JP2010149375A - Method for manufacturing nozzle substrate, and method for manufacturing liquid droplet delivering head - Google Patents

Abstract

A method of manufacturing a nozzle substrate and a method of manufacturing a droplet discharge head capable of preventing adhesive residue generated during the manufacturing process are provided.
An uneven shape is formed on an ink protective film 103 formed on the surface of a silicon substrate 100 before a support substrate 110 is attached to a silicon substrate 100 to be a nozzle substrate 1. Then, the support substrate 110 is affixed on the ink protective film 103 on which the uneven shape is formed.
[Selection] Figure 5

Description

  The present invention relates to a method for manufacturing a nozzle substrate having nozzle holes for discharging droplets and a method for manufacturing a droplet discharge head.

  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 substrate in which a plurality of nozzle holes for discharging ink droplets are formed, and ink such as a pressure chamber and a reservoir that are joined to the nozzle substrate and communicate with the nozzle holes. And a cavity substrate on which a flow path is formed, and an ink droplet is ejected from a selected nozzle hole by applying pressure to the pressure chamber by a driving unit. As the 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 an ink jet head, in order to improve 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. Therefore, as a method of manufacturing a nozzle substrate, a recess that becomes a nozzle hole is previously formed in a silicon substrate in advance, and a support substrate is bonded to the recess forming surface side, and a desired surface is formed from the side opposite to the recess forming surface of the silicon substrate. There has been a method in which grinding is performed until the thickness is reached, and the nozzle holes are penetrated simultaneously with thinning (see, for example, Patent Document 1).

JP 2007-168344 A (pages 6 to 8, FIGS. 4 to 8)

  The method of Patent Document 1 has a problem that adhesive residue is generated on the surface of the silicon substrate when the support substrate is peeled from the silicon substrate. Since the concave surface where the support substrate is bonded corresponds to the bonding surface bonded to the cavity substrate of the inkjet head, if adhesive residue is left on the bonding surface, bonding failure may occur when bonding to the cavity substrate. It was. In addition, adhesive residue tends to occur at the edge portion of the ink inlet of the nozzle hole (opposite to the ink discharge port). If adhesive residue occurs at this portion, the discharge characteristics are affected, and desired discharge characteristics cannot be obtained. There was a problem.

  SUMMARY An advantage of some aspects of the invention is that it provides a method for manufacturing a nozzle substrate and a method for manufacturing a droplet discharge head that can prevent adhesive residue generated during the manufacturing process.

The method for manufacturing a nozzle substrate according to the present invention includes a step of dry etching a silicon substrate to form a recess that becomes a nozzle hole, and a step of forming a droplet protective film on the inner wall of the recess and the formation surface of the recess in the silicon substrate. A step of forming a concavo-convex shape on the surface of the droplet protective film on the forming surface, a step of attaching a first support substrate to the surface of the droplet protective film on which the concavo-convex shape is formed, and a first support substrate The process of thinning the silicon substrate to the desired thickness from the surface opposite to the surface on which the wafer is bonded and opening the tip of the recess to form nozzle holes, and droplet protection on the thinned surface of the silicon substrate Forming a film and forming a liquid repellent film on the surface; and bonding a second support substrate to the surface of the silicon substrate on which the liquid repellent film is formed and peeling the first support substrate from the silicon substrate And the second support substrate is silicon It is obtained by a step of peeling from the plate.
As a result, the first support substrate can be easily peeled off from the silicon substrate, and adhesive residue can be prevented.

Moreover, the manufacturing method of the nozzle substrate which concerns on this invention forms an uneven | corrugated shape by dry etching process.
Thereby, the degree of freedom in design of the concavo-convex shape is high, and the depth of the concave portion can be easily controlled. Therefore, it is possible to easily form a desired uneven shape on the droplet protective film.

Moreover, the manufacturing method of the nozzle substrate according to the present invention includes a step of cleaning the silicon substrate after the step of peeling the second support substrate from the silicon substrate.
Since the concavo-convex shape is formed in the droplet protective film, the cleaning liquid enters between the surface of the concavo-convex shape and the glue residue in the cleaning process, and a high cleaning effect can be obtained. Therefore, even if a paste residue is generated at the nozzle edge portion of the droplet inlet of the nozzle hole, it can be effectively removed.

In the method for manufacturing a nozzle substrate according to the present invention, the first support substrate is attached to a silicon substrate via a double-sided adhesive sheet having a self-peeling layer whose adhesive strength is reduced by applying ultraviolet light or heat to the adhesive surface. It is to match.
Using such a double-sided adhesive sheet, the first support substrate can be bonded to the silicon substrate.

Further, in the method of manufacturing the nozzle substrate according to the present invention, in the step of forming the recess serving as the nozzle hole, the recess whose cross-sectional area decreases stepwise or continuously from the liquid inlet to the discharge port is formed. Is.
Thereby, the discharge direction of droplets can be aligned with the direction of the central axis of the nozzle hole, and a nozzle substrate having stable discharge characteristics can be manufactured.

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 for applying pressure, and a pressure chamber. A method for manufacturing a droplet discharge head having a droplet supply path for supplying droplets and a pressure generating means for generating a discharge pressure in the pressure chamber for discharging the droplets, the nozzle having a plurality of nozzle holes The substrate is manufactured by the nozzle substrate manufacturing method described above.
When processing a silicon substrate to be a nozzle substrate in the manufacturing process of the droplet discharge head, the support substrate bonded to the silicon substrate during the processing can be easily peeled off as described above. Since the adhesive residue can be prevented, the yield of the nozzle substrate can be improved and the productivity can be dramatically improved.

  FIG. 1 is an exploded perspective view of a droplet discharge head manufactured by a method for manufacturing a droplet discharge head according to an embodiment of the present invention. 2 is a longitudinal sectional view of the droplet discharge head of FIG. Here, an electrostatic drive type inkjet head will be described with reference to FIGS. 1 and 2 as an example of a droplet discharge head. In addition, in order to illustrate the constituent members and make it easy to see, the relationship between the sizes of the constituent members in the following drawings including FIG. 1 may be different from the actual one.

  As shown in FIGS. 1 and 2, the inkjet head 10 according to the present embodiment has a three-layer structure in which three substrates of a nozzle substrate 1, a cavity substrate 2, and an electrode substrate 3 are bonded together. Although an example of a three-layer structure is shown here, the inkjet head 10 of this example is not limited to a three-layer structure, and four substrates, a nozzle substrate, a reservoir substrate, a cavity substrate, and an electrode substrate, are stacked. Of course, it may be a four-layer head.

Hereinafter, the configuration of each substrate will be described in more detail.
The nozzle substrate 1 is manufactured from a silicon substrate thinned to a required thickness (for example, about 65 μm) by a manufacturing method described later. The nozzle substrate 1 is provided with a plurality of nozzle holes 11 for ejecting ink droplets at a predetermined pitch. Here, two nozzle rows are formed. Each nozzle hole 11 is composed of a cylindrical first nozzle hole 11a on the tip end side in the ejection direction and a cylindrical second nozzle hole 11b having a diameter larger than that of the first nozzle hole 11a, and the first nozzle hole 11a. And the second nozzle hole 11b are provided coaxially. With such a configuration, 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 ink droplets, there is no scattering of ink droplets, and it is possible to suppress variations in the ejection amount of ink droplets.

  Further, an ink protective film 105 is formed on the discharge surface 1a of the nozzle substrate 1, the surface opposite to the discharge surface 1a, and the inner wall of the nozzle hole 11 as a protective film for protecting these surfaces from ink. An ink repellent film 106 as a liquid repellent film is formed on the entire discharge surface 1 a on the film 105, and the ink repellent film is formed on the inner wall of the nozzle hole 11 and the surface on the opposite side with the discharge port edge of the nozzle hole 11 as a boundary. The configuration is such that 106 is not formed. Thereby, the durability against ink is improved and ink droplets remaining on the ejection surface 1a are prevented.

  The cavity substrate 2 is made of, for example, a silicon substrate having a thickness of about 140 μm. By performing wet etching on the silicon substrate, a recess 25 that becomes the pressure chamber 21, a recess 26 that becomes the orifice 23, and a recess 27 that becomes the reservoir 24 are formed. A plurality of recesses 25 are independently formed at positions corresponding to the nozzle holes 11. Therefore, when the nozzle substrate 1 and the cavity substrate 2 are joined as shown in FIG. 2, each recess 25 constitutes a pressure chamber 21, communicates with the nozzle hole 11, and communicates with the orifice 23. The bottom wall of the pressure chamber 21 (concave portion 25) is a diaphragm 22.

The recess 26 constitutes a narrow groove-shaped orifice 23, and the recess 25 (pressure chamber 21) and the recess 27 (reservoir 24) communicate with each other through the recess 26.
The recess 27 is for storing a liquid material such as ink, and constitutes a reservoir (common ink chamber) 24 common to the pressure chambers 21. The reservoirs 24 (recesses 27) communicate with all the pressure chambers 21 via the orifices 23, respectively. The orifice 23 (concave portion 26) can also be provided on the back surface of the nozzle substrate 1 (the surface on the bonding side with the cavity substrate 2). An ink supply hole 28 is provided at the bottom of the reservoir 24.

Further, an insulating film 2a made of SiO ₂ or TEOS (tetraethylsilane: tetraethoxysilane, ethyl silicate) film or the like is formed on the entire surface of the cavity substrate 2 by thermal oxidation or plasma CVD (Chemical Vapor Deposition) to a thickness of 0.1 μm. Has been. This insulating film 2a is provided for the purpose of preventing dielectric breakdown and short circuit when the inkjet head 10 is driven.

  The electrode substrate 3 is made from a glass substrate having a thickness of about 1 mm, for example. Among them, it is suitable to use a borosilicate heat-resistant hard glass having a thermal expansion coefficient close to that of the silicon substrate of the cavity substrate 2. This is because when the electrode substrate 3 and the cavity substrate 2 are anodically bonded, the thermal expansion coefficients of the two substrates are close to each other, so that the stress generated between the electrode substrate 3 and the cavity substrate 2 can be reduced. This is because the electrode substrate 3 and the cavity substrate 2 can be firmly bonded without causing the above problem.

  The electrode substrate 3 is provided with a recess 32 at a position on the surface of the cavity substrate 2 facing each diaphragm 22. The recess 32 is formed with a depth of about 0.3 μm by etching. And in each recessed part 32, the individual electrode 31 which generally consists of ITO (Indium Tin Oxide: Indium tin oxide) is formed by the thickness of 0.1 micrometer, for example. The material of the individual electrode 31 is not limited to ITO, and a metal such as chrome may be used. However, since ITO is transparent, it is generally easy to confirm whether it has been discharged or not. Is used.

  The individual electrode 31 has a lead part 31a and a terminal part 31b connected to a flexible wiring board (not shown). As shown in FIG. 2, these terminal portions 31b are exposed in the electrode extraction portion 30 in which the end portion of the cavity substrate 2 is opened for wiring.

  The electrode substrate 3 is provided with an ink supply hole 33 connected to an external ink cartridge (not shown). The ink supply hole 33 communicates with the ink supply hole 28 provided in the cavity substrate 2, and ink is supplied from an ink cartridge (not shown) through the ink supply holes 28 and 33. Ink supplied from an ink cartridge (not shown) is supplied to the pressure chamber 21 via a reservoir 24 and an orifice 23 that serve as an ink supply path to the pressure chamber 21.

  As described above, the nozzle substrate 1, the cavity substrate 2, and the electrode substrate 3 are generally manufactured separately, and the main body of the inkjet head 10 is manufactured by bonding them together as shown in FIG. 2. Furthermore, the open end portion of the interelectrode gap formed between the diaphragm 22 and the individual electrode 31 is sealed with a sealing material 34 made of resin such as epoxy. Thereby, moisture and dust can be prevented from entering the gap between the electrodes, and the reliability of the inkjet head 10 can be kept high.

  2, a drive control circuit 35 such as an IC driver is connected to the terminal portion 31b of each individual electrode 31 and the common electrode 29 provided on the cavity substrate 2 (not shown). The inkjet head 10 is formed.

Next, the operation of the inkjet head 10 configured as described above will be described.
The drive control circuit 35 is an oscillation circuit that controls supply and stop of electric charges to the individual electrodes 31. This oscillation circuit oscillates at, for example, 24 kHz, and supplies electric charges by applying pulse potentials of, for example, 0 V and 30 V to the individual electrodes 31. When the oscillation circuit is driven and charges are supplied to the individual electrode 31 to be positively charged, the diaphragm 22 is negatively charged and an electrostatic force (Coulomb force) is generated between the individual electrode 31 and the diaphragm 22. Therefore, the diaphragm 22 is attracted to the individual electrode 31 by this electrostatic force and bends (displaces). As a result, the volume of the pressure chamber 21 increases. When the supply of electric charges to the individual electrode 31 is stopped, the diaphragm 22 returns to its original state due to its elastic force, and at this time, the volume of the pressure chamber 21 decreases rapidly. Part of the ink is ejected from the nozzle hole 11 as an ink droplet. When the diaphragm 22 is similarly displaced next, ink is supplied from the reservoir 24 through the orifice 23 into the pressure chamber 21.

Next, a method for manufacturing the inkjet head 10 will be described with reference to FIGS. 3-7 is sectional drawing which shows the manufacturing process of a nozzle substrate. 8 and 9 are cross-sectional views of the manufacturing process showing the manufacturing method of the cavity substrate 2 and the electrode substrate 3. Here, the cavity substrate 2 is mainly manufactured after the silicon substrate 200 is bonded to the electrode substrate 3. The method is shown.
First, a manufacturing method of the nozzle substrate 1 which is a characteristic part of the present invention will be described.

(1) Manufacturing Method of Nozzle Substrate 1 (A) First, as shown in FIG. 3A, a silicon substrate 100 having a thickness of 725 μm is prepared, set in a thermal oxidation apparatus (not shown), and an oxidation temperature of 1075 ° C. Then, a thermal oxidation treatment is performed for 4 hours under conditions in a mixed atmosphere of oxygen and water vapor, and a thermal oxide film (SiO ₂ film) 101 having a film thickness of 0.5 μm is uniformly formed on the surface of the silicon substrate 100. Then, the portion 101a to be the second nozzle is patterned on the thermal oxide film 101 on the bonding surface (surface to be bonded to the cavity substrate 2) 100a of the silicon substrate 100.

(B) Next, as shown in FIG. 3B, a resist film 102 having a thickness of 1.0 μm is formed on the bonding surface 100b, and a portion 102a serving as the first nozzle is patterned by photolithography.
(C) Next, as shown in FIG. 3C, the portion 102a to be the first nozzle of the resist film 102 is vertically anisotropic with a depth of 40 μm, for example, by an ICP dry etching apparatus (not shown). Dry etching is performed to form a recess 102b to be a first nozzle hole. In this case, C4F8 and SF6 are used as the etching gas, and these etching gases may be used alternately. Here, C4F8 is used to protect the groove side surface so that etching does not proceed to the side surface of the groove to be formed, and SF6 is used to promote the etching of the silicon substrate 100 in the vertical direction.
(D) Next, as shown in FIG. 3D, after removing the resist film 102, the portion 101 a serving as the second nozzle of the thermal oxide film 101 is vertically different at a depth of 40 μm using an ICP dry etching apparatus. Isotropic dry etching. At this time, the recess 102b to be the first nozzle is also etched to a depth of about 70 to 80 μm, and the recess 11c to be the nozzle hole 11 is formed.

(E) Next, as shown in FIG. 4E, after the thermal oxide film 101 remaining on the surface of the silicon substrate 100 is removed with a hydrofluoric acid aqueous solution, the entire surface of the silicon substrate 100, that is, the ejection surface 100a, the bonding surface. An ink protective film 103 is formed by dry oxidation on the inner walls of the recesses 11c that become the nozzle holes 11b. The film thickness of the ink protective film 103 is a value obtained by adding a film thickness necessary for the ink protective film (for example, 0.1 μm) to the desired surface roughness Rz. Since the ink protective film 103 serves as a bonding surface when the silicon substrate 100 (nozzle substrate 1) and the cavity substrate 2 are bonded to each other, the surface roughness Rz is reduced as a design constraint for obtaining a desired bonding strength. In this case, the surface roughness Rz is set to about 1 to 2 μm.

  After forming the recess 11c to be the nozzle hole 11 in the silicon substrate 100 as described above, prior to attaching the support substrate 110 as the first support substrate to the bonding surface 100b side in the step (G) described later, In the invention, the following step (F) is performed.

FIG. 5 is an enlarged view of a dotted line A part in the step (F) of FIG. 4, and is a detailed explanatory view of the step (F) of FIG. In FIG. 5, the dotted line A portion of FIG. 4 is shown in a vertically inverted state.
(F1) First, as shown in FIG. 5 (F1), a resist 104 is applied on the bonding surface 100b, and a plurality of openings 104a are formed by photolithography. The shape and arrangement pattern of the openings 104a are not particularly limited, but here, the rectangular openings 104a are formed in a staggered pattern.

(F2) Next, the silicon substrate 100 is put into a reactive ion etching (RIE) apparatus, and CHF3 and CF4 as etching gases and Ar for plasma stabilization are introduced. The flow rates are CHF3: 30 sccm, CF4: 30 sccm, Ar: 600 sccm, and the pressure is 300 Pa. The RF power is 1300W. Under the above conditions, the openings 104 a of the resist 104 are etched to form a plurality of recesses 103 a in the ink protective film 103. Next, FIG. 7 shows a plurality of recesses 103 a formed on the ink protective film 103.

  FIG. 7 is a plan view of the ink protective film 103. As shown in FIG. 7, each recess 103a has a quadrangular shape when seen in a plan view, and is arranged in a staggered pattern. The plurality of recesses 103a are formed for the purpose of providing the ink protective film 103 with an uneven shape, and the shape and arrangement of each recess 103a are not particularly limited to the shape and arrangement shown in FIG.

  As shown in FIG. 5F2, the depth of the recess 103a corresponds to the surface roughness Rz (here, about 1 to 2 μm as described above), and the remaining film thickness h of the recess 103a is the ink protection. This corresponds to the film thickness required for the film, and is about 0.1 μm here. In addition, since the surface roughness of the ink protective film 103 in a state where the recess 103a is not formed is usually about 10 nm, the surface is sufficiently and sufficiently rough due to the formation of the recess 103a.

(F3) Next, as shown in FIG. 5 (F3), the silicon substrate 100 is immersed in a mixed solution of sulfuric acid and hydrogen peroxide solution, and the resist 104 is peeled off. Thereby, the ink protective film 103 in which the plurality of concave portions 103a are formed in a staggered pattern is formed.

Returning now to FIG.
(G) As shown in FIG. 4G, the double-sided adhesive sheet 50 is interposed on the side of the joint surface 110b (the surface on which the concave portion 103a is formed) having the ink protective film 103 in which the concavo-convex shape is formed by the step (F). A support substrate 110 made of a transparent material such as glass is attached. For this double-sided adhesive sheet 50, for example, Selfa BG (registered trademark: Sekisui Chemical Co., Ltd.) is used. The double-sided adhesive sheet 50 is a sheet having a self-peeling layer 51 (self-peeling type sheet), which has an adhesive surface on both surfaces, and further includes a self-peeling layer 51 on one surface. The adhesive strength is reduced by stimuli such as ultraviolet rays or heat.

  As described above, since the support substrate 110 is bonded using the double-sided adhesive sheet 50 having the self-peeling layer 51, the support substrate 110 is firmly bonded to the silicon substrate 100 when the silicon substrate 100 is thinned. The silicon substrate 100 can be processed without being damaged, and after the processing, the support substrate 110 can be easily peeled off from the silicon substrate 100 without any adhesive residue as will be described later.

  Next, grinding is performed by a back grinder (not shown) from the discharge surface 100a side of the silicon substrate 100 to reduce the thickness until the thickness becomes 65 μm. As a result, the tip of the recess 11 c that becomes the nozzle hole 11 is opened, and the nozzle hole 11 is formed. After the thinning, the discharge surface 100a may be further polished by a polisher and a CMP apparatus.

(H) Next, as shown in FIG. 4H, a 0.2 μm-thick silicone polymer film that forms the ink protective film 105 is formed on the surface of the discharge surface 100a of the silicon substrate 100 by plasma CVD using a siloxane material. To do. Then, UV irradiation is performed in the air to cause dehydration condensation, and the surface of the ink protective film 105 is changed to SiO ₂ .

(I) Next, as shown in FIG. 4I, the ink repellent treatment is further performed on the ejection surface 100a of the silicon substrate 100. Specifically, a silane coupling material is dip coated, and an ink repellent film 106 is formed on the ejection surface 100a. At this time, the ink repellent film 106 is also formed on the inner wall of the nozzle hole 11.

(J) Next, as shown in FIG. 6 (J), a support tape 120 as a second support substrate is attached to the ejection surface 100a, and UV light is irradiated from the support substrate 110 side in this state.
(K) By irradiating UV light, the self-peeling layer 51 of the double-sided adhesive sheet 50 is peeled off from the bonding surface 100b surface of the silicon substrate 100 as shown in FIG. Remove from.
Here, when the support substrate 110 is peeled off, since the ink protective film 103 having a concavo-convex shape is formed on the bonding surface 100b of the silicon substrate 100, which is an adhesion surface of the support substrate 110, the support substrate 110 is formed. Can be easily peeled off. That is, the formation of the recess 103a reduces the bonding area between the support substrate 110 and the double-sided adhesive sheet 50, and prevents adhesive residue and can be easily peeled off.

(L) Then, as shown in FIG. 6 (L), oxygen or argon plasma treatment is performed from the bonding surface 100b side, and the ink repellent film 106 on the inner wall of the nozzle hole 11 is destroyed and rendered hydrophilic.
(M) Then, after the support tape 120 is peeled off, it is washed by sulfuric acid washing or the like. Here, even if the adhesive residue is generated after the support substrate 110 is peeled off, the cleaning liquid enters between the uneven surface of the ink protective film 103 and the adhesive residue portion during the cleaning in the step (M). As compared with the case where there is no uneven shape, a high cleaning effect can be exhibited, and the glue can be effectively removed. Therefore, for example, even if adhesive residue is generated at the nozzle edge portion of the nozzle hole 11 on the ink introduction port side (joining surface 110b side), it can be removed by washing, and the discharge characteristics due to the adhesive remaining in the portion can be removed. Changes can be prevented.
As described above, the nozzle substrate 1 can be manufactured.

  As described above, according to the manufacturing method of the nozzle substrate of the present embodiment, when the support substrate 110 is attached to the silicon substrate 100 to be the nozzle substrate 1, the uneven shape is formed on the ink protective film 103 formed on the surface of the silicon substrate 100. Since the support substrate 110 is pasted after the formation, the support substrate 110 can be easily peeled off and the adhesive residue can be prevented.

  Further, since the recess 103a is formed by dry etching, the design freedom of the shape of the recess 103a is high, and the depth control can be easily performed. Accordingly, it is possible to easily form a desired uneven shape on the ink protective film 103.

  Further, by providing the uneven shape on the surface of the ink protective film 103, the cleaning liquid enters between the uneven surface and the adhesive residue when cleaning at the final stage of the manufacturing process of the nozzle substrate 1. can get. Therefore, even if a paste residue is generated at the nozzle edge portion of the nozzle hole 11 on the joint surface 110b side, it can be effectively removed. Therefore, it is possible to prevent a change in ejection characteristics due to the glue remaining on the nozzle edge portion.

  In the present embodiment, the nozzle hole 11 is formed in a shape in which the cross-sectional area gradually decreases from the ink introduction port to the ejection port (in this case, two steps). In this nozzle substrate manufacturing method, the shape of the nozzle hole 11 is not limited to this shape. For example, the cross-sectional area may be continuously reduced from the ink introduction port toward the ejection port. In short, in the present invention, after forming a recess to be a nozzle hole in a silicon substrate, a support substrate is bonded to the surface where the recess is formed, and the tip of the recess is made thin from the surface opposite to the surface where the recess is formed. The present invention is applicable to a processing method for opening and forming nozzle holes.

  The method for manufacturing the nozzle substrate 1 according to the present embodiment has been described by taking the case of a nozzle substrate used in an electrostatic drive type inkjet head as an example. However, other methods such as a piezoelectric drive method and a bubble jet (registered trademark) method may be used. The present invention can also be applied to a nozzle substrate of an ink jet head using an actuator (pressure generating means).

(2) Manufacturing Method of Cavity Substrate 2 and Electrode Substrate 3 Here, a method of manufacturing the cavity substrate 2 from the silicon substrate 200 after bonding the silicon substrate 200 to the electrode substrate 3 will be described with reference to FIGS. Briefly described.

The electrode substrate 3 is manufactured as follows.
(A) First, the concave portion 32 is formed by etching with a hydrofluoric acid using, for example, a gold / chromium etching mask on a glass substrate 300 made of borosilicate glass or the like and having a thickness of about 1 mm. Note that the recess 32 has a groove shape slightly larger than the shape of the individual electrode 31, and a plurality of the recesses 32 are formed for each individual electrode 31.
Then, an individual electrode 31 made of ITO (Indium Tin Oxide) is formed inside the recess 32 by sputtering, for example.
Thereafter, the ink supply hole 33 is formed by a drill or the like, whereby the electrode substrate 3 is manufactured.

(B) Next, after both surfaces of a silicon substrate 200 having a thickness of, for example, 525 μm are mirror-polished, one side of the silicon substrate 200 is made of silicon made of TEOS (TetraEthylorthosilicate) having a thickness of 0.1 μm by plasma CVD (Chemical Vapor Deposition). An oxide film (insulating film) 2a is formed. Note that before the silicon substrate 200 is formed, a boron doped layer for forming the thickness of the diaphragm 22 with high accuracy may be formed using an etching stop technique. Etching stop is defined as a state in which bubbles generated from the etching surface are stopped, and in actual wet etching, it is determined that the etching is stopped when the generation of bubbles is stopped.

(C) The silicon substrate 200 and the electrode substrate 3 manufactured as shown in FIG. 8A are heated to, for example, 360 ° C., and the anode is connected to the silicon substrate 200 and the cathode is connected to the electrode substrate 3. Then, a voltage of about 800 V is applied to join by anodic bonding.
(D) After anodic bonding of the silicon substrate 200 and the electrode substrate 3, the silicon substrate 200 in a bonded state is etched with an aqueous potassium hydroxide solution or the like, thereby reducing the thickness of the silicon substrate 200 to, for example, 140 μm. .

(E) Next, as shown in FIG. 9E, the entire surface of the upper surface of the silicon substrate 200 (the surface opposite to the surface to which the electrode substrate 3 is bonded) is, for example, 1.5 μm thick by plasma CVD. A TEOS film is formed.
Then, the TEOS film is patterned with a resist for forming a recess 25 to be the pressure chamber 21, a recess 26 to be the orifice 23, and a recess 25 to be the reservoir 24, and the TEOS film in these portions is removed by etching.
Thereafter, the silicon substrate 200 is etched with a potassium hydroxide aqueous solution or the like to form a recess 25 that becomes the pressure chamber 21, a recess 26 that becomes the orifice 23, and a recess 27 that becomes the reservoir 24. At this time, the portion that becomes the electrode extraction portion 30 for wiring is also etched and thinned. In the wet etching step of FIG. 9E, for example, a 35% by weight potassium hydroxide aqueous solution can be used first, and then a 3% by weight potassium hydroxide aqueous solution can be used. Thereby, surface roughness of the diaphragm 22 can be suppressed.

(F) After the etching of the silicon substrate 200 is completed, the TEOS film formed on the upper surface of the silicon substrate 200 is removed by etching with a hydrofluoric acid aqueous solution.
(G) Next, a TEOS film (insulating film 2a) is formed to a thickness of, for example, 0.1 μm by plasma CVD on the surface of the silicon substrate 200 where the recesses 25 to be the pressure chambers 21 are formed.
(H) After that, the electrode extraction unit 30 is opened by RIE (Reactive Ion Etching) or the like. Further, laser processing is performed from the ink supply hole 33 of the electrode substrate 3 so as to penetrate the bottom of the concave portion 27 that becomes the reservoir 24 of the silicon substrate 200, thereby forming the ink supply hole 28. Further, the open end of the gap between the diaphragm 22 and the individual electrode 31 is sealed by filling a sealing material such as an epoxy resin (see FIG. 2). Further, as shown in FIG. 1, the common electrode 29 is formed on the end portion of the upper surface of the silicon substrate 200 (the surface on the bonding side with the nozzle substrate 1) by sputtering.

As described above, the cavity substrate 2 is manufactured from the silicon substrate 200 bonded to the electrode substrate 3.
Finally, the ink jet head 10 shown in FIG. 1 is completed by bonding the nozzle substrate 1 manufactured as described above to the cavity substrate 2 by bonding or the like.

  In the manufacturing process of the inkjet head 10 according to the present embodiment, when the silicon substrate 100 to be the nozzle substrate 1 is processed, the support substrate 110 bonded to the silicon substrate 100 is easily peeled off as described above. Moreover, since the adhesive residue at the time of peeling can be prevented, the yield of the nozzle substrate 1 can be improved and the productivity can be dramatically improved.

  In the above embodiment, the nozzle substrate manufacturing method and the inkjet head manufacturing method have been described. However, the present invention is not limited to the above embodiment, and is within the scope of the technical idea of the present invention. Various changes can be made. For example, by changing the liquid material discharged from the nozzle hole, in addition to the inkjet printer 400 shown in FIG. 10, it is used for manufacturing a color filter of a liquid crystal display, forming a light emitting portion of an organic EL display device, 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.

1 is an exploded perspective view of a droplet discharge head manufactured by a method for manufacturing a droplet discharge head according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the droplet discharge head 10 of FIG. 1. Sectional drawing which shows the manufacturing process of the nozzle substrate. Sectional drawing which shows the manufacturing process of the nozzle substrate 1 following FIG. The enlarged view of the dotted-line A part of the process (F) of FIG. Sectional drawing which shows the manufacturing process of the nozzle substrate 1 following FIG. FIG. 6 is a plan view of the ink protective film 103 in FIG. 5. Sectional drawing of the manufacturing process which shows the manufacturing method of the cavity board | substrate 2 and the electrode substrate 3. FIG. Sectional drawing of the manufacturing process following FIG. 1 is a perspective view of an ink jet printer using an ink jet head 10 according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Nozzle board | substrate, 1a discharge surface, 2 cavity board | substrate, 2a insulating film, 3 electrode board | substrate, 10 inkjet head, 11 nozzle hole, 11a 1st nozzle hole, 11b 2nd nozzle hole, 11c recessed part used as a nozzle hole, 21 pressure chamber , 22 Diaphragm, 23 Orifice, 24 Reservoir, 25 Recessed part, 26 Recessed part, 27 Recessed part, 28 Ink supply hole, 29 Common electrode, 30 Electrode extracting part, 31 Individual electrode, 31a Lead part, 31b Terminal part, 32 Recessed part, 33 Ink supply hole, 34 sealing material, 35 drive control circuit, 50 double-sided adhesive sheet, 51 self-peeling layer, 100 silicon substrate, 100a ejection surface, 100b bonding surface, 101 thermal oxide film, 101a part to be second nozzle, 102 Resist film, 102a portion to be the first nozzle, 103 ink protective film ( Monolayer), 103a recess 104 resist, 104a opening 105 ink protective layer, 106 an ink repellent layer, 110 a support substrate, 110b bonding surface 120 supports the tape, 200 silicon substrate, 300 a glass substrate, 400 an ink jet printer.

Claims (6)

Forming a recess to be a nozzle hole by dry etching the silicon substrate;
Forming a droplet protective film on the inner wall of the recess of the silicon substrate and the formation surface of the recess;
Forming a concavo-convex shape on the surface of the droplet protective film on the formation surface;
A step of attaching a first support substrate to the surface of the droplet protective film on which the uneven shape is formed;
A step of thinning the silicon substrate to a desired thickness from the surface opposite to the surface on which the first support substrate is bonded, opening the tip of the recess, and forming a nozzle hole;
Forming a droplet protective film on the thinned processed surface of the silicon substrate, and forming a liquid repellent film on the surface;
Bonding a second support substrate to the surface of the silicon substrate on which the liquid repellent film is formed, and peeling the first support substrate from the silicon substrate;
And a step of peeling the second support substrate from the silicon substrate.   The method for manufacturing a nozzle substrate according to claim 1, wherein the uneven shape is formed by dry etching.   3. The method for manufacturing a nozzle substrate according to claim 1, further comprising a step of cleaning the silicon substrate after the step of peeling the second support substrate from the silicon substrate.   The first support substrate is bonded to the silicon substrate through a double-sided adhesive sheet having a self-peeling layer whose adhesive strength is reduced by applying ultraviolet light or heat to the adhesive surface. Item 4. A method for manufacturing a nozzle substrate according to Item 3.   5. The step of forming a concave portion to be a nozzle hole forms a concave portion whose cross-sectional area decreases stepwise or continuously from a droplet introduction port toward a discharge port. A method for producing a nozzle substrate according to any one of the above. A plurality of nozzle holes for discharging droplets, a pressure chamber provided in communication with each nozzle hole for applying pressure, a droplet supply path for supplying droplets to the pressure chamber, and a droplet A method for manufacturing a droplet discharge head, comprising pressure generating means for generating a discharge pressure for discharging in the pressure chamber,
6. 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 5.

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