JP2011083899A - Method for manufacturing passage forming substrate of ink-jet recording head, passage forming substrate, and ink-jet recording head - Google Patents

Abstract

There has been a demand for an etching method capable of reducing the opening of a nozzle communication hole for increasing the density of an ink jet recording head.
A method of manufacturing a flow path forming substrate comprising a nozzle communication hole, a reservoir, and an ink supply port by etching in a silicon single crystal substrate, the communication direction of the nozzle communication hole in the nozzle communication hole forming region. And a modified phase forming step of continuously laminating the modified portion of the silicon single crystal substrate by laser irradiation, and a first etching step of drilling a formation range of the nozzle communication hole and a formation range of the reservoir by etching. And a second etching step of forming the ink supply port by etching the formation range of the ink supply port.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a flow path forming substrate of an ink jet recording head, a flow path forming substrate, and an ink jet recording head.

  The ink jet recording head is supplied with ink from an external ink tank to the reservoir, and the ink sucked from the reservoir by the expansion of the pressure generating chamber provided with the pressure generating device is contracted to open the nozzle communication hole. Then, the ink is ejected as ink droplets from the nozzle openings.

  In order to reduce the ink amount of ejected ink droplets, reduce the dot size, and increase the recording density, this ink jet recording head reduces the pressure generation chamber by photolithography and anisotropic etching on a silicon single crystal substrate, In addition, a manufacturing method of a flow path forming substrate arranged in high density is known (for example, see Patent Document 1).

  However, due to the difference in the etching rate with respect to the crystal axis of the silicon single crystal substrate, the nozzle communication hole opening becomes large even in the above-described method, and there is a limit to increasing the density. In order to solve such a problem, it is known that a minute through hole is previously drilled in an opening region of the nozzle communication hole, and the nozzle communication hole opening is made small by using the through hole as an etching guide hole (for example, Patent Document 2).

  In the formation of nozzle communication holes by this method, since the silicon single crystal substrate to be processed is a hard and brittle material, it is necessary to perform processing of the through holes over time, which is a low productivity method. . Thus, a method has been proposed in which the etching induction hole is not a through-hole but a non-through-hole, thereby simplifying the through-hole forming operation (see, for example, Patent Document 3).

JP 58-40509 A JP-A-5-309835 JP-A-10-166600

  However, even in the above-described conventional technology, the etching induction hole (through hole or non-through hole) is formed by laser drilling, and the opening of the nozzle communication hole is etched in the etching area with the laser irradiation area taken into account. It formed in the protective film. Therefore, there has been a demand for a method for forming an etching guiding portion that can reduce the etching region, that is, the nozzle communication hole opening.

  The present invention is realized as the following forms or application examples so as to solve at least one of the above-described problems.

  Application Example 1 A manufacturing method of a flow path forming substrate of this application example is a manufacturing method of a flow path forming substrate provided with a nozzle communication hole, a reservoir, and an ink supply port by etching on a silicon single crystal substrate. A modified portion forming step of continuously laminating the modified portion of the silicon single crystal substrate by laser irradiation in the communication direction of the nozzle communication hole in the formation region of the communication hole, the formation range of the nozzle communication hole, and the The method includes a first etching step of perforating a reservoir formation range by etching, and a second etching step of forming the ink supply port by etching the formation range of the ink supply port.

  According to this application example, the modified portion of silicon is formed in the communication direction of the nozzle communication hole by laser irradiation before the etching process for drilling the nozzle communication hole. This modified portion does not have the etching anisotropy of the silicon single crystal. By forming the modified portion continuously in the thickness direction of the silicon single crystal substrate in the communication hole forming range, that is, the communication direction of the communication hole, the modified portion is etched first in the communication hole etching step, A through hole having a minute diameter is formed. The formed minute through-hole is introduced into the through-hole as an etching guide hole for the communication hole. Thus, etching is started on the entire inner peripheral surface of the through hole (etching induction hole), and a small diameter nozzle communication hole can be formed.

[Application Example 2] In the application example described above, in the modified portion forming step, the modified portion is formed from the depth D from the surface of the silicon single crystal substrate in the laser irradiation.
The depth D is
0 ≦ D ≦ 0.7W
However, W: Nozzle communication hole opening minimum diameter.

  According to the above application example, the focus (condensing part) position of the laser irradiation is not set on the surface of the silicon single crystal substrate, so that the etching mask (oxide film pattern) for forming the communication holes formed on the surface of the silicon single crystal substrate is used. ) Is not impaired. Furthermore, since the laser irradiation is performed with an energy amount sufficient to form the modification inside the silicon single crystal substrate, the opening of the communication hole forming portion in the etching mask can be formed with a minimum shape.

  Application Example 3 In the application example described above, the etching protective film forming step of forming silicon oxide as an etching protective film on the silicon single crystal plate is before the modified portion forming step.

  According to the application example described above, the etching protective film is transparent silicon oxide, so that laser irradiation can be performed through the etching protective film. In addition, since the laser irradiation in the modified portion forming step is focused on the inside of the surface of the silicon single crystal substrate, damage to the etching protective film due to the laser irradiation does not occur. Further, since the formation of the silicon oxide film is performed at the initial stage of the manufacturing process in the application example described above, it also has an effect as a film for preventing damage to the surface of the silicon single crystal substrate during handling.

Application Example 4 In the above application example, the etching protective film forming step of forming silicon nitride as an etching protective film on the silicon single crystal plate is between the modified portion forming step and the first etching step. It is characterized by that.
According to the application example described above, a nozzle communication hole having a small opening can be formed even when silicon nitride having excellent characteristics as an etching protective film is applied.

  Application Example 5 A flow path forming substrate manufactured by the manufacturing method described in the above application example.

  Application Example 6 An ink jet recording head using the above-described flow path forming substrate.

  According to the application example described above, it is possible to realize a flow path forming substrate that further reduces the particle size of the discharged droplets. A high-density, high-definition printed matter can be output by an ink jet recording apparatus using an ink jet recording head using the flow path forming substrate.

The schematic sectional drawing of the flow-path unit in embodiment. The top view which shows the schematic cross section of the flow-path formation board | substrate of the flow-path unit in embodiment. The schematic perspective view of the flow-path formation board | substrate in embodiment. The manufacturing flowchart of the flow-path formation board | substrate in 1st Embodiment. The schematic sectional drawing which shows the manufacturing method of the flow-path formation board | substrate in 1st Embodiment. The schematic sectional drawing which shows the manufacturing method of the flow-path formation board | substrate in 1st Embodiment. The schematic diagram explaining the modification part formation part in 1st Embodiment. The manufacturing flowchart of the flow-path formation board | substrate in 2nd Embodiment. The schematic sectional drawing which shows the manufacturing method of the flow-path formation board | substrate in 2nd Embodiment. FIG. 10 is a schematic cross-sectional view showing the configuration of an ink jet recording head in a third embodiment. The top view which shows typically the nozzle plate in 3rd Embodiment.

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

(First embodiment)
One embodiment of a method for manufacturing a flow path forming substrate will be described below. FIG. 1 is a schematic sectional view of a flow path unit of an ink jet recording head. The flow path unit 100 includes a flow path forming substrate 10, an elastic plate 20 that seals one surface of the flow path forming substrate 10, and a nozzle opening 31 that seals the other surface of the flow path forming substrate 10. It consists of a nozzle plate 30. The flow path forming substrate 10 includes a reservoir 11 that receives ink supply from an external tank, a pressure generation chamber 12 that receives external pressure, an ink supply port 13 that connects the reservoir 11 and the pressure generation chamber 12, and a pressure generation chamber. 12 and a nozzle communication hole 14 that connects the nozzle opening 31 of the nozzle plate 30.

  When the piezoelectric vibrator 40 is brought into contact with the elastic plate 20 of the flow path unit 100 and the piezoelectric vibrator 40 is displaced (vibrated), the elastic plate 20 is displaced, and the volume of the pressure generating chamber 12 is expanded to increase the reservoir 11. Ink is sucked into the pressure generating chamber 12 through the ink supply port 13, the volume of the pressure generating chamber 12 is contracted to pressurize the ink in the pressure generating chamber 12, and ink droplets are formed from the nozzle openings 31 of the nozzle plate 30. It is configured to discharge.

  FIG. 2 shows a schematic plane of the A-A ′ cross section of the flow path forming substrate 10 in FIG. 1. As shown in FIG. 2, the flow path forming substrate 10 includes a plurality of pressure generation chambers 12, ink supply ports 13, and nozzle communication holes 14 in one reservoir 11, and each nozzle communication hole 14 has a nozzle plate 30. The nozzle opening 31 corresponds. Furthermore, in order to make the configuration of the flow path forming substrate 10 easy to understand, a perspective view of the flow path forming substrate 10 is shown in FIG.

Next, a method for manufacturing the flow path forming substrate 10 will be described. The flow path forming substrate 10 uses a silicon single crystal substrate as a material, and is formed by the flowchart shown in FIG.
[Protective film formation process]
In the protective film forming step (S101), as shown in FIG. 5A, a silicon oxide film is formed on the entire surface of the silicon single crystal substrate 50 (hereinafter referred to as the substrate 50) by a thermal oxidation method, and the etching protective film 60 is formed. Form as. The thickness of the etching protective film 60 is preferably about 1 μm.

[First etching pattern forming step]
The process proceeds to a first etching pattern forming step (S102) in which the etching protection film 60 is formed into a mask shape for the first etching described later by photolithography. As shown in FIG. 5B, in the first etching pattern forming step (S102), a resist agent is applied to the etching protective film 60 formed in the protective film forming step (S101) by a method such as spin coating. The resist agent in a range corresponding to the formation range of the reservoir 11 and the nozzle communication hole 14 is exposed, and the resist agent in the exposed portion is removed. Next, a first etching mask 63 for etching the substrate 50 is formed, which is immersed in a buffered hydrofluoric acid solution and includes a reservoir forming opening 61 and a nozzle communication hole forming opening 62 from which the etching protective film 60 has been removed.

  In the first etching pattern forming step (S102), although not shown, the area where the ink supply port 13 and the pressure generating chamber 12 are formed is formed by forming a half-etched portion 64 obtained by half-etching the etching protective film 60. deep.

[Modified part forming process]
Next, the process proceeds to the reforming part forming step (S103). In the modified portion forming step (S103), as shown in FIG. 5C, the laser 70 is applied to any one of the nozzle communication hole forming openings 62 with respect to the substrate 50 including the first etching mask 63 described above. Irradiate from one side or both sides. At this time, a modified portion 51 of silicon single crystal is formed at the focal point 71 of the laser 70. The reforming part 51 is formed in a substantially spindle shape that is vertically long in the irradiation direction of the laser 70, and the reforming part 51 is stacked inside the substrate 50 by moving the focal point 71 of the laser 70 in the irradiation direction.

  The laser 70 to be irradiated preferably has a wavelength of 1000 to 1200 nm, which is a wavelength region that transmits the inside of the single crystal silicon that is the material of the substrate 50. When the laser has a wavelength shorter than 1000 nm, the transmittance in the single crystal silicon is abruptly deteriorated. When the laser has a wavelength exceeding 1200 nm, the transmittance is completely transmitted, and the modified portion 51 cannot be formed at the focal point 71. Moreover, it does not specifically limit as a laser, A YAG laser, a YLF laser, a YVO4 laser etc. can be used.

  Although not shown, the substrate 50 of this embodiment is generally in the form of a wafer substrate on which a large number of flow path forming substrates 10 can be formed. In the modified portion forming step (S103), the laser 70 is irradiated on the wafer-like substrate 50 as follows. For example, when the laser 70 is irradiated only from one surface side of the substrate 50, the modified portion 51 that is closest to the opposite surface side of the laser irradiation side is first placed on all the flows formed on the wafer-like substrate 50. A laser beam 70 is irradiated with a focal point 71 so as to be formed at a position corresponding to the formation position of the nozzle communication hole 14 of the path forming substrate 10.

  Next, the nozzle communication holes 14 of all the flow path forming substrates 10 formed on the wafer-like substrate 50 are formed in the modified portion 51 on the irradiation side of the laser 70 of the modified portion 51 formed as described above. The laser beam 70 is irradiated with the focal point 71 so as to be formed at the position corresponding position. By repeating this a predetermined number of times, the modified portion 51 closest to the irradiation side surface of the laser 70 is formed. Thereby, the board | substrate 50 with which the modification part 51 was laminated | stacked can be formed with high productivity.

  The method for forming the reforming portion 51 is not limited to the above. For example, the reforming portion 51 is modified to a position corresponding to each nozzle communication hole 14 at the position where the nozzle communication hole 14 is formed in the wafer-like substrate 50. The material portion 51 may be stacked, and this may be repeated to form a wafer including a plurality of substrates 50 on which the modified portions 51 are stacked.

  The modified portion 51 is formed in the modified portion forming step (S103) as a through hole that is etched first when the nozzle communication hole 14 that is a through hole is formed by etching described later. That is, the modified portion 51 is a portion where the crystallinity of the silicon single crystal substrate 50 is broken, and there is no etching anisotropy and the etching rate is high. Etching for forming the nozzle communication hole 14 is performed by using the through hole formed from the modified portion 51 as a pilot hole.

FIG. 7 shows details of the A portion in the vicinity of the nozzle communication hole forming opening 62 in FIG. As shown in FIG. 7, the reforming portion 51 is preferably formed from the surface of the substrate 50 at a depth D position.
0 ≦ D ≦ 0.7W
W: Nozzle communication hole opening minimum diameter In other words, the position of the focal point 71 of the laser 70 that forms the modified portion 51 closest to the surface of the substrate 50 is set to be closer to the inside of the substrate 50 than the surface of the substrate 50. The

  The pyramid portion M defined by the opening width W and the depth D is a region etched first by etching in the first etching step (S104) described later, and the crystal plane (111) 52 of the silicon single crystal is formed. It is exposed and the etching stops. Preferably, the modified portion 51 is formed in the range of the pyramid portion M of the etchable range, that is, “0 ≦ D ≦ 0.7 W”. Further, when the focal point 71 of the laser 70 that forms the modified portion 51 closest to the surface of the substrate 50 is located on the inner side of the substrate 50 from the surface of the substrate 50, that is, the surface portion of the substrate 50. Since there is no scattered matter generated during the surface processing, the workpiece does not adhere to the objective lens surface of the laser device. Therefore, it is possible to prevent surface damage and transmittance reduction of the lens, which is preferable.

[First etching step]
Next, the process proceeds to the first etching step (S104). In the first etching step (S104), the reservoir 11 which is a through hole and the nozzle communication hole 14 are formed by etching. An aqueous solution of 20% by mass KOH is used as the etchant, and this KOH aqueous solution is heated to 80 ° C. so that the substrate 50 provided with the first etching mask 63 is immersed for about 2 hours to form a through hole.

  In the first etching step (S104), as shown in the schematic diagram of FIG. 5D, first, the modified portion 51 formed by the modified portion forming step (S103) and the reservoir forming opening 61 are formed. Etched. At this time, since the etching rate of the portion where the modified portion 51 is formed is high, the through hole 14a is formed. Since the modified portion 15 is formed to be extremely thin with a cross-sectional diameter of about 1 μm, the through hole 14a formed by etching the modified portion 15 can also be a very thin through hole. Etching from the reservoir forming opening 61 is performed by etching the silicon single crystal substrate 50 along the crystal plane. Etching is further advanced, and as shown in FIG. 5E, the reservoir 11 and the nozzle communication hole 14 are formed as through holes.

[Second etching pattern forming step]
Next, the process proceeds to the second etching pattern forming step (S105). In the second etching pattern forming step (S105), the half etching portion 64 shown in FIG. 5B is removed by photolithography in the first etching pattern forming step (S102), and the second etching shown in FIG. 6A is performed. A mask 65 is formed.

[Second etching step]
Next, the process proceeds to the second etching step (S106). As the etching solution, the same etching solution as that used in the first etching step (S104) is used, and the dipping time is shortened to form the recess 16 for forming the pressure generating chamber 12 and the recess 17 for forming the ink supply port 13 shown in FIG. Form.

[Protective film removal process]
Finally, in the protective film removing step (S107), the second etching mask 65 is removed, and the flow path forming substrate 10 is formed.

  In the formation of the nozzle communication hole 14 in the present embodiment, the modified portion 15 is formed in the substrate 50 by laser irradiation in advance, so that the modified portion 15 having a very small diameter with a high etching rate and a cross-sectional diameter of about 1 μm. Etching proceeds first, and the nozzle communication hole 14 is formed. Therefore, the etching pilot hole formed from the modified portion 15 is also a minute through hole, and the nozzle communication hole 14 having a small opening area can be easily formed.

  Further, since the laser for forming the modified portion 15 has a long wavelength and can form the modified portion 15 even at a low output, a short wavelength, high output laser in a through hole (etching pilot hole) processing by a conventional laser. Compared to the above, there is no risk of damage to the substrate 50.

  Moreover, in the conventional through-hole formation by laser, laser processing is started from the surface of the substrate 50, and in addition, in order to obtain a through-hole, the opening becomes a 30 to 40 μm hole. For this reason, the nozzle communication hole forming opening 62 must be formed with a larger opening area in order to avoid damage due to laser irradiation, and the opening of the nozzle communication hole 14 cannot be at least less than 30 μm. . On the other hand, in the present embodiment in which the etching pilot hole of the through hole is formed from the modified portion 15 with the cross-sectional diameter of about 1 micron as described above, the nozzle communication hole 14 is formed with the size of the opening of several μm. Is possible. However, from the viewpoint of practical use, a nozzle communication hole having an opening of about 10 μ, which is downsized by 70% or more, is preferable with respect to the prior art.

(Second Embodiment)
Next, another manufacturing method of the flow path forming substrate 10 will be described. In this embodiment, a silicon nitride film is formed as an etching protective film, and the flow path forming substrate 10 is manufactured. FIG. 8 shows a flowchart of the present embodiment.

(Modified part forming process)
In this embodiment, as will be described later, a silicon nitride film is formed as an etching protective film, and the flow path forming substrate 10 is manufactured. In the present embodiment, a modified portion forming step (S201) by laser irradiation is first performed.

  As shown in FIG. 9A, the modified portion 51 is formed by irradiating the substrate 50 (silicon single crystal substrate) with the laser 70 at the nozzle communication hole 14 formation position. Since the conditions and method for forming the modified portion are the same as those in the first embodiment, description thereof is omitted.

(Protective film formation process)
In the protective film forming step (S202), as shown in FIG. 9B, an etching protective film 80 is formed on the entire surface of the substrate 50 on which the modified portion 51 is formed. The etching protection film 80 is a silicon nitride film, and is coated on the entire substrate 50 by a thermal oxidation method.

(First etching pattern forming step)
In the first etching pattern forming step (S203), as shown in FIG. 9C, the etching protective film 80 is formed by photolithography to form the reservoir forming opening 81 and the nozzle communication hole by the same method as in the first embodiment. A mask 83 having an opening 82 and a half-etched portion 84 is formed.

  Thereafter, the first etching step (S204), the second etching pattern forming step (S205), the second etching step (S206), and the protective film removing step (S207) are the same as those in the first embodiment, and the description thereof is omitted.

  As shown in the present embodiment, the etching protection film 80 is made of a silicon nitride film, thereby improving the resistance to the etching solution and eroding the end portion of the etching protection film 80 that becomes the minute nozzle communication hole forming opening 82. Therefore, the shape of the nozzle communication hole forming opening 82 can be faithfully realized as the shape of the nozzle communication hole 14. In addition, this makes it possible to prevent the walls between the adjacent reservoir 11, pressure generation chamber 12, ink supply port 13, and nozzle communication hole 14 from becoming too thin.

(Third embodiment)
An ink jet recording head using the flow path forming substrate 10 obtained by the above embodiment will be described. FIG. 10 shows a cross section of the main part of an ink jet recording head. An ink jet recording head 1000 (hereinafter referred to as recording head 1000) mainly includes a case 200, a flow path unit 100, an actuator unit 300, and the like. The flow path unit 100 uses the flow path forming substrate obtained by the manufacturing method of the above-described embodiment. The case 200 is a synthetic resin hollow box-like member. The flow path unit 100 is joined to the tip, and the actuator unit 300 is accommodated in the accommodating space 201 formed inside. A circuit board (not shown) for supplying a drive signal from the printing apparatus main body side to the actuator unit 300 is attached to the base end surface on the side opposite to the joint portion of the flow path unit 100.

  The actuator unit 300 includes a plurality of piezoelectric vibrators 301 arranged in a comb shape, a fixing plate 302 for fixing the piezoelectric vibrators 301, and a TCP for supplying drive signals from the circuit board to the piezoelectric vibrators 301. And a wiring member 303 such as (tape carrier package). Each piezoelectric vibrator 301 has a fixed end joined to and fixed to the fixed plate 302 and a free end protruding from the end of the fixed plate 302 and is attached to the fixed plate 302 in a so-called cantilever state. . The actuator unit 300 is housed in the case 200 by bonding and fixing the surface of the stationary plate 302 opposite to the surface of the piezoelectric vibrator 301 to the inner wall surface 202 of the case 200 that defines the housing space 201. .

  The flow path unit 100 is formed by laminating, bonding, and integrating the elastic plate 20, the flow path forming substrate 10, and the nozzle plate 30, passing through the ink supply port 13 and the pressure generation chamber 12 from the reservoir 11, and opening the nozzle through the nozzle communication hole 14. This is a member that forms a series of ink flow paths up to 31. The pressure generation chamber 12 is formed as a long and narrow chamber in a direction orthogonal to the direction in which the nozzle openings 31 are arranged (nozzle row direction). The reservoir 11 is a chamber into which ink is introduced from an ink supply source such as an ink cartridge. The ink introduced into the reservoir 11 is distributed and supplied to each pressure generating chamber 12 through the ink supply port 13.

  As shown in FIG. 11, the nozzle plate 30 is provided with a plurality of nozzle openings 31 at a pitch corresponding to the dot formation density in a metal plate in a row in the feeding direction of a recording medium such as recording paper. . Each nozzle row corresponds to an ink type, and the nozzle plate 30 shown in FIG. 11 is configured to be able to eject, for example, eight types of ink.

  The resolution in the ink jet printing apparatus is indicated by a dot formation density so-called “dpi (Dots Per Inchi)”. This indicates how many ink dots (droplets) per inch can be placed on the recording medium. In the arrangement of the nozzle openings 31 shown in FIG. 11, the reciprocal of the arrangement pitch P of the nozzle openings 31 is obtained. In order to increase the resolution, it is necessary to make the pitch P smaller. One factor determining the pitch P is the size of the opening of the nozzle communication hole 14.

  The flow path forming substrate 10 obtained in the first embodiment and the second embodiment realizes the nozzle communication hole 14 with an opening area smaller than that of the conventional one, and is 70% of the conventional technology even in a practical region. Things can be downsized. Accordingly, the nozzle openings 31 of the nozzle plate 30 corresponding to the flow path forming substrate 10 conventionally have a pitch P of about 35 μm, but in this embodiment, the pitch P can be reduced to 20 μm.

  As described above, the ink jet recording apparatus using the recording head 1000 according to the present embodiment can improve the resolution by about 75% or more compared to the prior art, and enables higher quality printing.

(Example)
A silicon oxide film of 2 μm was coated on the surface of a 220 μm thick silicon single crystal wafer. An opening for forming the reservoir and the nozzle communication hole, and a half etching part for forming the pressure generating chamber and the ink supply port are formed in the silicon oxide film by photolithography, and the first etching mask is formed. Formed. At this time, the mask opening for forming the nozzle communication hole had a side of 7 μm and a pitch of 20 μm.

  Next, a YAG laser (wavelength: 1064 nm) is output at an energy of 3 μJ, and the focal point of the laser is moved from one surface of the wafer to the other surface at a nozzle communication hole forming site at a moving speed of 1 mm / sec. Then, a modified portion continuous in the thickness direction of the wafer was formed. During the laser irradiation, the laser focus of the first irradiation and the last laser irradiation were adjusted to a depth of 4 μm from the wafer surface.

  The wafer on which the modified portion was formed was immersed in a 19.7 mass% KOH solution heated to 80 ° C. for 2 hours, and the reservoir and nozzle communication hole forming portions were etched to form through holes.

  Next, the first etching mask is further removed by photolithography to remove the silicon oxide film in the half-etched portion and immersed in an aqueous solution of KOH (19.7% by mass) heated to 80 ° C. for 2 hours to supply ink. A concave portion that becomes the mouth and the pressure generating mouth was formed to obtain a flow path forming substrate.

  The obtained flow path forming substrate had a side of the nozzle communication hole opening of 11 μm and a pitch of 20 μm. Moreover, the partition of the adjacent nozzle communicating hole was able to be formed by 5.1 micrometers.

(Comparative example)
A silicon oxide film of 2 μm was coated on the surface of a 220 μm thick silicon single crystal wafer. An opening for forming a reservoir, nozzle communication holes, a half-etching portion for forming a pressure generating chamber, and an ink supply port were formed in the silicon oxide film by photolithography, and a first etching mask was formed. At this time, the mask opening for forming the nozzle communication hole had a side of 90 μm and a pitch of 141 μm.

  Next, a YAG laser (wavelength: 532 nm) was applied at an output energy of 130 μJ to the nozzle communication hole forming portion from one surface of the wafer to form a through hole. The wafer in which the through hole was formed was immersed in a 19.7 mass% KOH solution heated to 80 ° C. for 2 hours, and the reservoir and the nozzle communication hole forming portion were etched to form a through hole.

  Next, the first etching mask is further removed by photolithography to remove the silicon oxide film in the half-etched portion and immersed in an aqueous solution of KOH (19.7% by mass) heated to 80 ° C. for 2 hours to supply ink. A concave portion that becomes the mouth and the pressure generating mouth was formed to obtain a flow path forming substrate.

  In the obtained flow path forming substrate, one side of the nozzle communication hole opening was 27.8 μm, and the pitch was 30 μm. Moreover, the partition walls of adjacent nozzle communication holes could be formed with 7.5 μm.

(result)
In the example, the length of one side of the nozzle communication hole could be shortened to about 40% as compared with the comparative example. Also, the pitch could be reduced to about 67%.

  DESCRIPTION OF SYMBOLS 10 ... Channel formation board | substrate, 11 ... Reservoir, 12 ... Pressure generation chamber, 13 ... Ink supply port, 14 ... Nozzle communication hole, 20 ... Elastic plate, 30 ... Nozzle plate, 31 ... Nozzle opening, 40 ... Piezoelectric vibrator, 100: Channel unit.

Claims (6)

A method of manufacturing a flow path forming substrate comprising a nozzle communication hole, a reservoir, and an ink supply port by etching in a silicon single crystal substrate,
A modified part forming step of continuously laminating the modified part of the silicon single crystal substrate by laser irradiation in the direction of communication of the nozzle communication hole in the nozzle communication hole forming region;
A first etching step of drilling a formation range of the nozzle communication hole and a formation range of the reservoir by etching;
A second etching step of forming the ink supply port by etching the formation range of the ink supply port;
The manufacturing method of the flow-path formation board | substrate characterized by including. In the modified part forming step, the modified part is formed from the depth D from the surface of the silicon single crystal substrate in the laser irradiation.
The depth D is
0 ≦ D ≦ 0.7W
However, W: Nozzle communication hole opening minimum part diameter,
The manufacturing method of the flow-path formation board | substrate of Claim 1 characterized by the above-mentioned. An etching protective film forming step of forming silicon oxide as an etching protective film on the silicon single crystal plate is before the modified portion forming step.
The method for producing a flow path forming substrate according to claim 1 or 2, wherein: The etching protective film forming step of forming silicon nitride as an etching protective film on the silicon single crystal plate is between the modified portion forming step and the first etching step.
The method for producing a flow path forming substrate according to claim 1 or 2, wherein:   A flow path forming substrate manufactured by the manufacturing method according to claim 1.   An ink jet recording head using the flow path forming substrate according to claim 5.

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