JP4665598B2 - Silicon substrate processing method - Google Patents

Description

The present invention relates to a method for processing a silicon substrate, a method for manufacturing a droplet discharge head, and a method for manufacturing a droplet discharge device. In particular, the silicon substrate is not cracked or chipped during processing and has high processing accuracy. And a manufacturing method of a droplet discharge head using the silicon substrate processing method and a manufacturing method of a droplet discharge device.

The ink jet recording apparatus has many advantages such as high-speed printing, extremely low noise during recording, high degree of freedom of ink, and use of inexpensive plain paper. In recent years, among ink jet recording apparatuses, ink droplets are ejected only when recording is required.
On-demand ink jet recording apparatuses have become mainstream. This ink on
The demand type ink jet recording apparatus has an advantage that it does not require collection of ink droplets unnecessary for recording.

As an ink-on-demand type ink jet recording apparatus, there is a so-called electrostatic driving type ink jet recording apparatus using electrostatic force as a driving means as a method of ejecting ink droplets. In addition, there are so-called piezoelectric drive type ink jet recording apparatuses that use piezoelectric elements (piezo elements) as driving means, and so-called bubble jet (registered trademark) type ink jet recording apparatuses that use heating elements and the like.

In the ink jet recording apparatus as described above, ink droplets are generally ejected from nozzles of an ink jet head. There are two methods for providing nozzles in an ink jet head: a side eject type that ejects ink droplets from the side surface of the ink jet head, and a face eject type that ejects ink droplets from the surface side of the ink jet head.
In the face eject type ink jet head, it is desirable to adjust the thickness of the nozzle substrate so as to optimize the length of the nozzle by adjusting the flow resistance of the nozzle hole.

For this reason, in a conventional face eject type nozzle plate manufacturing method for an inkjet head, after the silicon substrate is ground to a desired thickness, the first nozzle hole and the first nozzle hole are dry-etched from both sides of the silicon substrate. A second nozzle hole communicating with the nozzle hole is formed (see, for example, Patent Document 1).

In addition, in the conventional face ejection type nozzle (droplet discharge head) nozzle forming method, the first nozzle hole having a different inner diameter is formed by anisotropic dry etching using ICP discharge from one surface of the silicon substrate. After the second nozzle hole is formed in two stages, the opposite surface is dug down by anisotropic wet etching to adjust the nozzle length (see, for example, Patent Document 2).

Furthermore, when water-soluble ink is used in an inkjet head, ink droplets are likely to adhere if the water repellency of the surface of the nozzle plate that ejects ink is insufficient, and the ink travels straight when ink is ejected by the adhered ink. There is a problem that the printing property is lost and printing disturbance occurs.

For this reason, in the conventional surface treatment method for an ink jet recording head, the filler is melted and filled in the nozzle holes with heat or a solvent, a water repellent film is formed on the surface of the nozzle plate, and then the filler in the nozzle holes is removed. A water-repellent film is formed only on the surface of the nozzle plate excluding the inside of the nozzle holes by dissolving and removing with heat or a solvent (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 9-57981 (FIGS. 1 and 2) Japanese Patent Laid-Open No. 11-28820 (FIGS. 1 to 4) JP 63-122560 A (FIGS. 2 and 4)

In a conventional method of manufacturing a nozzle plate for an inkjet head (see, for example, Patent Document 1), before forming the first nozzle hole and the second nozzle hole by dry etching, the silicon substrate is ground and thinned. There has been a problem that the silicon substrate may be broken or chipped during the manufacturing process. For this reason, there is a problem that the yield is lowered and the manufacturing cost is increased.
Further, in this method of manufacturing a nozzle plate for an inkjet head, cooling is performed with helium gas or the like from the opposite side of the processing surface of the nozzle plate in order to stabilize the processing shape during dry etching processing. And the like leaks to the processed surface side, which makes etching impossible.

Further, in the conventional nozzle forming method of the ejecting apparatus (see, for example, Patent Document 2), the ejection surface where the first nozzle hole opens is formed at a position that is deeply lowered from the substrate surface. There was a problem that it would turn. Also, with such a structure, there is a problem that it is difficult to perform wiping work for removing paper dust, ink, and the like that cause nozzle clogging from the ejection surface with rubber pieces or felt pieces.

Furthermore, in the conventional surface treatment method of an ink jet recording head (see, for example, Patent Document 3), it is difficult to select a filler and a solvent that do not affect the material of the water repellent film, and the filler in the nozzle holes cannot be completely removed. In addition, there is a problem that a process for filling and removing the filler is necessary and the manufacturing process becomes complicated.

The present invention relates to a method for processing a silicon substrate that is easy to be water-repellent without cracking or chipping the silicon substrate during processing, a method for manufacturing a droplet discharge head using the method for processing a silicon substrate, and the liquid It is an object of the present invention to provide a method for manufacturing a droplet discharge device to which a method for manufacturing a droplet discharge head is applied.

The silicon substrate processing method according to the present invention includes a silicon substrate, a first nozzle hole, a nozzle that communicates with the first nozzle hole and includes a second nozzle hole having a diameter larger than the first nozzle hole. A step of forming a recess, a step of bonding a support substrate to a surface on which a recess serving as a nozzle of a silicon substrate is formed using a resin, and a surface opposite to the surface on which the support substrate of the silicon substrate is bonded, The step of thinning the silicon substrate and the step of peeling the support substrate from the silicon substrate after thinning the silicon substrate, and filling the recesses that serve as nozzles in the step of bonding the support substrate to the silicon substrate It is intended to be done.
A concave portion that becomes a nozzle is formed by forming a concave portion that becomes a nozzle, laminating the support substrate on the surface on which the concave portion that becomes the nozzle is formed, and thinning the silicon substrate from the surface opposite to the surface on which the supporting substrate is laminated. A thick silicon substrate can be used when forming the substrate, and the silicon substrate can be prevented from cracking or chipping. Further, in this method for manufacturing a droplet discharge head, there is no process for processing a thin silicon substrate, and the silicon substrate can be effectively prevented from being cracked or chipped.
Furthermore, in the step of bonding the support substrate to the silicon substrate, the resin is filled in the recesses that become the nozzles, so that the tip of the nozzle can be prevented from being chipped when the silicon substrate is thinned.

The silicon substrate processing method according to the present invention includes a step of peeling the resin from the silicon substrate after the step of peeling the support substrate from the silicon substrate.
If the resin is peeled off from the silicon substrate after the step of peeling the support substrate from the silicon substrate, the resin in the nozzle is also pulled out together with the resin layer, so that the step of removing the filler in the nozzle becomes unnecessary, and silicon Substrate productivity is improved.

In the silicon substrate processing method according to the present invention, the step of bonding the support substrate to the silicon substrate is performed in a vacuum.
By performing the process of bonding the support substrate to the silicon substrate in a vacuum, it is possible to fill the recesses that become the nozzles with resin without the accumulation of bubbles or the like in the recesses that become the nozzles.

In the silicon substrate processing method according to the present invention, the supporting substrate is coated with resin in the step of bonding the supporting substrate to the silicon substrate.
By coating the resin on the support substrate side, it is possible to fill the resin into the concave portion serving as the nozzle without causing bubbles or the like to accumulate in the concave portion serving as the nozzle.

In the silicon substrate processing method according to the present invention, the silicon substrate is polished by a back grinder, polisher and / or CMP in the step of thinning the silicon substrate.
By performing the thinning process of the silicon substrate by a back grinder, polisher and / or CMP, the surface of the silicon substrate can be finished finely.

The silicon substrate processing method according to the present invention includes a step of thinning the silicon substrate,
In the state where the support substrate is bonded to the silicon substrate, a step of removing a part of the resin filling the first nozzle hole is provided.
After the step of thinning the silicon substrate, a part of the resin filled in the first nozzle holes is removed in a state where the support substrate is bonded to the silicon substrate, for example, ink repellent on the surface of the silicon substrate. When forming the film, it is possible to form an ink repellent film also in a part of the first nozzle hole.

In addition, the silicon substrate processing method according to the present invention is to remove a part of the resin filled in the first nozzle hole by O ₂ plasma treatment.
If a part of the resin filled in the first nozzle hole is removed by the O ₂ plasma treatment, a part of the resin can be easily and cleanly removed.

In addition, the silicon substrate processing method according to the present invention includes a step of forming an ink-resistant protective film and an ink-repellent film on the thinned surface of the silicon substrate before the step of peeling the support substrate from the silicon substrate. Is.
By forming the ink-resistant protective film and the ink repellent film in a state where the supporting substrate is bonded to the silicon substrate with the resin, the ink-resistant protective film and the ink repellent film are formed only on the surface of the silicon substrate except inside the nozzle. Is possible.

In the silicon substrate processing method according to the present invention, the ink-resistant protective film is formed by room temperature sputtering.
If the ink-resistant protective film is formed by room temperature sputtering, for example, even when the silicon substrate and the support substrate are bonded using a heat-sensitive resin, it is possible to prevent the resin layer from deteriorating.

In the method for processing a silicon substrate according to the present invention, a peeling layer that is separated by light is formed between the silicon substrate and the support substrate in the step of bonding the support substrate to the silicon substrate.
By forming a release layer that is separated by light between the silicon substrate and the support substrate, the support substrate can be easily peeled off by light such as laser.

In the silicon substrate processing method according to the present invention, the support substrate is made of a transparent material.
If the support substrate is made of a transparent material such as glass, the release layer can be easily irradiated with light such as a laser, and the support substrate can be easily peeled off.

In the silicon substrate processing method according to the present invention, the step of forming the recess to be the nozzle is performed by C
₄ is performed by dry etching using the F ₈ and SF _6.
Forming the cylindrical first nozzle hole and the second nozzle hole precisely by performing the step of forming the recess to be the nozzle by anisotropic dry etching using C ₄ F ₈ and SF _6. Can do.

A method for manufacturing a droplet discharge head according to the present invention is a method for manufacturing a droplet discharge head using any one of the above-described silicon substrate processing methods.
If a nozzle substrate of a droplet discharge head is manufactured using any of the above silicon substrate processing methods, it is possible to manufacture a highly accurate nozzle substrate without cracking or chipping in the silicon substrate. Yield is also improved.

A method for manufacturing a droplet discharge device according to the present invention is a method for manufacturing a droplet discharge device by applying the method for manufacturing a droplet discharge head described above.
If a droplet discharge device is manufactured by applying the above method for manufacturing a droplet discharge head, a droplet discharge device having high printing performance and the like can be obtained.

Embodiment 1. FIG.
FIG. 1 is a longitudinal sectional view showing a droplet discharge head according to Embodiment 1 of the present invention. 1
FIG. 6 schematically shows the portion of the drive circuit 21. FIG. 1 shows a face ejection type droplet ejection head by an electrostatic drive method as an example of the droplet ejection head.
The droplet discharge head 1 according to the first embodiment is mainly configured by bonding a cavity substrate 2, an electrode substrate 3, and a nozzle substrate 4. The nozzle substrate 4 is made of silicon,
For example, a cylindrical first nozzle hole 6 and a nozzle 8 communicating with the first nozzle hole 6 and having a cylindrical second nozzle hole 7 having a diameter larger than that of the first nozzle hole 6 are formed. Yes. The first nozzle hole 6 is formed so as to open on the droplet discharge surface 10 (the surface opposite to the bonding surface 11 with the cavity substrate 2), and the second nozzle hole 7 is bonded with the cavity substrate 2. It is formed so as to open on the surface 11.
The nozzle substrate 4 is preferably made of single crystal silicon so that predetermined processing described later can be easily performed.

The cavity substrate 2 is made of, for example, single crystal silicon, and has a plurality of recesses serving as discharge chambers 13 whose bottom wall is the diaphragm 12. It is assumed that the plurality of discharge chambers 13 are formed in parallel from the front side to the back side in FIG. In addition, the cavity substrate 2 includes
A recess serving as a reservoir 14 for supplying a droplet of ink or the like to each discharge chamber 13 and a recess serving as a narrow groove-like orifice 15 communicating with the reservoir 14 and each discharge chamber 13 are formed.
In the droplet discharge head 1 shown in FIG. 1, the reservoir 14 is formed from a single recess, and one orifice 15 is formed for each discharge chamber 13. The orifice 15 may be formed on the bonding surface 11 of the nozzle substrate 4.
Furthermore, an insulating film 16 (a droplet protective film 24 described later) made of silicon oxide or the like is formed on the entire surface of the cavity substrate 2 by, for example, CVD or thermal oxidation. This insulating film 16 is
Insulation breakdown or short-circuit during driving of the droplet discharge head 1 is prevented, and the discharge chamber 13 or the reservoir 1 is prevented.
This is to prevent the cavity substrate 2 from being etched by the liquid droplets inside 4.

An electrode substrate 3 made of borosilicate glass, for example, is bonded to the cavity substrate 2 side of the cavity substrate 2. A plurality of electrodes 17 facing the diaphragm 12 are formed on the electrode substrate 3. The electrode 17 is formed, for example, by sputtering ITO (Indium Tin Oxide). In addition, an ink supply hole 18 communicating with the reservoir 14 is formed in the electrode substrate 3. The ink supply hole 18 is connected to a hole provided in the bottom wall of the reservoir 14 and is provided to supply droplets such as ink to the reservoir 14 from the outside.
When the cavity substrate 2 is made of single crystal silicon and the electrode substrate 3 is made of borosilicate glass, the cavity substrate 2 and the electrode substrate 3 can be joined by anodic bonding.

Here, the operation of the droplet discharge head 1 shown in FIG. 1 will be described. A drive circuit 21 is connected to the cavity substrate 2 and each electrode 17. When a pulse voltage is applied between the cavity substrate 2 and the electrode 17 by the drive circuit 21, the vibration plate 12 bends toward the electrode 17, and droplets of ink or the like accumulated in the reservoir 14 enter the discharge chamber 13. Flows in. When the voltage applied between the cavity substrate 2 and the electrode 17 disappears, the diaphragm 12 returns to the original position, the pressure inside the discharge chamber 13 increases, and droplets such as ink from the nozzle 8 are discharged. Discharged.
In the first embodiment, an electrostatic drive type droplet discharge head is shown as an example of the droplet discharge head. However, the manufacturing method of the nozzle substrate 4 shown in the first embodiment is a piezoelectric drive method or bubble jet (registered). The present invention can also be applied to a droplet discharge head of a trademark type.

FIG. 2 is a top view of the nozzle substrate 4 as viewed from the droplet discharge surface 10 side. As shown in FIG.
A plurality of first nozzle holes 6 are opened on the droplet discharge surface 10 side of the nozzle substrate 4. The second nozzle hole 7 is formed on the back side of the paper surface of each nozzle hole 6 in FIG. The discharge chamber 13 of the cavity substrate 2 is formed for each individual first nozzle hole 6 (nozzle 8), and each discharge chamber 13 is elongated in the direction of the line AA in FIG.
In the first embodiment, a silicon substrate processing method for mainly manufacturing the nozzle substrate 4 will be described below. In the droplet discharge head 1 according to the first embodiment, it is assumed that the central axes of the first nozzle hole 6 and the second nozzle hole 7 coincide with each other with high accuracy. As a result, it is possible to improve the straightness of the droplet when the droplet is discharged from the nozzle 8.

3 to 9 are longitudinal sectional views showing manufacturing steps when manufacturing a droplet discharge head using the silicon substrate processing method according to the first embodiment of the present invention. 3 to 7 mainly show the manufacturing process of the nozzle substrate 4, and FIGS. 8 and 9 show the manufacturing process of the bonded substrate 5 in which the cavity substrate 2 and the electrode substrate 3 are bonded. 3 to 7 show a peripheral portion of the nozzle 8 in a longitudinal section along the line AA in FIG. First, a process of manufacturing the droplet discharge head 1 by manufacturing the nozzle substrate 4 from the silicon substrate 30 and bonding the nozzle substrate 4 to the bonding substrate will be described with reference to FIGS.
First, for example, a silicon substrate 30 having a thickness of 525 μm is prepared, and a silicon oxide film 31 is uniformly formed on the entire surface of the silicon substrate 30 (FIG. 3A). The silicon oxide film 31 is formed, for example, by thermal oxidation for 4 hours in a mixed atmosphere of oxygen and water vapor at a temperature of 1075 ° C. using a thermal oxidation apparatus.

Next, a resist 32 is coated on one surface of the silicon substrate 30, and the portion 7a that becomes the second nozzle hole 7 is patterned to remove the resist 32 in the portion 7a that becomes the second nozzle hole 7 (FIG. 3B). )). The coated surface of the resist 32 will later become the bonding surface 11 of the nozzle substrate 4.
Then, for example, the silicon oxide film 31 is half-etched with a buffered hydrofluoric acid aqueous solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed in a ratio of 6 to 6, and a portion 7 a that becomes the second nozzle hole 7
The silicon oxide film 31 is thinned (FIG. 3C). At this time, the silicon oxide film 31 on the surface where the resist 32 is not formed is also thinned.
Then, the resist 32 formed on one surface of the silicon oxide film 31 is removed (FIG. 3D
)).

Thereafter, a resist 33 is coated on the surface to be the bonding surface 11 again, and the first nozzle hole 6
Then, the portion 6a to be formed is patterned to remove the resist 33 in the portion 6a to be the first nozzle hole 6 (FIG. 4E).
Then, for example, the silicon oxide film 31 is half-etched with a buffered hydrofluoric acid aqueous solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed in a 1: 6 ratio, and a portion 6 a that becomes the first nozzle hole 6
The silicon oxide film 31 is removed (FIG. 4F). At this time, all the silicon oxide film 31 on the surface where the resist 33 is not formed is also removed.
Then, the resist 33 formed in the step of FIG. 4E is peeled off (FIG. 4G).
Next, anisotropic etching is performed from the portion 6a serving as the first nozzle hole 6 by dry etching using ICP (Inductively Coupled Plasma) discharge, thereby forming a recess 6b having a depth of 25 μm, for example (FIG. 4H). In addition, this recessed part 6b is 1st.
This is the source of the recess 6c that becomes the nozzle hole 6 (see FIG. 5J). C ₄ F ₈ and SF ₆ can be used alternately as etching gases for this anisotropic dry etching.
At this time, C ₄ F ₈ is used to protect the side surface of the recess 6 b so that the etching does not proceed in the side direction of the recess 6 b, and SF ₆ is used to promote the etching of the recess 6 b in the vertical direction.

Thereafter, the silicon oxide film 31 is half-etched to form a portion 7 that becomes the second nozzle hole 7.
The silicon oxide film 31 of a is removed (FIG. 5I). At this time, the silicon oxide film 31
The other parts of the also become thinner.
Then, by dry etching by ICP discharge again, anisotropic dry etching is performed by a depth of, for example, 40 μm from the portion 7a (including the recess 6b) that becomes the second nozzle hole 7, and the recess 6c that becomes the first nozzle hole 6 and A recess 7b to be the second nozzle hole 7 is formed (FIG. 5 (
J)).
Then, after all the silicon oxide film 31 remaining on the silicon substrate 30 is removed with, for example, a hydrofluoric acid aqueous solution, a silicon oxide film 34 having a thickness of, for example, 0.1 μm is uniformly formed on the entire surface of the silicon substrate 30 (FIG. 5 (K )). This silicon oxide film 34 is formed, for example, by performing thermal oxidation for 2 hours in an oxygen atmosphere at a temperature of 1000 ° C. using a thermal oxidation apparatus. In FIG. 5K, since the silicon oxide film 34 is formed by thermal oxidation, the silicon oxide film is uniformly formed on the inner walls of the recess 6c to be the first nozzle hole 6 and the recess 7b to be the second nozzle hole 7. 34 can be formed.

Next, a release layer 41 is spin-coated on one surface of a support substrate 40 made of a transparent material such as glass, and a resin layer 42 made of resin is spin-coated thereon. The surface of the support substrate 40 on which the release layer 41 and the resin layer 42 are spin-coated, and the second nozzle hole 7 of the silicon substrate 30.
The first support substrate 40 and the silicon substrate 30 are bonded together by curing the resin layer 42 with the surfaces on which the recesses 7b and the like are formed facing each other (FIG. 5L). Note that FIG.
L) In the subsequent steps, the orientation of the silicon substrate 30 is upside down from FIGS.
In the first embodiment, the support substrate 40 and the silicon substrate 30 in FIG. 5L are bonded together in a vacuum, and the resin constituting the resin layer 42 is formed with the recesses 6c and the second nozzle holes 6 serving as the first nozzle holes 6. The concave portion 7b to be the nozzle hole 7 is filled. In this way, the bonding of the support substrate 40 and the silicon substrate 30 is performed in a vacuum, whereby the concave portion 6c to be the first nozzle hole 6 and the second
It is possible to prevent air bubbles and the like from accumulating in the concave portion 7b serving as the nozzle hole 7 of the nozzle.

Here, the peeling layer 41 and the resin layer 42 in the step of FIG.
The peeling layer 41 causes peeling (referred to as intra-layer peeling or interface peeling) inside the peeling layer 41 or at the interface with the silicon substrate 31 when irradiated with light such as laser light (FIG. 6).
(See (O)). That is, the release layer 41 receives a certain intensity of light, and ablation (ablation, removal or removal) occurs due to disappearance or reduction of the bonding force between atoms or molecules of the material constituting the release layer 41. When the release layer 41 receives light of a certain intensity, the component of the material constituting the release layer 41 becomes a gas and causes peeling. This
The support substrate 40 can be removed from the thinned silicon substrate 30 (nozzle substrate 4) in the following step of FIG.
The support substrate 40 is preferably made of glass that transmits light. Thus, when the support substrate 40 is peeled from the silicon substrate 30, the release layer 41 is irradiated with light from the back surface of the support substrate 40 (the surface opposite to the surface to which the silicon substrate 30 is bonded) to give sufficient peel energy Is possible.

The material constituting the release layer 41 is not particularly limited as long as it has the above functions. For example, amorphous silicon (a-Si, amorphous silicon), silicon oxide, silicate compound, silicon nitride, Nitride ceramics such as aluminum nitride and titanium nitride, organic polymer materials whose atomic bonds are broken by light irradiation, or aluminum, lithium, titanium, manganese, indium, tin, yttrium, lanthanum, cerium, neodymium, praseodymium, gadolinium And a metal such as samarium, or an alloy containing at least one of the above metals. Among these materials, it is preferable to use amorphous silicon as a constituent material of the peeling layer 41, and it is more preferable that hydrogen is contained in the amorphous silicon. By using such a material, when the peeling layer 41 receives light, hydrogen is released, and an internal pressure is generated in the peeling layer 41, so that peeling can be promoted. In this case, the content of hydrogen in the release layer 41 is preferably 2% by weight or more, and more preferably 2 to 20% by weight.

The resin layer 42 is for absorbing irregularities of the silicon substrate 30 and bonding the silicon substrate 30 and the support substrate 40 together. The material constituting the resin layer 42 is not particularly limited as long as it has a function of joining the silicon substrate 30 and the first support substrate 40. For example, curing is performed using a thermosetting adhesive or a photocurable adhesive. Adhesives can be used. The resin layer 42 is preferably made of a material having high dry etching resistance.

In the first embodiment, the release layer 41 and the resin layer 42 are formed as separate layers. However, for example, these layers may be configured from one layer. For example, the silicon substrate 3
This can be realized by forming a layer having a function of bonding 0 and the support substrate 40 and having a function of causing peeling by light energy or thermal energy. For materials having such a function, refer to, for example, Japanese Patent Application Laid-Open No. 2002-338771.

Here, returning to the description of the manufacturing process, after the silicon substrate 30 and the support substrate 40 are bonded together, the back surface of the silicon substrate 30 opposite to the surface to which the support substrate 40 is bonded is back grinder, polisher, CMP (Chemical Mechanical Polishing), or the like. Polishing is performed, and the silicon substrate 30 is thinned until the silicon oxide film 34 at the tip of the recess 6c to be the first nozzle hole 6 is removed (FIG. 6M). At this time, for example, if the silicon substrate 30 is thinned to the vicinity of the silicon oxide film 34 at the tip of the recess 6c to be the first nozzle hole 6 with a back grinder, the thinning is finished by a polisher or CMP. The surface of the silicon substrate 30 can be finished in a mirror shape.

Next, an ink-resistant protective film 35 made of silicon oxide is formed with a thickness of, for example, 0.1 μm on the opposite surface of the silicon substrate 30 to the surface to which the support substrate 40 is bonded using a sputtering apparatus. In the first embodiment, ECR (Electron C) is used to form the ink-resistant protective film 35.
A room-temperature sputtering apparatus such as a yclotron resonance) sputtering apparatus is used.
This is because the dense ink-resistant protective film 35 is formed using an ECR sputtering apparatus and the resin layer 42 is prevented from being deteriorated by heat. If the resin layer 42 has a temperature at which the resin layer 42 does not deteriorate (about 200 ° C. or less), the ink-resistant protective film 35 can be obtained by another sputtering apparatus or another method.
May be formed.
Then, for example, vapor deposition or dipping (on the surface of the ink-resistant protective film 35 of the silicon substrate 30).
The ink repellent film 36 is formed by dipping) or the like (FIG. 6N). As a material of the ink repellent film 36, an ink repellent material containing fluorine atoms can be used. At this stage, the processing of the silicon substrate 30 itself is finished, and the nozzle substrate 4 is completed. In the process of FIG. 6N, since the resin is filled in the first nozzle hole 6 and the second nozzle hole 7, the inside of the nozzle 8 is not subjected to ink repellent treatment.

Next, the support substrate 40 is irradiated with laser light or the like from the side of the release layer 41 to support the substrate 40.
Is peeled off (FIG. 6 (O)), and then the resin layer 42 is slowly peeled off from the silicon substrate 30 (FIG. 6 (P)). At this time, the resin layer 42 is peeled off from the outer peripheral portion of the silicon substrate 30. 6P, the resin inside the nozzle 8 is also pulled out together with the resin layer.
Then, an adhesive layer 37 is formed by transferring an adhesive or the like to the surface of the silicon substrate 30 (nozzle substrate 4) where the second nozzle holes 7 are formed, and the cavity substrate 2 to which the electrode substrate 3 is bonded.
Then, the silicon substrate 30 is bonded (FIG. 7Q).
Finally, for example, the bonded substrate to which the cavity substrate 2, the electrode substrate 3, and the nozzle substrate 4 are bonded is separated by dicing (cutting), and the droplet discharge head 1 is completed.

8 and 9 are vertical cross-sectional views showing a manufacturing process of a bonded substrate in which the cavity substrate 2 and the electrode substrate 3 are bonded. Hereinafter, a manufacturing process of a bonded substrate obtained by bonding the cavity substrate 2 and the electrode substrate 3 will be briefly described. The manufacturing method of the cavity substrate 2 and the electrode substrate 3 is shown in FIG.
And it is not limited to what is shown in FIG.
First, a recess 19 is formed by etching a glass substrate made of borosilicate glass or the like with hydrofluoric acid using, for example, a gold / chromium etching mask. A plurality of the recesses 19 are formed in a groove shape slightly larger than the shape of the electrode 17 and are formed.
Then, in the recess 19, for example, ITO (Indium Tin O 2) is formed by sputtering.
An electrode 17 made of xide) is formed.
Thereafter, a hole 18a to be the ink supply hole 18 is formed by a drill or the like to form the electrode substrate 3 (FIG. 8A).

Next, for example, after both surfaces of a silicon substrate 2a having a thickness of 525 μm are mirror-polished, plasma CVD (Chemical Vapor Deposition) is applied to one surface of the silicon substrate 2a.
on), a silicon oxide film 22 made of TEOS (TetraEthyl Orthosilicate) and having a thickness of 0.1 μm is formed (FIG. 8B). Silicon oxide film 2
Before forming 2, a boron doped layer for etching stop may be formed. By forming the diaphragm 12 from a boron-doped layer, the diaphragm 12 with high thickness accuracy is obtained.
Can be formed.
Then, the silicon substrate 2a shown in FIG. 8B and the electrode substrate 3 shown in FIG. 8A are heated to, for example, 360 ° C., and the anode is connected to the silicon substrate 2a and the cathode is connected to the electrode substrate 3, so that the voltage is about 800V. Anodic bonding is performed by applying a voltage (FIG. 8C).
After the anodic bonding of the silicon substrate 2a and the electrode substrate 3, a potassium hydroxide aqueous solution or the like is used for FIG.
By etching the bonding substrate obtained in the step c), the entire silicon substrate 2a is thinned to a thickness of, for example, 140 μm (FIG. 8D).

Then, a TEOS film having a thickness of, for example, 1.5 μm is formed on the entire upper surface of the silicon substrate 2a (the surface opposite to the surface to which the electrode substrate 3 is bonded) by plasma CVD.
The TEOS film is provided with a recess 13a that becomes the discharge chamber 13 and a recess 14 that becomes the reservoir 14.
The resist for forming a and the recess 15a to be the orifice is patterned, and the TEOS film in this portion is removed by etching.
Thereafter, the silicon substrate 2a is etched with a potassium hydroxide aqueous solution or the like to thereby form a recess 13a serving as a discharge chamber 13, a recess 14a serving as a reservoir 14, and a recess 1 serving as an orifice.
5a is formed (FIG. 9E). At this time, the part which becomes the electrode extraction part 23 is also etched and thinned. Note that, in the wet etching step of FIG.
A weight percent aqueous potassium hydroxide solution can be used followed by a 3 weight percent aqueous potassium hydroxide solution. Thereby, surface roughness of the diaphragm 12 can be suppressed.

After the etching of the silicon substrate 2a is completed, the bonding substrate is etched with a hydrofluoric acid aqueous solution to remove the TEOS film formed on the silicon substrate 2a. Further, laser processing is performed on the hole 18a that becomes the ink supply hole 18 of the electrode substrate 3 so that the ink supply hole 18 penetrates the electrode substrate 3 (FIG. 9F).
Next, the surface of the silicon substrate 2a on which the recesses 13a to be the discharge chambers 13 are formed, for example, C
A droplet protective film 24 made of TEOS or the like is formed by VD, for example, with a thickness of 0.1 μm (
FIG. 9 (g)).
Then, the electrode take-out part 23 is opened by RIE (Reactive Ion Etching) or the like. Further, the silicon substrate 2 a is machined or laser processed to penetrate the ink supply hole 18 to the concave portion 14 a serving as the reservoir 14. Thereby, the bonded substrate 5 in which the cavity substrate 2 and the electrode substrate 3 are bonded is completed. The bonded substrate 5 is bonded to the nozzle substrate 4 in the process of FIG.
In addition, a sealant (for sealing the space between the diaphragm 12 and the electrode 17 in the electrode extraction portion 23 (
(Not shown) may be applied.

In the first embodiment, the nozzle 8 is formed by etching one surface of the silicon substrate 30.
In order to reduce the thickness of the silicon substrate 30 from the surface opposite to the surface to which the support substrate 40 is bonded, the support substrate 40 is bonded to the surface where the recess to be the nozzle 8 is formed. A thick silicon substrate 30 can be used when forming the recesses to be 8,
It is possible to prevent the silicon substrate 30 from being cracked or chipped. Moreover, since there is no process for processing the thinned silicon substrate 30, it is possible to effectively prevent the silicon substrate 30 from being cracked or chipped.
Further, in the step of bonding the support substrate 40 to the silicon substrate 30, the silicon substrate 30 is formed so that the resin is filled in the recesses 6 c serving as the first nozzle holes 6 and the recesses 7 b serving as the second nozzle holes 7. It is possible to prevent the tip of the nozzle 8 from being chipped when thinning the plate.
Further, since the concave portion that becomes the nozzle 8 is formed in the thick silicon substrate 30 in a non-penetrating state, it is possible to prevent helium gas or the like from leaking to the processing surface side to prevent etching.

Embodiment 2. FIG.
FIG. 10 is a longitudinal sectional view showing a manufacturing process when a droplet discharge head is manufactured using the silicon substrate processing method according to the second embodiment of the present invention. Note that the manufacturing process up to FIG. 6M and the manufacturing process after FIG.
In the second embodiment, after the silicon substrate 30 is thinned in the process of FIG. 6M of the first embodiment, the silicon substrate 30 is set in a dry etching apparatus (not shown), and the first is performed by O ₂ plasma treatment. The resin filling the tip of the nozzle hole 6 is removed by a thickness a (FIG. 10 (M ′)). The thickness a is, for example, about several μm to 10 μm.
Thereafter, similarly to the process of FIG. 6N, an ink-resistant protective film 35 and an ink repellent film 36 are formed on the surface of the silicon substrate 30 (FIG. 10N ′). At this time, the ink-repellent treatment is also applied to the portion of the first nozzle hole 6 where the resin is removed. The ink repellent area in the first nozzle hole 6 can be adjusted by adjusting the thickness a of the resin to be removed.

In the second embodiment, by removing a part of the resin filling the first nozzle hole 6, for example, when forming the ink repellent film 36 on the surface of the silicon substrate 30, the first nozzle hole 6 It is possible to form the ink repellent film 36 on a part of the inside.
The reason why the ink repellent film 36 is formed in a part of the first nozzle hole 6 is as follows. That is, the meniscus may become unstable due to thickening from a meniscus of a droplet such as ink (a droplet at the tip of the nozzle 8 or a portion where the droplet is in contact with air). Therefore, as in the second embodiment, by adjusting the ink repellent area in the nozzle 8 and pulling the meniscus position from the ejection surface 10 into the nozzle 8, the meniscus in the nozzle 8 is stabilized and the ejection stability of droplets is improved. There is an effect of improving.

Embodiment 3. FIG.
FIG. 11 is a perspective view showing an example of a droplet discharge device equipped with the droplet discharge head obtained by the manufacturing method of the first or second embodiment. A droplet discharge device 100 shown in FIG. 11 is a general inkjet printer. The droplet discharge device 100 can be manufactured by a known manufacturing method.
The droplet discharge head 1 obtained in the first embodiment or the second embodiment has no cracks or chips as described above, and the droplet discharge device 100 has high discharge performance.
In addition to the ink jet printer shown in FIG. 11, the droplet discharge head 1 obtained by the manufacturing method of Embodiment 1 or Embodiment 2 can be used to manufacture liquid crystal display color filters, The present invention can also be applied to formation of a light emitting portion of an EL display device, discharge of a biological liquid, and the like.
Further, the droplet discharge head 1 obtained by the manufacturing method of Embodiment 1 or Embodiment 2 can be used for a piezoelectric drive type droplet discharge device and a bubble jet (registered trademark) type droplet discharge device.

In addition, the manufacturing method of the droplet discharge head, the droplet discharge head, and the droplet discharge apparatus of the present invention are:
It is not limited to the embodiment of the present invention, and can be changed within the scope of the idea of the present invention. For example, the peeling layer 41 is not necessarily formed in the manufacturing process of FIG.

1 is a longitudinal sectional view showing a droplet discharge head according to Embodiment 1 of the present invention. The top view which looked at the nozzle substrate from the droplet discharge surface side. FIG. 3 is a longitudinal sectional view showing a manufacturing process when manufacturing a droplet discharge head using the silicon substrate processing method according to the first embodiment of the present invention. FIG. 4 is a longitudinal sectional view showing a step subsequent to the manufacturing step of FIG. 3. FIG. 5 is a longitudinal sectional view showing a step subsequent to the manufacturing step of FIG. 4. FIG. 6 is a longitudinal sectional view showing a process subsequent to the manufacturing process of FIG. 5. FIG. 7 is a longitudinal sectional view showing a step subsequent to the manufacturing step of FIG. 6. The longitudinal cross-sectional view which shows the manufacturing process of the bonded substrate which joined the cavity substrate and the electrode substrate. FIG. 9 is a longitudinal sectional view showing a step subsequent to the manufacturing step of FIG. 8. FIG. 9 is a longitudinal sectional view showing a manufacturing process when manufacturing a droplet discharge head using a silicon substrate processing method according to Embodiment 2 of the present invention. FIG. 4 is a perspective view showing an example of a droplet discharge device equipped with a droplet discharge head obtained by the manufacturing method of Embodiment 1 or Embodiment 2.

Explanation of symbols

1 droplet ejection head, 2 cavity substrate, 3 electrode substrate, 4 nozzle substrate, 6 first
Nozzle hole, 7 second nozzle hole, 8 nozzle, 10 droplet discharge surface, 11 bonding surface, 12
Diaphragm, 13 discharge chamber, 14 reservoir, 15 orifice, 16 insulating film, 17 electrode, 18 ink supply hole, 21 drive circuit, 100 droplet discharge device.

Claims (4)

Forming a first nozzle hole in the silicon substrate and a recess that communicates with the first nozzle hole and becomes a nozzle including a second nozzle hole having a diameter larger than that of the first nozzle hole;
Bonding a support substrate made of a transparent material to a surface where the recess is formed using the resin so that the recess serving as the nozzle of the silicon substrate is filled with resin ;
A step of thinning the silicon substrate from the opposite surface of the silicon substrate to which the support substrate is bonded;
After the step of thinning the silicon substrate, with the support substrate bonded to the silicon substrate, after removing a part of the resin filling the first nozzle hole by O2 plasma treatment, Forming an ink-resistant protective film and an ink-repellent film on the thinned surface of the silicon substrate;
Separating the support substrate from the silicon substrate after the step of forming the ink-resistant protective film and the ink repellent film ,
A method for processing a silicon substrate , wherein in the step of attaching a support substrate to the silicon substrate, a release layer having a hydrogen content of 2 to 20 wt% is formed between the silicon substrate and the support substrate .   The method for processing a silicon substrate according to claim 1, further comprising a step of peeling the resin from the silicon substrate after the step of peeling the support substrate from the silicon substrate.   3. The method for processing a silicon substrate according to claim 1, wherein the step of bonding the support substrate to the silicon substrate is performed in a vacuum.   4. The method for processing a silicon substrate according to claim 3, wherein in the step of attaching the support substrate to the silicon substrate, the resin is coated on the support substrate.

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