JP2009196139A - Defect detecting method for diaphragm part of liquid droplet delivering head, and manufacturing method for liquid droplet delivering head using the defect detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect detecting method or the like for a diaphragm part of a liquid droplet delivering head wherein defect inspection of the diaphragm part of a silicon base material having the diaphragm part for pressure buffering prepared therein can be efficiently, highly accurately and easily carried out. <P>SOLUTION: The method is equipped with a process for dipping in an etching liquid for defect detection the silicon base material 200 which has a part 210a to be the diaphragm part 210 with a metal thin film 25 to be a base coat formed on a surface and a resin thin film 26 formed on the film, and a process for detecting the presence or absence of a defective part A of the resin thin film 26 by detecting the presence or absence of etching erosion of the metal thin film 25 after the dipping. At this time, the presence or absence of etching erosion of the metal thin film 25 can be inspected by using a passing light and a reflecting light by a microscope. The resin thin film 26 is made a Parylene(R) thin film, and the metal thin film 25 is made a platinum thin film or chromium thin film. The etching liquid for defect detection is a mixed liquid of hydrochloric acid and nitric acid heated to 60°C-80°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a defect detection method for a diaphragm portion of a droplet discharge head, and a method for manufacturing a droplet discharge head using the defect detection method.

As a droplet discharge head for discharging droplets, for example, an inkjet head mounted on an inkjet recording apparatus is known.
In such an ink jet head, an ink jet head having a structure having a plurality of nozzle rows is required for the purpose of increasing the printing speed and colorization. Further, in recent years, the number of nozzles per row has increased and the number of actuators in an ink jet head has been increasing as the number of nozzles has increased.

In such an ink jet head, a reservoir that communicates in common with each of the discharge chambers is provided, and as the nozzle density increases, the pressure in the discharge chamber is also transmitted to the reservoir, and the influence of the pressure is influenced by other discharge chambers. It extends to the chamber and the nozzle hole communicating with it.
For example, when the actuator is driven and positive pressure is applied to the reservoir, ink droplets leak from non-driving nozzles other than the driving nozzle that should eject ink droplets. Conversely, when negative pressure is applied to the reservoir, the driving nozzle The print quality deteriorates due to a decrease in the discharge amount of ink droplets to be discharged from the printer.

For this reason, in conventional inkjet heads, pressure fluctuation buffering parts, or diaphragm parts, for buffering pressure fluctuations are made of resin on part of the substrate wall that forms the reservoir, preventing pressure interference between nozzles. is doing.
In order to form such a diaphragm part, a base material is etched, the layer of a resin thin film is vapor-deposited, and a pressure interference member is provided (for example, refer patent document 1).

Japanese Patent Laying-Open No. 2005-1190 (page 10, FIG. 4)

  In the inkjet head manufacturing method of Patent Document 1, after the reservoir is completed, another substrate is bonded to the nozzle substrate, and the chip is processed to complete the inkjet head. After that, ink is filled into the flow path of the ink jet head, but until the ink is filled, it is impossible to detect the presence or absence of minute defects present in the diaphragm portion. In spite of this, the inkjet head itself must be discarded, which is inefficient, yield is reduced, and product cost loss increases.

  The present invention has been made to solve the above-described problems, and can perform defect inspection of a diaphragm portion of a silicon base material provided with a pressure buffering diaphragm portion quickly, efficiently, with high accuracy and easily. It is an object of the present invention to provide a defect detection method for a diaphragm portion of a droplet discharge head and a method for manufacturing a droplet discharge head using the defect detection method.

  The defect detection method for a diaphragm portion of a droplet discharge head according to the present invention is a method for detecting a defect in a silicon substrate having a portion that becomes a diaphragm portion by forming a metal thin film as a base on the surface and forming a resin thin film thereon. And a step of detecting the presence or absence of a defective portion of the resin thin film after the immersion by detecting the presence or absence of etching erosion of the metal thin film.

Since the diaphragm part is provided in the droplet discharge head, the compliance of the reservoir is reduced, pressure fluctuations in the reservoir are suppressed, and pressure interference between nozzles that occurs during droplet discharge is prevented, resulting in good droplet discharge characteristics Can be obtained. In this case, since the metal thin film is formed on the base of the resin thin film, the adhesion between the resin thin film and the reservoir substrate surface is improved.
In the droplet discharge head provided with such a diaphragm portion, when detecting a defect in the diaphragm portion, an easy process of immersing the reservoir base material can be used, and at this time, the resin thin film is not etched. Since only the underlying metal thin film is etched, defects in the resin thin film in the diaphragm can be detected early, efficiently, and with high accuracy by increasing the defects in the underlying metal thin film. It is possible to provide a droplet discharge head having an excellent reservoir substrate that is improved and has no defects in the pressure interference portion.

The defect detection method for a diaphragm portion of a droplet discharge head according to the present invention detects the presence or absence of etching erosion of a metal thin film with a microscope.
Since the underlying metal thin film of the defective portion of the resin thin film is immersed by etching below the defective portion and the defect is enlarged to improve the visibility, the defective portion of the resin thin film can be easily recognized by a microscope.

In addition, the defect detection method for the diaphragm portion of the droplet discharge head according to the present invention detects the presence / absence of etching erosion of the metal thin film by one or both of transmitted light and reflected light.
Since the underlying metal thin film of the defective portion of the resin thin film is immersed by etching under the defective portion to enlarge the defect, the defective portion of the resin thin film can be detected by transmitted light or reflected light.

Moreover, the defect detection method of the diaphragm part of the droplet discharge head which concerns on this invention makes a resin thin film a parylene thin film.
Since the resin thin film is a parylene thin film, it is excellent in covering properties and has high heat resistance, chemical resistance and moisture permeability resistance. Moreover, since the flexibility is higher than that of the silicon thin film, a high pressure absorbing effect is exhibited.

In the defect detection method for a diaphragm portion of the droplet discharge head according to the present invention, the metal thin film serving as a base is a platinum thin film or a chromium thin film.
Since the metal thin film is formed on the base of the resin thin film and the metal thin film is a platinum thin film or a chromium thin film, the adhesion between the resin thin film and the surface of the reservoir substrate can be improved.

In addition, the defect detection method for the diaphragm portion of the droplet discharge head according to the present invention comprises a mixed solution of hydrochloric acid and nitric acid heated to 60 ° C. to 80 ° C. by a defect detection etching solution.
Since the etching solution for detecting defects is a mixed solution of hydrochloric acid and nitric acid heated to 60 ° C. to 80 ° C., the defect expansion of the metal thin film by etching can be performed efficiently and easily with high accuracy. .

  A manufacturing method of a droplet discharge head using a defect detection method of a diaphragm portion according to the present invention includes a nozzle substrate having a plurality of nozzle holes, a cavity substrate having discharge chambers, and a reservoir substrate having a reservoir communicating with the discharge chambers A droplet discharge head having a diaphragm portion provided with a resin thin film and a metal thin film as a base film on the inner wall surface of the reservoir, wherein one of the silicon base materials to be a reservoir substrate is provided. Forming a reservoir recess serving as a reservoir from the surface by wet etching, and covering one surface of the silicon substrate and the surface opposite to the one surface with a mask member other than the opening of the reservoir recess. Forming a metal thin film as a base film on the entire inner wall of the reservoir recess, forming a resin thin film on the metal thin film, and removing the mask member Then, the silicon substrate is removed by dry etching until the resin thin film is exposed from the opposite side of the step of detecting the presence or absence of a defective portion of the resin thin film by the defect detection method of the diaphragm portion of the droplet discharge head. And a step of forming a diaphragm portion.

  In the manufacturing process of the droplet discharge head, it is possible to detect defects of the resin thin film in the diaphragm portion with high efficiency and high accuracy by using an easy process such as immersion etching. In this way, it is possible to provide a droplet discharge head having excellent discharge characteristics with no defects in the pressure interference portion.

  Hereinafter, an embodiment of a droplet discharge head to which the present invention is applied will be described. Here, as an example of a droplet discharge head, a face discharge type inkjet head that discharges ink droplets from nozzle holes provided on the surface of a nozzle substrate will be described. The present invention is not limited to the structure and shape shown in the following drawings. For example, the present invention is also applicable to an edge discharge type liquid droplet discharge head that discharges ink droplets from nozzle holes provided at the end of a substrate. can do. Moreover, although the actuator is shown by the electrostatic drive system, other drive systems may be used.

FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet head (an example of a droplet discharge head) according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing an assembled state of the ink jet head shown in FIG. is there.
1 and 2, the inkjet head 10 has a four-layer structure in which a nozzle substrate 1, a reservoir substrate 2, a cavity substrate 3, and an electrode substrate 4 are bonded together in this order.
The nozzle substrate 1 is made of, for example, a silicon substrate having a thickness of about 50 μm, and a large number of nozzle holes 11 are provided at a predetermined pitch. However, FIG. 1 is simplified and shows five nozzle holes 11 in one row.
The nozzle hole 11 includes an injection port portion 11a having a small diameter and an introduction port portion 11b having a large diameter, and is formed perpendicular to and coaxial with the substrate surface.

The reservoir substrate 2 is made of, for example, a silicon substrate having a thickness of about 180 μm and a plane orientation of (100). The reservoir substrate 2 is provided with a nozzle communication hole 21 that penetrates the substrate vertically and communicates coaxially with the same diameter as the introduction port portion 11 b of the nozzle hole 11.
Reservoir recesses 23a serving as reservoirs (common ink chambers) 23 communicating with the nozzle communication holes 21 via the supply ports 22 and discharge chambers 31 (described later) are formed, and are bonded to the nozzle substrate 1 (N It also has a substantially inverted trapezoidal cross section that expands to the side. The bottom wall 23b of the reservoir recess 23a is provided with a space 211 that penetrates to the bonding surface with the cavity substrate 3 (also referred to as the C surface).
The supply port 22 (downstream of the reservoir recess 23a) and the ink supply hole 27 (upstream of the reservoir recess 23a) pass through the bottom wall 23b of the reservoir recess 23a at a position avoiding the space 211. Further, on the C surface of the reservoir substrate 2, a narrow groove-like second concave portion 28 constituting a part of a discharge chamber 31 (described later) is formed, and the discharge chamber 31 is formed by thinning the cavity substrate 3. Although an increase in channel resistance is prevented, it can be omitted.

A resin thin film 26 is formed on the inner wall of the reservoir recess 23 a (including the upper portion of the space 211) of the reservoir substrate 2 and the inner walls of the supply port 22 and the ink supply port 27. A portion of the resin thin film 26 that covers the upper portion of the space 211 is a part of the bottom wall 23b of the reservoir recess 23a, and constitutes a diaphragm 210 that is a pressure fluctuation buffer. The resin thin film 26 is in a floating state between the space 211 and the reservoir recess 23 a, and the deflection of the resin thin film 26 is allowed by the space 211. The resin thin film 26 is formed by film formation in the manufacturing process of the reservoir substrate 2 (described later) and is made of parylene. Cytop or the like may be used instead of parylene.
In addition, a metal thin film made of platinum (Pt), for example, is formed on the resin thin film 26 (not shown), and this metal thin film improves the adhesion between the resin thin film 26 and the silicon substrate. Yes. The metal thin film is not limited to platinum but may be chromium (Cr).

The cavity substrate 3 is made of, for example, a silicon base material having a thickness of about 30 μm. A first recess 33 constituting a part of the discharge chamber 31 that communicates with each of the nozzle communication holes 21 is provided. The first recess 33 and the second recess 28 provided in the reservoir substrate 2 are provided. Thus, each discharge chamber 31 is partitioned and formed. The bottom wall of the first recess 33 (discharge chamber 31) constitutes the diaphragm 32.
An insulating film made of SiO ₂ is formed on at least the lower surface of the cavity substrate 3 with a thickness of, for example, 0.1 μm (not shown), and prevents dielectric breakdown and short circuit when the inkjet head 10 is driven. An ink protective film similar to that of the reservoir substrate 2 is formed on the upper surface of the cavity substrate 3 (not shown).
In addition, the cavity substrate 3 is provided with an ink supply hole 35 communicating with the ink supply hole 27 of the reservoir substrate 2.

  The electrode substrate 4 is made of, for example, a glass substrate having a thickness of about 1 mm. This glass base material uses a borosilicate heat-resistant hard glass having a thermal expansion coefficient close to that of the silicon base material of the cavity substrate 3, and when the electrode substrate 4 and the cavity substrate 3 are anodically bonded, Since the expansion coefficient is close, the stress generated between the electrode substrate 4 and the cavity substrate 3 can be reduced, and a strong bonding can be achieved.

  The electrode substrate 4 is provided with a recess 42 at a depth of about 0.3 μm on the surface of the cavity substrate 3 facing each diaphragm 32. An individual electrode 41 made of ITO (Indium Tin Oxide) is formed on the bottom surface of each recess 42 with a thickness of 0.1 μm, for example. Accordingly, the air gap G formed between the vibration plate 32 and the individual electrode 41 is determined by the depth of the concave portion 42 and the thickness of the insulating film covering the individual electrode 41 and the vibration plate 32, and is discharged from the inkjet head 10. The characteristics are greatly affected. The open end of the air gap G is hermetically sealed with a sealing material 43 made of an epoxy adhesive or the like.

  The terminal portion 41a of the individual electrode 41 is exposed to the electrode extraction portion 44 in which the end portions of the reservoir substrate 2 and the cavity substrate 3 are opened, and a flexible wiring board (for example, a driver control circuit 5 such as a driver IC is mounted ( (Not shown) are connected to the terminal portions 41 a of the individual electrodes 41 of the electrode extraction portion 44 and the common electrode 36 provided at the end of the cavity substrate 3.

  The electrode substrate 4 is provided with an ink supply hole 45 connected to an ink cartridge (not shown), an ink supply hole 35 provided in the cavity substrate 3, and an ink supply hole provided in the reservoir substrate 2. 27 through the reservoir 23.

The operation of the inkjet head 10 configured as described above will be described.
Ink jet head 10 is supplied with ink in an ink cartridge into reservoir 23 through ink supply holes 45, 35, and 27, and from each supply port 22 to each discharge chamber 31 and nozzle communication hole 21, nozzle hole 11. Filled up to the tip.
When a pulse voltage is applied between the individual electrode 41 and the common electrode 36 by the drive control circuit 5, the individual electrode 41 is positively charged and the diaphragm 32 is negatively charged. Then, electrostatic force is generated between the individual electrode 41 and the diaphragm 32, and the diaphragm 32 is attracted and bent toward the individual electrode 41 side, and the volume of the discharge chamber 31 is increased. When the pulse voltage is turned off, the electrostatic force disappears and the diaphragm 32 returns to its original state due to the elastic force. At this time, since the volume of the discharge chamber 31 decreases rapidly, a part of the ink in the discharge chamber 31 passes through the nozzle communication hole 21 and is discharged from the nozzle hole 11. When the pulse voltage is applied again and the diaphragm 32 bends toward the individual electrode 41, ink is supplied from the reservoir 23 through the supply port 22 into the discharge chamber 31.

  At this time, the pressure in the discharge chamber 31 is transmitted to the reservoir 23. Since the diaphragm portion 210 made of the resin thin film 26 is provided on the bottom wall 23b of the reservoir 23, the resin thin film 26 is applied when the reservoir 23 becomes positive pressure. Bends toward the space 211, and when the reservoir 23 becomes negative pressure, the resin thin film 26 bends away from the space 211. In this way, pressure fluctuations in the reservoir 23 are buffered, and pressure interference between the nozzle holes 11 is prevented. For this reason, ink does not leak from nozzles other than the drive nozzle, and the discharge amount required for discharge from the drive nozzle does not decrease.

Next, the manufacturing method of the inkjet head 10 is demonstrated using FIGS. The values of the substrate thickness, etching depth, temperature, pressure and the like shown below are examples, and the present invention is not limited to these values.
First, a method for manufacturing the reservoir substrate 2 will be described with reference to FIGS.

(A) As shown in FIG. 3A, a silicon reservoir substrate 200 having a surface orientation (100) and a thickness of about 180 μm is prepared, and a thermal oxide film 201 is formed on the outer surface of the reservoir substrate 200. About 1.5 μm is formed.

(B) As shown in FIG. 3 (b), a nozzle communication hole 21, a second recess 28, a supply port 22, a diaphragm are formed on the surface (C surface) on the side to be bonded to the cavity substrate 3 by photolithography. The portions 210 and the portions that become the ink supply holes 27 (outer edges of the portions that become the ink supply holes 27) 21a, 28a, 22a, 210a, and 27a are patterned. At this time, the etching is performed so that the remaining film thickness of the thermal oxide film 201 in each of the portions 21a, 28a, 22a, 210a, and 27a on the C plane has the following relationship.
Portion 21a that becomes nozzle communication hole 21 <0 portion 22 that becomes supply port 22 = portion 27a that becomes ink supply hole 27 <portion 28a that becomes second recess 28 = portion 210a that becomes diaphragm 210

(C) As shown in FIG. 3C, the portion 21a which becomes the nozzle communication hole 21 on the C surface is dry-etched by ICP by about 150 μm.

(D) As shown in FIG. 4D, the thermal oxide film 201 is etched by an appropriate amount to open a portion 22 a that becomes the supply port 22 and a portion 27 a that becomes the ink supply hole 27.
Next, dry etching is performed by ICP to about 15 μm.

(E) As shown in FIG. 4 (e), the thermal oxide film 201 is etched by an appropriate amount to open the portion 28 a that becomes the second recess 28 and the portion 210 a that becomes the diaphragm portion 210.
Next, dry etching is performed by ICP to about 25 μm. At this time, the portion 21a that becomes the nozzle communication hole 21 is also dry-etched up to the N surface.

(F) As shown in FIG. 4 (f), after removing the thermal oxide film 201, the thermal oxide film 201 is formed again with a thickness of about 1.0 μm on the surface (N surface) on the side to be bonded to the nozzle substrate 1. Then, the portion 230 that becomes the reservoir recess 23a is opened by photolithography.

(G) As shown in FIG. 5G, the reservoir recess 23a is formed by wet etching with potassium hydroxide (KOH) for about 150 μm.
At this time, the silicon material of the portion 27 a that becomes the ink supply hole 27 is separated from the reservoir base material 200 at the outer edge thereof.

(H) As shown in FIG. 5H, after the thermal oxide film 201 is removed, a thermal oxide film 201a is formed again with a thickness of about 0.2 μm.

(I) As shown in FIG. 5I, dry etching is performed by covering a C surface with a metal or silicon mask member (protective film) 202 having an opening only in a portion 210a to be a diaphragm portion 210, and performing a dry etching. The thermal oxide film 201a in the portion 210a that becomes the portion 210 is removed.

(J) The mask member 202 shown in FIG. 5 (i) is removed, and the entire C surface of the reservoir substrate 200 is protected again by the mask member (protective film) 203 as shown in FIG. 6 (j). . Further, the N surface of the reservoir substrate 200 is protected by a mask member (protective film) 204 having an opening 204a smaller than the opening of the reservoir recess 23a. The reason why the opening 204a of the mask member 204 is made smaller than the opening of the reservoir recess 23a is that even if the mask member 204 is misaligned with the reservoir base material 200, the reservoir base material 200 is bonded to the nozzle substrate 1. This is because the N surface, which is a surface, is reliably protected by the mask member 204 to prevent the resin thin film 26 from being formed on the N surface (see FIG. 6 (k)). That is, if the resin thin film 26 is formed on the adhesion surface of the reservoir base material 200 to the nozzle substrate 1, sufficient adhesion strength with the nozzle substrate 1 cannot be obtained.
Next, 0.1 μm of a metal thin film 25 made of platinum is formed on the entire inner wall of the reservoir recess 23a.

(K) The mask member 203 on the C surface shown in FIG. 6 (j) is replaced with a new mask member (protective film) 206 as shown in FIG. 6 (k), and the supply port 22 and the ink supply hole 27 are replaced. The metal thin film 25 made of platinum adhering to this portion is removed.
Next, the silicon substrate 200 is set in a vacuum chamber (not shown), and a resin thin film 26 made of parylene is formed on the entire surface including the mask members 204 and 206 by 1.0 μm.
This parylene film formation is performed by sublimating and thermally decomposing diparaxylylene (dimer). Since parylene is softer than a silicon thin film, it exhibits a pressure absorbing effect that is 100 to 1000 times that of a silicon thin film.
Thus, the resin thin film 26 is formed by film formation in the manufacturing process of the reservoir substrate 2.

(L) As shown in FIG. 6 (l), the mask members 204 and 206 on the N surface and C surface of the silicon substrate 200 are peeled off. Since the parylene resin thin film 26 is in close contact with the inner wall of the reservoir recess 23a by the platinum metal thin film 25 formed as a base film, the resin thin film 26 is not peeled off simultaneously when the mask member 204 is peeled off.
Next, the resin thin film 26 of the supply port 22 and the ink supply hole 27 is removed from the C surface side by oxygen plasma, and the surface is hydrophilized so that the resin thin film 26 is not removed from the N surface side by oxygen plasma.

(M) A silicon substrate 200 (a silicon substrate having a parylene resin thin film 26 formed with a platinum metal thin film 25 as a base) formed as shown in FIG. That is, it is immersed in a mixed solution of hydrochloric acid and nitric acid heated to 60 ° C. to 80 ° C. The dipping time is set so that the defective portion of the resin thin film 26, that is, the underlying metal thin film 25 in the portion without the resin thin film 26 can be sufficiently etched away. After being immersed for a certain time, the silicon substrate 200 is taken out, and the presence or absence of etching erosion of the metal thin film 25 made of the underlying platinum is observed with a microscope. For observation of the presence or absence of erosion, either transmitted light or reflected light or both are used.

As shown in FIG. 7 (m), if there is a defective portion A such as a pinhole in the parylene resin thin film 26, etching proceeds from the portion to the metal thin film 25 made of underlying platinum. The resin thin film 26 is not etched in the etching solution, and only the underlying metal thin film 25 is etched. Therefore, by taking a sufficiently long etching time, the area of the metal thin film 25 that is the base of the defective portion A of the resin thin film 26 is increased by the etching, and the visibility is improved.
Thus, if there is a defect A in the parylene resin thin film 26, the silicon substrate 200 is discarded as a defective product.
If there is no defect A in the parylene resin thin film 26, the process proceeds to the next step (FIG. 8 (n)).

(N) If no defect is detected by the defect detection operation in the above step (m), the diaphragm portion 210 of the silicon substrate 200 shown in FIG. 8 (n) is changed to the next step in FIG. 7 (o). Etch further as shown.

(0) As shown in FIG. 8 (o), the silicon material 200 of the diaphragm portion 210 is etched from the C surface of the silicon substrate 200 by SF ₆ plasma until the resin thin film 26 (metal thin film 25) is exposed. As a result, the resin thin film 26 (metal thin film 25) is exposed, the space 211 is formed, and the diaphragm 210 is completed.
As described above, the reservoir substrate 2 having the diaphragm portion 210 is manufactured.

  Next, the manufacturing process of the electrode substrate 4 and the cavity substrate 3 will be described with reference to FIGS. 9 to 11, and the manufacturing process until the completion of the inkjet head 10 will be described with reference to FIG. 12.

(A) As shown in FIG. 9A, a recess 42 is formed by etching a glass substrate 400 made of borosilicate glass or the like with a thickness of about 1 mm with hydrofluoric acid using an etching mask. The recess 42 has a groove shape larger than the individual electrode 41, and a plurality of the recesses 42 are formed for each individual electrode 41.
Next, an individual electrode 41 made of ITO (Indium Tin Oxide) is formed inside the recess 42 by sputtering and patterning.
Next, the ink supply hole 45 is formed by blasting or the like, and the electrode substrate 4 is formed.

(B) As shown in FIG. 9B, a silicon cavity base material 300 having a thickness of about 220 μm is prepared. The cavity base 300 has a boron-doped layer (not shown) having a required thickness formed on a surface (also referred to as an E surface) to be bonded to the electrode substrate 4, and further, plasma CVD using TEOS as a raw material ( Chemical Vapor Deposition ) To form an insulating film 34 made of an oxide film having a thickness of about 0.1 μm.

(C) The cavity substrate 300 shown in FIG. 9B and the electrode substrate 4 shown in FIG. 9A are made to face each other with the insulating film 34 and the individual electrode 41 facing each other as shown in FIG. 9C. And anodic bonding. The anodic bonding is performed by heating the cavity base material 300 and the electrode substrate 4 to about 360 ° C., then connecting the negative electrode to the electrode substrate 4 and the positive electrode to the cavity base material 300 and applying a voltage of about 800V.

(D) As shown in FIG. 9 (d), the surface of the anodic bonded cavity base material 300 (the F surface opposite to the E surface) is ground by a back grinder or polisher, and further, an aqueous potassium hydroxide solution is used. The surface is etched by 10 μm to 20 μm to remove the work-affected layer, and is thinned until the thickness becomes about 30 μm.

(E) As shown in FIG. 10E, a TEOS oxide film 301 serving as an etching mask is formed on the surface (also referred to as FA surface) of the thinned cavity base material 300 by plasma CVD to a thickness of about 1.0 μm. Form.

(F) The surface of the TEOS oxide film 301 is coated with a resist (not shown), patterned by photolithography, the TEOS oxide film 301 is etched, and as shown in FIG. The first concave portion 33, the ink supply hole 35, and the portions 33a, 35a, and 44a that become the electrode extraction portion 44 are opened. The resist is peeled off after opening.

(G) As shown in FIG. 10 (g), the bonded base material that has been subjected to anodic bonding is etched with an aqueous potassium hydroxide solution to form the first recess 33 of the discharge chamber 31 in the thinned cavity base material 300. A portion 33 a and a portion 35 a that becomes the ink supply hole 35 are formed. At this time, since the boron doped layer is formed in the portion 44a that becomes the electrode extraction portion 44, it remains with the same thickness as the portion 32a that becomes the diaphragm 32. Further, a boron dope layer is also formed in the portion 35 a which becomes the ink supply hole 35, but since it is also exposed to the potassium hydroxide aqueous solution entering from the ink supply hole 45, it is removed during etching.
In the above etching process, first, etching is performed using a 35 wt% potassium hydroxide aqueous solution until the remaining thickness of the cavity substrate 300 reaches about 5 μm, and then a 3 wt% potassium hydroxide aqueous solution. Etching by switching to. As a result, the etching stop sufficiently works, so that the surface roughness of the portion 32a that becomes the diaphragm 32 is prevented and the thickness thereof is formed with high accuracy of 0.80 ± 0.05 μm.

(H) As shown in FIG. 10H, after the cavity base material 300 is etched, the TEOS oxide film 301 formed on the upper surface of the cavity base material 300 is removed by etching with a hydrofluoric acid aqueous solution.

(I) As shown in FIG. 11 (i), an ink protective film 37 made of a TEOS film is formed to a thickness of about 0.1 μm by plasma CVD on the surface of the portion 33 a that becomes the first recess 33 of the cavity substrate 300. To do.

(J) As shown in FIG. 11 (j), a portion 44a that becomes the electrode extraction portion 44 is opened by RIE (Reactive Ion Etching) or the like. The open end of the air gap G between the diaphragm 32 and the individual electrode 41 is hermetically sealed with a sealing material 43 such as an epoxy resin. Furthermore, a common electrode 36 made of a metal electrode such as platinum is formed at the end of the surface of the cavity base material 300 by sputtering.
Thus, the cavity substrate 3 is manufactured from the cavity base material 300 bonded to the electrode substrate 4.

(K) As shown in FIG. 12 (k), the reservoir substrate 2 on which the nozzle communication hole 21, the supply port 22, the reservoir recess 23a, the diaphragm portion 210 and the like are formed is bonded to the cavity substrate 3 with an adhesive.

(L) As shown in FIG. 12 (l), the nozzle substrate 1 in which the nozzle holes 11 are formed in advance is bonded onto the reservoir substrate 2 with an adhesive.

(M) As shown in FIG. 12 (m), each head is separated by dicing.
Thus, the main body of the inkjet head 10 shown in FIG. 2 is completed.

  In the above description, the diaphragm portion 210 of the inkjet head 10 is provided on the adhesion surface side (C surface side) with the cavity substrate 3, but may be provided on the adhesion surface side (N surface side) with the nozzle substrate 1.

According to the embodiment of the present invention, the diaphragm portion 210 including the resin thin film 26 is provided on the adhesion surface side (C surface side or N surface side) of the reservoir 23 of the ink jet head 10 (droplet discharge head). The pressure fluctuation in the reservoir 23 can be suppressed, and good discharge characteristics can be obtained.
Since the defect detection method is used to detect the defect of the diaphragm portion 210 when the droplet discharge head 10 is manufactured, the excellent droplet protrusion head 10 having no defect in the pressure interference portion can be obtained. Can be provided. In this defect detection method, the defect portion A of the diaphragm portion 210 is detected by being enlarged using a process called immersion etching, so that the defect can be detected easily and accurately with high efficiency.

In the above description, the electrostatic drive type ink jet head (droplet discharge head) has been described. However, the present invention is not limited to this, and various modifications can be made within the scope of the technical idea of the present invention. .
For example, the present invention can be applied to an ink jet head using a driving method other than the electrostatic driving method. In the case of the piezoelectric method, a piezoelectric element may be bonded to the bottom of each discharge chamber instead of the electrode substrate, and in the case of the bubble method, a heating element may be provided inside each discharge chamber.
In addition to the ink jet printer shown in FIG. 13, the ink jet head 10 according to the above-described embodiment can be used to manufacture a color filter for a liquid crystal display and a light emitting portion of an organic EL display device by changing various droplets. It can be applied to a droplet discharge apparatus for various uses such as formation, formation of a wiring portion of a wiring board manufactured by a printed wiring board manufacturing apparatus, and discharge of a biological liquid (manufacture of a protein chip and a DNA chip). In addition, a liquid droplet ejection apparatus equipped with the above-described ink jet head (liquid droplet ejection head) is a liquid equipped with a liquid droplet ejection head that has good ejection characteristics by preventing pressure interference between the nozzles 11 that occurs during liquid droplet ejection. A droplet discharge device can be obtained.

1 is an exploded perspective view showing a schematic configuration of an inkjet head according to an embodiment of the present invention. Sectional drawing which shows the assembly state of the inkjet head of FIG. Sectional drawing of the manufacturing process of the reservoir substrate of the inkjet head which concerns on one embodiment. Sectional drawing of the manufacturing process of the reservoir | reserver board | substrate following FIG. Sectional drawing of the manufacturing process of the reservoir substrate following FIG. Sectional drawing of the manufacturing process of the reservoir | reserver board | substrate following FIG. Sectional drawing of the manufacturing process of the reservoir substrate following FIG. Sectional drawing of the manufacturing process of the reservoir substrate following FIG. Sectional drawing of the manufacturing process of an electrode substrate and a cavity board | substrate. Sectional drawing of the manufacturing process following FIG. Sectional drawing of the manufacturing process following FIG. Sectional drawing of the manufacturing process until completion of an inkjet head. 1 is a perspective view showing an ink jet printer according to the present invention.

Explanation of symbols

  1 nozzle substrate, 2 reservoir substrate, 3 cavity substrate, 4 electrode substrate, 10 inkjet head, 11 nozzle hole, 21 nozzle communication hole, 22 supply port, 23 reservoir, 23a reservoir recess, 23b reservoir bottom wall, 25 metal thin film, 26 Resin thin film, 27, 35, 45 Ink supply hole, 31 Discharge chamber, 32 Vibration plate, 41 Individual electrode, 200 Silicon base material (reservoir base material) serving as reservoir substrate, 202, 203, 204, 206 Mask member, 210 Diaphragm part, 210a Diaphragm part, 211 space part, A defective part of resin thin film, C Adhering surface with cavity substrate (surface opposite to one surface), N Adhering surface with nozzle substrate (one surface) ).

Claims (7)

A step of immersing a silicon base material having a portion that becomes a diaphragm portion by forming a metal thin film as a base on the surface and forming a resin thin film thereon, in an etching solution for detecting defects;
After the immersion, detecting the presence or absence of etching erosion of the metal thin film to detect the presence or absence of a defective portion of the resin thin film,
A defect detection method for a diaphragm portion of a droplet discharge head, comprising:   2. A defect detection method for a diaphragm portion of a droplet discharge head according to claim 1, wherein the presence or absence of etching erosion of the metal thin film is detected by a microscope.   3. A defect detection method for a diaphragm portion of a droplet discharge head according to claim 2, wherein the presence or absence of etching erosion of the metal thin film is detected by one or both of transmitted light and reflected light.   The defect detection method for a diaphragm portion of a droplet discharge head according to claim 1, wherein the resin thin film is a parylene thin film.   The defect detection method for a diaphragm portion of a droplet discharge head according to claim 1, wherein the metal thin film is a platinum thin film or a chromium thin film.   6. The defect of the diaphragm portion of the droplet discharge head according to claim 1, wherein the defect detection etching solution is composed of a mixed solution of hydrochloric acid and nitric acid heated to 60 ° C. to 80 ° C. Detection method. A nozzle substrate having a plurality of nozzle holes, a cavity substrate having a discharge chamber, and a reservoir substrate having a reservoir communicating with the discharge chamber, and a resin thin film on the inner wall surface of the reservoir and a metal thin film that is an underlying film thereof A method for manufacturing a droplet discharge head using a defect detection method for a diaphragm portion provided with a diaphragm portion comprising:
Forming a reservoir recess serving as the reservoir from one surface of a silicon base material serving as the reservoir substrate by wet etching;
Of the one surface of the silicon substrate and the surface opposite to the one surface, the surface other than the opening of the reservoir recess is covered with a mask member, and a metal thin film is formed as a base film on the entire inner wall of the reservoir recess And further forming the resin thin film on the metal thin film,
Removing the mask member;
Detecting the presence / absence of a defect portion of the resin thin film by the defect detection method for a diaphragm portion according to any one of claims 1 to 6;
Removing the silicon substrate by dry etching until the resin thin film is exposed from the opposite surface, and forming the diaphragm part,
A method of manufacturing a droplet discharge head using a defect detection method for a diaphragm portion, comprising:

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