JP2006272659A - Liquid jet head, its manufacturing method, and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet head for simply preventing a malfunction caused by a noise, while preventing a reduction in wiring density, and a manufacturing method for the liquid jet head. <P>SOLUTION: This liquid jet head equipped with a plurality of piezoelectric elements driven according to different signals comprises a channel forming substrate (10) wherein the plurality of piezoelectric elements (300) are formed, a joint substrate (30) which is formed of wholly grounded silicon, and a plurality of signal wires (200) which are formed on the joint substrate and which are each fed with different signals. The liquid jet head is formed in such a shape that the area, per unit length, of the contact of the signal wire (203), which may generate the noise with high probability, among the plurality of signal wires with the joint substrate is larger than the area, per unit length, of the contact of the other signal wires with the joint substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording head, and more particularly, to a head structure and a method for manufacturing the head that can easily prevent malfunction due to noise in a head in which pressure generating elements are formed with high density.

  The ink jet recording head is provided with a plurality of piezoelectric elements, and a plurality of signal lines are wired in order to supply drive signals to each piezoelectric element from a drive IC that outputs a drive signal for each piezoelectric element. ing. A power supply wiring is also wired in parallel with such a signal line.

Here, there has been proposed a semiconductor integrated circuit in which the influence of noise is not exerted on a subsequent circuit in the case where power supply noise at the time of power supply startup or noise on an adjacent signal line is present. Japanese Patent Application Laid-Open No. 7-74610 is an example of such a circuit. When the capacitor detects the fluctuation of the power supply voltage and the node of the signal line is at the L level, the level of the node is not increased by the change of the power supply voltage. A transistor that supplies a GND level voltage that suppresses the increase is provided for each signal line (Patent Document 1). According to the present invention, it is possible to prevent malfunction of the circuit due to the power supply noise even when the power supply voltage fluctuates when the power is turned on or due to noise.
JP-A-7-74610 (paragraphs 0029 to 0030)

  However, according to the invention described in the above publication, since it is necessary to provide a circuit including a transistor and a capacitor for each signal line, it is difficult to apply to a portion that requires high-density mounting.

  For example, a liquid ejecting head represented by an ink jet recording head has increased the number of piezoelectric elements mounted per head in order to cope with the recent high definition. A control signal for a large number of piezoelectric elements must be supplied to a single drive IC, and a drive signal having a constant voltage amplitude must be supplied to each piezoelectric element. In such a liquid jet head, since the structure itself is complicated because a plurality of complicatedly shaped silicon substrates are stacked, a circuit for countermeasures against noise is further provided in each signal line for supplying a control signal. That was impossible. Further, if noise prevention is an essential issue, it is necessary to expand the area for providing a conventional noise prevention circuit. The area for such a circuit is required for high-density mounting. It was forced to make some concessions.

  If an erroneous determination of the logic state occurs due to noise, incorrect print control is performed, and unnecessary ink ejection or necessary ink ejection failure occurs. Must be provided for each signal line.

  SUMMARY An advantage of some aspects of the invention is to provide a liquid ejecting head and a manufacturing method thereof for easily preventing malfunction due to noise while preventing reduction in wiring density.

  The present invention is a liquid ejecting head including a plurality of pressure generating elements driven by different signals, a flow path forming substrate on which a plurality of pressure generating elements are formed, a bonding substrate formed of grounded silicon, A plurality of signal lines that are formed on the bonding substrate and are supplied with different signals, and a contact area of the signal line that is highly likely to generate noise among the plurality of signal lines is The other signal lines are formed to have a larger area than the contact area to the bonding substrate.

  According to another aspect of the invention, there is provided a liquid ejecting head including a plurality of pressure generating elements driven by different signals, a flow path forming substrate on which the plurality of pressure generating elements are formed, and a junction formed of grounded silicon And a plurality of signal lines that are formed on the bonding substrate and to which different signals are respectively supplied, and among the plurality of signal lines, the wiring width of the signal lines that are highly likely to generate noise is different. The signal line is formed to be larger than the wiring width.

  According to another aspect of the invention, there is provided a method of manufacturing a liquid ejecting head including a plurality of pressure generating elements driven by different signals, the step of forming a flow path forming substrate including a plurality of pressure generating elements, and a flow path forming substrate. A step of forming a bonding substrate on which a space including a plurality of pressure generating elements is formed, and driving for driving the pressure generating element and the pressure generating element on a surface of the bonding substrate opposite to the space including the pressure generating element; Forming a plurality of signal lines for electrically connecting the device, and the contact area of the signal lines that are likely to generate noise among the plurality of signal lines to the bonding substrate is different. The signal line is formed to have a larger area than the contact area to the bonding substrate.

  According to another aspect of the invention, there is provided a method of manufacturing a liquid jet head including a plurality of pressure generating elements driven by different signals, the step of forming a flow path forming substrate including a plurality of pressure generating elements, Forming a bonding substrate for forming a space including a plurality of pressure generating elements on the surface, and a driving device for driving the pressure generating elements and the pressure generating elements on a surface of the bonding substrate opposite to the space including the pressure generating elements Forming a plurality of signal lines for electrically connecting to each other, and among the plurality of signal lines, a wiring width of a signal line that is likely to generate noise is set to a wiring width of another signal line. It is characterized by being formed larger than the width.

  The liquid ejecting head includes a large number of channels, and a pressure generating element is provided for each channel. A large number of signal lines for supplying driving signals to the pressure generating elements are formed. In particular, as signal lines are gathered around the drive device that supplies drive signals to these signal lines, signal lines and power supply lines are densely arranged around the drive device. At this time, if the main body of the bonding substrate to which the signal line is wired is grounded, each of the signal lines formed on the bonding substrate is connected to the stray capacitance and path resistance of the signal line. Will be grounded. Here, according to the present invention, the width of the signal line that is highly likely to generate noise among the signal lines is set larger than that of the other signal lines. Since the stray capacitance is proportional to the electrode area, if the signal line area and width are large, the stray capacitance also increases, and the impedance can be lowered for high frequency components, and the impedance can be reduced to lower frequency components. Can be kept low. Accordingly, the voltage amplitude of the noise component can be reduced, and it is possible to prevent malfunction.

  Here, the “liquid ejecting head” is a concept including an ink jet recording head capable of ejecting so-called ink, but also includes the entire liquid ejecting means used for industrial applications for ejecting liquid other than ink. . For example, an alkaline solution, a color material for producing a color filter, an organic EL display device, an electrode pattern material such as an EFD (surface emitting display device), a sample solution for producing a biochip, or the like may be discharged.

  Furthermore, in the present invention, when the power supply wiring is provided, it is preferable that the contact area of the power supply wiring to the bonding substrate is larger than the contact area of the other signal lines to the bonding substrate. Moreover, it is preferable that the wiring width in the power supply wiring is formed larger than the wiring width in the other signal lines.

  Although noise at the time of power-on and noise at the time of operation may occur in the power supply line, if this noise component interferes with the signal line, it may cause malfunction of the circuit. According to the configuration of the present invention, the width of the power supply line is set larger than that of the signal line. For this reason, the stray capacitance in the power supply line is increased, the impedance can be lowered for the high frequency component, and the impedance can be lowered to the lower frequency component. Therefore, it is possible to reduce the voltage amplitude of the noise component in the power supply line and to prevent malfunction in other signal lines.

  Here, among the plurality of signal lines, a signal line that is highly likely to generate noise is a power supply wiring, a drive signal wiring of the pressure generating element, and a common electrode wiring of the pressure generating element. Switching noise at power-on / off may be mixed in the power supply wiring, and the drive signal wiring and common electrode wiring include a pulse signal for driving the pressure generating element. This is because it contains possible components.

  Further, the plurality of signal lines include a ground wiring, and an insulating film is formed between the bonding substrate and the plurality of signal lines, and a part of the insulating film in the ground wiring is removed to remove the ground wiring. It is preferable that the bonding substrate is grounded by being in contact with the bonding substrate. In the present invention, the silicon forming the bonding substrate is grounded. However, if the signal line includes a ground wiring (GND wiring, grounding line), an insulating film that insulates the ground wiring from the bonding substrate is provided. If they are removed and both are connected, the bonded substrate can be grounded easily.

  The present invention is also a printing apparatus including the liquid ejecting head. Here, the “printing apparatus” includes a printer that performs printing by so-called ink, but also includes an entire ejection apparatus that is used for industrial applications that eject liquids other than ink (see above).

Next, embodiments of the present invention will be described with reference to the drawings.
The following embodiment exemplifies an ink jet recording head as the liquid jet head of the present invention, and the present invention is not limited to the following embodiment and can be modified and applied.

(Embodiment 1)
The principle of the present invention will be described with reference to FIG. FIG. 1A is a plan view showing a state in which signal lines S1 to S5, a high potential power supply line Vdd, and a low potential power supply line Vss are laid in parallel, and FIG. 1B is a cross-sectional view thereof. These signal lines and power supply lines are laid on the silicon substrate, which is a bonding substrate, by patterning with an insulating film therebetween. Here, in the case where the low-potential power supply wiring Vss is a ground wiring, the insulating film between the ground wiring and the bonding substrate is partially removed, so that the silicon substrate is grounded via the ground wiring. Is preferred.

  Different signals are supplied to the signal lines S1 to S5, respectively. Among these signal lines S1 to S5, a signal line that is highly likely to generate noise is a signal line S3. In the present invention, the contact area (wiring width d3 of the signal line S3) of the signal line S3 where the noise is highly likely to occur is equal to the bonding substrate of the other signal lines S1, S2, S4, and S5. It is characterized in that it is formed larger than the contact area (wiring widths d1, d2, d4, d5 of the signal lines S1, S2, S4, S5).

  FIG. 1C shows an equivalent circuit in the case where the floating resistances of these signal lines and power supply lines and the path resistance to the ground potential are taken into consideration. As shown in FIG. 1C, stray capacitances C1 to C5 exist between the signal lines S1 to S5 and the ground potential. This stray capacitance is connected in series with the path resistors R1 to R5. Similarly, a series connection of the stray capacitance C0 and the path resistance R0 is connected in parallel with the load resistance Rdd of the high potential power supply between the high potential power supply wiring Vdd and the ground potential. Between the low potential power supply line Vss and the ground potential, a series connection of the stray capacitance C6 and the path resistance R6 is connected in parallel with the load resistance Rss of the low potential power supply. However, if the low-potential power supply wiring Vss is a ground wiring, C6 and R6 can be virtually ignored.

Here, the wiring width d3 of the signal line S3 that is highly likely to generate noise is larger than the wiring width of the other signal lines,
d3> d1, d2, d4, d5
There is a relationship. Since the stray capacitance is proportional to the electrode area, the area s1 to s5 of each signal line is
s3> s1, s2, s4, s5
It becomes the relationship. Since the stray capacitance C3 of the signal line S3 in which noise is generated is larger than that of the other signal lines, if the path resistance is assumed to be substantially equal in the comparison between the signal lines, the cutoff frequency of the signal line S3 is the other signal line. It becomes lower than the cut-off frequency.

For example, if the path resistance of the signal line itself is r, the cutoff frequency fc of the signal line S3 is
fc = 1 / 2πC3 (r + R3)
It becomes. If the wiring width is increased and the wiring area is increased, the cut-off frequency can be lowered accordingly, and the voltage amplitude can be expected to decrease more if the frequency components are the same. That is, among the harmonic components contained in the noise, the impedance can be lowered with respect to a relatively high frequency component, and the impedance can be lowered to a relatively low frequency component. Therefore, the voltage amplitude of noise about the signal line S3 can be reduced.

  If the voltage amplitude of noise in the signal line is large, the drive IC that is the drive device determines that the logic state is different and may cause a malfunction. However, as in the present invention, a signal line that is expected to generate noise. Increasing the wiring width (for example, S3) can prevent this malfunction. If the noise level of a signal line that may generate noise is reduced, noise interference with other signal lines is also reduced.

  Since the noise reduction effect is greater as the path resistance is smaller, the noise reduction effect is higher when the resistance of the substrate on which the wiring is provided is lower to some extent. For example, when the substrate is silicon, an appropriate amount of impurities may be mixed in the silicon substrate to reduce the sheet resistance and the noise level within a range where crosstalk and level reduction of the signal itself do not matter. In particular, if the low potential power supply wiring Vss adjacent to the signal lines S1 to S5 is a ground wiring, the impurity density of the silicon substrate in the region where the ground wiring and the signal lines S1 to S5 are formed can be increased. The sheet resistance can be lowered. In the present embodiment, the principle of FIG. 1 is applied to signal wiring of an ink jet recording head.

  Of course, if the wiring width of all the signal lines is increased, the noise level can be lowered, but the increase in the wiring width is contrary to the demand for higher wiring density. Here, the noise level between the signal lines is not necessarily the same because the type of signal supplied to each signal line and the routing of the wiring are different. Therefore, the present invention is devised to suppress the reduction of the wiring density as much as possible by increasing the wiring width or wiring area of the signal line only for signals expected to be mounted when the noise level is high. There is also a feature in the point. In particular, it is possible to reduce the size of the head by increasing the wiring width or wiring area of the power supply wiring, the drive signal wiring for the pressure generating element, the common electrode wiring for the pressure generating element, or the wiring area that is highly likely to generate noise. Thus, it is possible to reduce the voltage amplitude of the noise component in the power supply line and to prevent malfunction in other signal lines. Next, the ink jet recording head of this embodiment using this principle will be described.

  FIG. 2 is an exploded perspective view showing an outline of the ink jet recording head according to the embodiment of the present invention. FIG. 3A is a plan view thereof, and FIG. 3B is a sectional view thereof.

  As shown in FIG. 2, the ink jet recording head according to the present embodiment includes a flow path forming substrate 10 on which a plurality of piezoelectric elements 300 are formed, a bonding substrate 30 formed of silicon with the substrate grounded, and a bonding substrate. Are provided with a plurality of signal line groups 200 to which different signals are supplied. In this signal line group 200, in particular, in the present invention, the contact area (wiring width) to the bonding substrate 30 in a signal line (in this case, 203) that is highly likely to generate noise is the other signal line (201). , 202, 204, 205) is characterized in that it is formed larger than the contact area (wiring width) to the bonding substrate. Each structure will be described in more detail.

In this embodiment, the flow path forming substrate 10 is formed by etching a silicon single crystal substrate having a plane orientation (110) to form a plurality of vertically long pressure generation chambers 12 partitioned by a plurality of partition walls on one surface thereof. Has been. A communication portion 13 is formed outside one end in the longitudinal direction of the pressure generation chamber 12, and the communication portion 13 communicates with each pressure generation chamber 12 via an ink supply path 14. The thickness of the flow path forming substrate 10 is appropriately selected according to the density at which the pressure generating chambers 12 are formed. For example, when the nozzle density is about 180 (180 dpi) per inch, that is, the pitch of the pressure generating chamber 12 is set, the rigidity of the partition wall is more than a certain value by setting the thickness to about 180 to 280 μm, more preferably about 220 μm. The crosstalk due to the bending of the partition wall can be prevented. For example, when the nozzle density is about 360 (360 dpi) per inch, the thickness of the flow path forming substrate 10 is preferably about 100 μm. A protective film 100 made of a material exhibiting ink resistance is formed on the inner surfaces of the pressure generating chamber 12, the communication portion 13, and the ink supply passage 14 with which the ink of the flow path forming substrate 10 comes into contact. The material exhibiting ink resistance is, for example, tantalum pentoxide (Ta ₂ O ₅ ) and may be formed to a thickness of about 50 nm. Since the protective film 100 made of tantalum oxide has very excellent ink resistance, the shape of the pressure generating chamber can be maintained for a long time.

A nozzle plate 20 is bonded to the opening surface side of the flow path forming substrate 10 where the pressure generating chamber 12 is opened. In the nozzle plate, nozzles 21 are formed at a pitch corresponding to each pressure generating chamber 12. The nozzle plate 20 is made of, for example, stainless steel (SUS), glass ceramics, or silicon. The thickness of the nozzle plate 20 is, for example, about 0.01 to 1 mm and has a small linear expansion coefficient (for example, 2.5 to 4.5 × 10 ⁻⁶ / ° C. at 300 ° C. or lower).

  A plurality of piezoelectric elements 300 are provided on the side opposite to the opening surface side of the flow path forming substrate 10 via the elastic film 50. The elastic film 50 is an insulating film made of silicon oxide having a thickness of about 1 μm, and changes the pressure in the pressure generating chamber 12 by being deformed in accordance with the deformation of the piezoelectric element 300. An insulator film 51 is further formed on the elastic film 50. On the insulator film 51, a lower electrode film 60 serving as one electrode for applying an electric field to the piezoelectric element is patterned in common to all the piezoelectric elements 300. The piezoelectric layer 70 is a ferroelectric ceramic such as lead zirconate titanate (PZT) or a relaxor ferroelectric ceramic obtained by adding a metal such as niobium, nickel, magnesium, bismuth, or yttrium to the perovskite type. It is a ceramic crystal body having a crystal structure. The piezoelectric layer 70 is formed to have a length that can sufficiently deform the elastic film 50 along the longitudinal direction of the pressure generating chamber 12. The upper electrode film 80 is formed on the piezoelectric layer 70 and serves as the other electrode for applying an electric field to the piezoelectric element 300. For example, the lower electrode film 60 is formed to a thickness of about 0.2 μm, the piezoelectric layer 70 is formed to a thickness of about 1 μm, and the upper electrode film 80 is formed to a thickness of about 0.1 μm. The upper and lower electrode films are made of, for example, platinum (Pt). The upper and lower electrodes of the piezoelectric element may all be electrically independent. However, since wiring becomes complicated, usually one electrode film (here, the lower electrode film 60) is used as a common electrode as in this embodiment. Yes. In each piezoelectric element 300, a lead electrode 90 having a laminated structure including an adhesion layer 91 and a metal layer 92 is patterned and serves as a voltage supply line to the upper electrode film 80. The metal layer 92 is made of, for example, gold (Au). The upper electrode film and the lower electrode film may all be electrically separated, or the common electrode may be the upper electrode film and the individual electrode may be the lower electrode film.

  In a region corresponding to the peripheral portion of the communication portion 13 of the elastic film 50, a through portion 54 from which the elastic film 50 and the insulator film 51 are removed is formed. A metal film 53 made of gold is formed on the inner edge of the penetrating portion 54 so as to cover the ends of the elastic film 50 and the insulator film 51. On the metal film 53, the same layer structure as the lead electrode 90 made of the adhesion layer 91 and the metal layer 92 is patterned.

  The bonding substrate 30 is a substrate that forms a space including such a margin that the assembly of the piezoelectric elements 300 does not hinder the deformation movement caused by the driving of the piezoelectric elements 300. The bonding substrate 30 is formed with a piezoelectric element holding portion 32 that covers the upper portion of the piezoelectric element 300 in common and forms a space. In addition, a reservoir portion 31 that forms a space common to the communication portion 13 and forms an ink storage space is formed at a position corresponding to the communication portion 13 of the flow path forming substrate 10. Since the bonding substrate 30 is preferably made of a material having substantially the same coefficient of thermal expansion as that of silicon, which is a material for forming the flow path forming substrate 10, silicon is used. An insulating film (not shown) made of a silicon dioxide film formed by thermally oxidizing the bonding substrate is formed on the surface of the bonding substrate 30.

  A through hole penetrating the bonding substrate in the thickness direction is illustrated in the region corresponding to the ink supply path 14 in the flow path forming substrate 10 between the piezoelectric element holding portion 32 and the reservoir portion 31 of the bonding substrate 30. It is provided in a position that does not.

  The bonding substrate 30 and the flow path forming substrate 10 are formed with an adhesive layer 35, and both the substrates are hermetically bonded. The adhesive for the adhesive layer is not particularly limited, but an ink resistant adhesive such as an epoxy resin adhesive is used.

  A compliance substrate 40 having a structure in which an elastic film 41 made of polyphenylene sulfide (PPS) having a thickness of about 6 μm is pressed by a holding substrate 42 is bonded to the upper portion of the reservoir portion 31 of the bonding substrate 30. The compliance substrate 40 relieves an instantaneous overpressure state of the ink that occurs when the ink flows into the reservoir portion 31 by the elastic extension of the elastic film 41, and is a pressure for appropriately filling the ink. It is an adjustment part.

  Further, the signal line group 200 according to the present invention is formed by patterning on the surface of the bonding substrate 30 opposite to the piezoelectric element holding portion 32. On the signal line group 200, a driving IC 210 as a driving device is flip-chip mounted in a state where it is directly electrically connected. The drive IC 210 is electrically connected to the piezoelectric element 300 by a drive wiring 220 that connects the tip end portion of the lead electrode 90 drawn from each piezoelectric element 300 to the outside of the bonding substrate 30 and the drive IC 210. . A drive signal from a control unit (not shown) is supplied and inputted to the drive IC 210 by the signal line group 200, and an output from the drive IC 210 is sent to each piezoelectric element 300 via the drive wiring 220 and the lead electrode 90. Pulse voltage is supplied. The mounting from the signal line group 200 to the driving IC 210 and from the driving IC 210 to each piezoelectric element can also be performed by wire bonding.

3A and 3B, in the signal line group 200, the wiring width D1 of the signal line 203 is larger than the wiring width D0 of the other signal lines 201, 202, 204, and 205. There is a feature of the invention. That is, the principle explained in FIG. 1 is applied.
As shown in FIG. 3A, in this embodiment, this principle is applied to the signal line group 200 on the bonding substrate 30 wired at high density, and the bonding substrate 30 may be grounded to generate noise. The wiring width D1 of the high signal line 203 is made larger than the wiring width D0 of the other signal lines 201, 202, 204, and 205. The noise of the signal line 203 connected to the driving IC 210 is reduced, so that the malfunction of the ink jet recording head is suppressed.

(Production method)
Next, a method for manufacturing these ink jet recording heads will be briefly described.
The assembly of the flow path forming substrate 10 and the piezoelectric element 300 shown in FIG. 2 is formed by first forming the piezoelectric element 300 on one surface of the flow path forming substrate 10 and then wet etching the other surface. .

  First, a silicon single crystal substrate having a surface orientation (110) is thermally oxidized in a diffusion furnace at about 1100 ° C. while maintaining a wafer shape to form a silicon dioxide film to be an elastic film 50, and then a zirconium layer on the elastic film 50 Is formed by sputtering or the like, and then thermally oxidized in a diffusion furnace at 500 to 1200 ° C. to form an insulator film 51 made of zirconium oxide.

  Next, a predetermined metal, such as platinum and iridium, is laminated on the insulator film 51 to form the lower electrode film 60, and then patterned into a predetermined shape as shown in FIG. Next, the piezoelectric layer 70 is formed using a predetermined method. Various methods such as a sol-gel method and a MOD method can be applied to the piezoelectric body forming method. When applying the sol-gel method, a piezoelectric material formed by a process consisting of coating, degreasing and drying of a precursor of a ferroelectric ceramic, for example, a metal alkoxide solution which is a precursor material of lead zirconate titanate (PZT). A plurality of thin films are stacked. A piezoelectric thin film is laminated to a required thickness, and finally fired to grow crystals and complete the piezoelectric layer 70. On the piezoelectric layer 70, a predetermined metal, for example, iridium, is laminated by a sputtering method or the like to form the upper electrode film 80. By these steps, the structure of the piezoelectric element in which the piezoelectric layer is sandwiched between the pair of electrode films is completed. Therefore, the upper electrode film 80 and the piezoelectric layer 70 are removed by etching all at once, and the shape of each piezoelectric element 300 is obtained. To form.

  Subsequently, a metal film 53 is formed on the upper electrode film 80 using a material having a different etching rate from the silicon material of the flow path forming substrate, such as silicon nitride (SiN). Then, the metal film in the region facing the piezoelectric element 300 is removed, and the metal film 53 is left only in the region corresponding to the reservoir portion.

  Next, the lead electrode 90 connected to the upper electrode film 80 of the piezoelectric element 300 is formed. First, the adhesion layer 91 is formed, and then the metal layer 92 is formed. At this time, a layer composed of the adhesion layer 91 and the metal layer 92 is also formed on the metal film 53. The shape of the lead electrode 90 is formed by patterning the metal layer 92 and the adhesion layer 91 with a predetermined mask pattern. As the adhesion layer 91, titanium (Ti), titanium tungsten compound (TiW), nickel (Ni), chromium (Cr), or the like can be applied. As the metal layer 92, gold (Au), aluminum (Al), Copper (Cu) or the like can be applied.

A shape as the bonding substrate 30 is formed on a reservoir forming silicon single crystal substrate different from the channel forming substrate silicon single crystal substrate. That is, one surface of the reservoir-forming silicon single crystal substrate is controlled and etched to form the piezoelectric element holding portion 32 and the concave portion that becomes the reservoir portion 31.
The signal line group 200 according to the present invention is formed on the surface of the reservoir forming silicon single crystal substrate opposite to the surface on which the piezoelectric element holding portion 32 is formed. That is, a signal line group for supplying a drive signal from a control unit (not shown) is patterned on the surface of the silicon single crystal substrate in a pattern shape corresponding to flip chip mounting or wire bonding. At this time, as shown in FIG. 3A, the wiring width of the signal line 203 that is likely to generate noise is D1, and the wiring widths of the other signal lines 201, 202, 204, and 205 are D0. Patterning.

  The reservoir forming silicon single crystal substrate is aligned so that the reservoir portion 31 communicates with the communicating portion 13 so that the piezoelectric element holding portion 32 covers the piezoelectric element 300, and the flow path forming substrate 10 is formed by the adhesive layer 35. And pasted together.

  Next, the silicon single crystal substrate for the flow path forming substrate is polished to a certain thickness, and further wet-etched with fluorinated nitric acid, so that the silicon single crystal substrate for the flow path forming substrate has a thickness of about 70 μm. Form. Next, a mask film made of silicon nitride is formed on the silicon single crystal substrate for the flow path forming substrate, and anisotropic etching as described above is performed, so that the pressure generating chamber is formed on the silicon single crystal substrate for the flow path forming substrate. 12, shapes of the communication portion 13, the ink supply path 14, and the like are formed. Specifically, the pressure generating chamber 12, the communication portion 13, and the ink are etched by etching with an etching solution such as an aqueous potassium hydroxide (KOH) solution until the elastic film 50, the metal film 53, and the adhesion layer 91 are exposed. The supply path 14 is formed at a stretch. When the silicon single crystal substrate is immersed in an alkaline solution such as KOH, the silicon is gradually eroded, and the first (111) plane perpendicular to the (110) plane and a predetermined angle (about 70 degrees) with the (111) plane. And a (110) plane and a second (111) plane forming a predetermined angle (about 35 degrees) appear. Here, the (111) plane is greatly eroded by utilizing the property that the difference in etching rate between the (110) plane and the (111) plane is 1: 180. The long side of the pressure generation chamber 12 is the first (111) plane and the short side is the second (111) plane. By performing the etching until the thickness of the flow path forming substrate 10 is penetrated, the parallelogram-shaped pressure generating chambers 12 are formed with high density.

  Here, since the boundary portion between the communication portion 13 and the reservoir portion 31 is sealed with the metal film 53, the etching solution flows from the flow path forming substrate silicon single crystal substrate side to the reservoir forming silicon single crystal substrate. In addition, the reservoir forming silicon single crystal substrate is not etched.

  After the reservoir portion 31 is formed, the drive IC 210 is flip-chip mounted on the wiring substrate on the bonding substrate 30. That is, the electrodes of the drive IC 210 are electrically connected to the pattern position where the flip chip mounting is performed on the pattern of the signal line group 200 formed on the bonding substrate 30. The mounting from the signal line group 200 to the driving IC 210 and from the driving IC 210 to each piezoelectric element can also be performed by wire bonding. Then, the output terminal for the piezoelectric element of the drive IC 210 and the lead electrode 90 are electrically connected by the drive wiring 220. Thereafter, the channel-forming substrate silicon single crystal substrate and the reservoir forming silicon single crystal substrate are cut into a substrate shape by dicing or the like. Then, the nozzle plate 20 in which the nozzles 21 are formed is bonded to the flow path forming substrate 10 on the side opposite to the bonding substrate 30 with a predetermined adhesive. Through the above steps, the shape of the ink jet recording head as shown in FIG. 2 is formed.

  As described above, according to the first embodiment, in the signal line group 200, the signal line 203 that is highly likely to generate noise has a larger wiring area per unit length, that is, a wiring width, than other signal lines. Thus, the voltage amplitude of noise generated in the signal line 203 can be relatively lowered.

(Embodiment 2)
In the second embodiment of the present invention, in addition to the signal line, it corresponds to noise in the power supply wiring.
The principle of the present invention will be described with reference to FIG. 4A is a plan view showing a state in which the signal lines S1 to S5, the high potential power supply wiring Vdd ′, and the low potential power supply wiring Vss ′ are laid in parallel, and FIG. 4B is a cross-sectional view thereof. These signal lines and power supply lines are laid and patterned on a silicon substrate with an insulating film therebetween. When the low-potential power supply wiring Vss ′ is a ground wiring, the insulating film between the ground wiring and the bonding substrate is partially removed, so that the silicon substrate can be grounded via the ground wiring. preferable.

  As for the signal lines S1 to S5, as in the principle of the first embodiment, it is assumed that the noise generated in the signal line S3 is large, and the bonding substrate per unit length in the signal line S3 that is highly likely to generate this noise. The contact area (wiring width d3 of the signal line S3) is the contact area (wiring of the signal lines S1, S2, S4, S5) to the bonding substrate per unit length in the other signal lines S1, S2, S4, S5. The widths d1, d2, d4, and d5) are larger.

  Further, in the second embodiment, it is assumed that there is a high possibility that noise is generated in both the high potential power supply wiring Vdd ′ and the low potential power supply wiring Vss ′. In the high potential power supply wiring Vdd ′ and the low potential power supply wiring Vss ′, The contact area to the bonding substrate (wiring widths d0 ′ and d6 ′ of both power supply wirings) is the contact area to the bonding substrate (signal lines S1, S2, S4, and S5 of the other signal lines S1, S2, S4, and S5). It is also characterized in that it is formed larger than the wiring widths d1, d2, d4, d5).

  FIG. 4C shows an equivalent circuit in the case where the floating resistance of the signal lines and the power supply wiring and the path resistance to the ground potential are taken into consideration. As shown in FIG. 4C, stray capacitances C1 to C5 exist between the signal lines S1 to S5 and the ground potential. This stray capacitance is connected in series with the path resistors R1 to R5. In addition, a series connection of the stray capacitance C0 'and the path resistance R0' is connected in parallel with the load resistor Rdd of the high potential power supply between the high potential power supply wiring Vdd 'and the ground potential. Between the low potential power supply line Vss' and the ground potential, a series connection of the stray capacitance C6 'and the path resistance R6' is connected in parallel with the load resistance Rss of the low potential power supply. The wiring widths d0 'and d6' of the high potential power wiring Vdd 'and the low potential power wiring Vss' in the second embodiment are larger than the conventional wiring width. For this reason, the cutoff frequency fc of noise is lower than that of the conventional power supply wiring because the stray capacitances C0 'and C6' and the path resistances R0 'and R6' are increased. Similarly, the impedance is also reduced. For this reason, among the harmonic components contained in the noise generated in the power supply wiring, the impedance can be made lower with respect to a relatively high frequency component, and the impedance can be lowered to a relatively low frequency component. Can do. Therefore, it is possible to reduce the voltage amplitude of noise for these power supply wirings.

  Further, since the noise reduction effect is greater as the path resistance is smaller, the noise reduction effect is higher when the resistance of the substrate on which the power supply wiring is laid is lower. For example, in the case where the substrate is silicon, an appropriate amount of impurities may be mixed into the silicon substrate to reduce the area resistance and the noise level within a range in which crosstalk generated in the signal line and a decrease in signal level are not a problem. Good.

  When an ink jet recording head is manufactured, the wiring width of the power supply wiring may be patterned in accordance with this principle. For example, in the case of the ink jet recording head described in the first embodiment, a power supply wiring is connected to the drive IC 210 in addition to a signal line (not shown). Therefore, the present invention is applied to this power supply wiring, and the wiring width of the power supply wiring may be set larger than the conventional one.

  According to the second embodiment, it is possible to reduce the noise level by applying the present invention to the power supply wiring. That is, conventionally, switching noise or the like may be mixed in the power supply wiring, which causes a malfunction in the drive IC. According to the second embodiment, the power supply wiring that is expected to generate noise is used. Since the wiring width is increased, it is possible to suppress the occurrence of malfunctions caused by nozzles generated in the power supply wiring. If the noise level of the power supply wiring is lowered, noise interference with other signal lines is also reduced.

(Embodiment 3)
The third embodiment relates to a printing apparatus for performing printing by the ink jet recording head.
FIG. 5 is a perspective view illustrating the structure of the printing apparatus. As shown in FIG. 5, in this printing apparatus, a carriage shaft 5 is attached to the apparatus main body 4 in the horizontal direction. The carriage 3 is attached to the carriage shaft 5 so as to be movable in the axial direction. The carriage 3 is provided with a pair of ink jet recording head units 1A and 1B that can move in the horizontal direction. The ink jet recording head units 1A and 1B are detachably provided with ink cartridges 2A and 2B. The carriage 3 is configured such that the rotational force of the drive motor 6 is exerted as the force of the moving motion in the axial direction by a plurality of gears (not shown) and the timing belt 7. The apparatus main body 4 is provided with a platen 8 along the carriage shaft 5 so that printing paper supplied by a paper feed roller (not shown) is conveyed on the platen 8 in a direction perpendicular to the axial direction. It is configured.
In the above configuration, the ink jet recording head units 1A and 1B are supplied with control signals and power from a control device (not shown) through signal lines and power wiring (not shown). And power wiring is applied. For this reason, the printing apparatus is resistant to noise.

(Modification)
The present invention is not limited to the above-described embodiment, and can be variously modified and applied.
For example, in the above-described embodiment, the present invention is applied to the signal line and the power supply wiring on the bonding substrate of the ink jet recording head. However, the present invention is not limited to this. For example, if high-density signal lines are laid on a substrate other than the bonded substrate, the present invention can be applied to signal lines and power supply wirings on the substrate.

  In the above embodiment, the piezoelectric element is used as the pressure generating element for discharging the ink in the pressure generating chamber from the nozzle opening. However, the present invention is not limited to the piezoelectric element.

  In addition, by applying the present invention to a liquid jet head for uses other than the head that ejects ink, similarly, it is possible to expect a noise reduction effect while suppressing a decrease in signal wiring density as much as possible. In other words, the basic configuration of the liquid ejecting head is not limited to that described above, and the liquid ejecting head can be applied to a liquid ejecting head that ejects liquid other than ink. For example, an alkaline liquid is ejected as a liquid other than ink, a color material for producing a color filter of a liquid crystal display device is ejected, or an electrode for an organic EL display device, FED (surface emitting display device) or the like is used. It is possible to discharge the electrode material. Moreover, you may discharge the organic material for samples of biochip manufacture. Any liquid ejecting head that ejects any liquid can be expected to exhibit the effects of the present invention.

A plan view of a signal line pattern for explaining the principle in the first embodiment Sectional drawing of the signal line pattern explaining the principle in Embodiment 1 1 is an equivalent circuit diagram of a signal line pattern according to the first embodiment. 1 is an exploded perspective view illustrating an outline of an ink jet recording head that is an example of a liquid ejecting head according to an embodiment of the invention. Sectional view of the ink jet recording head according to the present embodiment The top view of the signal line pattern explaining the principle in Embodiment 2 Sectional drawing of the signal line pattern explaining the principle in Embodiment 2 Equivalent circuit diagram of signal line pattern in embodiment 2 Schematic perspective view of a printing apparatus according to Embodiment 3

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Flow path formation board | substrate, 12 ... Pressure generation chamber, 13 ... Communication part, 14 ... Ink supply path, 20 ... Nozzle plate, 21 ... Nozzle, 30 ... Bonding board, 31 ... Reservoir part, 32 ... Piezoelectric element holding part, 35 ... Adhesive layer, 40 ... Compliance substrate, 41 ... Elastic film, 42 ... SUS substrate, 50 ... Elastic film, 51 ... Insulator film, 53 ... Metal film, 54 ... Penetration part, 60 ... Lower electrode film, 70 ... Piezoelectric Body layer: 80 ... Upper electrode film, 90 ... Lead electrode, 91 ... Adhesion layer, 92 ... Metal layer, 100 ... Protective film, 200 ... Signal line group, 201-205 ... Signal line, 210 ... Drive IC, 220 ... Drive Wiring, 300 ... piezoelectric element, C0-C6 ... stray capacitance, d0-d6 ... wiring width, R0-R6 ... path resistance, Rdd ... load resistance, Rss ... load resistance, S1-S5 ... signal line, Vdd ... high potential power supply Wiring, Vss ... Low-potential power wiring

Claims (9)

A liquid ejecting head including a plurality of pressure generating elements driven by different signals,
A flow path forming substrate on which a plurality of the pressure generating elements are formed;
A bonding substrate formed of grounded silicon;
A plurality of signal lines formed on the bonding substrate and supplied with different signals, respectively.
Of the plurality of signal lines, a contact area of the signal line that is highly likely to generate noise is larger than a contact area of the other signal line to the junction board. A liquid ejecting head. A liquid ejecting head including a plurality of pressure generating elements driven by different signals,
A flow path forming substrate on which a plurality of the pressure generating elements are formed;
A bonding substrate formed of grounded silicon;
A plurality of signal lines formed on the bonding substrate and supplied with different signals, respectively.
A liquid ejecting head, wherein a wiring width of a signal line that is likely to generate noise among the plurality of signal lines is formed larger than a wiring width of the other signal lines. Further equipped with power supply wiring,
2. The liquid jet head according to claim 1, wherein a contact area of the power supply wiring to the bonding substrate is larger than a contact area of the other signal line to the bonding substrate. Further equipped with power supply wiring,
The liquid jet head according to claim 2, wherein a wiring width of the power supply wiring is formed larger than a wiring width of the other signal lines.   The signal lines that are likely to generate noise among the plurality of signal lines are a power supply wiring, a driving signal wiring of the pressure generating element, and a common electrode wiring of the pressure generating element. The liquid ejecting head according to 1 or 2. The plurality of signal lines include ground wiring,
An insulating film is formed between the bonding substrate and the plurality of signal lines,
3. The bonding substrate is grounded by removing a part of the insulating film from the ground wiring and contacting the ground wiring with the bonding substrate. 4. Liquid jet head. A method of manufacturing a liquid jet head including a plurality of pressure generating elements driven by different signals,
Forming a flow path forming substrate comprising a plurality of the pressure generating elements;
Forming a bonding substrate for forming a space including the plurality of pressure generating elements on the flow path forming substrate;
A plurality of signal lines for electrically connecting the pressure generating element and a driving device for driving the pressure generating element are formed on the surface of the bonding substrate opposite to the space including the pressure generating element. A process,
The contact area of the signal line that is likely to generate noise among the plurality of signal lines to be larger than the contact area of the other signal line to the junction board is formed. A method for manufacturing a liquid jet head. A method of manufacturing a liquid jet head including a plurality of pressure generating elements driven by different signals,
Forming a flow path forming substrate comprising a plurality of the pressure generating elements;
Forming a bonding substrate for forming a space including the plurality of pressure generating elements on the flow path forming substrate;
A plurality of signal lines for electrically connecting the pressure generating element and a driving device for driving the pressure generating element are formed on the surface of the bonding substrate opposite to the space including the pressure generating element. A process,
A method of manufacturing a liquid jet head, comprising: forming a wiring width of a signal line that is highly likely to generate noise among the plurality of signal lines to be larger than a wiring width of the other signal lines.   A printing apparatus comprising the liquid ejecting head according to claim 1.

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