JP2007210198A - Liquid droplet ejection head, its manufacturing method, and liquid droplet ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly control the quantity of liquid droplets ejected through nozzles and direction properties by highly precisely forming pressure chambers. <P>SOLUTION: A sacrificial layer 200 is formed on a flow channel substrate 70 and a pressure chamber 50 is formed in the inside region of the sacrificial layer 200 through etching from a side opposite to the sacrifice layer 200. The removal of the sacrificial layer 200 forms a recessed part 50B along the outer shape of the sacrificial layer 200, in a region where the wall part 50A of the pressure chamber 50 and a diaphragm 48 come into contact with each other. The recessed part 50B expands the region in the circumference directions where the wall part 50A of the pressure chamber 50 and the diaphragm 48 come into contact with each other, enabling the opening size of the pressure chamber 50 in contact with the diaphragm 48 to be highly precisely formed. Thereby, the displacement quantity of the diaphragm 48 can be properly controlled. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to, for example, a method for manufacturing a droplet discharge head that performs image recording by discharging droplets typified by an ink jet recording method, a droplet discharge head, and a droplet discharge apparatus.

  2. Description of the Related Art Conventionally, there is an ink jet recording apparatus as a liquid droplet ejecting apparatus that ejects liquid droplets from a plurality of nozzles and prints on a recording medium such as paper. The ink jet recording apparatus is small, inexpensive, and quiet. It has advantages and is widely available commercially. In particular, piezo inkjet systems that eject ink droplets by changing the pressure in the pressure chamber using piezoelectric elements and thermal inkjet recording devices that eject ink droplets by expanding the ink by the action of thermal energy are high-speed printing. It has many advantages such as high resolution.

  In such an ink jet recording apparatus, for example, a recording head having a structure in which a pressure chamber, a nozzle communicating with the pressure chamber, and a piezoelectric element are formed with a diaphragm interposed therebetween is employed. In this recording head, ink is supplied from the ink pool to the pressure chamber and the nozzle via the ink supply port. Then, by applying a voltage to the lower electrode formed on the diaphragm side of the piezoelectric element and the upper electrode formed above the piezoelectric body, the piezoelectric element is deformed and ink is ejected from the nozzle by ejecting ink. Is configured to inject fuel. Such a recording head is superior in miniaturization by pulling out the connection from the piezoelectric element to the outside (control IC) to the upper part of the piezoelectric body, and can cope with high resolution (matrix array nozzle). is there.

  Such a recording head is manufactured based on a semiconductor process, and a recording head is manufactured by aligning and laminating a plurality of plate materials on a Si or glass substrate and cutting out with a die. Through such steps, the cost is reduced and a highly accurate recording head is obtained.

  For example, in a recording head using a piezoelectric element, there is a method in which a piezoelectric element is bonded to a plate material serving as a vibration plate, and a pressure chamber and a nozzle plate that are separately formed are stacked at a position facing the piezoelectric element with the vibration plate interposed therebetween. Widely used (see, for example, Patent Document 1). In such a manufacturing method, since the accuracy of the plate material to be laminated and the alignment between the piezoelectric element and the pressure chamber have a great influence on the amount of ink droplets ejected from the nozzle, the directionality, etc., it is necessary to perform lamination with high accuracy. There is.

  However, with high density and high image quality, it has become difficult to obtain the required dimensional accuracy and alignment accuracy in the manufacturing method using lamination.

  On the other hand, with respect to alignment accuracy, a manufacturing method (semiconductor process-based manufacturing method) in which a necessary material is laminated on a Si or glass substrate from a precision processing part such as conventional SUS has been proposed (for example, Patent Document 2).

However, in this method, the alignment dimension can be improved by introducing a semiconductor process, but it is very difficult to control the dimension size in processing in the depth direction of several hundred μm size such as a pressure chamber. That is, the alignment accuracy in stacking precision processed parts is generally about ± 10 μm, and the dimensional accuracy of the parts is also about ± 10 μm. On the other hand, in the semiconductor process, the processing accuracy in the depth direction of several μm or less is very high, and the dimensional accuracy and reproducibility are good, but in the case of processing exceeding a depth of 100 μm like a pressure chamber, the dimensional accuracy is also large descend.
Japanese Patent No. 3108771 JP 2003-341070 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to form a pressure chamber with high accuracy and to obtain good print quality.

  The present inventors have found that the items that affect the printing quality by the dimensions of the pressure chamber are the opening dimension of the pressure chamber in contact with the diaphragm and the volume (depth × area) of the pressure chamber. In particular, the opening size of the pressure chamber in contact with the diaphragm is very important because it greatly affects the displacement of the diaphragm. Therefore, parts that require dimensional accuracy of the pressure chamber should be made with high accuracy, and parts that do not require much accuracy should be machined to improve accuracy and throughput (production efficiency and cost reduction). Yes.

  The invention according to claim 1 is a method of manufacturing a droplet discharge head that discharges droplets from a nozzle communicating with the pressure chamber by the vibration of a vibration plate in contact with the pressure chamber in which the liquid is stored. Forming a sacrificial layer on a portion of the substrate to be formed, a step of forming a diaphragm layer serving as a diaphragm on the sacrificial layer, and etching from the side of the substrate where the nozzle is formed, Forming a pressure chamber in an inner region of the sacrificial layer, and removing the sacrificial layer to form a concave shape along the outer shape of the sacrificial layer in a region where the wall of the pressure chamber and the diaphragm are in contact with each other Forming a portion.

  In the first aspect of the present invention, the sacrificial layer is formed on the portion of the substrate that becomes the pressure chamber, and then the diaphragm layer is formed on the sacrificial layer. Further, by etching from the side of the substrate where the nozzle is formed, a pressure chamber is formed in the inner region of the sacrificial layer leaving the sacrificial layer. Thereafter, by removing the sacrificial layer, a concave portion along the outer shape of the sacrificial layer is formed in a region where the wall of the pressure chamber and the diaphragm are in contact with each other. In this manufacturing method, since the concave portion along the outer shape of the sacrificial layer becomes a region where the pressure chamber and the diaphragm come into contact with each other, the opening dimension of the pressure chamber in contact with the diaphragm can be formed with high accuracy. For this reason, the displacement amount of the diaphragm can be appropriately controlled, and the discharge amount and directionality of droplets from the nozzle are stabilized.

  According to a second aspect of the present invention, in the method of manufacturing a droplet discharge head according to the first aspect, the step of forming the sacrificial layer patterns the sacrificial layer on the substrate.

  According to the second aspect of the present invention, it is possible to form the sacrificial layer at a predetermined position of the substrate to be the pressure chamber by patterning the sacrificial layer on the substrate. Thereby, the opening dimension of the pressure chamber in contact with the diaphragm can be formed with high accuracy.

  According to a third aspect of the present invention, in the method of manufacturing a droplet discharge head according to the first aspect, the step of forming the sacrificial layer forms a recess by cutting away a portion of the substrate corresponding to the pressure chamber. A step of applying a sacrificial layer material to be the sacrificial layer to the substrate on the side where the recess is formed, a step of cutting the sacrificial layer material and forming the sacrificial layer with the substrate being flat, It is characterized by having.

  In a third aspect of the invention, a portion of the substrate corresponding to the pressure chamber is cut away to form a recess, and a sacrificial layer material to be a sacrificial layer is applied to the substrate on which the recess is formed. Thereafter, the sacrificial layer material is shaved, and the sacrificial layer is formed by flattening the substrate, whereby the sacrificial layer can be formed at a predetermined position of the substrate to be the pressure chamber. Thereby, the opening dimension of the pressure chamber in contact with the diaphragm can be formed with high accuracy.

  The invention according to claim 4 includes a pressure chamber that contains a liquid and communicates with a nozzle that discharges liquid droplets, and a diaphragm that contacts the pressure chamber and applies pressure to the liquid in the pressure chamber, A droplet discharge head that discharges droplets from the nozzle by vibration of a vibration plate, wherein a concave portion that enlarges an opening area of the pressure chamber is formed in a region where the wall of the pressure chamber and the vibration plate are in contact with each other It is characterized by being.

  In the invention according to claim 4, a concave portion that enlarges the opening area of the pressure chamber is formed in a region where the wall of the pressure chamber and the diaphragm are in contact with each other, and the opening size of the pressure chamber that is in contact with the diaphragm by the concave portion. Can be formed with high accuracy. As a result, the displacement amount of the diaphragm can be appropriately controlled, and the discharge amount and directionality of the droplets from the nozzle are stabilized.

  According to a fifth aspect of the present invention, a liquid droplet ejection apparatus includes the liquid droplet ejection head according to the fourth aspect.

  According to the fifth aspect of the present invention, since the droplet discharge head according to the fourth aspect is provided, the opening size of the pressure chamber in contact with the diaphragm can be accurately formed by the concave portion. This makes it possible to appropriately control the displacement amount of the diaphragm, stabilize the discharge amount and directionality of droplets from the nozzle, and obtain good image quality.

  According to the present invention, since the displacement amount of the diaphragm of the droplet discharge head can be appropriately controlled, the droplet discharge amount and directionality from the nozzle can be stabilized, and good image quality can be obtained. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating an inkjet recording apparatus (droplet ejection apparatus) 10 including an inkjet recording head (droplet ejection head) 32 according to the first embodiment of the present invention. FIG. 2 is a schematic diagram showing the arrangement of the recording heads of the inkjet recording unit 30 in the inkjet recording apparatus 10, and FIG. 3 is a diagram showing a print area by the inkjet recording unit 30 in the inkjet recording apparatus 10.

  An ink jet recording apparatus 10 shown in FIG. 1 forms an image on a paper (recording medium) P by ejecting ink droplets (droplets), a paper supply unit 12 for feeding paper, a registration adjusting unit 14 for controlling the posture of the paper, and the like. The recording unit 20 includes a recording head unit 16 that performs maintenance and a maintenance unit 18 that performs maintenance of the recording head unit 16, and a discharge unit 22 that discharges a sheet on which an image is formed by the recording unit 20.

  The sheet supply unit 12 includes a stocker 24 in which sheets are stacked and stocked, and a transport device 26 that transports the sheets one by one from the stocker 24 to the registration adjusting unit 14.

  The registration adjusting unit 14 includes a loop forming unit 28 and a guide member 29 for controlling the posture of the paper. By passing through this portion, the skew is corrected using the stiffness of the paper and the conveyance timing is controlled. The recording unit 20 is entered.

  The discharge unit 22 stores a sheet on which an image is formed by the recording unit 20 in a tray 25 via a discharge belt 23.

  Between the recording head unit 16 and the maintenance unit 18, a sheet conveyance path through which the sheet P is conveyed is configured. A plurality of star wheels 17 and transport rolls 19 are arranged along the paper transport path, and the paper P is transported continuously (without stopping) while being pinched by the star wheels 17 and the transport rolls 19. Then, ink droplets are ejected from the recording head unit 16 on the paper P, and an image is formed on the paper P.

  The maintenance unit 18 includes a maintenance device 21 disposed to face the inkjet recording unit 30 (inkjet recording head 32). The maintenance unit 18 performs capping, wiping, and dummy jetting on the inkjet recording unit 30 (inkjet recording head 32). And vacuum processing can be performed.

  As shown in FIG. 2, each of the inkjet recording units 30 includes a plurality of inkjet recording heads 32 arranged in a direction orthogonal to the paper transport direction. In the inkjet recording head 32, a plurality of nozzles 56 are formed in a matrix. An image is recorded on the paper P by ejecting ink droplets from the nozzle 56 onto the paper P that is continuously transported through the paper transport path. For example, in order to record a so-called full-color image, at least four inkjet recording units 30 are arranged corresponding to each color of YMCK.

  As shown in FIG. 3, the print area width by the nozzle 56 of each ink jet recording unit 30 is longer than the maximum paper width PW of the paper P on which image recording by the ink jet recording apparatus 10 is assumed. It is possible to record an image over the entire width of the paper P without moving the recording unit 30 in the paper width direction (so-called Full Width Array (FWA)). Here, the printing area is basically the maximum of the recording area obtained by subtracting the margin not to be printed from both ends of the sheet, but is generally larger than the maximum sheet width PW to be printed. This is because there is a possibility that the sheet is conveyed at an angle (skew) with respect to the conveyance direction, and there is a high demand for borderless printing.

  Next, the ink jet recording head 32 according to the first embodiment of the present invention mounted on the ink jet recording apparatus 10 having the above configuration will be described in detail. FIG. 4 is a schematic cross-sectional view showing the ink jet recording head 32 partially taken out so that the main part becomes clear. 5 and 6 are process diagrams showing an example of the manufacturing process of the method for manufacturing the ink jet recording head 32.

  A top plate member 40 is disposed on the ink jet recording head 32. In the present embodiment, the glass plate top plate 41 constituting the top plate member 40 is plate-shaped and has wiring, and serves as a top plate for the entire inkjet recording head 32. The top plate member 40 is provided with a driving IC 60 and a metal wiring 90 for energizing the driving IC 60. The metal wiring 90 is covered and protected with a resin protective film 92.

  In addition, a plurality of bumps (not shown) protrude in a matrix shape at a predetermined height on the lower surface of the drive IC 60 and are flip-chip mounted on the metal wiring 90 on the top plate 41. Therefore, it is possible to easily realize high-density wiring and low resistance for the piezoelectric element 46, and thus, the ink jet recording head 32 can be miniaturized. The periphery of the drive IC 60 is sealed with a resin material 58.

  A pool chamber member 39 made of an ink-resistant material is attached to the top plate member 40, and an ink pool chamber 38 having a predetermined shape and volume is formed between the top plate member 40 and the top plate member 40. ing. The pool chamber member 39 is provided with an ink supply port 36 communicating with the ink tank at a predetermined location, and the ink 110 injected from the ink supply port 36 is stored in the ink pool chamber 38.

  The top plate 41 is formed with an ink supply through-hole 112 that has a one-to-one correspondence with a pressure chamber 50 to be described later, and the inside thereof is a first ink supply path 114A.

  The top plate 41 has an electrical connection through hole 42 at a position corresponding to an upper electrode 54 described later. The metal wiring 90 of the top plate 41 extends into the electrical connection through hole 42 and covers a part of the inner surface of the electrical connection through hole 42. The inside of the electrical connection through hole 42 is filled with solder 86 so as to be in contact with the metal wiring 90. Thereby, the metal wiring 90 is reinforced, the metal wiring 90 and the upper electrode 54 are electrically connected via the solder 86, and the individual wiring of the piezoelectric element substrate 70 becomes unnecessary. Further, the electrical connection state is improved by the solder 86. For example, the electrical connection between the metal wiring 90 and the upper electrode 54 is satisfactorily maintained by the solder 86 even when subjected to thermal stress or mechanical stress. .

  A pressure chamber 50 filled with ink supplied from the ink pool chamber 38 is formed in the flow path substrate 72. In addition, a nozzle plate 74 in which a communication path 51 and a nozzle 56 are formed is joined to the lower portion of the pressure chamber 50 so that ink droplets are ejected from the nozzle 56 communicating with the pressure chamber 50. The ink pool chamber 38 and the pressure chamber 50 are configured not to exist on the same horizontal plane. Therefore, the pressure chambers 50 can be arranged close to each other, and the nozzles 56 can be arranged in a matrix at high density.

  A piezoelectric element substrate 70 is attached to the surface of the flow path substrate 72 opposite to the nozzle 56 side, and constitutes one surface of the pressure chamber 50. The piezoelectric element substrate 70 has a vibration plate 48, and by generating a pressure wave by increasing / decreasing the volume of the pressure chamber 50 by the vibration of the vibration plate 48, ink droplets can be ejected from the nozzle 56.

  This pressure chamber 50 has a concave shape in which the opening size of the pressure chamber 50 is enlarged to the surrounding area in the region where the pressure chamber 50 and the vibration plate 48 are in contact with each other above the wall portion 50A in the direction orthogonal to the vibration plate 48. Part 50B is formed. That is, a step is formed between the concave portion 50 </ b> B and the wall portion 50 </ b> A of the pressure chamber 50, and the opening size of the pressure chamber 50 with respect to the diaphragm 48 (area where the pressure chamber 50 contacts the diaphragm 48). ) Is prescribed. The natural period (volume of the pressure chamber 50) is defined by the dimension of the wall portion 50A of the pressure chamber 50. The manufacturing process of the wall part 50A and the recessed part 50B will be described later.

  The piezoelectric element 46 is disposed above the diaphragm 48 for each pressure chamber 50. A lower electrode 52 having one polarity is disposed on the lower surface of the piezoelectric body 46A constituting the piezoelectric element 46, and an upper electrode 54 having the other polarity is disposed on the upper surface of the piezoelectric element 46. The diaphragm 48 is formed of glass, has elasticity in at least the vertical direction, and is configured to bend and deform (displace) in the vertical direction when the piezoelectric element 46 is energized (when a voltage is applied). Yes. The diaphragm 48 may be a metal material such as SUS.

  The piezoelectric element 46 is covered and protected by a low water-permeable insulating film (for example, a SiOx film) 80. Since the low water-permeable insulating film 80 covering and protecting the piezoelectric element 46 is deposited under the condition that the moisture permeability is low, moisture penetrates into the piezoelectric element 46 and becomes unreliable (PZT). Deterioration of piezoelectric characteristics caused by reducing oxygen in the film can be prevented.

  Further, a partition resin layer 119 is laminated on the insulating film 80. Although illustration is omitted, the partition resin layer 119 defines a space between the piezoelectric element substrate 70 and the top plate member 40.

  The partition resin layer 119 is formed with an ink supply through-hole 44 that communicates with the ink supply through-hole 112 of the top plate 41, and the inside thereof is a second ink supply path 114 </ b> B. The second ink supply path 114B has a cross-sectional area smaller than the cross-sectional area of the first ink supply path 114A, and is adjusted so that the flow path resistance in the entire ink supply path becomes a predetermined value. On the other hand, the cross-sectional area of the first ink supply path 114A is sufficiently larger than the cross-sectional area of the second ink supply path 114B, and is substantially ignored as compared with the flow path resistance in the second ink supply path 114B. It is supposed to be possible. That is, the flow resistance of the ink supply path 114 from the ink pool chamber 38 to the pressure chamber 50 is defined only by the second ink supply path 114B. Further, since ink is supplied through the ink supply through-hole 44 formed in the partition resin layer 119 in this way, ink leakage during supply is prevented.

  A partition resin layer 118 is also laminated at a position corresponding to the electrical connection through hole 42. In FIG. 4, a cross section is shown at a position where the partition resin layer 118 and the partition resin layer 119 are separated, but these are actually partially connected. By the partition resin layers 118 and 119, a gap is formed between the top plate member 40 and the piezoelectric element 46 (strictly speaking, the insulating film 80 on the piezoelectric element 46) to form an air layer. This air layer does not affect the driving of the piezoelectric element 46 or the vibration of the diaphragm 48.

  In such an ink jet recording head 32, a signal from the driving IC 60 is energized to the metal wiring 90 of the top plate member 40, and is further energized from the metal wiring 90 to the upper electrode 54 via the solder 86. Then, a voltage is applied to the piezoelectric element 46 at a predetermined timing, and the vibration plate 48 is bent and deformed in the vertical direction, whereby the ink 110 filled in the pressure chamber 50 is pressurized and ink droplets are ejected from the nozzle 56. Discharge.

  The partition resin layer 119 and the partition resin layer 118 are configured such that the heights of the upper surfaces thereof are constant, that is, flush with each other. Therefore, the height (distance) of the opposing surfaces of the partition resin layer 119 and the partition resin layer 118 measured from the top plate 41 is also the same. Thereby, the contact property at the time of the top plate 41 contacting becomes high, and the sealing performance is also high.

  Next, a method for manufacturing the main part of the ink jet recording head 32 having the above-described configuration, which is a method for manufacturing the ink jet recording head 32 according to the first embodiment of the present invention, will be described in detail with reference to FIGS. explain.

As shown in FIG. 5A, a sacrificial layer 200 is laminated and patterned on a portion on the flow path substrate 72 that becomes the pressure chamber 50 (see FIG. 4). The sacrificial layer 200 is formed in a portion corresponding to the pressure chamber 50 in contact with the vibration plate 48 (see FIG. 4), and the size of the sacrificial layer 200 is the opening size of the pressure chamber 50. The thickness of the sacrificial layer 200 is 2.0 μm or less, and particularly preferably 0.2 to 0.3 μm. The material of the sacrificial layer 200 is, for example, Poly-Si is used, SiO ₂ or Ge, or the like may be used refractory metals (Ta, W, etc.). Specifically, the sacrificial layer 200 is formed by stacking a sacrificial layer film by RF or DC sputtering, resist formation by photolithography, patterning (etching), resist stripping by oxygen plasma, or the like.

Next, as shown in FIG. 5B, the diaphragm 48 is laminated on the sacrificial layer 200 of the flow path substrate 72. For example, SiO ₂ , CrN, TaAl or the like is used as the material of the diaphragm 48. Further, the lower electrode 52 is laminated on the vibration plate 48 by sputtering. The material of the lower electrode 52 is Ir or Pt.

  Next, the material of the piezoelectric body 46A and the upper electrode 54 are sequentially laminated on the lower electrode 52 by sputtering, and the piezoelectric body 46A and the upper electrode 54 are patterned as shown in FIG. Specifically, resist formation by photolithography, patterning (etching), and resist removal by oxygen plasma. For example, PZT, PNN, or the like is used as the material of the piezoelectric body 46A. For example, Ir or Pt is used as the material of the upper electrode 54. The film deposition of the piezoelectric body 46A may be selected from a sol-gel method, an MOCVD method, etc. in addition to the sputtering method.

  Next, as shown in FIG. 6A, the back surface side of the flow path substrate 72 (the side opposite to the surface on which the diaphragm 48 is formed) is etched, leaving the sacrificial layer 200 and the wall portion of the pressure chamber 50. 50A is formed. Specifically, resist formation by photolithography, patterning (etching), resist stripping by oxygen plasma, or the like is performed. Etching is performed by plasto, wet, dry or the like. At this time, the wall portion 50 </ b> A is formed in the inner region of the sacrificial layer 200 so that the opening size of the pressure chamber 50 is smaller than the sacrificial layer 200.

Next, as shown in FIG. 6B, by removing the sacrificial layer 200, a concave portion 50B along the outer shape of the sacrificial layer 200 is formed in a region where the wall portion 50A of the pressure chamber 50 and the diaphragm 48 are in contact with each other. Form. At this time, the concave portion 50 </ b> B is formed in a portion of the diaphragm 48 on the upper side of the wall portion 50 </ b> A of the pressure chamber 50. The sacrificial layer 200 is removed by isotropic removal by chemical dry etching (CDE) or removal by phosphoric acid when the sacrificial layer 200 is Poly-Si or SiN. If the sacrificial layer 200 is made of SiO ₂ , it is removed by hydrofluoric acid, and if it is Ta, it is removed by chemical dry etching (CDE). The removal of the sacrificial layer 200 is appropriately set depending on the selectivity between the flow path substrate 72 and the diaphragm 48.

  Thereafter, as shown in FIG. 6C, a separately prepared nozzle plate 74 is joined to the flow path substrate 72 in accordance with the position of the pressure chamber 50.

  In such a manufacturing method of the ink jet recording head 32, the sacrificial layer 200 is formed on the portion of the flow path substrate 72 to be the pressure chamber 50, and then the sacrificial layer 200 is removed, so that the wall portion 50 </ b> A of the pressure chamber 50 is removed. A concave portion 50B along the outer shape of the sacrificial layer 200 is formed in a region where the diaphragm 48 contacts. With this concave portion 50B, the opening size of the pressure chamber 50 in contact with the diaphragm 48 (area of the pressure chamber 50 in contact with the diaphragm 48) can be manufactured with high accuracy. Further, the natural period (volume of the pressure chamber 50) can be defined by the dimension of the wall portion 50A of the pressure chamber 50. For this reason, the displacement amount of the vibration plate 48 can be controlled appropriately, the ejection amount and directionality of the ink droplets from the nozzles 56 are stabilized, and good image quality can be obtained.

  In addition, the opening size of the pressure chamber 50 can be manufactured with high accuracy, and a portion that does not require much accuracy can be manufactured using machining, etc., and accuracy and throughput (production efficiency and cost reduction) can be improved. Can do.

  Next, the manufacturing method of the inkjet recording head in 2nd Embodiment of this invention is demonstrated in detail based on FIGS.

  In addition, the same code | symbol is attached | subjected to the same member as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 7A, the flow path substrate 272 is etched with a predetermined pattern to form a recess 272A. Specifically, resist formation by photolithography, patterning (etching), and resist removal by oxygen plasma. Etching is performed by dry, wet, or the like. For example, Si or glass is used as the material of the flow path substrate 272. The depth of the recess 272A is preferably 0.5 μm to 1.0 μm because the dimensional variation increases as the etching amount increases.

Next, as shown in FIG. 7B, a sacrificial layer material to be the sacrificial layer 202 is applied to the entire surface of the channel substrate 272 that covers the recess 272A of the channel substrate 272 and its periphery. For example, Poly-Si is used as the sacrificial layer material, but SiO ₂ , Ge, refractory metals (Ta, W, etc.), etc., may also be used. The sacrificial layer 202 to be the sacrificial layer 202 is applied by applying a resin material or printing.

  Next, as shown in FIG. 7C, the sacrificial layer material to be the sacrificial layer 202 is etched or polished, and the surface of the flow path substrate 272 is flattened. As a result, the sacrificial layer 202 is embedded in the recess 272A. The sacrificial layer 202 is formed in a portion corresponding to the pressure chamber 250 (see FIG. 9) in contact with the diaphragm 48 (see FIG. 9), and the size of the sacrificial layer 202 becomes the opening size of the pressure chamber 50. .

Next, as shown in FIG. 7D, the vibration plate 48 is stacked on the sacrificial layer 202 of the flow path substrate 272. For example, SiO ₂ , CrN, TaAl or the like is used as the material of the diaphragm 48.

  Next, as shown in FIG. 8A, the lower electrode 52 is stacked on the diaphragm 48 by sputtering. The material of the lower electrode 52 is Ir or Pt.

  Next, the material of the piezoelectric body 46A and the upper electrode 54 are sequentially laminated on the lower electrode 52 by sputtering, and the piezoelectric body 46A and the upper electrode 54 are patterned as shown in FIG. 8B. Specifically, resist formation by photolithography, patterning (etching), and resist removal by oxygen plasma. For example, PZT, PNN, or the like is used as the material of the piezoelectric body 46A. For example, Ir or Pt is used as the material of the upper electrode 54. The film deposition of the piezoelectric body 46A may be selected from a sol-gel method, an MOCVD method, etc. in addition to the sputtering method.

  Next, as shown in FIG. 8C, the back surface side of the flow path substrate 272 is polished to form a flow path substrate 272B having a desired thickness (100 μm to 300 μm). Note that the polishing of the flow path substrate 272 is not an essential step, and a thin substrate may be used from the beginning.

  Next, as shown in FIG. 9A, the back surface side of the flow path substrate 272B (the side opposite to the surface on which the vibration plate 48 is formed) is wet-etched, leaving the sacrificial layer 202 and the wall of the pressure chamber 250. Part 250A is formed. Specifically, resist formation by photolithography, patterning (etching), and resist removal by oxygen plasma are performed. Etching may be carried out by plasty, dry, etc. in addition to wet. At this time, the wall portion 250 </ b> A is formed in the inner region of the sacrificial layer 202 so that the opening size of the pressure chamber 250 is smaller than the sacrificial layer 202.

Next, as shown in FIG. 9B, by removing the sacrificial layer 202, a concave portion 250B along the outer shape of the sacrificial layer 202 is formed in a region where the wall portion 250A of the pressure chamber 250 and the diaphragm 48 come into contact. Form. At this time, the concave portion 250 </ b> B is formed on the wall surface of the pressure chamber 250 above the wall portion 250 </ b> A of the pressure chamber 250. The sacrificial layer 202 is removed by isotropic removal by chemical dry etching (CDE) or removal by phosphoric acid when the sacrificial layer 202 is Poly-Si or SiN. If the sacrificial layer 202 is made of SiO ₂ , it is removed by hydrofluoric acid, and if it is Ta, it is removed by chemical dry etching (CDE). The removal of the sacrificial layer 202 can be appropriately set depending on the selectivity with respect to the flow path substrate 272B and the diaphragm 48.

  After that, as shown in FIG. 9C, an ink jet recording head 232 is manufactured by joining a separately prepared nozzle plate 74 to the flow path substrate 272B in accordance with the position of the pressure chamber 250.

  In such a method of manufacturing the ink jet recording head 232, the sacrificial layer 202 embedded in the concave portion 272 </ b> A is formed, and then the sacrificial layer 202 is removed, so that the diaphragm 48 above the wall portion 250 </ b> A of the pressure chamber 250 is formed. A concave portion 250B is formed at the contacting portion. With this concave portion 250B, the opening size of the pressure chamber 250 in contact with the diaphragm 48 (area of the pressure chamber 250 in contact with the diaphragm 48) can be manufactured with high accuracy. Further, the natural period (volume of the pressure chamber 250) can be defined by the dimension of the wall portion 250A of the pressure chamber 250. For this reason, the displacement amount of the vibration plate 48 can be controlled appropriately, the ejection amount and directionality of the ink droplets from the nozzles 56 are stabilized, and good image quality can be obtained. In addition, the opening size of the pressure chamber 250 can be manufactured with high accuracy, and a portion that does not require much accuracy can be manufactured using machining, etc., and accuracy and throughput (production efficiency and cost reduction) can be improved. Can do.

  In the example shown in FIG. 1 and the like, an example of FWA corresponding to the paper width has been described. However, the inkjet recording head of the present invention is not limited to this, and a partial width array (PWA) having a main scanning mechanism and a sub-scanning mechanism. It can also be applied to the apparatus of

  In the example shown in FIG. 1 and the like, an image (including characters) is recorded on the paper P as a recording medium. However, the liquid droplet ejection head and the liquid droplet ejection apparatus of the present invention are not limited to this. Is not to be done. That is, the recording medium is not limited to paper, and the liquid to be ejected is not limited to ink. For example, it is industrially useful to create color filters for displays by discharging ink onto polymer films or glass, or to form bumps for component mounting by discharging solder in a welded state onto a substrate. The present invention can be applied to all droplet discharge heads and droplet discharge apparatuses used.

1 is a schematic configuration diagram illustrating an ink jet recording apparatus (droplet discharge apparatus) including an ink jet recording head (droplet discharge head) according to a first embodiment of the present invention. It is the schematic which shows the recording head arrangement | positioning of the inkjet recording unit in the inkjet recording device shown in FIG. It is a figure which shows the printing area | region by the inkjet recording unit in the inkjet recording device shown in FIG. 1 is a schematic cross-sectional view showing an ink jet recording head according to a first embodiment of the present invention. It is process drawing which shows the manufacturing process of the manufacturing method of the inkjet recording head which is 1st Embodiment of this invention. It is process drawing which shows the manufacturing process of the manufacturing method of the inkjet recording head which is 1st Embodiment of this invention. It is process drawing which shows the manufacturing process of the manufacturing method of the inkjet recording head which is 2nd Embodiment of this invention. It is process drawing which shows the manufacturing process of the manufacturing method of the inkjet recording head which is 2nd Embodiment of this invention. It is process drawing which shows the manufacturing process of the manufacturing method of the inkjet recording head which is 2nd Embodiment of this invention.

Explanation of symbols

10 Inkjet recording device (droplet ejection device)
16 Recording Head 30 Inkjet Recording Unit 32 Inkjet Recording Head (Droplet Discharge Head)
46 Piezoelectric element 46A Piezoelectric body 48 Diaphragm 50 Pressure chamber 50A Wall portion 50B Concave portion 56 Nozzle 72 Channel substrate 110 Ink 200 Sacrificial layer 202 Sacrificial layer 232 Inkjet recording head (droplet ejection head)
250 Pressure chamber 250A Wall portion 250B Concave portion 272 Channel substrate 272A Concave portion 272B Channel substrate

Claims (5)

A method of manufacturing a droplet discharge head for discharging droplets from a nozzle communicating with the pressure chamber by vibration of a vibration plate in contact with a pressure chamber in which a liquid is stored,
Forming a sacrificial layer on the portion of the substrate that becomes the pressure chamber;
Forming a diaphragm layer to be a diaphragm on the sacrificial layer;
Etching from the nozzle forming side of the substrate, leaving the sacrificial layer and forming a pressure chamber in an inner region of the sacrificial layer;
Removing the sacrificial layer to form a concave portion along the outer shape of the sacrificial layer in a region where the wall of the pressure chamber and the diaphragm are in contact with each other;
A method of manufacturing a droplet discharge head, comprising:   The method of manufacturing a droplet discharge head according to claim 1, wherein the step of forming the sacrificial layer patterns the sacrificial layer on the substrate. Forming the sacrificial layer comprises:
Cutting the portion of the substrate corresponding to the pressure chamber to form a recess;
Applying a sacrificial layer material to be the sacrificial layer to the substrate on the side where the recess is formed;
Scraping the sacrificial layer material to form the sacrificial layer with the substrate flat;
The method for manufacturing a droplet discharge head according to claim 1, wherein: A pressure chamber containing liquid and communicating with a nozzle for discharging droplets;
A diaphragm that contacts the pressure chamber and applies pressure to the liquid in the pressure chamber;
A droplet discharge head for discharging droplets from the nozzle by vibration of the diaphragm,
A droplet discharge head, wherein a concave portion that enlarges an opening area of the pressure chamber is formed in a region where the wall of the pressure chamber and the diaphragm are in contact with each other.   A droplet discharge device comprising the droplet discharge head according to claim 4.

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