JP2009166449A - Manufacturing method of nozzle substrate, nozzle substrate, liquid-droplet ejecting head, manufacturing method of liquid-droplet ejecting head and liquid-droplet ejecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle substrate manufacturing method of not forming a nozzle substrate with multi-step structure nozzle holes by thin-plate machining such as grinding, but forming the nozzle substrate by deposition, thereby achieving enhancement in accuracy in substrate-thickness and nozzle-length. <P>SOLUTION: A nozzle substrate base material 110 is formed by depositing a sacrificial layer 101 on a deposition substrate 100, successively and alternatively laminating a phosphorus-doped polysilicon layer and a stop layer on the sacrificial layer 101. Then, a mask layer 105 having n-stepped apertures 105a is formed on the nozzle substrate base material 110, and the nozzle substrate base material 110 is repeatedly etched while successively enlarging each aperture of the mask layer 105 until the etching process is stopped by each stop layer, and finally, the nozzle substrate base material 110 is dry-etched until the etching process is stopped by the sacrificial layer 101 and thus, the nozzle holes are formed. Further, the sacrificial layer 101 is removed by etching, and the nozzle substrate base material 110 is peeled off the deposition substrate 100. <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. Ink jet heads generally include a nozzle plate in which a plurality of nozzle holes for discharging ink droplets are formed, and an ink in a discharge chamber, a reservoir, or the like that is joined to the nozzle plate and communicates with the nozzle holes. And a cavity plate in which a flow path is formed, and an ink droplet is ejected from a selected nozzle hole by applying pressure to the ejection chamber by a driving unit. As a driving means, there are a method using an electrostatic force, a piezoelectric method using a piezoelectric element, a bubble jet (registered trademark) method using a heating element, and the like.
In recent years, there has been an increasing demand for high quality printing, image quality, and the like for inkjet heads, and thus there is a strong demand for higher density and improved ejection performance. Against this background, various devices and proposals have been made for the nozzle portion of an inkjet head.

  In order to improve the ink ejection characteristics, it is desirable to adjust the flow path resistance at the nozzle hole and adjust the thickness of the substrate so that the nozzle length becomes the optimum length. Also, the nozzle shape is not a cylindrical nozzle hole as a whole, but a multistage structure (a structure having a plurality of holes with different diameters on the same axis and having a plurality of steps (for example, different diameters). There is also a method of improving the ejection characteristics by aligning the direction of the ink pressure applied to the nozzle in the nozzle axis direction with a two-stage nozzle shape comprising a first nozzle portion and a second nozzle portion)).

  As described above, as a nozzle plate manufacturing method in which the nozzle shape is a multistage structure or the nozzle length is adjusted, anisotropic dry etching using ICP discharge is performed from one side of the Si substrate, After forming the first nozzle portion and the second nozzle portion different from each other to form the nozzle holes in two stages, a part of the surface opposite to the one surface is anisotropically etched and dug down, A method in which the nozzle length is adjusted (see, for example, Patent Document 1), or after the Si substrate is polished in advance to a desired thickness, dry etching is performed on both sides of the Si substrate, respectively, There is a method of forming two nozzle portions (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 11-28820 Japanese Patent Laid-Open No. 9-57981

  However, as described in Patent Documents 1 and 2, when the adjustment of the nozzle length is performed by thinning the substrate such as grinding or etching, thickness variation in the wafer surface or thickness variation between wafers occurs. In other words, since the nozzle length varies, there is a problem that the ejection performance varies, and the yield decreases.

  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 thickness required as the nozzle substrate base material, it takes a grinding time, and when the area becomes large, it becomes difficult to cut uniformly in the surface. As a result, there has been a problem that the substrate thickness varies.

  The present invention has been made in view of the above points, and by forming a nozzle substrate having a nozzle hole having a multi-stage structure not by thinning processing such as grinding, but by forming a film, the thickness / nozzle It is an object of the present invention 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 capable of improving the accuracy of length.

The method for manufacturing a nozzle substrate according to the present invention includes a nozzle having n-stage (n is a natural number of 2 or more) multi-stage nozzle holes whose opening cross section gradually increases from the front end side to the rear end side in the ejection direction. A method for manufacturing a substrate, comprising: a sacrificial layer forming step for forming a sacrificial layer on a film forming substrate; and forming a doped polysilicon layer doped with phosphorus on the sacrificial layer; A nozzle that forms a nozzle substrate substrate by repeatedly forming a stop layer on a silicon layer n-1 times, and then forming an n-th doped polysilicon layer doped with phosphorus on the surface. Substrate base material forming step, and mask layer for forming a mask layer having n stepped openings on the nozzle substrate base material, the opening cross-sectional area of which gradually decreases from the surface side to the nozzle substrate base material side Forming process and nozzle substrate base material The nozzle substrate substrate is dry-etched on the portion of the doped polysilicon layer exposed from the opening of the mask layer until the etching stops at the stop layer formed immediately below the doped polysilicon layer. In the stopped stop layer, an etching process is performed to etch and remove the exposed portion of the doped polysilicon layer formed immediately above the stop polysilicon layer, and simultaneously expand the opening of the mask layer to the next stage. A nozzle hole forming step of forming a nozzle hole by dry etching until the nozzle substrate base material is etched with the sacrificial layer, and removing the sacrificial layer by etching to remove the nozzle substrate base material from the film forming substrate. And a peeling step for peeling.
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 addition, since the stop layer is provided in the portion of the nozzle hole where the step is to be etched, the multi-stage structure of the nozzle hole can be easily formed with high accuracy.

Moreover, the manufacturing method of the nozzle substrate according to the present invention includes a step of annealing each time the nozzle substrate base material forming step forms a doped polysilicon layer.
Thereby, internal stress can be relieved and warpage can be prevented when the nozzle substrate base material is formed as a laminated structure of doped polysilicon.

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.

The method for manufacturing a nozzle substrate according to the present invention is to add a phosphine to a silane-based gas and form a doped polysilicon layer using CVD.
Thereby, a doped polysilicon layer can be formed while relaxing the stress.

The method for manufacturing a nozzle substrate according to the present invention includes a nozzle having n-stage (n is a natural number of 2 or more) multi-stage nozzle holes whose opening cross section gradually increases from the front end side to the rear end side in the ejection direction. A method of manufacturing a substrate, wherein after forming an amorphous silicon layer doped with phosphorus on a deposition substrate, a step of forming a stop layer on the amorphous silicon layer is repeated n-1 times, and then the surface thereof In addition, a nozzle substrate base material forming step of forming an nth amorphous silicon layer doped with phosphorus to form a nozzle substrate base material, and on the nozzle substrate base material, from the surface side to the nozzle substrate base material side A mask layer forming step of forming a mask layer having an n-step staircase opening having a reduced opening cross-sectional area, and an amorphous portion of the nozzle substrate substrate exposed from the opening of the mask layer The nozzle substrate substrate is dry-etched until the etching is stopped at the stop layer formed immediately below the amorphous silicon layer, and then the amorphous silicon formed immediately above the stop layer where the etching is stopped. Etching is performed on the portion exposed from the layer to remove it, and at the same time, the etching process for expanding the opening of the mask layer to the next stage is repeated n-1 times, and finally the etching is stopped at the sacrificial layer on the nozzle substrate base material. A nozzle hole forming step for forming a nozzle hole by dry etching until a nozzle substrate base material is peeled off 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 addition, since the stop layer is provided in the portion of the nozzle hole where the step is to be etched, the multi-stage structure of the nozzle hole can be easily formed with high accuracy.

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.

The method for manufacturing a nozzle substrate according to the present invention is to add an phosphine to a silane-based gas and form an amorphous silicon layer using CVD.
Thereby, an amorphous silicon layer can be formed while relaxing the stress.

In the nozzle substrate manufacturing method according to the present invention, the sacrificial layer is made of SiN.
SiN can be easily formed and peeled off.

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 liquid 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 has an n-stage (n is a natural number of 2 or more) multi-stage structure in which the opening cross section gradually increases from the front end side to the rear side in the ink ejection direction. Have. In this example, a two-stage multi-stage structure formed by two cylindrical nozzle holes having different opening diameters is illustrated. Hereinafter, the first nozzle portion 11a and the second nozzle are sequentially arranged from the front end side in the discharge direction. It is called part 11b. Thus, by making the nozzle hole 11 into a multi-stage structure, the discharge direction of ink droplets can be aligned with the central axis direction of the nozzle hole 11, and stable ink discharge 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.

  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 deposition substrate by film formation, and the nozzle substrate is formed from the doped polysilicon layer.

  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. Here, a method for manufacturing a nozzle substrate having the nozzle holes having the two-stage structure shown in FIG. 1 will be described.

(A) First, a sacrificial layer (for example, SiN film) 101 is formed on the film formation substrate 100 with a thickness of, for example, 1 μm using sputtering or CVD. 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. Here, the sacrificial layer 101 is made of SiN that can be easily formed and peeled off. However, for example, SiO ₂ or DLC (diamond-like carbon) may be used in addition to SiN.

(B) Next, on the sacrificial layer 101, a first doped polysilicon layer 102 doped with phosphorus, which becomes a nozzle substrate base material, is formed to a thickness of, for example, 40 μm by using low pressure CVD. The first doped polysilicon layer 102 is a layer for forming the first nozzle portion 11a. The first doped polysilicon layer 102 is formed 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 first doped polysilicon layer 102 can be prevented, and the peeling from the deposition substrate 100 can be prevented.

(C) A stop layer 103 is formed on the first doped polysilicon layer 102. This stop layer 103 is a layer formed for the purpose of stopping the processing when nozzle holes are processed in the second doped polysilicon layer 104 described later. Here, the stop layer 103 is made of SiO ₂ and has a thickness of, for example, about several hundred nm to 1 μm.
The formation of the doped polysilicon layer (B) and the stop layer (C) are repeated n-1 times, where n is the number of stages of the nozzle holes 11. Here, since n = 2, the steps (B) and (C) are performed only once.

(D) Next, a second doped polysilicon layer 104 doped with phosphorus is formed on the stop layer 103 by low pressure CVD. The second doped polysilicon layer 104 is a layer for processing the second nozzle portion 11b. The thickness of the second doped polysilicon layer 104 is determined in consideration of the nozzle length, and is formed with a thickness of 20 μm, for example. Further, it is formed under the same film formation conditions as those for the first doped polysilicon layer 102.
The first doped polysilicon layer 102, the stop layer 103, and the second doped polysilicon layer 104 formed as described above constitute a nozzle substrate base 110.

(E) A mask layer 105 is formed on the second doped polysilicon layer 104. The mask layer 105 serves as an etching mask for processing the nozzle holes 11 in the nozzle substrate base 110, and is formed to a thickness of 1 μm, for example. Here, the mask layer 105 is composed of the same SiO ₂ film as the stop layer 103. In forming the nozzle hole 11, since dry etching such as RIE and wet etching such as BHF are used, the mask layer 105 is preferably composed of an SiO ₂ film.
(F) A stepped opening 105a for forming a nozzle shape is formed in the mask layer 105 using photolithography. That is, n-step (here, n = 2) step-like openings 105a whose opening cross-sectional area gradually decreases from the surface side toward the nozzle substrate base 110 side are formed.

(G) The opening of the mask layer 105 is anisotropically dry etched vertically by dry etching using ICP (Inductively Coupled Plasma), and the second nozzle portion of the nozzle hole 11 is formed in the second doped polysilicon layer 104. An opening 104a to be 11a is formed. At this time, dry etching stops at the stop layer 103.
(H) Wet etching is performed with a hydrofluoric acid (HF) -based etchant such as BHF (Buffered Hydrogen Fluoride), and the stop layer 103 is opened. That is, in the stop layer 103, the portion exposed from the second doped polysilicon layer 104 immediately above is etched and removed. At this time, the mask layer 105 is also etched in the same manner, and the etching is stopped when the second doped polysilicon layer 104 is reached. As a result, in the mask layer 105, the opening of the portion where the second doped polysilicon layer 104 is exposed is expanded to the next stepped portion, that is, the portion 105b corresponding to the second nozzle portion 11b. . The wet etching here may be performed in place of dry etching by RIE.
The dry etching of the doped polysilicon layer (G) and the etching of the stop layer and the mask layer (H) are repeated n-1 times when the number of nozzle holes 11 is n. Here, since n = 2, the steps (G) and (H) are performed only once.

(I) Next, similarly to (G) above, the opening of the mask layer 105 is anisotropically dry etched vertically by ICP dry etching to form the first nozzle portion 11a and the second nozzle portion 11b. To do. At this time, etching is stopped at the sacrificial layer 101 for the first doped polysilicon layer 102 and at the stop layer 103 for the second doped polysilicon layer 104. Further, the mask layer 105 is also etched in the same manner as in the step (G) or (H).
(J) Using BHF, the outermost mask layer 105 is removed by wet etching.

  Here, as described in the steps (G) to (I), the mask layer 105 is etched and thinned gradually during dry etching or wet etching. Therefore, it is assumed that the thickness of each step of the mask layer 105 is set so that the surface of the second doped polysilicon layer 104 is not exposed when it should function as a mask.

(K) On the surface of the nozzle substrate base 110, for example, an SiO ₂ film is formed as an ink resistant film (discharge liquid protective film) 106 by CVD or sputtering.
(L) Then, the surface of the second doped polysilicon layer 104, that is, the surface (bonding surface) 110 a on the nozzle substrate base 110 that is bonded to the cavity substrate 2 is bonded to the glass via the double-sided adhesive sheet 50. A support substrate 120 made of a transparent material such as is attached. 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 second doped polysilicon. Facing the surface of the layer 104, these surfaces are bonded together under reduced pressure (10 Pa or less), for example, in a vacuum. By doing so, no bubbles remain at the bonding interface, and clean bonding is possible. In addition, since the second doped polysilicon layer 104 and the support substrate 120 need only be bonded together via the double-sided adhesive sheet 50, the second double-sided adhesive sheet 50 is separated from the second doped polysilicon layer 104. The second doped polysilicon layer 104 is not cracked or chipped.

  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.

(M) Next, the sacrificial layer 101 is wet-etched with hot phosphoric acid, and the nozzle substrate base 110 is peeled from the deposition substrate 100.
In this way, when the nozzle substrate base 110 is peeled from the film formation substrate 100, the sacrificial layer 101 may be wet-etched, that is, the entire substrate may be immersed in an etching solution. Can be processed together).
(N) A SiO ₂ film, for example, is formed as an ink resistant film (discharge liquid protective film) 107 on the surface (discharge surface) 110b on the ink discharge side of the nozzle substrate 110 with a sputtering apparatus. Here, the ink-resistant film 107 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.
(O) Next, an ink repellent treatment is further performed on the ejection surface 110 b of the nozzle substrate base 110. 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) 108. 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.

(P) Next, the dicing tape 60 is attached as a support tape to the ejection surface 110b that has been subjected to the ink repellent treatment.
(Q) Next, UV light is irradiated from the support substrate 120 side.
(R) In this way, the self-peeling layer 51 of the double-sided adhesive sheet 50 is peeled off from the bonding surface 110a of the nozzle substrate base 110, and the support substrate 120 is removed from the nozzle substrate base 110.
(S) Next, an ink repellent film formed excessively on the bonding surface 110a side of the nozzle substrate base 110 and the inner walls of the first nozzle portion 11a and the second nozzle portion 11b by Ar sputtering or O ₂ plasma treatment. 108 is removed.
As a result, the ink repellent film 108 is formed on the entire discharge surface 110b, and the ink repellent film 108 is not formed on the inner wall of the nozzle hole with the discharge port edge portion of the nozzle hole 11 as a boundary. That is, since the inner wall of the nozzle hole is hydrophilic and the discharge surface 110b is liquid repellent up to the discharge port edge of the nozzle hole 11, there is no ink remaining on the discharge surface 110b, and good discharge characteristics with no flight bending can be obtained. It becomes possible.

(T) Next, the bonding surface 110a of the nozzle substrate 110 (the surface located on the opposite side of the discharge surface 110b to which the dicing tape 60 is attached) is sucked and fixed to the suction jig 70, and is attached to the discharge surface 110b. The dicing tape 60 attached as the support tape is peeled off.

(U) Finally, the suction fixing of the suction jig 70 is released, and the nozzle substrate 1 composed of the nozzle substrate base 110 is collected.

<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 the nozzle substrate is formed from the amorphous silicon layer.

  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. Here, a method for manufacturing a nozzle substrate having the nozzle holes having the two-stage structure shown in FIG. 1 will be described.

(A) First, a first amorphous silicon layer 201 doped with phosphorus, which serves as a nozzle substrate base material, is deposited on the deposition substrate 200 to a thickness of, for example, 40 μm using low pressure CVD. Note that since the first 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.) is used for the deposition substrate 200. Can do. Quartz or the like may be used. The first 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, a stop layer 202 is formed on the first amorphous silicon layer 201. The stop layer 202 is a layer formed for the purpose of stopping processing when nozzle holes are processed in a second amorphous silicon layer 203 described later. Here, the stop layer 202 is made of SiO ₂ and has a thickness of, for example, about several hundred nm to 1 μm.
The formation of the doped polysilicon layer (A) and the stop layer (B) are repeated n-1 times, where n is the number of stages of the nozzle holes 11. Here, since n = 2, the steps (A) and (B) are performed only once.

(C) Next, a second amorphous silicon layer 203 doped with phosphorus is formed on the stop layer 202 by low pressure CVD. The second amorphous silicon layer 203 is a layer for processing the second nozzle portion 11b. The thickness of the second amorphous silicon layer 203 is determined in consideration of the nozzle length, and is, for example, 20 μm here. Further, the first amorphous silicon layer 201 is formed under the same film formation conditions.
The nozzle substrate base 210 is constituted by the first amorphous silicon layer 201, the stop layer 202, and the second amorphous silicon layer 203 formed as described above.

(D) A mask layer 204 is formed on the second amorphous silicon layer 203. The mask layer 204 serves as an etching mask for processing the nozzle holes 11 in the nozzle substrate base 210, and is formed to a thickness of 1 μm, for example. Here, the mask layer 204 is composed of the same SiO ₂ film as the stop layer 103. In forming the nozzle hole 11, the mask layer 204 is preferably composed of a SiO ₂ film in order to perform dry etching such as RIE and wet etching such as BHF.
(E) A stepped opening 204a for forming a nozzle shape is formed in the mask layer 204 using photolithography. That is, n-step (here, n = 2) step-like openings 204a whose opening cross-sectional area gradually decreases from the surface side toward the nozzle substrate base material 210 side are formed.

(F) The opening of the mask layer 204 is vertically anisotropic dry etched by dry etching using ICP (Inductively Coupled Plasma), and the second nozzle portion 11 a of the nozzle hole 11 is formed in the second amorphous silicon layer 203. Opening 203a is formed. At this time, the mask layer 204 is similarly etched. At this time, dry etching stops at the stop layer 202.
(G) The stop layer 202 is opened by wet etching with a hydrofluoric acid (HF) -based etchant such as BHF (Buffered Hydrogen Fluoride). That is, in the stop layer 202, the portion exposed from the second amorphous silicon layer 203 thereon is etched and removed. At this time, the mask layer 204 is similarly etched, and the etching stops when the second amorphous silicon layer 203 is reached. As a result, in the mask layer 204, the opening of the portion where the second amorphous silicon layer 203 is exposed is in a state where it extends to the next step portion, that is, the portion 204b corresponding to the second nozzle portion 11b. Note that the wet etching here may be performed by dry etching by RIE.
The dry etching of the doped polysilicon layer (F) and the etching of the stop layer (G) are repeated n-1 times when the number of nozzle holes 11 is n. Here, since n = 2, the steps (F) and (G) are performed only once.

(H) Next, similarly to the above (F), the opening of the mask layer 204 is anisotropically dry etched vertically by ICP dry etching to form the first nozzle portion 11a and the second nozzle portion 11b. To do. At this time, the etching of the first amorphous silicon layer 201 is stopped by the deposition substrate 200 and the second amorphous silicon layer 203 is stopped by the stop layer 202. Further, the mask layer 204 is also etched in the same manner as in the step (F) or (G).
(I) The uppermost mask layer 204 is removed by wet etching with BHF.

  Here, as described in the above steps (F) to (H), the mask layer 204 is etched and gradually thinned during dry etching or wet etching. Therefore, it is assumed that the thickness of each step of the mask layer 204 is set so that the surface of the second amorphous silicon layer 203 is not exposed when it should function as a mask.

(J) On the surface of the nozzle substrate base 210, for example, an SiO ₂ film is formed as an ink resistant film (discharge liquid protective film) 205 by CVD or sputtering.
(K) And, on the surface of the second amorphous silicon layer 203, that is, on the surface (joint surface) 210a on the side of the nozzle substrate base 210 that is joined to the cavity substrate 2 through the double-sided adhesive sheet 50, glass or the like A support substrate 120 made of a transparent material is attached. 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 on the side of the double-sided adhesive sheet 50 provided with the self-peeling layer 51 is the second amorphous silicon layer 203. These surfaces are bonded together under reduced pressure (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 second amorphous silicon layer 203 and the support substrate 120 need only be bonded together via the double-sided adhesive sheet 50, the second amorphous silicon layer is separated when the double-sided adhesive sheet 50 is separated from the second amorphous silicon layer 203. The layer 203 is not cracked or chipped.

  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 support substrate 120 side toward the nozzle substrate base 210. (L) Thereby, a part of the first amorphous silicon layer 201 of the nozzle substrate base 210 becomes polysilicon, and the nozzle substrate base 210 is peeled from the film formation substrate 200.
As described above, in the nozzle substrate manufacturing method 2, when the nozzle substrate base material 210 is peeled from the film formation substrate 200, it is only necessary to irradiate the laser, and therefore, the following advantages over the manufacturing method 1 described above. There is. 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 106 and 107, and the support substrate 120, and the etching takes a long time. It was necessary. However, since the nozzle substrate manufacturing method 2 does not use an etching solution, the degree of freedom in selecting materials for the above-described members (the film formation substrate 100, the ink-resistant films 106 and 107, and the support substrate 120) is improved.

  After the support substrate 120 is peeled off, the steps (N) to (U) 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) Since the stop layers 103 and 202 are provided in the step portions of the nozzle holes 11 to stop the etching, the multi-stage structure of the nozzle holes 11 can be easily formed with high accuracy.
(4) 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.
(5) Since the etching is stopped at the sacrificial layer 101 or the film formation substrate 200 when the first nozzle portion 11a is formed, chipping at the discharge-side nozzle edge portion, etc., which has occurred in the conventional thinning by grinding, may occur. No nozzle shape and nozzle length can be configured with high accuracy.
(6) 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.
(7) 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.

(8) 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.
(9) 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 droplets remaining on the discharge surface and no flight deflection.

<Special effects of production method 1>
(1) By performing the annealing step, the internal stress in the first doped polysilicon layer 102 and the second doped polysilicon layer 104 can be relaxed, and each of these doped polysilicon layers 102 and 104 can be relaxed. Can be prevented.
(2) When the nozzle substrate base 110 is peeled from the film formation substrate 100, the sacrificial layer 101 may be wet-etched, that is, the entire substrate may be immersed in an etching solution. A plurality of wafers can be processed together).
(3) Since quartz used as the film formation substrate 100 is expensive, it is desired to reuse it repeatedly. However, since wet etching of the sacrificial layer 101 is used for peeling from the nozzle substrate base 110, Damage to the film formation substrate 100 can be suppressed, and the film formation substrate 100 can be reused.

<Specific effects of production method 2>
(1) Since low-temperature film formation is possible by low pressure CVD, inexpensive borosilicate glass can be used for the film formation substrate instead of expensive quartz.
(2) Since laser irradiation is used to peel the first amorphous silicon layer 201 of the nozzle substrate base 210 from the deposition substrate 200, the processing time is shortened compared to the peeling method using the sacrificial layer 101 etching in the manufacturing method 1. In addition, the large area substrate can be peeled off. Further, since an etching solution is not used, the degree of freedom in selecting materials for the deposition substrate 100, the ink-resistant film 108, and the support substrate 120 in the water repellent treatment process is improved.

In the above embodiment, an example in which the mask layer and the stop layer are formed of the same material (SiO ₂ ) is shown, but the present invention is not limited to this, and the mask layer is SiO ₂ , the stop layer is SIN, and The sacrificial layer may be a metal film (for example, chromium).

  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, 2 Cavity substrate, 10 Inkjet head, 11 Nozzle hole, 21 Pressure chamber, 22 Vibrating plate, 23 Reservoir, 28 Common electrode, 31 Individual electrode, 100 Film-forming substrate, 101 Sacrificial layer, 102 1st doped Polysilicon layer, 103 stop layer, 104 second doped polysilicon layer, 105 mask layer, 105a opening, 106 ink resistant film (discharge liquid protective film), 107, ink resistant film (discharge liquid protective film), 108 Ink film (liquid repellent film), 110 nozzle substrate, 110a bonding surface, 110b ejection surface, 120 support substrate, 200 film formation substrate, 201 first amorphous silicon layer, 202 stop layer, 203 second amorphous silicon layer 204 mask layer, 204a opening, 210 nozzle substrate, 300 ink Ettopurinta.

Claims (17)

A method of manufacturing a nozzle substrate having n-stage (n is a natural number of 2 or more) multi-stage nozzle holes whose opening cross section gradually increases from the front end side to the rear end side in the discharge direction,
A sacrificial layer film forming step of forming a sacrificial layer on the film formation substrate;
After forming a doped polysilicon layer doped with phosphorus on the sacrificial layer, a step of forming a stop layer on the doped polysilicon layer is repeated n-1 times, and then on the surface. A nozzle substrate base material forming step of forming a nozzle substrate base material by forming an nth doped polysilicon layer doped with phosphorus;
On the nozzle substrate base material, a mask layer forming step of forming a mask layer having an n-stage stepped opening in which the opening cross-sectional area gradually decreases from the surface side toward the nozzle substrate base material side;
In the nozzle substrate base material, the portion of the doped polysilicon layer exposed from the opening of the mask layer is etched until the etching stops at a stop layer formed directly under the doped polysilicon layer. In the stop layer where dry etching is performed and then the etching is stopped, a portion exposed from the doped polysilicon layer formed immediately above is etched and removed, and at the same time, the opening of the mask layer is formed next. A nozzle hole forming step of forming a nozzle hole by repeatedly etching the nozzle substrate base material until the etching is stopped at the sacrificial layer.
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 each time the doped polysilicon layer is formed.   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 method for manufacturing a nozzle substrate according to claim 1, wherein the doped polysilicon layer is formed by adding phosphine to a silane-based gas and using CVD.   The method of manufacturing a nozzle substrate according to claim 1, wherein the sacrificial layer is made of SiN. A method for manufacturing a nozzle substrate having nozzle holes with an n-stage multi-stage structure in which the opening cross section gradually increases from the front end side to the rear end side in the discharge direction,
After forming an amorphous silicon layer doped with phosphorus on the deposition substrate, the step of forming a stop layer on the amorphous silicon layer is repeated n-1 times, and then the surface is doped with phosphorus. Forming a nozzle substrate substrate by forming a second amorphous silicon layer;
On the nozzle substrate base material, a mask layer forming step of forming a mask layer having an n-stage stepped opening in which the opening cross-sectional area gradually decreases from the surface side toward the nozzle substrate base material side;
Dry etching the nozzle substrate substrate until the etching stops at the stop layer formed immediately below the amorphous silicon layer of the amorphous silicon layer exposed from the opening of the mask layer in the nozzle substrate substrate, Thereafter, in the stop layer where the etching is stopped, etching is performed to remove the portion exposed from the amorphous silicon layer formed immediately above the etching layer, and at the same time, the etching step of expanding the opening of the mask layer to the next stage N-1 times, and finally, a nozzle hole forming step of forming a nozzle hole by dry etching until the nozzle substrate substrate is etched with the sacrificial layer, and
A method for producing a nozzle substrate, comprising: a separation step of separating the nozzle substrate base material from the film formation substrate.   The method of manufacturing a nozzle substrate according to claim 7, 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 7 or 8, wherein the deposition substrate is made of borosilicate glass.   10. The method for manufacturing a nozzle substrate according to claim 7, wherein the amorphous silicon layer is formed by adding phosphine to a silane-based gas and using CVD.   A nozzle substrate manufactured from the method for manufacturing a nozzle substrate according to claim 1.   12. The nozzle according to claim 11, 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 12, wherein a liquid film is not formed.   14. The nozzle substrate according to claim 13, 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 11. 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 10.   A liquid droplet ejection apparatus comprising the liquid droplet ejection head according to claim 15.

Images