JP2009154347A - Method for manufacturing nozzle substrate, nozzle substrate, liquid droplet discharge head, method for manufacturing liquid droplet discharge head, and liquid droplet discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a nozzle substrate or the like which enables accuracy improvements of a plate thickness and a nozzle length by forming the nozzle substrate by film formation instead of forming by plate-thinning working such as grinding. <P>SOLUTION: The method for manufacturing the nozzle substrate includes a process for film-forming a sacrificial layer 101 on a film formation substrate 100, a nozzle substrate base material forming process for film-forming a doped polysilicone layer 102 with phosphor doped therein as a nozzle substrate base material on the sacrificial layer 101, a nozzle hole forming process for forming nozzle holes in the doped polysilicone layer 102 by dry etching, and a stripping process for stripping the doped polysilicone layer 102 from the film formation substrate 100 by removing the sacrificial layer 101 by etching. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nozzle substrate manufacturing method, a nozzle substrate, a droplet discharge head, a droplet discharge head manufacturing method, and a droplet discharge apparatus.

  As a droplet discharge head for discharging droplets, for example, an inkjet head mounted on an inkjet recording apparatus is known. A conventional general inkjet head includes a nozzle substrate in which a plurality of nozzle holes for discharging ink droplets are formed, and a pressure chamber and a reservoir that are bonded to the nozzle substrate and communicate with the nozzle holes. And a cavity substrate on which an ink flow path is formed, and is configured to eject ink droplets from selected nozzle holes by applying pressure to the pressure chamber by a driving unit (see, for example, Patent Document 1). ). As the driving means, there are a method using an electrostatic force, a piezoelectric method using a piezoelectric element, a method using a heating element, and the like.

  In recent years, there has been an increasing demand for ink jet heads with higher quality such as printing and image quality, and higher density and improved ejection performance have been demanded. For this reason, various devices and proposals have been made for the nozzle portion of the inkjet head.

  In the ink jet head, in order to improve the ink ejection characteristics, it is desirable to adjust the flow path resistance of the nozzle portion and adjust the thickness of the nozzle substrate so that the optimum nozzle length is obtained. In a conventional nozzle substrate manufacturing method, there is a method in which a silicon substrate to be a nozzle substrate is ground in advance to a desired thickness and then nozzle holes are formed by dry etching (see, for example, Patent Document 1).

  Conventionally, a concave portion to be a nozzle hole is previously formed in a silicon substrate, a support substrate is bonded to the concave surface of the concave surface, and grinding is performed from the surface opposite to the concave surface of the silicon substrate to a desired thickness. There is a method of penetrating the nozzle hole simultaneously with the thinning (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 9-57981 JP 2006-159661 A (FIGS. 4 to 6)

  However, as in Patent Document 1 and Patent Document 2, when grinding is used to adjust the thickness of the substrate, variations occur in the in-plane thickness and the thickness between the substrates. In this case, there is a problem in that the nozzle length varies, and in turn the ejection performance varies.

  In recent years, a silicon wafer has been increased in diameter to increase the number of head chips that can be obtained from a single silicon wafer to reduce the cost. For example, when a large wafer such as an 8-inch wafer is obtained, In order to maintain the strength, it is necessary to increase the wafer thickness. In this case, when grinding to the necessary thickness as the nozzle substrate substrate, it takes time to grind, and when the area becomes large, it becomes more difficult to cut uniformly in the surface, resulting in variations in the substrate thickness. there were.

  The present invention has been made in view of these points, and it is possible to improve the accuracy of the plate thickness and the nozzle length by forming the nozzle substrate not by thinning such as grinding but by forming a film. An object of the present invention is to provide a method for manufacturing a nozzle substrate, a nozzle substrate, a droplet discharge head, a method for manufacturing a droplet discharge head, and a droplet discharge apparatus.

The method for manufacturing a nozzle substrate according to the present invention includes a step of forming a sacrificial layer on a film forming substrate, and a nozzle for forming a doped polysilicon layer doped with phosphorus on the sacrificial layer as a nozzle substrate base material. A substrate base material forming step, a nozzle hole forming step for forming nozzle holes in the nozzle substrate base material by dry etching, and a peeling step for removing the sacrificial layer by etching to separate the nozzle substrate base material from the film formation substrate. It is characterized by this.
Thus, since the nozzle substrate base material is formed by film formation, it is only necessary to form a film with a necessary thickness, and the accuracy of the plate thickness and nozzle length can be improved compared to the case where the plate thickness is controlled by grinding. it can.

In the nozzle substrate manufacturing method according to the present invention, the nozzle substrate base material forming step includes a step of annealing the doped polysilicon layer.
Thereby, internal stress can be relieved and the curvature of a nozzle substrate base material can be prevented.

In the method for manufacturing a nozzle substrate according to the present invention, the film formation substrate is formed of a material having heat resistance against a temperature of 1000 ° C. or higher.
Thereby, an annealing process can be performed.

In the method for manufacturing a nozzle substrate according to the present invention, the deposition substrate is made of quartz, silicon, or silicon carbide.
As described above, any of quartz, silicon, and silicon carbide can be used as the deposition substrate.

In the nozzle substrate manufacturing method according to the present invention, in the nozzle substrate base material forming step, phosphine is added to a silane-based gas and a doped polysilicon layer is formed using CVD.
Thereby, a doped polysilicon layer can be formed while relaxing the stress.

The nozzle substrate manufacturing method according to the present invention includes a nozzle substrate base material forming step of forming an amorphous silicon layer doped with phosphorus on a film forming substrate as a nozzle substrate base material, and a nozzle hole in the nozzle substrate base material. A nozzle hole forming step for forming the substrate by dry etching, and a peeling step for peeling the nozzle substrate base material from the film formation substrate.
Thus, since the nozzle substrate base material is formed by film formation, it is only necessary to form a film with a necessary thickness, and the accuracy of the plate thickness and nozzle length can be improved compared to the case where the plate thickness is controlled by grinding. it can.

In the method for manufacturing a nozzle substrate according to the present invention, the peeling step is a step of irradiating the nozzle substrate base material with a laser from the film formation substrate side.
In this way, the nozzle substrate substrate can be peeled off from the deposition substrate simply by laser irradiation, so that the processing time can be shortened compared to the peeling method by sacrificial layer etching, and a large area substrate can also be peeled off. .

In the nozzle substrate manufacturing method according to the present invention, the film formation substrate is made of borosilicate glass.
By using generally inexpensive borosilicate glass as the film formation substrate, it is possible to reduce the manufacturing cost.

In addition, the nozzle substrate manufacturing method according to the present invention is a method of forming an amorphous silicon layer using CVD by adding phosphine to a silane-based gas in a nozzle substrate base material forming step.
Thereby, an amorphous silicon layer can be formed while relaxing the stress.

The nozzle substrate according to the present invention is manufactured from any one of the above-described nozzle substrate manufacturing methods.
Thereby, it is possible to obtain a nozzle substrate that has high accuracy in plate thickness and nozzle length and can exhibit good discharge characteristics.

The nozzle substrate according to the present invention has a discharge liquid protective film on the discharge surface having the discharge port of the nozzle hole, the surface opposite to the discharge surface, and the inner wall of the nozzle hole in the nozzle substrate base material.
Since the discharge liquid protective film is formed on all surfaces that come into contact with the discharge liquid, durability against the discharge liquid can be improved.

In the nozzle substrate according to the present invention, a liquid repellent film is formed on the entire surface of the discharge liquid protective film on the nozzle substrate base material, and the inner wall of the nozzle hole and the opposite side with the discharge port edge of the nozzle hole as a boundary. The liquid repellent film is not formed on the side surface.
Since the inner wall of the nozzle hole is hydrophilic and the discharge surface is water-repellent up to the discharge port edge of the nozzle hole, it is possible to obtain a nozzle substrate that can provide good discharge characteristics with no droplets remaining on the discharge surface and no flight deflection. it can.

In the nozzle substrate according to the present invention, the liquid repellent film is mainly composed of a fluorine-containing organosilicon compound.
Thereby, it can be set as a nozzle substrate with good liquid repellency.

In addition, a droplet discharge head according to the present invention includes any one of the nozzle substrates described above.
Thereby, it is possible to obtain a droplet discharge head capable of realizing good discharge characteristics.

Further, the method for manufacturing a droplet discharge head according to the present invention includes a plurality of nozzle holes for discharging droplets, a pressure chamber provided in communication with each nozzle hole and for applying pressure to the droplets, A method for manufacturing a droplet discharge head, comprising: a droplet supply path for supplying droplets to a pressure chamber; and pressure generating means for generating a discharge pressure for discharging the droplets in the pressure chamber. The nozzle substrate having the above is manufactured by any one of the above-described nozzle substrate manufacturing methods.
Thereby, a droplet discharge head capable of realizing good discharge characteristics can be manufactured.

A droplet discharge device according to the present invention is equipped with the above-described droplet discharge head.
Thereby, it is possible to obtain a droplet discharge device that can realize good discharge characteristics.

  Hereinafter, an embodiment of a droplet discharge head including a nozzle substrate of the present invention will be described with reference to the drawings. Here, as an example of a droplet discharge head, an electrostatic drive type inkjet head will be described with reference to FIGS. The present invention is not limited to the structure and shape shown in the following drawings except for the nozzle shape, and can be applied not only to the face discharge type but also to the edge discharge type. Furthermore, the driving method of the pressure generating means can also be applied to a droplet discharging head and a droplet discharging device that discharge droplets by other different driving methods.

  FIG. 1 is an exploded perspective view showing an exploded schematic configuration of an ink jet head according to the present embodiment, and a part thereof is shown in cross section. 2 is a cross-sectional view of the ink jet head showing a schematic configuration of the right half of FIG. 1 in the assembled state, and FIG. 3 is a top view of the ink jet head of FIG.

  As shown in FIGS. 1 and 2, the inkjet head 10 of the present embodiment has a nozzle substrate 1 in which a plurality of nozzle holes 11 are provided at a predetermined pitch, and an ink supply path independently for each nozzle hole 11. The cavity substrate 2 provided is bonded to the electrode substrate 3 on which the individual electrodes 31 are disposed so as to face the diaphragm 22 of the cavity substrate 2.

  The nozzle substrate 1 is made of doped polysilicon or amorphous silicon. Here, the nozzle hole 11 for ejecting ink droplets is composed of a first nozzle portion 11a and a second nozzle portion 11b. The first nozzle portion 11a is formed in a small-diameter cylindrical shape perpendicular to the surface (ink discharge surface) 1a of the nozzle substrate 1, and the second nozzle portion 11b is coaxial with the first nozzle portion 11a. The cross-sectional area is larger than the 1st nozzle part 11a, and the cross-sectional shape is formed in the cylindrical shape. Thus, by making the nozzle hole 11 have a two-stage hole, the ink droplet ejection direction can be aligned with the central axis direction of the nozzle hole 11, and stable ink ejection characteristics can be exhibited. . That is, there is no variation in the flying direction of the ink droplets, there is no scattering of the ink droplets, and variations in the ejection amount of the ink droplets can be suppressed. Here, an example in which the nozzle hole 11 has a structure having two-stage holes is shown, but a multi-stage structure is also possible, and the cross-sectional area of the nozzle holes continuously decreases toward the discharge direction. Also good.

  The cavity substrate 2 is made of, for example, a single crystal silicon substrate having a plane orientation of (110). The silicon substrate is subjected to anisotropic wet etching, so that recesses 24 and 25 for forming the pressure chamber 21 and the reservoir 23 of the ink flow path are defined. The nozzle substrate 1 is bonded and bonded onto the cavity substrate 2, and an ink flow path communicating with each nozzle hole 11 is defined between the nozzle substrate 1 and the cavity substrate 2 as shown in FIG. The bottom wall of the pressure chamber 21 (recessed portion 24) functions as the diaphragm 22.

  The other concave portion 25 is for storing ink of a liquid material, and constitutes a reservoir (common ink chamber) 23 that communicates with each pressure chamber 21 in common. The reservoirs 23 (recesses 25) communicate with the pressure chambers 21 through narrow groove-shaped orifices 26, respectively. A hole penetrating the electrode substrate 3 described later is provided in the bottom of the reservoir 23, and ink is supplied from an ink tank (not shown) through the ink supply hole 34 of the hole. The orifice 26 may be formed on the back surface of the nozzle substrate 1, that is, on the side of the bonding surface 1 b that is bonded to the cavity substrate 2.

Further, the entire surface of the cavity substrate 2 or at least the surface facing the electrode substrate 3 is subjected to a thermal oxidation method or a plasma CVD (Chemical Vapor Deposition) method using TEOS (Tetraethylorthosilicate Tetraethoxysilane) as a source gas. _An insulating film 27 made of _two films or a so-called High-k material (high dielectric constant gate insulating film) is formed. The insulating film 27 is provided for the purpose of preventing dielectric breakdown or short circuit when driving the inkjet head.

  The electrode substrate 3 bonded to the lower side of the cavity substrate 2 is made of a glass substrate having a thickness of about 1 mm, for example. In the electrode substrate 3, a recess 32 having a desired depth is formed by etching at a position facing each diaphragm 22 of the cavity substrate 2. Further, in each recess 32, an individual electrode 31 made of ITO (Indium Tin Oxide) is generally formed by sputtering with a thickness of 0.1 μm, for example. Accordingly, a gap (gap) having a predetermined interval is formed between the diaphragm 22 and the individual electrode 31.

  The individual electrode 31 has a lead part 31a and a terminal part 31b connected to a flexible wiring board (not shown). The terminal portion 31b is exposed in the electrode extraction portion 35 where the end portion of the cavity substrate 2 is opened for wiring.

  The nozzle substrate 1, the cavity substrate 2, and the electrode substrate 3 manufactured as described above are bonded together as shown in FIG. That is, the cavity substrate 2 and the electrode substrate 3 are joined by anodic bonding, and the nozzle substrate 1 is joined to the upper surface of the cavity substrate 2 by adhesion. Further, the open end of the gap formed between the diaphragm 22 and the individual electrode 31 is hermetically sealed with a sealing material 36 made of epoxy resin or the like. Thereby, moisture, dust, etc. can be prevented from entering the gap, and the reliability of the inkjet head 10 can be kept high.

Finally, as shown in a simplified manner in FIGS. 2 and 3, the flexible wiring board (not shown) on which the drive control circuit 40 such as a driver IC is mounted includes the terminal portions 31 b of the individual electrodes 31 and the cavity board 2. It is connected to the common electrode 28 provided on the top using a conductive adhesive or the like.
Thus, the ink jet head 10 is completed.

Next, the operation of the inkjet head 10 configured as described above will be described.
The ink is filled from the reservoir 23 to the tip of the nozzle hole 11 of the nozzle substrate 1 without generating bubbles in each ink flow path.
When performing printing, when a nozzle is selected by a drive control circuit 40 such as a driver IC and a predetermined pulse voltage is applied between the diaphragm 22 and the individual electrode 31, electrostatic attraction is generated, and the diaphragm 22 The individual electrode 31 is attracted toward the individual electrode 31 to bend and contact the individual electrode 31 to generate a negative pressure in the pressure chamber 21. As a result, the ink in the reservoir 23 is sucked into the pressure chamber 21 through the orifice 26 to generate ink vibration (meniscus vibration). When the voltage is released when the vibration of the ink becomes substantially maximum, the vibration plate 22 is detached from the individual electrode 31, and the ink is pushed out from the nozzle hole 11 by the restoring force of the vibration plate 22 at that time. The ink is discharged toward a recording sheet (not shown).

Next, a manufacturing method of the inkjet head 10 will be described here with reference to FIGS. 4 to 10 mainly about a manufacturing method of the nozzle substrate 1.
As a method for manufacturing the nozzle substrate, two manufacturing methods will be described here.

<Nozzle substrate 1 manufacturing method 1>
The manufacturing method 1 of the nozzle substrate 1 is a manufacturing method in which a doped polysilicon layer is formed on a film-forming substrate, and nozzle holes are formed in the doped polysilicon layer to form a nozzle substrate.

  4-7 is a figure which shows the manufacturing method 1 of a nozzle substrate. The nozzle substrate manufacturing method 1 will be described below with reference to FIGS.

(A) First, a sacrificial layer 101 (for example, a SiN film) is formed on the film formation substrate 100 by sputtering or CVD (film thickness is several hundred nm to several μm). Note that the film formation substrate 100 is a substrate that can withstand an annealing process, which will be described later, and here, for example, quartz, Si, or SiC is used as a material having heat resistance to a temperature of 1000 ° C. or higher. The sacrificial layer 101 may be made of SiO ₂ or DLC (diamond-like carbon) in addition to SiN.
(B) Next, a doped polysilicon layer 102 doped with phosphorus and serving as a nozzle substrate base material is formed on the sacrificial layer 101 to a thickness of, for example, 60 μm. The doped polysilicon layer 102 is formed by using low pressure CVD while adding phosphine (Ph ₃ ) to a silane-based gas (SiH ₄ ). The film is formed under the conditions of a SiH ₄ flow rate during film formation of 200 cm ³ / min (sccm), a temperature of 600 ° C. to 650 ° C., and a chamber pressure of 1 to 10 Pa. Thereafter, annealing is performed at 900 ° C. to 1000 ° C. In this manner, the internal stress can be relieved by performing the annealing, the warp of the doped polysilicon layer 102 can be prevented, and the peeling from the deposition substrate 100 can be prevented.

(C) To form an etching mask (for example, SiO ₂ film) 103 of 1 μm, for example, on the doped polysilicon layer 102 using CVD or sputtering, and to form a nozzle shape on the etching mask 103 using photolithography. A two-stage shape is created.
(D) Next, the first nozzle portion 11 a of the nozzle hole 11 is formed in the doped polysilicon layer 102 by performing anisotropic dry etching of the opening of the etching mask 103 vertically by a Bosch process using Deep-RIE. To do. At this time, dry etching stops at the sacrificial layer 101. Thereby, it is possible to produce the nozzle shape with high accuracy. That is, in the conventional thinning by grinding, there is a possibility that chipping may occur at the discharge-side nozzle edge portion, but dry etching does not cause such inconvenience and can be manufactured with high accuracy.
In the Bosch process, for example, C ₄ F ₈ (fluorocarbon) and SF ₆ (sulfur fluoride) are used as etching gases, and these etching gases are used alternately. Here, C ₄ F ₈ is used to protect the side surface of the first nozzle portion 11a so that etching does not proceed in the direction of the side surface of the first nozzle portion 11a, and SF ₆ is used to protect the first nozzle portion 11a. Used to facilitate vertical etching.

(E) Next, in the etching mask 103, for example, hydrogen fluoride such as BHF (Buffered Hydrogen Fluoride) so that only the portion 103a that becomes the second nozzle portion 11b of the nozzle hole 11 is eliminated. Half-etch with an acid (HF) -based etchant.
(F) Then, the opening of the etching mask 103 is anisotropically dry-etched perpendicularly to a depth of 20 μm, for example, by Deep-RIE again to form the second nozzle portion 11b.
(G) Using BHF, the outermost etching mask 103 is removed by wet etching.

(H) On the doped polysilicon layer 102, for example, an SiO ₂ film is formed as an ink resistant film (discharge liquid protective film) 104 by CVD or sputtering. Then, a support substrate 120 made of a transparent material such as glass is attached to one side of the doped polysilicon layer 102, that is, the side (joint surface) 102a on the side to be joined to the cavity substrate 2 through the double-sided adhesive sheet 50. . This double-sided adhesive sheet 50 is a sheet provided with a UV foaming self-peeling layer 51 (self-peeling type sheet), has an adhesive surface on both sides thereof, and further comprises a self-peeling layer 51 on one side thereof, The self-peeling layer 51 has an adhesive force that is reduced by stimuli such as ultraviolet rays or heat.
In this way, the surface 50a consisting only of the adhesive surface of the double-sided adhesive sheet 50 faces the surface of the support substrate 120, and the surface 50b of the double-sided adhesive sheet 50 provided with the self-peeling layer 51 is the surface of the doped polysilicon layer 102. The bonding surfaces 102a face each other, and these surfaces are bonded together under a reduced pressure environment (10 Pa or less), for example, in a vacuum. By doing so, no bubbles remain at the bonding interface, and clean bonding is possible. Further, since it is only necessary to bond the doped polysilicon layer 102 and the support substrate 120 through the double-sided adhesive sheet 50, when the double-sided adhesive sheet 50 is separated from the doped polysilicon layer 102, No cracking or chipping occurs.

  In the above description, the case where the self-peeling layer 51 is provided only on one surface 50b of the double-sided adhesive sheet 50 is shown, but the self-peeling layer 51 is provided on both surfaces 50a and 50b of the double-sided adhesive sheet 50. It may be a thing.

(I) Next, the sacrificial layer 101 is wet-etched with hot phosphoric acid, and the doped polysilicon layer 102 is peeled off from the deposition substrate 100.
In this way, when the doped polysilicon layer 102 is peeled from the deposition substrate 100, the sacrificial layer 101 may be wet-etched, that is, the entire substrate may be immersed in an etching solution. Because the wafers can be processed together).
(J) An SiO ₂ film, for example, is formed as an ink-resistant film (discharge liquid protective film) 105 on the ink discharge side surface (discharge surface) 102b of the doped polysilicon layer 102 by a sputtering apparatus. Here, the ink-resistant film 105 may be formed at a temperature (about 200 ° C.) or less at which the double-sided adhesive sheet 50 does not deteriorate, and is not limited to the sputtering method. However, in consideration of ink resistance and the like, it is necessary to form a dense film, and it is desirable to use an apparatus capable of forming a dense film at room temperature, such as an ECR sputtering apparatus.
(K) Next, the ink-repellent treatment is further performed on the ejection surface 102 b of the doped polysilicon layer 102. In this case, an ink repellent material containing a fluorine-containing organosilicon compound as a main component is formed by vapor deposition or dipping to form an ink repellent film (liquid repellent film) 106. At this time, the inner walls of the first nozzle portion 11a and the second nozzle portion 11b are also subjected to ink repellent treatment. A material containing a fluorine-containing organosilicon compound as a main component has good ink repellency and has an advantage that it can be easily formed by dipping.

(L) Next, the dicing tape 60 is attached as a support tape to the ejection surface 102b that has been subjected to the ink repellent treatment.
(M) Next, UV light is irradiated from the support substrate 120 side.
(N) Thus, the self-peeling layer 51 of the double-sided adhesive sheet 50 is peeled off from the bonding surface 102 a of the doped polysilicon layer 102, and the support substrate 120 is removed from the doped polysilicon layer 102.
(O) Next, ink repellent formed excessively on the bonding surface 102a side of the doped polysilicon layer 102 and the inner walls of the first nozzle portion 11a and the second nozzle portion 11b by Ar sputtering or O ₂ plasma treatment. The film 106 is removed.
As a result, the ink repellent film 106 is formed on the entire discharge surface 102b, and the ink repellent film 106 is not formed on the inner wall of the nozzle hole with the discharge port edge of the nozzle hole 11 as a boundary. That is, since the inner wall of the nozzle hole is hydrophilic and the discharge surface 102b is liquid repellent up to the edge of the discharge port of the nozzle hole 11, it is possible to obtain good discharge characteristics with no ink remaining on the discharge surface 102b and no flying curvature. It becomes possible.

(P) Next, the bonding surface 102a of the doped polysilicon layer 102 is suction-fixed to the suction jig 70, and the dicing tape 60 attached as a support tape to the discharge surface 102b is peeled off.

(Q) Finally, the suction fixing of the suction jig 70 is released, and the nozzle substrate 1 composed of the doped polysilicon layer 102 is recovered.

<Manufacturing method 2 of nozzle substrate 1>
The manufacturing method 2 of the nozzle substrate 1 is a manufacturing method in which an amorphous silicon layer is formed on a film-forming substrate and nozzle holes are formed in the amorphous silicon layer to form a nozzle substrate.

  8-10 is a figure which shows the manufacturing method 2 of a nozzle substrate. Hereinafter, the nozzle substrate manufacturing method 2 will be described with reference to FIGS.

(A) First, an amorphous silicon layer 201 serving as a nozzle substrate base material is formed on a film formation substrate 200 by film formation with a thickness of, for example, 60 μm using low pressure CVD. Note that since the amorphous silicon layer 201 can be formed at a low temperature (eg, 500 ° C.), for example, an inexpensive borosilicate glass (heat-resistant temperature, eg, 700 ° C.) can be used for the deposition substrate 200. Quartz or the like may be used. The amorphous silicon layer 201 is formed using low pressure CVD while adding phosphine to a silane-based gas (Si ₂ H ₆ ). The film is formed under the conditions of a SiH ₄ flow rate during film formation of 300 cm ³ / min (sccm), a temperature of 500 ° C. to 550 ° C., and a chamber pressure of 1 to 10 Pa.
(B) Next, an etching mask (for example, SiO ₂ film) 202 is formed on the amorphous silicon layer 201 by CVD or sputtering, for example, with a thickness of 1 μm, and a nozzle shape is formed on the etching mask 202 by using photolithography. To create a two-stage shape.
(C) Next, an opening of the etching mask 202 is anisotropically dry-etched vertically by a Bosch process using Deep-RIE to form the first nozzle portion 11 a of the nozzle hole 11 in the amorphous silicon layer 201. At this time, dry etching stops on the film formation substrate 200. Thereby, it is possible to produce the nozzle shape with high accuracy. That is, in the conventional thinning by grinding, there is a possibility that chipping may occur at the discharge-side nozzle edge portion, but dry etching does not cause such inconvenience and can be manufactured with high accuracy.
In the Bosch process, for example, C ₄ F ₈ (fluorocarbon) and SF ₆ (sulfur fluoride) are used as etching gases, and these etching gases are used alternately. Here, C ₄ F ₈ is used to protect the side surface of the first nozzle portion 11a so that etching does not proceed in the direction of the side surface of the first nozzle portion 11a, and SF ₆ is used to protect the first nozzle portion 11a. Used to facilitate vertical etching.

(D) Next, in the etching mask 202, hydrogen fluoride such as BHF (Buffered Hydrogen Fluoride) is used so that only the portion 202a that becomes the second nozzle portion 11b of the nozzle hole 11 is eliminated. Half-etch with an acid (HF) -based etchant.
(E) Then, the opening of the etching mask 202 is again anisotropically dry etched to a depth of, for example, 20 μm by Deep-RIE to form the second nozzle portion 11b.
(F) Using BHF, the outermost etching mask 202 is removed by wet etching.

(G) On the amorphous silicon layer 201, for example, an SiO ₂ film is formed as an ink resistant film (discharge liquid protective film) 203 by CVD or sputtering.
(H) Next, the support substrate 120 made of a transparent material such as glass is disposed on one surface of the amorphous silicon layer 201, that is, the surface (bonding surface) 201a on the side bonded to the cavity substrate 2 with the double-sided adhesive sheet 50 interposed therebetween. paste. This double-sided adhesive sheet 50 is a sheet provided with a UV foaming self-peeling layer 51 (self-peeling type sheet), has an adhesive surface on both sides thereof, and further comprises a self-peeling layer 51 on one side thereof, The self-peeling layer 51 has an adhesive force that is reduced by stimuli such as ultraviolet rays or heat.
In this way, the surface 50a consisting only of the adhesive surface of the double-sided adhesive sheet 50 faces the surface of the support substrate 120, and the surface 50b of the double-sided adhesive sheet 50 provided with the self-peeling layer 51 is the bonding surface of the amorphous silicon layer 201. These surfaces are bonded to each other in a vacuum environment (10 Pa or less), for example, in a vacuum. By doing so, no bubbles remain at the bonding interface, and clean bonding is possible. Further, since the amorphous silicon layer 201 and the support substrate 120 need only be bonded together via the double-sided adhesive sheet 50, the amorphous silicon layer 201 is cracked or chipped when the double-sided adhesive sheet 50 is separated from the amorphous silicon layer 201. There is no.

  In the above description, the case where the self-peeling layer 51 is provided only on one surface 50b of the double-sided adhesive sheet 50 is shown, but the self-peeling layer 51 is provided on both surfaces 50a and 50b of the double-sided adhesive sheet 50. It may be a thing.

Then, laser light is irradiated from the film formation substrate 200 side toward the amorphous silicon layer 201.
(I) Thereby, a part of the amorphous silicon layer 201 becomes polysilicon, and the amorphous silicon layer 201 is peeled off from the deposition substrate 200.
As described above, in the manufacturing method 2 of the nozzle substrate, when the amorphous silicon layer 201 that is the nozzle substrate base material is peeled off from the deposition substrate 200, it is only necessary to irradiate the laser. There are the following advantages. That is, in the manufacturing method 1 described above, since wet etching is used, a material having etching resistance is required for the deposition substrate 100, the ink resistant films 104 and 105, and the support substrate 120, and the etching takes a long time. It was necessary. However, since the manufacturing method 2 of the nozzle substrate does not use an etching solution, the degree of freedom of material selection for each of the members (the film formation substrate 100, the ink resistant films 104 and 105, and the support substrate 120) can be improved.

  After the support substrate 200 is peeled off, the same steps as in (J) to (Q) of the manufacturing method 1 are performed to obtain the nozzle substrate 1.

Next, the bonding surface of the cavity substrate 2 is bonded to the bonding surface of the nozzle substrate 1 manufactured by the above manufacturing methods 1 and 2 (the bonding process is not shown).
By passing through the above process, the bonded body of the nozzle substrate 1 and the cavity substrate 2 is formed.

Thereafter, in the joined body composed of the nozzle substrate 1 and the cavity substrate 2, the joining surface of the electrode substrate 3 is attached to the other joining surface of the cavity substrate 2 (the joining process is not shown).
By passing through the above process, the joined body of the nozzle substrate 1, the cavity substrate 2, and the electrode substrate 3 is formed, and the inkjet head 10 is completed.

The method for manufacturing a nozzle substrate according to the present embodiment has the following effects.
<Effect common to Manufacturing Method 1 and Manufacturing Method 2>
(1) Since the nozzle substrate is formed by film formation, it is only necessary to form a film having a required thickness (for example, 50 μm to 70 μm).
(2) Since the plate thickness of the nozzle substrate is determined by the film thickness by film formation, the accuracy of the plate thickness and nozzle length is improved as compared with the case where the plate thickness is controlled by grinding. The plate thickness accuracy by grinding is on the order of microns, whereas in the case of film formation, sub-micron order is possible, and the plate thickness can be controlled with a single digit and high accuracy.
(3) By doping phosphorus, doped polysilicon or amorphous silicon can be formed while relaxing the stress, and the film can be formed to a film thickness sufficient to constitute a nozzle substrate.

(4) Since the etching is stopped at the sacrificial layer 101 or the film formation substrate 200 when forming the first nozzle portion 11a, chipping of the discharge-side nozzle edge portion, etc., which has occurred in the conventional thinning by grinding, etc. The nozzle shape and nozzle length can be configured with high accuracy.
(5) Since there is no grinding process, there is no clogging of foreign matter into the nozzle hole, and the cleaning process can be omitted. In addition, it is possible to prevent a decrease in yield due to foreign matter.
(6) Since doped polysilicon or amorphous silicon is used for the nozzle substrate, it can be manufactured at a lower cost than when single crystal silicon is used.
(7) Since the discharge liquid protective film is formed on all surfaces that come into contact with the discharge liquid, durability against the discharge liquid can be improved.
(8) Since the inner wall of the nozzle hole is hydrophilic and the discharge surface is water-repellent up to the discharge port edge of the nozzle hole, it is possible to obtain good discharge characteristics with no droplet remaining on the discharge surface and no flight bending.

<Special effects of production method 1>
(1) By performing the annealing step, the internal stress in the doped polysilicon layer 102 can be further relaxed, and the warp of the doped polysilicon layer 102 can be prevented.
(2) When the doped polysilicon layer 102 is peeled from the deposition substrate 100, the sacrificial layer 102 may be wet-etched, that is, the entire substrate may be immersed in an etching solution, so that it is easy and low cost. (Because a plurality of wafers can be processed together).

<Specific effects of production method 2>
(1) Since the amorphous silicon layer 201 can be formed at a low temperature by low pressure CVD, inexpensive borosilicate glass can be used as the deposition substrate 200 instead of expensive quartz.
(2) Since laser irradiation is used to peel the amorphous silicon layer 201 from the deposition substrate 200, the processing time can be shortened compared to the peeling method using the sacrificial layer etching in the manufacturing method 1, and a large area substrate can be peeled off. is there. In addition, since an etching solution is not used, the degree of freedom in selecting materials for the deposition substrate 200, the ink-resistant film 104, and the support substrate 120 in the water repellent treatment process is improved.

  In the present embodiment, an example in which the nozzle shape is a two-stage shape is shown, but the present invention is not limited to this, and a straight shape without a step may be used.

  In the above embodiment, the nozzle substrate, the inkjet head, and the manufacturing method thereof have been described. However, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the idea of the present invention. it can. For example, by changing the liquid material discharged from the nozzle holes, in addition to the inkjet printer 300 shown in FIG. 11, it is used for manufacturing color filters for liquid crystal displays, forming light emitting portions of organic EL display devices, genetic testing, and the like. It can be used as a droplet discharge device for various uses such as the production of a biomolecule solution microarray. A droplet discharge head and a liquid that can realize good discharge characteristics by mounting the nozzle substrate manufactured by the nozzle substrate manufacturing method of the present embodiment on a droplet discharge head (inkjet head) and a droplet discharge device 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. FIG. 2 is a partial cross-sectional view of an inkjet head showing a schematic configuration of a right half of FIG. FIG. 3 is a top view of the ink jet head of FIG. 2. The fragmentary sectional view which shows the manufacturing process 1 of a nozzle substrate. The fragmentary sectional view which shows the manufacturing process following FIG. FIG. 6 is a partial cross-sectional view illustrating a manufacturing process subsequent to FIG. 5. FIG. 7 is a partial cross-sectional view illustrating a manufacturing process following FIG. 6. The fragmentary sectional view which shows the manufacturing process 2 of a nozzle substrate. FIG. 9 is a partial cross-sectional view illustrating a manufacturing process following FIG. 8. FIG. 10 is a partial cross-sectional view showing the manufacturing process following FIG. 9. 1 is a perspective view of an ink jet printer using an ink jet head according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Nozzle substrate, 10 Inkjet head, 11 Nozzle hole, 21 Pressure chamber, 22 Diaphragm, 28 Common electrode, 31 Individual electrode, 100 Film-forming substrate, 102 Doped polysilicon layer, 102a Bonding surface, 102b Ejection surface, 104 Resistance Ink film (discharge liquid protective film), 105 ink-resistant film (discharge liquid protective film), 106 ink repellent film (liquid repellent film), 200 film formation substrate, 201 amorphous silicon layer, 300 ink jet printer.

Claims (16)

Forming a sacrificial layer on the deposition substrate;
A nozzle substrate base material forming step of forming a doped polysilicon layer doped with phosphorus as a nozzle substrate base material on the sacrificial layer;
A nozzle hole forming step of forming a nozzle hole in the nozzle substrate base material by dry etching;
A method for producing a nozzle substrate, comprising: a peeling step of removing the sacrificial layer by etching to peel the nozzle substrate base material from the film formation substrate.   The method for manufacturing a nozzle substrate according to claim 1, wherein the nozzle substrate base material forming step includes a step of annealing the doped polysilicon layer.   3. The method for manufacturing a nozzle substrate according to claim 2, wherein the film formation substrate is formed of a material having heat resistance against a temperature of 1000 [deg.] C. or more.   4. The method for manufacturing a nozzle substrate according to claim 3, wherein the deposition substrate is made of quartz, silicon, or silicon carbide.   5. The nozzle substrate base material forming step, wherein phosphine is added to a silane-based gas, and the doped polysilicon layer is formed using CVD. A method for manufacturing a nozzle substrate. A nozzle substrate base material forming step of forming an amorphous silicon layer doped with phosphorus as a nozzle substrate base material on the film formation substrate;
A nozzle hole forming step of forming a nozzle hole in the nozzle substrate base material by dry etching;
A peeling step of peeling the nozzle substrate base material from the film-forming substrate;
A method for manufacturing a nozzle substrate, comprising:   The method of manufacturing a nozzle substrate according to claim 6, wherein the peeling step is a step of irradiating the nozzle substrate base material with a laser from the film forming substrate side.   The method for manufacturing a nozzle substrate according to claim 6 or 7, wherein the deposition substrate is made of borosilicate glass.   9. The nozzle according to claim 6, wherein, in the nozzle substrate base material forming step, the amorphous silicon layer is formed by adding phosphine to a silane-based gas and using CVD. A method for manufacturing a substrate.   A nozzle substrate manufactured from the method for manufacturing a nozzle substrate according to claim 1.   11. The nozzle according to claim 10, wherein the nozzle substrate has a discharge liquid protective film on a discharge surface having a discharge port of the nozzle hole, a surface opposite to the discharge surface, and an inner wall of the nozzle hole. substrate.   In the nozzle substrate substrate, a liquid repellent film is formed on the entire discharge surface on the discharge liquid protective film, and the inner wall of the nozzle hole and the surface on the opposite side are repelled with the discharge port edge of the nozzle hole as a boundary. The nozzle substrate according to claim 11, wherein a liquid film is not formed.   The nozzle substrate according to claim 12, wherein the liquid repellent film contains a fluorine-containing organosilicon compound as a main component.   A liquid droplet ejection head comprising the nozzle substrate according to claim 10. A plurality of nozzle holes for discharging droplets, a pressure chamber provided in communication with each nozzle hole to apply pressure to the droplets, a droplet supply path for supplying droplets to the pressure chambers, A method of manufacturing a droplet discharge head having pressure generating means for generating a discharge pressure in the pressure chamber for discharging a droplet,
A method for manufacturing a droplet discharge head, wherein the nozzle substrate having the plurality of nozzle holes is manufactured by the method for manufacturing a nozzle substrate according to any one of claims 1 to 8.   A liquid droplet ejection apparatus comprising the liquid droplet ejection head according to claim 13.

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