Forming a surface discharge film on the movable film forming layer; forming a surface protection film made of polyimide covering the insulating film and the wiring; and etching the substrate from below to form the movable film. A step of forming a pressure chamber facing the formation region; and an ink discharge hole communicating with the ink discharge passage by dry etching the surface protective film from the pressure chamber side using the movable film forming layer as a hard mask. Forming on the surface protective film.

  In this manufacturing method, since the ink discharge hole is formed by dry etching using the movable film forming layer as a hard mask, a side surface (processed surface) with good perpendicularity can be obtained. Further, it is not necessary to remove the movable film forming layer used as the hard mask. Therefore, according to this manufacturing method, the side surface of the ink ejection hole can be made substantially perpendicular to the surface of the movable film without increasing the number of steps.

  The step of forming the piezoelectric element includes a step of forming a lower electrode film, a piezoelectric film material film, and an upper electrode film on the movable film forming layer, and the upper electrode film, the piezoelectric film material film, and the lower electrode film. Forming a piezoelectric element including the lower electrode, the upper electrode, and the piezoelectric film sandwiched therebetween by forming an upper electrode, a piezoelectric film, and a lower electrode. May be.

The step of patterning the hydrogen barrier film and the insulating film includes a first contact hole exposing a part of the lower electrode and a second contact exposing a part of the upper electrode to the hydrogen barrier film and the insulating film. A step of forming a hole may be further included.
The step of forming the wiring includes forming a wiring film on the insulating film and then patterning the wiring film, thereby connecting the lower wiring connected to the lower electrode through the first contact hole, A step of forming an upper wiring connected to the upper electrode through two contact holes may be included.

FIG. 1 is a schematic plan view of an ink jet print head according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the ink jet print head taken along section line II-II shown in FIG. FIG. 3 is a block diagram of an integrated circuit formed in the circuit formation region shown in FIG. 4A is a schematic cross-sectional view for explaining a method of manufacturing the ink jet print head shown in FIG. FIG. 4B is a schematic cross-sectional view showing a step subsequent to FIG. 4A. FIG. 4C is a schematic cross-sectional view showing a step subsequent to FIG. 4B. FIG. 4D is a schematic cross-sectional view showing a step subsequent to FIG. 4C. FIG. 4E is a schematic cross-sectional view showing a step subsequent to FIG. 4D. FIG. 4F is a schematic cross-sectional view showing a step subsequent to FIG. 4E. FIG. 4G is a schematic cross-sectional view showing a step subsequent to FIG. 4F. FIG. 4H is a schematic cross-sectional view showing a step subsequent to FIG. 4G. FIG. 4I is a schematic cross-sectional view showing a step subsequent to FIG. 4H. FIG. 4J is a schematic sectional view showing a step subsequent to FIG. 4I. FIG. 4K is a schematic cross-sectional view showing a step subsequent to FIG. 4J. FIG. 4L is a schematic sectional view showing a step subsequent to FIG. 4K. FIG. 4M is a schematic cross-sectional view showing a step subsequent to FIG. 4L. FIG. 4N is a schematic cross-sectional view showing a step subsequent to FIG. 4M. FIG. 4O is a schematic sectional view showing a step subsequent to FIG. 4N. FIG. 4P is a schematic sectional view showing a step subsequent to FIG. 4O. FIG. 4Q is a schematic sectional view showing a step subsequent to FIG. 4P. FIG. 4R is a schematic sectional view showing a step subsequent to FIG. 4Q. FIG. 4S is a schematic cross-sectional view showing a step subsequent to FIG. 4R. FIG. 4T is a schematic cross-sectional view showing a step subsequent to FIG. 4S. FIG. 4U is a schematic cross-sectional view showing a step subsequent to FIG. 4T.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic plan view of an ink jet print head according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the ink jet print head taken along section line II-II shown in FIG. In FIG. 2, hatching is given only to a portion made of a conductor, and hatching is not given to other portions.

The ink jet print head 1 includes a silicon substrate 2. A nozzle formation region 3 and a circuit formation region 4 are set on the silicon substrate 2.
In the nozzle forming region 3, a movable film forming layer 5 is formed on the entire surface of the silicon substrate 2 as shown in FIG. The movable film forming layer 5 is made of SiO ₂ (silicon oxide). The thickness of the movable film forming layer 5 is, for example, 0.5 to 2 μm.

  On the movable film forming layer 5, as shown in FIG. 1, a plurality of piezoelectric elements 6 are arranged in a matrix with equal intervals in the row direction and the column direction. The piezoelectric element 6 includes a lower electrode 7, a piezoelectric film 8 formed on the lower electrode 7, and an upper electrode 9 formed on the piezoelectric film 8. In other words, the piezoelectric element 6 is formed by sandwiching the piezoelectric film 8 between the upper electrode 9 and the lower electrode 7 from above and below. A through hole 10 is formed in the piezoelectric element 6 so as to penetrate in the thickness direction. That is, the piezoelectric element 6 is formed in an annular shape in plan view as viewed from the normal direction with respect to the main surface of the movable film forming layer 5.

The lower electrode 7 is integrally provided with an annular main electrode portion 11 constituting the piezoelectric element 6 and an extension portion 12 extending linearly from the periphery of the main electrode portion 11. The lower electrode 7 has a two-layer structure in which a Ti (titanium) layer and a Pt (platinum) layer are sequentially stacked from the movable film forming layer 5 side.
The piezoelectric film 8 is formed on an annular plate having the same shape as that of the main electrode portion 11 of the lower electrode 7 in plan view. The piezoelectric film 8 is made of PZT (lead zirconate titanate: Pb (Zr, Ti) O ₃ ).

The upper electrode 9 is formed in an annular shape having the same shape as that of the piezoelectric film 8 in plan view. The upper electrode 9 has a two-layer structure in which an IrO ₂ (iridium oxide) layer and an Ir (iridium) layer are sequentially laminated from the piezoelectric film 8 side.
In the nozzle forming region 3, the surfaces of the movable film forming layer 5 and the piezoelectric element 6 are covered with a hydrogen barrier film 13. The hydrogen barrier film 13 is made of Al ₂ O ₃ (alumina). Thereby, characteristic deterioration due to hydrogen reduction of the piezoelectric film 8 can be prevented.

An interlayer insulating film 14 is laminated on the hydrogen barrier film 13. Interlayer insulating film 14 is made of SiO _2. In the laminated film of the hydrogen barrier film 13 and the interlayer insulating film 14, a circular opening 19 in plan view that exposes the periphery of the ink discharge passage 63 on the surface of the movable film 5 </ b> A in the inner region of the through hole 10 of each piezoelectric element 6. Is formed. A lower wiring 15 and an upper wiring 16 are formed on the interlayer insulating film 14. These wirings 15 and 16 are made of a metal material containing Al (aluminum).

  One end of the lower wiring 15 is disposed above the tip of the extension 12 of the lower electrode 7. Between the one end portion of the lower wiring 15 and the extension portion 12, a first contact hole 17 that continuously penetrates the hydrogen barrier film 13 and the interlayer insulating film 14 is formed. One end of the lower wiring 15 enters the first contact hole 17 and is connected to the extension 12 in the first contact hole 17.

  One end of the upper wiring 16 is disposed above the peripheral edge of the upper electrode 9. A second contact hole 18 that continuously penetrates the hydrogen barrier film 13 and the interlayer insulating film 14 is formed between one end of the upper wiring 16 and the upper electrode 9. One end of the upper wiring 16 enters the second contact hole 18 and is connected to the upper electrode 9 in the second contact hole 18. The other end portions of the lower wiring 15 and the upper wiring 16 are connected to a driver 72 (see FIG. 3) described later.

In the circuit formation region 4, an integrated circuit including, for example, an N-channel MOSFET (Negative-channel Metal Oxide Semiconductor Field Effect Transistor) 21 and a P-channel MOSFET (Positive-channel Metal Oxide Semiconductor Field Effect Transistor) 22 is formed.
In the circuit formation region 4, the NMOS region 23 in which the N-channel MOSFET 21 is formed and the PMOS region 24 in which the P-channel MOSFET 22 is formed are insulated and isolated from each other by the element isolation unit 25. The element isolation portion 25 includes a thermal oxide film 27 formed on the inner surface of a groove (for example, a shallow trench having a depth of 0.2 to 0.5 μm) dug relatively shallowly from the surface of the silicon substrate 2, and thermal oxidation. And an insulator 28 filling the inside of the film 27. The insulator 28 is made of, for example, SiO ₂ . The surface of the insulator 28 is flush with the surface of the silicon substrate 2.

  A P-type well 31 is formed in the NMOS region 23. The depth of the P-type well 31 is larger than the depth of the groove 26. In the surface layer portion of the P-type well 31, an N-type source region 33 and a drain region 34 are formed with a channel region 32 interposed therebetween. The depth and impurity concentration of the end portions of the source region 33 and the drain region 34 on the channel region 32 side are reduced. That is, in the N-channel MOSFET 21, an LDD (Lightly Doped Drain) structure is applied.

A gate insulating film 35 is formed on the channel region 32. The gate insulating film 35 is made of SiO _2. A gate electrode 36 is formed on the gate insulating film 35. The gate electrode 36 is made of N-type polysilicon. Sidewalls 37 are formed around the gate insulating film 35 and the gate electrode 36. The sidewall 37 is made of SiN.
Silicides 38, 39, and 40 are formed on the surfaces of the source region 33, the drain region 34, and the gate electrode 36, respectively.

  An N-type well 41 is formed in the PMOS region 24. The depth of the N-type well 41 is larger than the depth of the groove 26. In the surface layer portion of the N-type well 41, a P-type source region 43 and a drain region 44 are formed with a channel region 42 interposed therebetween. The depth and impurity concentration of the end portions of the source region 43 and the drain region 44 on the channel region 42 side are reduced. That is, the LD channel structure is applied to the P-channel MOSFET 22.

A gate insulating film 45 is formed on the channel region 42. The gate insulating film 45 is made of SiO _2. A gate electrode 46 is formed on the gate insulating film 45. The gate electrode 46 is made of P-type polysilicon. A sidewall 47 is formed around the gate insulating film 45 and the gate electrode 46. The side wall 47 is made of SiN.
Silicides 48, 49, and 50 are formed on the surfaces of the source region 43, the drain region 44, and the gate electrode 46, respectively.

In the circuit formation region 4, an interlayer insulating film 51 is formed on the surface of the silicon substrate 2. Interlayer insulating film 51 is made of SiO _2. On the interlayer insulating film 51, wirings 52, 53, and 54 are formed. The wirings 52, 53, 54 are made of a metal material containing Al.
The wiring 52 is formed above the source region 33. Between the wiring 52 and the source region 33, the interlayer insulating film 51 is provided with a contact plug 55 for electrically connecting them. The contact plug 55 is made of W (tungsten).

  The wiring 53 is formed above the drain region 34 and the drain region 44 so as to straddle them. Between the wiring 53 and the drain region 34, the interlayer insulating film 51 is provided with a contact plug 56 for electrically connecting them. In addition, between the wiring 53 and the drain region 44, a contact plug 57 is provided through the interlayer insulating film 51 to electrically connect them. The contact plugs 56 and 57 are made of W.

The wiring 54 is formed above the source region 43. Between the wiring 54 and the source region 43, the interlayer insulating film 51 is provided with a contact plug 58 for electrically connecting them. The contact plug 58 is made of W.
On the movable film forming layer 5, a surface protective film 61 covering the interlayer insulating films 14 and 51, the wirings 15, 16, 52, 53 and 54 and the movable film forming layer 5 exposed from the opening 19 is formed. . The surface protective film 61 is made of polyimide.

  In the silicon substrate 2, pressure chambers 62 as ink reservoirs are formed at positions facing the respective piezoelectric elements 6. In this embodiment, the pressure chamber 62 is formed through the silicon substrate 2. In this embodiment, the pressure chamber 62 is formed in a circular shape in plan view. An ink tank (not shown) storing ink is attached to the back surface of the silicon substrate 2. The pressure chamber 62 is filled with ink supplied from the ink tank.

  The top wall portion of each pressure chamber 62 in the movable film forming layer 5 constitutes a movable film 5A. In this specification, the movable film 5 </ b> A means a top wall portion that partitions the top surface portion of each pressure chamber 62 in the movable film forming layer 5. Therefore, portions of the movable film forming layer 5 other than the top wall portion of each pressure chamber 62 do not constitute the movable film 5A. A piezoelectric element 6 is provided on each movable film 5A. In each movable film 5A, an ink discharge passage 63 that penetrates the movable film 5A in the thickness direction and communicates with the pressure chamber 62 is formed in an inner region of the through hole 10 of the piezoelectric element 6. In this embodiment, the cross-sectional shape of the ink discharge passage 63 is circular. The side surface of the ink discharge passage 63 is formed substantially perpendicular to the surface of the movable film 5A.

  Inside the through hole 10 of each piezoelectric element 6, an ink discharge hole (nozzle hole) 64 that penetrates the surface protective film 61 in the thickness direction and communicates with the ink discharge passage 63 is formed in the surface protective film 61. Yes. The ink discharge passage 63 and the ink discharge hole 64 formed inside the through hole 10 of each piezoelectric element 6 are aligned with each other when viewed from the pressure chamber 62 side, and the shape and size of the cross section thereof are as follows. Almost equal. The side surface of the ink discharge hole 64 is formed substantially perpendicular to the surface of the movable film 5A.

  A portion in the vicinity of each ink discharge passage 63 in the surface protective film 61 constitutes a nozzle 61 </ b> A having an ink discharge hole 64. In other words, the piezoelectric element 6 is formed in an annular shape surrounding the periphery of the nozzle 61 </ b> A (ink discharge hole 64) except for the extension 12 of the lower electrode 7. The piezoelectric element 6 is formed in an annular shape that is disposed on the side of the nozzle 61A and surrounds the periphery of the nozzle 61A (ink discharge hole 64). The side refers to a side in a direction parallel to the surface of the silicon substrate 2.

FIG. 3 is a block diagram of an integrated circuit formed in the circuit formation region shown in FIG.
An example of the integrated circuit formed in the circuit formation region 4 is a control circuit 71 that controls driving (ink ejection) of the piezoelectric element 6. The control circuit 71 includes a driver (drive circuit) 72 individually connected to each piezoelectric element 6 and a serial input parallel output type shift register 73 to which a plurality of drivers 72 are connected. The N-channel MOSFET 21 and the P-channel MOSFET 22 shown in FIG. 2 are used for the driver 72, for example.

  Each driver 72 is connected to the power supply voltage VDD and the ground GND. The shift register 73 is connected to the power supply voltage VDD and the ground GND. The shift register 73 is provided with a clock terminal and a data terminal. The clock CLK is input to the clock terminal. Data DATA of an image to be formed on the paper is input to the data terminal. In the shift register 73, every time the clock CLK is input from the clock terminal, the data DATA input from the data terminal is shifted (transferred) between the flip-flops.

A voltage is applied from the driver 72 to the piezoelectric element 6 based on the data DATA held in the shift register 73. When a voltage is applied from the driver 72 to the piezoelectric element 6, the movable film 5 </ b> A is deformed together with the piezoelectric element 6. By this deformation, the ink in the pressure chamber 62 is pressurized and the ink is ejected from the ink ejection holes 64.
4A to 4U are schematic cross-sectional views sequentially showing manufacturing steps of the ink jet print head shown in FIG. In FIGS. 4A to 4U, hatching is given only to a portion made of a conductor, and hatching is not given to other portions.

In the manufacturing process of the inkjet print head 1, first, as shown in FIG. 4A, an oxidation made of SiO _{2 is performed} on the surface of the silicon substrate 2 by a thermal oxidation method or a CVD (Chemical Vapor Deposition) method. A film 81 is formed. Subsequently, a nitride film 82 made of SiN (silicon nitride) is formed by CVD. A resist pattern 83 is formed on the nitride film 82 by photolithography. The resist pattern 83 exposes only the portion of the silicon substrate 2 where the groove 26 is to be formed and covers the other portions.

Next, as shown in FIG. 4B, the nitride film 82, the oxide film 81, and the surface layer portion of the silicon substrate 2 are selectively removed in order by etching using the resist pattern 83 as a mask. As a result, a groove 26 is formed in the surface layer portion of the silicon substrate 2. After the formation of the groove 26, the resist pattern 83 is removed.
Thereafter, as shown in FIG. 4C, a thermal oxide film 27 is formed on the inner surface of the groove 26 by a thermal oxidation method. Next, the material of the insulator 28 is deposited on the thermal oxide film 27 and the nitride film 82 by the CVD method. Then, the deposited material and the nitride film 82 are polished by a CMP (Chemical Mechanical Polishing) method. This polishing is continued until the surface of the oxide film 81 is exposed. As a result, an insulator 28 is obtained on the thermal oxide film 27. At this point, the insulator 28 is flush with the surface of the oxide film 81.

  Thereafter, a resist pattern 84 is formed on the insulator 28 and the oxide film 81 by photolithography. The resist pattern 84 is formed over the entire region other than the PMOS region 24 on the insulator 28 and the oxide film 81. Then, an N-type impurity (for example, P (phosphorus)) is implanted into the PMOS region 24 by ion implantation using the resist pattern 84 as a mask. As a result, an N-type well 41 is formed in the PMOS region 24 as shown in FIG. 4D. After the implantation of the N-type impurity, the resist pattern 84 is removed.

  Next, a resist pattern 85 is formed on the insulator 28 and the oxide film 81 by photolithography. The resist pattern 85 is formed over the entire region other than the NMOS region 23 on the insulator 28 and the oxide film 81. Then, by ion implantation, a P-type impurity (for example, B (boron)) is implanted into the NMOS region 23 using the resist pattern 85 as a mask. As a result, a P-type well 31 is formed in the NMOS region 23 as shown in FIG. 4E. After the implantation of the P-type impurity, the resist pattern 85 is removed.

Thereafter, the oxide film 81 is removed by wet etching. At this time, the upper end portion of the insulator 28 is also etched, and the insulator 28 becomes substantially flush with the surface of the silicon substrate 2. Thereafter, a silicon oxide film 86 is formed over the entire surface of the silicon substrate 2 by thermal oxidation or CVD.
Subsequently, as shown in FIG. 4F, a polysilicon layer 87 is formed on the silicon oxide film 86 by the CVD method.

Thereafter, as shown in FIG. 4G, a resist pattern 88 is formed on the polysilicon layer 87 by photolithography. Resist pattern 88 covers only the portions of polysilicon layer 87 that are to become gate electrodes 36 and 46.
Then, the polysilicon layer 87 is patterned by etching using the resist pattern 88 as a mask. Thereby, as shown in FIG. 4H, gate electrodes 36 and 46 are formed. After the patterning of the polysilicon layer 87, the resist pattern 88 is removed. Thereafter, N-type impurities are implanted into the surface layer portion of the P-type well 31 and the gate electrode 36 by ion implantation. Also, P-type impurities are implanted into the surface layer portion of the N-type well 41 and the gate electrode 46 by ion implantation.

  Next, as shown in FIG. 4I, the silicon oxide film 86 is selectively removed by etching using the gate electrodes 36 and 46 as a mask, and the gate insulating films 35 and 45 are obtained on the silicon substrate 2. Thereafter, SiN is deposited on the entire area of the silicon substrate 2 by the CVD method. Then, the sidewalls 37 and 47 are formed by etching back the deposited layer of SiN.

  After the formation of the sidewalls 37 and 47, as shown in FIG. 4J, the surface layer of the P-type well 31 is implanted to a position deeper than the N-type impurity into which the N-type impurity has been previously implanted by ion implantation. A source region 33 and a drain region 34 are formed. Further, by ion implantation, a source region 43 and a drain region 44 are formed in the surface layer portion of the N-type well 41 up to a position deeper than the P-type impurity into which the P-type impurity has been previously implanted. Thereafter, silicides 38, 39, 40, 48, 49, 50 are formed.

Next, as shown in FIG. 4K, the movable film forming layer 5 and the interlayer insulating film 51 are formed by the CVD method. The movable film forming layer 5 and the interlayer insulating film 51 are made of, for example, SiO ₂ .
Thereafter, as shown in FIG. 4L, a lower electrode film 89 having the same laminated structure as that of the lower electrode 7 is formed over the entire area of the movable film forming layer 5 and the interlayer insulating film 51 by sputtering. Further, a piezoelectric material film 90 made of the same material as the piezoelectric film 8 is formed on the entire area of the lower electrode film 89 by sputtering or sol-gel method. Further, the upper electrode film 91 having the same laminated structure as the upper electrode 9 is formed on the entire area of the piezoelectric material film 90 by sputtering.

Next, as shown in FIG. 4M, a resist pattern 92 is formed on the upper electrode film 91 so as to cover the portion of the upper electrode film 91 that becomes the upper electrode 9 by photolithography.
Thereafter, as shown in FIG. 4N, the upper electrode film 91 is patterned by etching using the resist pattern 92 as a mask, and the upper electrode 9 is formed. Subsequently, the piezoelectric material film 90 is patterned by etching to form the piezoelectric film 8. After the formation of the piezoelectric film 8, the resist pattern 92 is removed. Next, a new resist pattern (not shown) is formed on the lower electrode film 89 by photolithography so as to cover the portion of the lower electrode film 89 that becomes the lower electrode 7. Then, the lower electrode film 89 is patterned by etching using a new resist pattern as a mask, and the lower electrode 7 is formed. After the formation of the lower electrode 7, the resist pattern is removed.

  Thereafter, through holes that penetrate the interlayer insulating film 51 in the thickness direction are formed in portions of the interlayer insulating film 51 facing the source regions 33 and 43 and the drain regions 34 and 44 by photolithography and etching. Then, W is supplied into each through hole by the CVD method, and each through hole is filled with W. As a result, as shown in FIG. 4O, contact plugs 55 to 58 are formed. Thereafter, an alumina film 93 is formed on the entire area of the silicon substrate 2 by sputtering. Further, a silicon oxide film 94 is formed over the entire area of the alumina film 93 by the CVD method.

  Next, as shown in FIG. 4P, the silicon oxide film 94 and the alumina film 93 are patterned by photolithography and etching. As a result, the silicon oxide film 94 and the alumina film 93 are removed from the circuit forming region 4. In addition, the alumina film 93 and the silicon oxide film 94 become the hydrogen barrier film 13 and the interlayer insulating film 14, respectively, and contact holes 17, 18 and an opening 19 that continuously penetrate the hydrogen barrier film 13 and the interlayer insulating film 14 are formed. The

Thereafter, an Al film is formed on the interlayer insulating films 14 and 51 by sputtering. Then, the Al film is patterned by photolithography and etching, and wirings 15, 16, 52, 53, and 54 are formed as shown in FIG. 4Q.
Thereafter, as shown in FIG. 4R, an ink discharge passage 63 is formed in the movable film forming layer 5 (movable film 5A) by photolithography and etching. The ink discharge passage 63 is formed at the center of the opening 19 in plan view.

Thereafter, as shown in FIG. 4S, the surface protective film 61 covering the movable film forming layer 5, the interlayer insulating films 14, 51 and the wirings 15, 16, 52, 53, 54 on the movable film forming layer 5 by the CVD method. Is formed. The surface protective film 61 is made of polyimide. At this time, the surface protective film 61 is also filled in the ink discharge passage 63.
After the surface protective film 61 is formed, a resist pattern (not shown) is formed on the back surface of the silicon substrate 2 by photolithography. This resist pattern exposes a portion to be the pressure chamber 62 in the silicon substrate 2 and covers other portions. Then, by dry etching using the resist pattern as a mask, a pressure chamber 62 is formed in the silicon substrate 2 as shown in FIG. 4T.

Thereafter, as shown in FIG. 4U, ink discharge holes 64 communicating with the ink discharge passages 63 are formed in the surface protective film 61 by dry etching from the pressure chamber 62 side using the movable film forming layer 5 as a hard mask. Thereby, the inkjet print head 1 is obtained.
In the above-described embodiment, since the ink discharge hole 64 is formed by dry etching using the movable film forming layer 5 as a hard mask, a side surface (processed surface) with good perpendicularity can be obtained. Further, the movable film forming layer 5 used as a hard mask for forming the ink discharge holes 64 does not need to be removed after the ink discharge holes 64 are formed. Therefore, according to the above-described embodiment, the side surface of the ink ejection hole 64 can be made substantially perpendicular to the surface of the movable film 5A without increasing the number of steps.

  Further, by using the silicon substrate 2, semiconductor elements such as an N channel MOSFET 21 and a P channel MOSFET 22 can be formed. Further, wirings 52, 53, 54 are formed on the silicon substrate 2 with the interlayer insulating film 51 interposed therebetween, and the wirings 52, 53, 54 are connected to the N-channel MOSFET 21 and the P-channel MOSFET 22 through contact plugs 55-58. Thus, the ink jet print head 1 can include an integrated circuit (control circuit 71).

Further, since the driver (driving circuit) 72 for applying a voltage to the piezoelectric element 6 is formed on the silicon substrate 2 provided with the movable film forming layer 5, the main body portion of the ink jet print head 1 and its driving circuit 72. Can be configured with one chip (one chip).
As mentioned above, although embodiment of this invention was described, this invention can also be implemented in another embodiment.

For example, in the above-described embodiment, the piezoelectric element 6 has an annular shape in a plan view, but may have a rectangular shape in a plan view, a circular shape, a C shape in a plan view, or the like.
In the embodiment, the piezoelectric element 6 is formed so as to surround the ink discharge passage 63 in a plan view, but the piezoelectric element 6 may be formed on the side of the ink discharge passage 63.

In the above-described embodiment, the silicon substrate 2 is used as an example of the semiconductor substrate. However, instead of the silicon substrate 2, a substrate made of a semiconductor material other than silicon such as SiC (silicon carbide) may be used. Good.
In the above-described embodiment, PZT is exemplified as the material of the piezoelectric film. In addition, lead titanate (PbPO ₃ ), potassium niobate (KNbO ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate A piezoelectric material made of a metal oxide typified by (LiTaO ₃ ) or the like may be applied.

  In addition, various design changes can be made within the scope of the matters described in the claims.

2 Silicon substrate (semiconductor substrate)
DESCRIPTION OF SYMBOLS 5 Movable film formation layer 5A Movable film 6 Piezoelectric element 7 Lower electrode 8 Piezoelectric film 9 Upper electrode 11 Main electrode part 12 Extension part 13 Hydrogen barrier film 14 Interlayer insulation film 15 Lower wiring 16 Upper wiring 17, 18 Contact hole 19 Opening 61 Surface protective film 61A Nozzle 62 Pressure chamber 63 Ink discharge passage 64 Ink discharge hole

Claims (14)

A substrate having a pressure chamber filled with ink;
A movable film forming layer including a movable film disposed on the pressure chamber and defining a top surface portion of the pressure chamber;
A piezoelectric element formed on the surface of the movable film opposite to the pressure chamber,
In the movable film, an ink discharge passage that penetrates the movable film in the thickness direction and communicates with the pressure chamber is formed in a region where the piezoelectric element is not formed,
On the surface of the movable film opposite to the pressure chamber, a nozzle made of polyimide having an ink discharge hole communicating with the ink discharge passage is formed in a region near the ink discharge passage.
The ink and discharge passage and the ink discharge hole is located aligned when viewed from the pressure chamber side, and rather substantially equal in shape and size of their cross section,
The ink discharge hole has a side surface that is a processed surface by dry etching from the pressure chamber side using the movable film having the ink discharge passage as a hard mask,
The ink jet print head , wherein the side surface is formed substantially perpendicular to the surface of the movable film . The inkjet print head according to claim 1, wherein a cross-sectional shape of the ink discharge passage and the ink discharge hole is circular . The ink jet print head according to claim 1 , wherein the nozzle is composed of a part of a surface protective film made of polyimide . 4. The piezoelectric element according to claim 1, wherein the piezoelectric element is formed in an annular shape surrounding the ink discharge passage in a plan view as viewed from a normal direction with respect to a main surface of the movable film . Inkjet printhead. The piezoelectric element is
A lower electrode formed on the surface of the movable film forming layer opposite to the pressure chamber;
An upper electrode disposed on the opposite side of the movable film forming layer with respect to the lower electrode;
The inkjet print head according to any one of claims 1 to 4, further comprising a piezoelectric film provided between the upper electrode and the lower electrode . A hydrogen barrier film formed on the movable film forming layer and covering the piezoelectric element and the movable film forming layer;
An interlayer insulating film formed on the hydrogen barrier film;
A lower wiring formed on the interlayer insulating film and connected to the lower electrode;
An upper wiring formed on the interlayer insulating film and connected to the upper electrode;
A surface protective film formed on the movable film forming layer and made of polyimide covering the area around the ink discharge passage on the movable film surface, the interlayer insulating film, and the wiring;
The ink jet print head according to claim 1 , wherein the nozzle is configured by a region near the ink discharge passage in the surface protective film . The inkjet print head according to claim 1 , further comprising a drive circuit formed on the substrate and applying a voltage to the piezoelectric element . It said movable membrane forming layer is made of SiO ₂ film, an inkjet printhead according to any one of claims 1-6. The ink jet print head according to claim 5 , wherein the piezoelectric film is made of a PZT film . The upper electrode, wherein the piezoelectric Ir0 ₂ film formed on the film, a stacked film of the Ir film formed on the Ir0 ₂ film, ink jet print head according to claim 9. 11. The ink jet print head according to claim 10 , wherein the lower electrode includes a laminated film of a Ti film formed on the movable film side and a Pt film formed on the Ti film . Forming a movable film forming layer including a movable film forming area having an ink discharge passage forming area on a substrate;
Forming a piezoelectric element in a region excluding the ink discharge passage forming region on the movable film forming region;
Forming a hydrogen barrier film and an insulating film covering the piezoelectric element and the lower electrode in order on the movable film forming layer;
Patterning the hydrogen barrier film and the insulating film to form an opening in the laminated film of the hydrogen barrier film and the insulating film to expose the ink discharge passage forming region and its peripheral portion on the surface of the movable film forming region; When,
Forming a wiring connected to the piezoelectric element on the insulating film;
Forming an ink discharge passage penetrating the movable film forming layer in a thickness direction in the ink discharge passage formation region;
Forming a surface protective film made of polyimide covering the insulating film and the wiring on the movable film forming layer;
Etching the substrate from below to form a pressure chamber facing the movable film forming region;
Using the movable film forming layer as a hard mask to dry-etch the surface protective film from the pressure chamber side, thereby forming an ink discharge hole communicating with the ink discharge passage in the surface protective film. A method for manufacturing a printhead. The step of forming the piezoelectric element includes:
Forming a lower electrode film, a piezoelectric film material film and an upper electrode film on the movable film forming layer;
The upper electrode film, the piezoelectric film material film, and the lower electrode film are patterned to form the upper electrode, the piezoelectric film, and the lower electrode, thereby forming the lower electrode, the upper electrode, and the piezoelectric body sandwiched between them. A method for manufacturing an ink jet print head according to claim 12, comprising forming a piezoelectric element including a film. The step of patterning the hydrogen barrier film and the insulating film includes a first contact hole exposing a part of the lower electrode and a second contact exposing a part of the upper electrode to the hydrogen barrier film and the insulating film. Further comprising forming a hole;
The step of forming the wiring includes forming a wiring film on the insulating film and then patterning the wiring film, thereby connecting the lower wiring connected to the lower electrode through the first contact hole, The method for manufacturing an ink jet print head according to claim 13 , comprising a step of forming an upper wiring connected to the upper electrode through two contact holes .

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