JP7020103B2 - Liquid spray head, liquid spray device and wiring board - Google Patents

Description

The present invention relates to a technique for injecting a liquid such as ink.

Conventionally, a liquid injection head that injects a liquid such as ink from a plurality of nozzles has been proposed. For example, Patent Document 1 includes a flow path forming substrate in which a pressure generating chamber is formed, a piezoelectric element for changing the pressure of a liquid in the pressure generating chamber, and a liquid injection provided with a drive circuit for supplying a drive signal to the piezoelectric element. The head is disclosed. A drive circuit board is installed between the flow path forming board and the drive circuit. The drive circuit board is formed with wiring for transmitting signals and power supplies supplied from the external circuit to the drive circuit and wiring for transmitting the drive signal output from the drive circuit to the piezoelectric element.

JP-A-2017-124540

Under the technique of Patent Document 1, it is actually difficult to sufficiently reduce the resistance of the wiring formed on the drive circuit board, and from the viewpoint of suppressing heat generation and waveform blunting of the drive signal due to the wiring resistance. Therefore, there is room for further improvement. In consideration of the above circumstances, it is an object of the present invention to reduce the resistance of the wiring formed on the wiring board constituting the liquid injection head.

In order to solve the above problems, the liquid injection head according to the preferred embodiment (aspect 1) of the present invention has a flow path forming portion in which a pressure chamber communicating with the nozzle is formed, and the liquid in the pressure chamber is transferred to the nozzle. A drive element to be injected from, a drive circuit that outputs a drive pulse for driving the drive element to the drive element, a base portion installed between the flow path forming portion and the drive circuit, and the base portion. A wiring board including wiring formed on the wiring surface and electrically connected to the drive circuit is provided, and the base portion includes a first portion and a second portion on the wiring surface side as viewed from the first portion. A groove including the portion is formed, the side wall surface of the first portion forms a first angle with respect to the wiring surface, and the side wall surface of the second portion is in contact with the wiring surface and with respect to the wiring surface. The wiring is an inclined surface inclined at a second angle, which is a sharp angle lower than the first angle, and the wiring is inside the first portion and inside a part of the second portion on the first portion side. A first layer formed in the above, and a second layer extending over the first layer, the side wall surface of the second portion, and the wiring surface are included. In the above embodiment, the side wall surface of the second portion of the groove portion is an inclined surface in contact with the wiring surface, and the second angle formed with respect to the wiring surface of the base portion is an acute angle. Therefore, for example, the side wall surface of the groove portion covers the entire area. Compared to the configuration that is perpendicular to the wiring surface (that is, the portion of the side wall surface of the groove that is in contact with the wiring surface is perpendicular to the wiring surface), the side wall surface of the second portion of the second layer It is possible to reduce the possibility of disconnection occurring in the portion extending over the wiring surface of the substrate portion. Further, since the first angle formed by the side wall surface of the first portion with respect to the wiring surface exceeds the second angle, for example, the entire groove portion is formed in a tapered shape (that is, the side wall surface of the groove portion is entirely on the wiring surface). Wiring resistance is reduced compared to the configuration with an acute angle.

In a preferred example of aspect 1 (aspect 2), the second portion has a smaller length in the depth direction than the first portion. In the above embodiment, since the second portion has a smaller length in the depth direction than the first portion, the wiring resistance is increased as compared with the configuration in which the second portion has a larger length in the depth direction than the first portion. The effect of reduction is more remarkable.

In a preferred example of Aspect 1 or Aspect 2 (Aspect 3), the groove portion includes a third portion on the bottom surface side when viewed from the first portion, and the side wall surface of the third portion is the above with respect to the wiring surface. It is an inclined surface inclined at a third angle, which is an acute angle lower than the first angle. In the above embodiment, the groove portion includes the third portion on the bottom surface side when viewed from the first portion, and the side wall surface of the third portion is inclined at an acute angle lower than the first angle with respect to the wiring surface. Compared to the configuration in which the groove portion does not include the third portion, the stress concentration at the corner portion between the bottom surface and the side wall surface of the groove portion is relaxed. Therefore, it is possible to reduce the damage to the substrate portion due to the concentration of stress.

In any of the preferred examples of Aspects 1 to 3 (Aspect 4), the second layer has a lower resistance than the first layer. In the above embodiment, since the second layer has a lower resistance than the first layer, the effect of reducing the wiring resistance is more remarkable as compared with the configuration in which the first layer has a lower resistance than the second layer. be.

In any of the preferred examples of Aspects 1 to 4 (Aspect 5), the wiring board is a long member, and the wiring extends along the longitudinal direction of the wiring board. In the above aspect, since the wiring extends along the longitudinal direction of the wiring board which is a long member, the signal or voltage can be supplied to the drive circuit over a wide range in the longitudinal direction of the wiring board.

In any preferred example of any of aspects 1 to 5, the first angle is 90 °. In the above embodiment, since the first angle is 90 °, the first portion can be easily manufactured as compared with a configuration in which the first angle is larger than 90 °, for example.

In the liquid injection head according to any of the preferred examples (Aspect 7) of Aspects 1 to 6, the length of the side wall surface of the second portion in the width direction of the groove portion is smaller than the width of the first portion. In the above embodiment, since the length of the side wall surface of the second portion in the width direction of the groove portion is smaller than the width of the first portion, the length of the side wall surface of the second portion in the width direction of the groove portion is the width of the first portion. The effect of reducing wiring resistance is more pronounced compared to larger configurations.

The liquid injection device according to the preferred embodiment (aspect 8) of the present invention includes the liquid injection head according to any of the above-exemplified embodiments. A good example of a liquid injection device is a printing device that injects ink, but the application of the liquid injection device according to the present invention is not limited to printing.

The wiring substrate according to a preferred embodiment (aspect 9) of the present invention includes a flow path forming portion in which a pressure chamber communicating with the nozzle is formed, a drive element for injecting liquid in the pressure chamber from the nozzle, and the drive element. A wiring board used for a liquid injection head including a drive circuit for outputting a drive pulse to the drive element, and a base portion installed between the flow path forming portion and the drive circuit. A wiring board including a wiring formed on the wiring surface of the base portion and electrically connected to the drive circuit is provided, and the base portion includes the first portion and the wiring as seen from the first portion. A groove including the second portion on the surface side is formed, the side wall surface of the first portion forms a first angle with respect to the wiring surface, and the side wall surface of the second portion is in contact with the wiring surface. An inclined surface that is inclined at a second angle that is a sharp angle lower than the first angle with respect to the wiring surface, and the wiring is inside the first portion and on the first portion side of the second portion. It includes a first layer formed on a part of the inside and a second layer extending over the first layer, the side wall surface of the second portion, and the wiring surface. In the above embodiment, the side wall surface of the second portion of the groove portion is an inclined surface in contact with the wiring surface, and the second angle formed with respect to the wiring surface of the base portion is an acute angle. Therefore, for example, the side wall surface of the groove portion covers the entire area. Compared to the configuration that is perpendicular to the wiring surface (that is, the portion of the side wall surface of the groove that is in contact with the wiring surface is perpendicular to the wiring surface), the side wall surface of the second portion of the second layer It is possible to reduce the possibility of disconnection occurring in the portion extending over the wiring surface of the substrate portion. Further, since the first angle formed by the side wall surface of the first portion with respect to the wiring surface exceeds the second angle, for example, the entire groove portion is formed in a tapered shape (that is, the side wall surface of the groove portion is entirely on the wiring surface). Wiring resistance is reduced compared to the configuration with an acute angle.

It is a block diagram which shows the structure of the liquid injection apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the functional structure of a liquid injection device. It is a waveform diagram of a drive signal. It is an exploded perspective view of a liquid injection head. It is sectional drawing (cross-sectional view of VV line in FIG. 4) of the liquid injection head. It is sectional drawing which shows the structure of a piezoelectric element. It is sectional drawing which shows the structure of wiring in a wiring board. It is an enlarged view on the side wall surface of a groove part. It is sectional drawing which shows the structure of the wiring in the wiring board which concerns on the inverse proportion 1. It is sectional drawing which shows the structure of the wiring in the wiring board which concerns on the inverse proportion 2. It is explanatory drawing of the process of forming a groove portion in a wiring board. It is explanatory drawing of the process of forming a groove portion in a wiring board. It is sectional drawing which shows the structure of the wiring in the wiring board which concerns on 2nd Embodiment. It is explanatory drawing of the process (process P7a and process P8a) of forming a groove portion in a wiring board.

<First Embodiment>
FIG. 1 is a block diagram illustrating the liquid injection device 100 according to the first embodiment of the present invention. The liquid injection device 100 of the first embodiment is an inkjet printing device that injects ink, which is an example of a liquid, onto a medium 12. The medium 12 is typically printing paper, but a printing target of any material such as a resin film or a cloth is used as the medium 12. As illustrated in FIG. 1, a liquid container 14 for storing ink is installed in the liquid injection device 100. For example, a cartridge that can be attached to and detached from the liquid injection device 100, a bag-shaped ink pack made of a flexible film, or an ink tank that can be refilled with ink is used as the liquid container 14. A plurality of types of ink having different colors are stored in the liquid container 14.

As illustrated in FIG. 1, the liquid injection device 100 includes a control unit 20, a transfer mechanism 22, a moving mechanism 24, and a liquid injection head 26. The control unit 20 includes, for example, a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage circuit such as a semiconductor memory, and comprehensively controls each element of the liquid injection device 100. The transport mechanism 22 transports the medium 12 in the Y direction under the control of the control unit 20.

The moving mechanism 24 reciprocates the liquid injection head 26 in the X direction under the control of the control unit 20. The X direction is a direction that intersects (typically orthogonally) the Y direction in which the medium 12 is conveyed. The moving mechanism 24 of the first embodiment includes a substantially box-shaped transport body 242 (carriage) for accommodating the liquid injection head 26, and a transport belt 244 to which the transport body 242 is fixed. It should be noted that a configuration in which a plurality of liquid injection heads 26 are mounted on the transport body 242 and a configuration in which the liquid container 14 is mounted on the transport body 242 together with the liquid injection head 26 can also be adopted.

The liquid injection head 26 ejects the ink supplied from the liquid container 14 to the medium 12 from a plurality of nozzles (injection holes) under the control of the control unit 20. The liquid injection head 26 ejects ink onto the medium 12 in parallel with the transfer of the medium 12 by the transfer mechanism 22 and the repetitive reciprocation of the transfer body 242, whereby a desired image is formed on the surface of the medium 12. The direction perpendicular to the XY plane (for example, a plane parallel to the surface of the medium 12) is hereinafter referred to as the Z direction. The ink injection direction (typically the vertical direction) by the liquid injection head 26 corresponds to the Z direction.

FIG. 2 is a configuration diagram focusing on the function of the liquid injection device 100. The illustration of the transport mechanism 22 and the moving mechanism 24 is omitted for convenience. As illustrated in FIG. 2, the control unit 20 of the first embodiment generates a control signal S, a drive signal D, and a plurality of voltages (VDD, VSS, VBS) and supplies them to the liquid injection head 26. The control signal S indicates whether or not ink is sprayed (spraying / non-spraying) for each nozzle N. The drive signal D is a periodic signal whose voltage changes with reference to a predetermined voltage (hereinafter referred to as “reference voltage”) VBS, and is used to inject ink into the liquid injection head 26. As illustrated in FIG. 3, the drive signal D is a voltage signal including the drive pulse P at predetermined intervals. It should be noted that a configuration may be configured in which a drive signal D having a waveform including a plurality of drive pulses P is used, or a configuration using a plurality of drive signals D having different waveforms. The plurality of voltages supplied from the control unit 20 to the liquid injection head 26 include a high-level power supply voltage VDD, a low-level power supply voltage VSS (ground voltage), and the above-mentioned reference voltage VBS.

As illustrated in FIG. 2, the liquid injection head 26 of the first embodiment has a plurality of piezoelectric elements 44 (examples of drive elements) corresponding to different nozzles, and a drive circuit for driving each of the plurality of piezoelectric elements 44. 50 and. The drive circuit 50 is configured to include a plurality of switches corresponding to different piezoelectric elements 44, and determines whether or not to supply the drive pulse P of the drive signal D to the piezoelectric element 44 for each piezoelectric element 44 according to the control signal S. To control. Specifically, the drive circuit 50 supplies the drive pulse P to the piezoelectric element 44 corresponding to the nozzle in which the control signal S instructs the injection of ink, and the control signal S corresponds to the nozzle instructing the non-injection of ink. The drive pulse P is not supplied to the piezoelectric element 44.

FIG. 4 is an exploded perspective view of the liquid injection head 26, and FIG. 5 is a cross-sectional view taken along the line VV in FIG. As illustrated in FIG. 4, the liquid injection head 26 includes a plurality of nozzles N arranged in the Y direction. The plurality of nozzles N of the first embodiment are divided into a first row L1 and a second row L2 arranged side by side at intervals in the X direction. Each of the first row L1 and the second row L2 is a set of a plurality of nozzles N linearly arranged in the Y direction. Although it is possible to make the positions of the nozzles N in the Y direction different between the first row L1 and the second row L2 (that is, staggered arrangement or stagger arrangement), the first row L1 and the second row L2 The configuration in which the positions of the nozzles N in the Y direction are matched with each other will be illustrated below for convenience. As can be understood from FIG. 5, in the liquid injection head 26 of the first embodiment, the elements related to each nozzle N in the first row L1 and the elements related to each nozzle N in the second row L2 are substantially line-symmetrical. It is an arranged structure.

As illustrated in FIGS. 4 and 5, the liquid injection head 26 includes a flow path forming portion 30. The flow path forming portion 30 is a structure for forming a flow path for supplying ink to a plurality of nozzles N. The flow path forming portion 30 of the first embodiment is configured by laminating the flow path substrate 32 and the pressure chamber substrate 34. The flow path substrate 32 and the pressure chamber substrate 34 are plate-shaped members elongated in the Y direction. The pressure chamber substrate 34 is fixed to the surface of the flow path substrate 32 on the negative side in the Z direction, for example, with an adhesive.

As illustrated in FIG. 4, a diaphragm 42, a wiring board 46, a housing portion 48, and a drive circuit 50 are installed on the negative side of the flow path forming portion 30 in the Z direction. On the other hand, the nozzle plate 62 and the vibration absorbing body 64 are installed on the positive side of the flow path forming portion 30 in the Z direction. Each element of the liquid injection head 26 is generally a plate-shaped member elongated in the Y direction similar to the flow path substrate 32 and the pressure chamber substrate 34, and is joined to each other by using, for example, an adhesive.

The nozzle plate 62 is a plate-shaped member in which a plurality of nozzles N are formed, and is installed on the surface on the positive side in the Z direction of the flow path substrate 32. Each of the plurality of nozzles N is a circular through hole through which ink is passed. The nozzle plate 62 of the first embodiment is formed with a plurality of nozzles N constituting the first row L1 and a plurality of nozzles N constituting the second row L2. For example, the nozzle plate 62 is manufactured by processing a single crystal substrate of silicon (Si) using semiconductor manufacturing technology (for example, processing technology such as dry etching or wet etching). However, a known material or manufacturing method may be arbitrarily adopted for manufacturing the nozzle plate 62.

As illustrated in FIGS. 4 and 5, the flow path substrate 32 includes a space Ra, a plurality of supply flow paths 322, a plurality of communication flow paths 324, and a supply liquid for each of the first row L1 and the second row L2. A chamber 326 is formed. The space Ra is an opening formed in a long shape along the Y direction in a plan view (that is, when viewed from the Z direction), and the supply flow path 322 and the communication flow path 324 are through holes formed for each nozzle N. .. The supply liquid chamber 326 is a space formed in a long shape along the Y direction over the plurality of nozzles N, and allows the space Ra and the plurality of supply flow paths 322 to communicate with each other. Each of the plurality of communication flow paths 324 overlaps one nozzle N corresponding to the communication flow path 324 in a plan view.

As illustrated in FIGS. 2 and 3, the pressure chamber substrate 34 is a plate-shaped member in which a plurality of pressure chambers C are formed for each of the first row L1 and the second row L2. The plurality of pressure chambers C are arranged in the Y direction. Each pressure chamber C (cavity) is a long space formed for each nozzle N and along the X direction in a plan view. The flow path substrate 32 and the pressure chamber substrate 34 are manufactured by processing a silicon single crystal substrate by using, for example, a semiconductor manufacturing technique, similarly to the nozzle plate 62 described above. However, known materials and manufacturing methods can be arbitrarily adopted for manufacturing the flow path substrate 32 and the pressure chamber substrate 34.

As illustrated in FIG. 4, a diaphragm 42 is formed on the surface of the pressure chamber substrate 34 opposite to the flow path substrate 32. The diaphragm 42 of the first embodiment is a plate-shaped member (diaphragm 42) that can vibrate elastically. By selectively removing a part of the plate-shaped member having a predetermined plate thickness in the plate thickness direction in the region corresponding to the pressure chamber C, a part or the whole of the diaphragm 42 is integrated with the pressure chamber substrate 34. May be formed in.

As can be understood from FIG. 4, the pressure chamber C is a space located between the flow path substrate 32 and the diaphragm 42. A plurality of pressure chambers C are arranged in the Y direction for each of the first row L1 and the second row L2. As illustrated in FIGS. 4 and 5, the pressure chamber C communicates with the communication flow path 324 and the supply flow path 322. Therefore, the pressure chamber C communicates with the nozzle N via the communication flow path 324 and communicates with the space Ra via the supply flow path 322 and the supply liquid chamber 326.

As exemplified in FIGS. 4 and 5, a plurality of diaphragms 42 corresponding to different nozzles N for each of the first row L1 and the second row L2 on the surface of the diaphragm 42 opposite to the pressure chamber C. The piezoelectric element 44 of the above is formed. Each piezoelectric element 44 is a passive element that is deformed by the supply of the drive pulse P.

FIG. 6 is a cross-sectional view of the piezoelectric element 44. As illustrated in FIG. 6, the piezoelectric element 44 is a laminated body in which a piezoelectric layer 443 is interposed between the first electrode 441 and the second electrode 442 facing each other. The first electrode 441 (lower electrode) is a common electrode formed on the surface of the diaphragm 42 and continuous over a plurality of piezoelectric elements 44. On the other hand, the second electrode 442 (upper electrode) is an individual electrode formed for each piezoelectric element 44. The portion where the first electrode 441, the second electrode 442, and the piezoelectric layer 443 overlap in a plan view functions as the piezoelectric element 44. When the diaphragm 42 vibrates in conjunction with the deformation of the piezoelectric element 44, the pressure of the ink in the pressure chamber C fluctuates, and the ink filled in the pressure chamber C passes through the communication flow path 324 and the nozzle N to the outside. Is sprayed on. It should be noted that a configuration in which the first electrode 441 is used as an individual electrode for each piezoelectric element 44 and the second electrode 442 is used as a common electrode, or a configuration in which both the first electrode 441 and the second electrode 442 are used as individual electrodes can be adopted.

The wiring board 46 of FIG. 4 is a long member that faces the surface of the diaphragm 42 on which a plurality of piezoelectric elements 44 are formed at intervals. The wiring board 46 of the first embodiment also functions as a reinforcing plate for reinforcing the mechanical strength of the liquid injection head 26 and a sealing plate for protecting and sealing the piezoelectric element 44. As illustrated in FIG. 4, the wiring board 46 is electrically connected to the control unit 20 via the external wiring 52. The external wiring 52 is a flexible wiring board for supplying various voltages (VDD, VSS, VBS) and signals (S, D) from the control unit 20 to the wiring board 46. For example, connection parts such as FPC (Flexible Printed Circuits) or FFC (Flexible Flat Cable) are suitably adopted as the external wiring 52.

The housing portion 48 is a case for storing ink supplied to a plurality of pressure chambers C (further, a plurality of nozzles N). As illustrated in FIG. 5, in the housing portion 48 of the first embodiment, a space Rb is formed for each of the first row L1 and the second row L2. The space Rb of the housing portion 48 and the space Ra of the flow path substrate 32 communicate with each other. The space composed of the space Ra and the space Rb functions as a liquid storage chamber (reservoir) R for storing ink supplied to the plurality of pressure chambers C. Ink is supplied to the liquid storage chamber R through the introduction port 482 formed in the housing portion 48. The ink in the liquid storage chamber R is supplied to the pressure chamber C via the supply liquid chamber 326 and each supply flow path 322. The vibration absorber 64 is a flexible film (compliance substrate) constituting the wall surface of the liquid storage chamber R, and absorbs pressure fluctuations of ink in the liquid storage chamber R.

The wiring board 46 includes a base portion 70 and a plurality of wirings 72. The substrate portion 70 is an insulating plate-shaped member that is long in the Y direction, and is located between the flow path forming portion 30 and the drive circuit 50. The substrate portion 70 is manufactured by processing a silicon single crystal substrate using, for example, semiconductor manufacturing technology. However, a known material or manufacturing method may be arbitrarily used for manufacturing the substrate portion 70.

As illustrated in FIG. 4, the substrate portion 70 includes a first surface F1 and a second surface F2 located on opposite sides of each other, and is a flow path substrate 32 in the pressure chamber substrate 34 (or diaphragm 42). It is fixed to the opposite surface using, for example, an adhesive. Specifically, the base portion 70 is installed so that the second surface F2 faces the surface of the diaphragm 42 at a distance. As illustrated in FIG. 4, the drive circuit 50 and the external wiring 52 are mounted on the first surface F1 of the base portion 70. The drive circuit 50 is an IC chip that is long along the longitudinal direction (Y direction) of the substrate portion 70. The external wiring 52 is mounted on the negative end portion in the Y direction of the first surface F1 of the substrate portion 70.

The plurality of wirings 72 are formed on the first surface F1 and the second surface F2 of the substrate portion 70. A plurality of wirings 72 extend along the longitudinal direction (Y direction) of the wiring board 46. The first surface F1 and the second surface F2 of the substrate portion 70 (hereinafter, both are collectively referred to as "wiring surface F") correspond to the {100} surface of the silicon single crystal, and the extending direction of the wiring 72. (Y direction) is a direction parallel to the {100} plane of the silicon single crystal.

The plurality of wirings 72 include a plurality of wirings for transmitting the voltage (VDD, VSS, VDC) and the signal (S, D) supplied from the control unit 20 via the external wiring 52. Specifically, as illustrated in FIG. 2, the power supply wiring 72a to which the power supply voltage VDD on the high side is supplied, the power supply wiring 72b to which the power supply voltage VSS on the low side is supplied, and the drive signal D are supplied. The signal wiring 72c, the signal wiring 72d to which the control signal S is supplied, and the reference wiring 72e to which the reference voltage VBS is supplied are formed on both the first surface F1 and the second surface F2. The power supply voltage VDD is supplied to the drive circuit 50 via the power supply wiring 72a, the power supply voltage VSS is supplied to the drive circuit 50 via the power supply wiring 72b, and the drive signal D is supplied to the drive circuit 50 via the signal wiring 72c. , The control signal S is supplied to the drive circuit 50 via the signal wiring 72d. On the other hand, the reference voltage VBS is supplied to the second electrode 442 of the plurality of piezoelectric elements 44 via the reference wiring 72e without passing through the drive circuit 50. Further, the plurality of wirings 72 formed in the substrate portion 70 include a plurality of wirings for supplying the drive pulse P generated by the drive circuit 50 to each of the plurality of piezoelectric elements 44. That is, the wiring board 46 includes wiring that is electrically connected to the drive circuit 50.

FIG. 7 is a cross-sectional view of the wiring 72. As illustrated in FIG. 7, a groove portion G along the wiring 72 is formed on the wiring surface F (first surface F1 or second surface F2) of the base portion 70. The groove portion G is a recessed portion with respect to the wiring surface F of the base portion 70. The groove portion G of the first embodiment includes a first portion G1 and a second portion G2 on the wiring surface F side when viewed from the first portion G1. The first portion G1 is formed on the bottom surface side of the second portion G2 when viewed from the wiring surface F. The second portion G2 is formed from the first portion G1 to the wiring surface F of the base portion 70. The first part G1 and the second part G2 communicate with each other. The cross-sectional shape of the first portion G1 is rectangular. On the other hand, the cross-sectional shape of the second portion G2 is a trapezoid (that is, a tapered shape) in which the lower base is smaller than the upper base. The length D2 in the depth direction (Z direction) in the second portion G2 is smaller than the length D1 in the depth direction in the first portion G1.

FIG. 8 is an enlarged view of the side wall surface Q1 of the first portion G1 and the side wall surface Q2 of the second portion G2. The side wall surface Q1 of the first portion G1 forms a first angle θ1 with respect to the wiring surface F of the base portion 70. The first angle θ1 of the first embodiment is 90 °. That is, the side wall surface Q1 of the first portion G1 is perpendicular to the wiring surface F. Therefore, the width (length in the X direction) W1 of the first portion G1 is constant over the depth direction. On the other hand, the side wall surface Q2 of the second portion G2 is an inclined surface that is in contact with the wiring surface F of the base portion 70 and is inclined at a second angle θ2 with respect to the wiring surface F. The second angle θ2 is an acute angle (θ2 <90 °) smaller than the first angle θ1. In other words, the internal angle (180 ° −θ2) formed by the side wall surface Q2 and the wiring surface F is an obtuse angle. The second angle θ2 of the first embodiment is 57.74 °. The width W2 of the second portion G2 increases monotonically from the first portion G1 side toward the wiring surface F side. The width W2 of the second portion G2 on the wiring surface F (the maximum width in the second portion G2) W2 is larger than the width W1 of the first portion G1. The width W2S of the second portion G2 on the side wall surface Q2 (that is, the length of the side wall surface Q2 of the second portion G2 in the width direction of the groove portion G) is smaller than the width W1 of the first portion. The side wall surface Q2 of the second portion G2 corresponds to the {111} surface of the silicon single crystal constituting the substrate portion 70.

Each of the plurality of wirings 72 is composed of a stack of the first layer 81 and the second layer 82. The first layer 81 is a conductive pattern formed of a low resistance metal such as copper (Cu). As illustrated in FIG. 7, the first layer 81 is a trench wiring formed (that is, embedded) inside the groove portion G.

Specifically, the first layer 81 is formed inside the first portion G1 and inside a part (a part in the depth direction) of the second portion G2 on the first portion G1 side. On the other hand, the second layer 82 is a conductive pattern that covers the first layer 81. Specifically, the second layer 82 is continuously formed over the side wall surface Q2 of the first layer 81 and the second portion G2 and the wiring surface F of the base portion 70. The second layer 82 has a lower resistance than the first layer 81. For example, a laminate of an adhesion layer formed on the surface of the first layer 81 with a metal such as titanium (Ti) or tungsten (W) and a wiring layer formed on the surface of the adhesion layer with a metal such as gold (Au). The second layer 82 is configured with. The adhesion layer is a conductive layer for improving the adhesion between the first layer 81 and the wiring layer. The adhesion layer is a conductive layer for improving the adhesion between the first layer 81 and the wiring layer. As described above, since the wiring 72 formed on the wiring board 46 includes the first layer 81 formed inside the groove portion of the base portion 70, only the conductive pattern formed on the wiring surface F of the base portion 70 The wiring resistance is reduced as compared with the configuration in which the wiring is formed in.

Here, it is assumed that the side wall surface Q of the groove portion G is perpendicular to the wiring surface F over the entire depth direction (hereinafter referred to as “inverse proportion 1”). FIG. 9 is a block diagram of the wiring 72 in inverse proportion 1. As illustrated in FIG. 9, in the inverse proportion 1, the portion of the side wall surface Q of the groove portion G in contact with the wiring surface F is perpendicular to the wiring surface F. Therefore, there is a problem that the wiring 72 is broken in the vicinity of the corner portion of the second layer 82 due to the stress concentrated on the corner portion between the wiring surface F and the side wall surface Q. On the other hand, in the configuration of the first embodiment, the second angle θ2 formed by the side wall surface Q2 of the second portion G2 formed on the wiring surface F of the substrate portion 70 and the wiring surface F is an acute angle, the wiring surface F and the wiring surface F. Since the corner portion between the side wall surface Q2 and the side wall surface Q2 becomes gentle, the concentration of stress generated in the corner portion is relaxed as compared with the inverse proportion 1. Therefore, it is possible to reduce the possibility of disconnection occurring in the portion of the second layer 82 that extends over the side wall surface Q1 of the second portion G2 and the wiring surface F of the base portion 70.

FIG. 10 is a configuration diagram of wiring in a configuration in which the angle formed by the side wall surface Q of the groove portion G with respect to the wiring surface F is an acute angle over the entire side wall surface Q (hereinafter referred to as “inverse proportion 2”). As illustrated in FIG. 10, in inverse proportion 2, it is possible to reduce the possibility of the above-mentioned disconnection, but the configuration of the first embodiment in which the groove portion G includes the first portion G1 and the second portion G2. Since the cross-sectional area of the wiring 72 is smaller than that of the wiring 72, there is a problem that the wiring resistance is high. On the other hand, according to the configuration of the first embodiment, it is possible to reduce the wiring resistance while reducing the possibility of disconnection.

A method of forming the groove G in the wiring board 46 will be described with reference to FIGS. 11 and 12. In FIGS. 11 and 12, the first surface F1 of the substrate portion 70 is focused on for convenience, but the wiring 72 is also formed on the second surface F2 by the same process.

In the step P1 exemplified in FIG. 11, a rectangular substrate portion 70 formed of a silicon single crystal is prepared, and the substrate portion 70 is thermally oxidized to form a first oxide film O1 of silicon oxide (SiO ₂ ). It is formed on the surface F1.

In step P2 after the execution of step P1, a photoresist is applied on the surface of the oxide film O1 and the photoresist is selectively removed by a photolithography technique to form a groove forming pattern R1. The groove forming pattern R1 covers a region other than the region where the first portion G1 of the groove portion G is formed on the first surface F1.

In step P3 after the execution of step P2, the oxide film O1 is selectively removed by wet etching using the groove forming pattern R1 as a mask. That is, the oxide film O1 in the region where the first portion G1 of the groove portion G is formed is removed.

In step P4 after the execution of step P3, dry etching is executed on the substrate portion 70. In step P4, the groove portion G0 is formed on the first surface F1 by removing the region of the first surface F1 of the substrate portion 70 that is not covered with the groove forming pattern R1 and the oxide film O1. The portion of the groove portion G0 on the bottom surface side corresponds to the above-mentioned first portion G1.

In step P5 after the execution of step P4, the groove forming pattern R1 and the oxide film O1 are removed by cleaning the substrate portion 70. As illustrated in FIG. 12, in step P6 after the execution of step P5, the oxide film O2 of silicon oxide is formed over the entire base portion 70 including the inner surface of the groove portion G0 by thermally oxidizing the base portion 70. ..

In step P7 after the execution of step P6, a photoresist is applied on the surface of the oxide film O2, and the photoresist is selectively removed by a photolithography technique to form a groove forming pattern R2. The groove forming pattern R2 covers the bottom surface of the groove portion G and a region other than the region where the second portion G2 of the groove portion G is formed. That is, the groove forming pattern R2 is not formed in the band-shaped region having a predetermined width located around the groove portion G0.

In step P8 after the execution of step P7, the oxide film O2 is selectively removed by wet etching using the groove forming pattern R2 as a mask.

In step P9 after the execution of step P8, wet etching is executed on the substrate portion 70. In step P9, the region from which the oxide film O2 has been removed is isotropically removed, so that the side wall surface Q2 (inclined surface) of the second portion G2 in the groove portion G is formed. In step P10 after the execution of step P9, the groove forming pattern R2 and the oxide film O2 are removed by cleaning the substrate portion 70.

<Second Embodiment>
A second embodiment of the present invention will be described. In each of the following examples, for the elements having the same functions as those of the first embodiment, the reference numerals used in the description of the first embodiment will be diverted and detailed description of each will be omitted as appropriate.

FIG. 13 is a cross-sectional view of the wiring 72 and the groove portion G according to the second embodiment. As illustrated in FIG. 13, the groove portion G of the second embodiment includes the first portion G1 and the second portion G2 similar to those of the first embodiment, as well as the third portion G3 on the bottom surface side when viewed from the first portion G1. include. The third portion G3 is formed from the first portion G1 to the bottom surface of the groove portion G. The first part G1 and the third part G3 communicate with each other. The cross-sectional shape of the third portion G3 is a tapered shape like the second portion G2. The length D3 in the depth direction (Z direction) in the third portion G3 is smaller than the length D1 in the depth direction in the first portion G1.

The side wall surface Q3 of the third portion G3 is an inclined surface inclined at a third angle θ3 (<90 °), which is an acute angle lower than the first angle θ1 with respect to the wiring surface F. In other words, the internal angle (180 ° −θ3) formed by the side wall surface Q3 and the wiring surface F is an obtuse angle. The width of the third portion G3 decreases monotonically from the first portion G1 side toward the bottom surface side. The width of the third portion G3 (the maximum width in the third portion G3) at the position connected to the first portion G1 is the same as the width W1 of the first portion G1.

FIG. 14 is a method of forming the third portion G3. Step P7 of FIG. 12 is replaced with step P7a of FIG. 14, and step P8 of FIG. 12 is replaced with step P8a of FIG. In the above-mentioned step P7, the groove forming pattern R2 is coated on the bottom surface of the groove portion G, whereas in the step P7a, the groove forming pattern R2 is not formed on the bottom surface of the groove portion G. In the step P8a after the execution of the step P7a, the oxide film O2 is selectively removed by wet etching using the groove forming pattern R2 as a mask. By the step P7a and the step P8a, the bottom surface of the groove portion G is exposed. In step P9 after the execution of step P8a, wet etching is executed on the substrate portion 70, so that the side wall surface (inclined surface) S2 of the second portion G2 and the side wall surface (inclined surface) of the third portion G3 are executed. S3 and are formed.

The same effect as that of the first embodiment is realized in the second embodiment. Further, in the configuration of the second embodiment in which the groove portion G includes the third portion G3, the groove portion G does not include the third portion G3 (for example, the groove portion G is formed by the first portion G1 and the second portion G2). Compared with the configuration of 1 embodiment), the concentration of stress at the corner portion between the bottom surface of the groove portion G and the side wall surface Q3 is relaxed. Therefore, it is possible to reduce the damage of the substrate portion 70 due to the concentration of stress.

<Modification example>
Each of the above-exemplified forms can be variously modified. Specific embodiments that can be applied to each of the above-mentioned embodiments are illustrated below. Two or more embodiments arbitrarily selected from the following examples can be appropriately merged to the extent that they do not contradict each other.

(1) In each of the above-described embodiments, the configuration in which the length D2 of the second portion G2 is smaller than the length D1 of the first portion G1 is exemplified, but the length D2 of the second portion G2 is the length of the first portion G1. It may be larger than D1. However, according to the configuration in which the second portion G2 has a smaller length in the depth direction than the first portion G1, the second portion G2 has a larger length in the depth direction than the first portion G1. , The effect of reducing wiring resistance is more remarkable.

(2) In each of the above-described embodiments, the case where the second layer 82 of the wiring 72 has a lower resistance than the first layer 81 is exemplified, but even if the first layer 81 has a lower resistance than the second layer 82. good. However, according to the configuration in which the second layer 82 has a lower resistance than the first layer 81, the effect of reducing the wiring resistance is compared with the configuration in which the first layer 81 has a lower resistance than the second layer 82. Is more prominent.

(3) In each of the above-described embodiments, the case where the first angle θ1 is 90 ° is illustrated, but the first angle θ1 is not limited to the above examples. The first angle θ1 is arbitrary as long as the first angle θ1 is larger than the second angle θ2. However, according to the configuration in which the first angle θ1 is 90 °, it is easier to manufacture the first portion G1 as compared with the configuration in which the first angle θ1 is larger than 90 °, for example.

(4) In each of the above-described embodiments, the length W2S of the side wall surface Q2 of the second portion G2 in the width direction (X direction) of the groove portion G is smaller than the width W1 of the first portion G1. The length W2S of may be larger than the width W1. However, according to the configuration in which the length W2S is smaller than the width W1, the effect of reducing the wiring resistance is more remarkable as compared with the configuration in which the length W2S of the side wall surface is larger than the width W1 of the first portion G. be.

(5) In each of the above-described embodiments, the wiring surface F of the substrate portion 70 corresponds to the {100} surface of the silicon single crystal, and the extending direction (Y direction) of the wiring 72 is the {100} surface of the silicon single crystal. Although the configuration in which the direction is parallel to the above is illustrated, another crystal plane of the silicon single crystal may be used as the wiring plane F. For example, the {110} plane of the silicon single crystal may be used as the wiring plane F, and the extending direction of the wiring 72 may be the <100> direction of the silicon single crystal. In the above configuration, the side wall surface Q2 of the second portion G2 corresponds to the {111} surface of the silicon single crystal constituting the substrate portion 70, and the second angle θ2 is 45 °. Further, the {110} surface of the silicon single crystal may be used as the wiring surface F, and the extending direction of the wiring 72 may be the <110> direction of the silicon single crystal. In the above configuration, the side wall surface Q2 of the second portion G2 corresponds to the {111} surface of the silicon single crystal constituting the substrate portion 70, and the second angle θ2 is 33.5 °.

(6) In each of the above-described embodiments, the base portion 70 may be formed with a through wiring for electrically connecting the wiring 72 on the first surface F1 and the wiring 72 on the second surface F2. The through wiring is a conductor (TSV: through-silicon via) formed inside the through hole formed in the substrate portion 70. A through hole is formed to connect the groove portion G formed on the first surface F1 side and the groove portion G formed on the second surface F2 side. The through hole in which the through wiring is formed is formed, for example, by irradiating the substrate portion 70 with a laser after forming the oxide film O2 in step P6.

(7) In the step P9 in each of the above-described embodiments, the second portion G2 was formed by performing wet etching on the substrate portion 70, but in the step P9, the second portion was formed by dry etching using an isotropic gas. G2 may be formed.

(8) In each of the above-described embodiments, the wiring 72 of the wiring board 46 is configured by laminating the first layer 81 and the second layer 82, but a part of the wiring 72 of the wiring board 46 is formed by a single layer. May be good. That is, the structure of the groove portion G and the wiring 72 exemplified in each of the above-described embodiments does not need to be applied to all the wiring 72 of the wiring board 46.

(9) The driving element for injecting the liquid (for example, ink) in the pressure chamber C from the nozzle N is not limited to the piezoelectric element 44 exemplified in each of the above-described embodiments. For example, it is also possible to use a heat generating element that generates bubbles inside the pressure chamber C by heating to fluctuate the pressure as a driving element. As understood from the above examples, the drive element is comprehensively expressed as an element for injecting the liquid in the pressure chamber C from the nozzle N (typically, an element for applying pressure to the inside of the pressure chamber C). It does not matter what the operation method (piezoelectric method / thermal method) or the specific configuration is.

(10) In each of the above-described embodiments, the serial type liquid injection device 100 that reciprocates the carrier 242 equipped with the liquid injection head 26 is exemplified, but the line type liquid in which a plurality of nozzles N are distributed over the entire width of the medium 12 is illustrated. The present invention can also be applied to an injection device.

(11) The liquid injection device 100 exemplified in each of the above-described embodiments can be adopted in various devices such as a facsimile machine and a copier, in addition to a device dedicated to printing. However, the application of the liquid injection device of the present invention is not limited to printing. For example, a liquid injection device that injects a solution of a coloring material is used as a manufacturing device for forming a color filter of a display device such as a liquid crystal display panel. Further, a liquid injection device for injecting a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board. Further, a liquid injection device for injecting a solution of an organic substance related to a living body is used, for example, as a manufacturing device for manufacturing a biochip.

100 ... liquid injection device, 12 ... medium, 14 ... liquid container, 20 ... control unit, 22 ... transfer mechanism, 24 ... movement mechanism, 242 ... transfer body, 244 ... transfer belt, 26 ... liquid injection head, 30 ... flow path Forming part, 32 ... Flow path board, 34 ... Pressure chamber board, 42 ... Vibration plate, 44 ... Piezoelectric element, 46 ... Wiring board, 48 ... Housing part, 50 ... Drive circuit, 52 ... External wiring, 62 ... Nozzle board , 64 ... Vibration absorber, 70 ... Base part, 72 (72a, 72b, 72c, 72d, 72e) ... Wiring.

Claims (9)

A flow path forming part in which a pressure chamber communicating with the nozzle is formed,
A drive element that injects the liquid in the pressure chamber from the nozzle,
A drive circuit that outputs a drive pulse that drives the drive element to the drive element,
A wiring board including a base portion installed between the flow path forming portion and the drive circuit and wiring formed on the wiring surface of the base portion and electrically connected to the drive circuit is provided. ,
A groove portion including a first portion and a second portion on the wiring surface side when viewed from the first portion is formed in the substrate portion.
The side wall surface of the first portion forms a first angle with respect to the direction away from the base portion in the direction along the wiring surface .
The side wall surface of the second portion is inclined at a second angle, which is an acute angle lower than the first angle, with respect to a direction that is in contact with the wiring surface and is separated from the substrate portion in the direction along the wiring surface. Is a sloping surface
The wiring is
A first layer formed inside the first portion and inside a part of the second portion on the first portion side, and
A liquid injection head including the first layer, a second layer extending over the side wall surface of the second portion and the wiring surface. The liquid injection head according to claim 1, wherein the second portion is smaller in length in the depth direction than the first portion. The groove portion includes a third portion on the bottom surface side when viewed from the first portion.
The liquid injection head according to claim 1 or 2, wherein the side wall surface of the third portion is an inclined surface that is inclined at a third angle, which is an acute angle lower than the first angle, with respect to the wiring surface. The liquid injection head according to any one of claims 1 to 3, wherein the second layer has a lower resistance than the first layer. The wiring board is a long member and has a long shape.
The liquid injection head according to any one of claims 1 to 4, wherein the wiring extends along the longitudinal direction of the wiring board. The liquid injection head according to any one of claims 1 to 5, wherein the first angle is 90 °. The liquid injection head according to claim 6, wherein the length of the side wall surface of the second portion in the width direction of the groove portion is smaller than the width of the first portion. A liquid injection device comprising the liquid injection head according to any one of claims 1 to 7. A flow path forming portion in which a pressure chamber communicating with the nozzle is formed, a drive element for injecting a liquid in the pressure chamber from the nozzle, and a drive circuit for outputting a drive pulse for driving the drive element to the drive element. A wiring board used for the liquid injection head provided.
A wiring board including a base portion installed between the flow path forming portion and the drive circuit and wiring formed on the wiring surface of the base portion and electrically connected to the drive circuit is provided. ,
A groove portion including a first portion and a second portion on the wiring surface side when viewed from the first portion is formed in the substrate portion.
The side wall surface of the first portion forms a first angle with respect to the direction away from the base portion in the direction along the wiring surface .
The side wall surface of the second portion is inclined at a second angle, which is an acute angle lower than the first angle, with respect to a direction that is in contact with the wiring surface and is separated from the substrate portion in the direction along the wiring surface. Is a sloping surface
The wiring is
A first layer formed inside the first portion and inside a part of the second portion on the first portion side, and
A wiring board including the first layer, the side wall surface of the second portion, and the second layer extending over the wiring surface.

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