WO1997034769A1

WO1997034769A1 - Ink jet head and method of manufacturing same

Info

Publication number: WO1997034769A1
Application number: PCT/JP1997/000830
Authority: WO
Inventors: Masahiro Fujii; Tarou Takekoshi; Tomohiro Makigaki; Hiroshi Koeda
Original assignee: Seiko Epson Corporation
Priority date: 1996-03-18
Filing date: 1997-03-14
Publication date: 1997-09-25

Abstract

In an ink jet head (1), a first silicon single crystal substrate (2) having a substrate surface (2a), of which a crystal face orientation corresponds to a crystal face (100), is subjected to a wet type crystal anisotropic etching to form ink nozzles (4) and grooves (7A) for formation of orifices, a second silicon single crystal substrate (3) having a substrate surface (3a), of which a crystal face orientation corresponds to a crystal face (110), is subjected to a wet type crystal anisotropic etching to form grooves (5A) for formation of ink cavities and grooves (6A) for formation of an ink reservoir, and these silicon single crystal substrates are joined to each other to define the ink nozzles (4), ink cavities (5) communicating with the respective ink nozzles, a common ink reservoir (6) for supplying ink to the respective ink cavities and orifices (7) which establishes communication between the respective ink cavities and the ink reservoir. Thus crystal face orientations of the respective substrates (2, 3) are set in such manner whereby the respective grooves can be formed with high precision, the respective nozzles vary least in ink delivery characteristics and ink jet heads with high printing qualities can be manufactured.

Description

Description Inkjet head and method of manufacturing the same

The present invention relates to an ink jet head for an ink jet printer, and more particularly to an ink jet head in which a groove such as an ink cavity is accurately etched on a semiconductor substrate and a method for manufacturing the same. Background art

In general, the ink jet head of an ink jet printer has a structure in which a plurality of ink nozzles for discharging ink droplets to the outside and an ink supply path communicating with these ink nozzles are formed on a semiconductor substrate. In recent years, there has been a demand for more precise and finer processing of ink jet heads so that high-definition characters can be printed. To this end, various inkjet head manufacturing methods have been developed.

For example, in Japanese Patent Application Laid-Open No. 5-50601 by the present applicant, a photolithography technique and wet crystal anisotropic etching are applied to a silicon single crystal substrate in an ink jet printer of an electrostatic drive system. Thus, a method of manufacturing an ink jet head for forming an ink nozzle and an ink supply path with high precision is disclosed.

-The ink jet head disclosed in this publication has a configuration including a plurality of ink nozzles, ink cavities communicating with the respective ink nozzles, and a common ink reservoir for supplying ink to the ink cavities. ing. Ink supplied from the external ink supply to the ink reservoir of the ink jet head is supplied from the ink reservoir via each orifice. Supplied to the ink cavity. The bottom surface of each ink cavity functions as a diaphragm, and the ink nozzles communicate with the ink nozzles using the ink volume fluctuations that fluctuate by vibrating the diaphragms by electrostatic force. Drops cannot be ejected to the outside.

Here, in order to suppress the dispersion of the ink ejection characteristics of each ink nozzle of the ink jet head, a portion constituting the ink supply path such as each ink nozzle, ink cavity, and orifice is formed with high precision. There is a need to. In particular, it is necessary to form the nozzle, orifice and diaphragm with high precision. If the shape of the orifice varies, the fluid resistance value of each orifice portion varies, so that the ink supply amount to each ink cavity varies, and as a result, the ink ejection amount of each ink nozzle varies. The fluid resistance created by an orifice depends on its cross-sectional area and length. For example, if the cross-sectional areas are the same, the fluid resistance of the orifice is proportional to the length. In a typical inkjet head, the length of the orifice is 150 to 3 in consideration of the amount of ink supplied, the damping characteristics of the diaphragm, and the amount of ink returning from the ink cavity to the ink reservoir during ink ejection. Set to 0 micron. If the length of this orifice fluctuates, for example, by 10%, the amount of ink supply also fluctuates by 10%. Here, if the ink weight fluctuates by 5%, the print quality will be adversely affected. Therefore, it is desirable that the variation in the orifice length be suppressed to less than 5%, that is, less than 20 microns.

However, for example, when the ink cavity and the orifice are simultaneously etched using a semiconductor substrate having the (100) crystal plane orientation, the (111) crystal plane appears due to anisotropic etching in the width direction of the orifice. The sectional shape of the orifice can be formed with high accuracy. However, in the length direction, the etching speed is high (1 1 2). It is difficult to accurately set the length of the orifice.

On the other hand, if the shape of the diaphragm varies, the vibration characteristics of the ink internal pressure in each ink cavity will be different. This variation in the vibration characteristics of the diaphragm directly leads to variations in the ink ejection amount, ink ejection speed, and the like of the ink nozzles, so that the print quality deteriorates.

Here, in the method for manufacturing an ink jet head disclosed in the above-mentioned publication, the grooves for ink cavities and the bottom surface of the cavities are defined by etching the surface of the same silicon single crystal substrate. By forming a plate, a groove for an orifice and a groove for an ink reservoir, and overlaying the silicon single crystal substrate having each groove with a silicon single crystal substrate having a flat surface, ink cavities, An inkjet head having an orifice and an ink reservoir is configured. However, in this method, it is necessary to control the dimensions of the grooves to be formed by controlling the etching conditions applied to a single silicon single crystal substrate. Can be difficult.

On the other hand, in the method for manufacturing a thermal ink jet recording head described in Japanese Patent Application Laid-Open No. 6-183008, anisotropic etching is performed on each of two silicon substrates. forming a plurality of grooves having different sizes by subjecting, thereafter, however _c method to superimpose these silicon substrate is disclosed, these silicon substrate has both (1 0 0) crystal plane on the surface It is a silicon substrate. Then, after forming a groove by performing anisotropic etching on the lower silicon substrate of the two silicon substrates, forming a through-hole by polishing from the rear surface side, a nozzle is formed on the upper surface side. The formed silicon substrates are laminated, and a flatter third silicon substrate is bonded to the lower surface side to form an ink jet head. For this reason, in order to form a groove in the intermediate silicon substrate, the substrate must be processed in addition to the step of performing anisotropic etching. This requires a polishing step, which not only complicates the process, but also lowers the accuracy of the depth of the formed groove as compared with the one formed only by etching. That is, the method for manufacturing a thermal ink jet head disclosed in Japanese Patent Application Laid-Open No. Hei 6-183008 is directly used in Japanese Patent Application Laid-Open No. Hei 6-183008. Even if it is applied to the described method of manufacturing an ink jet head, it is not possible to accurately form the cross-sectional area of the orifice connecting the ink cavity and the ink reservoir and to form the diaphragm with high precision. Can not. Disclosure of the invention

In view of the above, an object of the present invention is to manufacture a portion of an ink cavity, an orifice, and the like on a silicon single crystal substrate with higher accuracy than in a conventional method in manufacturing an ink jet head. To make it possible.

In order to achieve this object, the present invention provides a plurality of ink nozzles, an ink cavity communicating with each of the ink nozzles, a common ink reservoir for supplying ink to each of the ink cavities, and an ink reservoir for each of the ink cavities. —In an ink jet head provided with an orifice communicating with a base and a diaphragm defining the bottom surface of each of the above-mentioned ink cavities,

It is characterized by adopting the configurations of (1) to (3).

(1) The first and second silicon single crystal substrates having the ink cavities, the orifices, and the ink reservoir formed by being bonded to each other.

(2) The first silicon single crystal substrate has an ink communicating with the ink nozzle, the orifice, or the ink reservoir formed by performing wet-crystal anisotropic etching on the surface of the substrate on the bonding side. It has a groove to form an intake. The shape of these grooves is (1 1 1) crystal plane Is defined by the wall surface formed by

(3) The second silicon single crystal substrate has a groove for forming the ink cavity and the ink reservoir formed by performing wet-crystal anisotropic etching on the surface of the substrate on the bonding side. There is a groove for

In the ink jet head of the present invention, relatively small-sized ink nozzles and grooves for forming orifices are formed in the first silicon single crystal substrate, and relatively large-sized ink cavities and ink reservoirs are formed. A forming groove is formed in the second silicon single crystal substrate. Therefore, compared to a case where all the grooves for forming the ink supply passages are etched only on one substrate, it is easier to control the etching conditions for forming the grooves of each dimension. It becomes easy to accurately etch the groove.

Further, in the present invention, when dry etching is used in combination with the first silicon single crystal substrate to form an ink nozzle, it is more general than when only wet crystal anisotropic etching is employed. This part can be created with high accuracy.

On the other hand, in the present invention, in the case where a groove is formed on the first silicon single crystal substrate by using wet crystal anisotropic etching, the first silicon single crystal substrate is used as the first silicon single crystal substrate. The crystal plane orientation of the substrate surface of (100) plane or (110) plane is used. _{C In} particular, when the crystal plane orientation is (100), By etching from the substrate surface with the crystal plane orientation, a (111) crystal plane with a low etching rate appears on both side walls in the width direction of the formed groove. Therefore, the cross-sectional area of the groove can be accurately defined by adjusting the etching width of the surface of the substrate.In the present invention, the second silicon single crystal substrate is formed on the surface of the substrate on the bonding side. Use the crystal orientation of (110) plane I am trying to do it. If a plurality of the grooves for the ink cavities are formed by performing anisotropic etching from the substrate surface having the crystal plane orientation, the (111) azimuthal plane perpendicular to the substrate surface is formed on the side wall of the partition wall between the respective ink cavities. Appears. Therefore, the grooves for ink cavities can be formed with high density and high precision. In this case, a groove for forming the orifice is formed in a partition wall between the groove for forming each of the ink cavities and the groove for forming the ink reservoir in the second silicon single crystal substrate. The wall portions located at both ends in the longitudinal direction can be defined by the (111) crystal plane. The length of the orifice is defined by the (111) crystal plane. Therefore, the length dimension of the formed orifice can be made with high accuracy.

On the other hand, the present invention relates to a method for manufacturing an ink jet head having the above-described configuration, and is characterized in that the ink head is manufactured as follows. That is, first, a first silicon single crystal substrate having a (100) or (110) crystal plane orientation on the substrate surface is prepared, and a wet crystal is formed on the substrate surface of the first silicon single crystal substrate. Anisotropic etching is performed to form at least the groove for forming the orifice. Next, a second silicon single crystal substrate having a crystal plane orientation of (110) or (100) crystal plane on the substrate surface is prepared, and a wet crystal anisotropic is provided on the substrate surface of the second silicon single crystal substrate. The grooves for forming the ink cavities and the grooves for forming the ink reservoir are formed by performing a reactive etching. After that, the first and the second

By joining the substrate surfaces of the two silicon single crystal substrates to each other, the ink nozzle, the ink cavity, the ink reservoir, and the orifice that connects the ink cavity and the ink reservoir are formed. In this method, both side walls in the width direction of the groove for forming the orifice in the first silicon single crystal substrate are (1 1 1) crystal planes, Etching of the groove for forming the orifice is performed, and the groove for forming the ink cavities in the second silicon single crystal substrate is separated from the groove for forming the ink reservoir. It is preferable that the groove for the ink cavity and the groove for the ink reservoir be etched so that the wall surfaces at both ends in the longitudinal direction of the orifice in the partition wall are (111) crystal planes. In this way, the cross-sectional area and length of the orifice can be accurately defined using the (111) crystal plane. Further, in these methods, before performing wet-crystal anisotropic etching on the substrate surface of the second silicon single crystal substrate, a high concentration of polon or the like is dropped on the back surface of the substrate surface. was it Nozomu Mashiku of forming an etch stop layer, thereby further bRIEF dESCRIPTION oF _c drawings the thickness of the diaphragm can be formed with high accuracy

FIG. 1 is a schematic sectional view of an ink jet head to which the present invention is applied. FIG. 2 is an exploded perspective view of the ink jet head of FIG. FIG. 3 is an exploded perspective view showing a modified example of the ink jet head of FIG.

FIG. 4 is a schematic sectional view showing another modified example of the ink jet head of FIG.

FIG. 5 is an exploded perspective view of the ink jet head of FIG. FIG. 6 is a view showing an ink jet head to which the present invention is applied, (A) is a schematic cross-sectional view, (B) is a partial plan view of the first silicon single crystal substrate, (C) FIG. 4 is a partial plan view of the second silicon single crystal substrate.

FIG. 7 shows an etching process for the second silicon single crystal substrate of FIG. FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an ink jet head and a method for manufacturing the same according to the present invention will be described with reference to the drawings.

(Example 1)

FIG. 1 is a schematic sectional view of an ink jet head driven by a piezoelectric element manufactured by applying the present invention, and FIG. 2 is an exploded perspective view.

Explaining with reference to these figures, the ink jet head 1 of this example is composed of a first silicon single crystal substrate 2 and a second silicon single crystal substrate 3 bonded to each other. The substrates 2 and 3 form a plurality of ink nozzles 4, an ink cavity 5 communicating with each ink nozzle 4, and a common ink reservoir 6 for supplying ink to each ink cavity 5. The orifices 7 communicate between the ink cavities 5 and the ink reservoirs 6, respectively. Further, the bottom surface of each ink cavity 5 is defined by a thin vibrating plate 8, and a piezoelectric element 9 for driving the vibrating plate is adhered and fixed to the back surface of the vibrating plate 8.

Ink is supplied to the ink reservoir 6 from the outside via an ink supply tube 12 connected to an ink intake port 11 communicating with the ink reservoir. The ink supplied to the ink reservoir 6 is supplied to each ink cavity 5 through each orifice 7. When a drive voltage is applied to the piezoelectric element 9 bonded and fixed to the plate 8 that defines the bottom surface of the ink cavity 5, the diaphragm 8 reduces the volume of the ink cavity 5 due to the bimorph effect of the piezoelectric element 9 and the diaphragm 8. Ink drops are ejected from the ink nozzle 4.

The inkjet head 1 having this configuration supplies the above-described ink to the substrate surfaces 2a and 3a on the bonding side of the first and second silicon single crystal substrates 2 and 3 respectively. The groove for forming the road is etched, and then the substrates 2 and 3 are bonded to each other.

The first silicon single crystal substrate 2 has a (100) plane crystal plane orientation of the substrate surface 2a on the bonding side, and the ink passes through the first silicon single crystal substrate 2 in a direction perpendicular to the substrate surface 2a. Nozzle 4 is formed. A groove 7A for forming the orifice 7 is formed on the substrate surface 2a.

The groove 7A for orifice formation is formed by wet-crystal anisotropic etching of the substrate surface 2a having a (100) crystal plane orientation. Therefore, the formed groove 7A has a quadrangular pyramid shape which is narrowed from the substrate surface side toward the groove bottom surface, and its four side surfaces are 54.7 degrees with respect to the substrate surface 2a. (11 1) defined by the crystal plane. When a groove is formed by wet-crystal anisotropic etching of the substrate surface having such a (100) plane orientation, the cross-sectional area of the groove can be accurately defined by the etching width of the substrate surface. Therefore, by prescribing the dimension of the mask opening covering the substrate surface with high precision, the cross-sectional area of the formed groove can be adjusted to the target value with high precision.

For this reason, in the inkjet head 1 of the present example, the cross-sectional area of each groove 7A for forming the orifice can be formed with high accuracy by suppressing the variation. As described later, since the length of the orifice 7 can be formed with high precision, the variation in the fluid resistance of the orifice 7 can be suppressed, so that the ink supply amount through the orifice 7 can be kept constant. As a result, variations in the ink ejection characteristics of each ink nozzle can be suppressed, and print quality can be improved.

Next, the ink nozzle 4 formed on the first silicon single crystal substrate 2 has a straight portion 4a having a constant cross-sectional area in the direction of the nozzle axis, and ink from the straight portion 4a. It has a cross-sectional shape with a tapered portion 4b whose cross-sectional area gradually increases toward the cavity 5. Story The flat portion 4a is a portion provided with a high fluid resistance necessary to attenuate the vibration of the meniscus after the ink is ejected, and the tapered portion 4b communicates with the straight portion 4a to form bubbles. This is a necessary part for discharging. The straight portion 4a is a circular opening formed by dry etching the back surface 2b of the first silicon single crystal substrate 2. On the other hand, the tapered portion 4b is formed by wet anisotropic etching of the substrate surface 2a on the bonding side of the first silicon single crystal substrate 2 having the (100) crystal orientation. It is formed by doing. Therefore, the tapered portion 4b has a truncated pyramid shape in which the cross-sectional area is reduced from the side of the substrate surface to the opposite straight portion 4a, and the four side surfaces are formed on the substrate surface. Appears with an inclination of 54.7 degrees to 2a. (1 1 1) Defined by crystal plane.

As described above, when a groove is formed by wet-crystal anisotropic etching of a substrate surface having such a (100) plane orientation, the cross-sectional area of the groove is determined by the etching width of the substrate surface. Can be well defined. Accordingly, the ink nozzle 4 composed of the tapered portion 4b formed with high accuracy and the straight portion 4a formed with high accuracy by dry etching as described above has a dimension and shape with little variation. ing. Accordingly, the ink ejection characteristics of each ink nozzle can be made constant, and as a result, a decrease in print quality can be suppressed.

On the other hand, in the second silicon single crystal substrate 3, the crystal plane orientation of the substrate surface 3a on the bonding side is the (110) plane orientation, and an ink cavity 5 is formed on the substrate surface 3a. 5A and a groove 6A for forming the ink reservoir 6 are formed. Further, an ink inlet 11 is opened on the bottom surface of the groove 6A for forming the ink reservoir.

Wet anisotropic etching of substrate surface 3a with crystal plane orientation of (110) plane In the case where the groove 5A for ink cavities is formed by forming, as shown in FIG. 2, four of the six sides defining the groove 5A are formed on the substrate surface 3a. A vertical (111) crystal plane is formed, and the remaining two side surfaces become (111) crystal planes that appear at an inclination of 35 degrees with respect to the substrate surface 3a. The groove 6A for the ink reservoir on the substrate surface 3a of the second silicon single crystal substrate 3 is also formed by wet anisotropic etching.

Here, a partition 15 is formed between the formed groove 5A for the ink cavity and the groove 6A for the ink reservoir. The side surfaces 15a and 15b facing the groove 5A and the groove 6A in the partition wall 15 are (111) crystal planes inclined by 35 degrees with respect to the substrate surface 3a.

The first and second silicon single crystal substrates 2 and 3 having the respective grooves formed in this way are bonded together with their bonded substrate surfaces 2a and 3a aligned with each other. It has a cross-sectional shape as shown in FIG. In this state, both side surfaces 15a and 15b of the partition wall 15 defining the length of the orifice 7 are (1 1 1) crystal planes. Well set. As described above, since the cross-sectional area of the orifice 7 is also set with high accuracy, the variation in the fluid resistance of each orifice 7 is small, and accordingly, the variation in the ink flow rate in each orifice 7 is small. Further, as described above, each ink nozzle 4 is also formed without variation. As a result, in the ink jet head 1 of this example, there is little variation in the ink ejection characteristics of each ink nozzle.

Here, in the manufacture of the inkjet head 1 of the present example, an etching solution used for wet anisotropic etching of each of the silicon single crystal substrates 2 and 3 is, for example, 20 weight percent heated to 80 degrees Celsius. An aqueous solution of the hydroxide of potassium hydroxide can be used. The concentration of this aqueous solution should be appropriately changed depending on the shape of the groove to be formed. Also, the etchant used should be A different composition such as an aqueous ammonia solution or an organic amine-based aqueous solution may be used.

The bonding of both silicon single crystal substrates 2 and 3 can be performed as follows. In other words, these silicon single crystal substrates 2 and 3 are aligned, bonded at room temperature, and then directly heated to 100 degrees Celsius for direct bonding. Instead, it is also possible to form eutectic film of gold on the interface between both substrates in advance and to form a eutectic bond at a low temperature by heating to 400 degrees Celsius in close contact. is there. In addition, an adhesive may be used, which enables bonding at room temperature.

When the ink jet head 1 of this example was actually manufactured as a prototype, the dimensional error in the width and length of each orifice 7 was ± 2 microns with respect to the standard value. When the diaphragm was driven at 8 KHz, the average weight of the ink droplets ejected from each ink nozzle was 0.025 micrograms and the average ink speed was 12 m / s. The variation in ink weight and ink speed was less than 5% in each case, and extremely uniform ejection characteristics were obtained.

In this example, a silicon substrate having a (110) plane crystal plane orientation on the bonding-side substrate surface was used as the second substrate, but a silicon substrate having a (100) plane crystal orientation was used. A substrate may be used.

(Modification 1 of Embodiment 1)

FIG. 3 is an exploded perspective view of an inkjet head 1A according to a modification of the first embodiment. In the inkjet head 1A, the substrate surface 2a of the first silicon single crystal substrate 2 has the same crystal plane orientation as that of the substrate surface 3a of the second silicon single crystal substrate 3 (110). ). The other configuration is the same as that of the ink jet head 1 of the first embodiment, and accordingly, corresponding portions in the drawings are denoted by the same reference numerals.

Also in this example, the grooves 7B for forming each orifice are formed by anisotropic etching. The two side surfaces of each orifice 7 are defined by (111) crystal planes that appear with an inclination of 35 degrees with respect to the substrate surface 2a. The other two sides are defined by (1 1 1) crystal planes that appear perpendicular to the substrate surface 2a.

In this example, the tapered portion 4 b of each ink nozzle 4 is formed along the 2 1 1> axis, so that the roof surface in which the groove opening shape of the substrate surface 2 a is a parallelogram is formed. It is a type.

The inkjet head 1A of this embodiment has an advantage that, in addition to the effects of the first embodiment, silicon single crystal substrates of the same standard can be used as the first and second silicon single crystal substrates 2 and 3.

(Modification 2 of Embodiment 1)

FIGS. 4 and 5 are a cross-sectional view and an exploded perspective view of an ink jet head 1B according to another modification of the first embodiment. Also in the eject head 1B of the present example, the crystal plane orientation of the substrate surface 2a on the bonding side of the first silicon single crystal substrate 2 is the (1 10) is there. However, the groove 7C for forming the orifice 7 is formed along the 211> axis, and the substrate surface has a parallelogram roof shape. The two inclined surfaces of the groove 7C are defined from the (1 1 1) crystal plane inclined at 35 degrees with respect to the substrate surface 2a, and the two side surfaces of the remaining triangle are formed on the substrate surface 2a. It is defined by a (111) crystal plane perpendicular to it. In the thus configured ink jet head 1B of the present example, the groove 7C for forming the orifice can have a greater groove depth by increasing its length. Therefore, even if the width of the groove 7C for forming the orifice is reduced, a necessary orifice cross-sectional area can be secured. Therefore, it is easy to cope with an increase in the nozzle pitch.

(Example 2) FIG. 6 is a sectional view of an ink jet head according to a second embodiment to which the present invention is applied. The ink jet head 1C of the present embodiment is an electrostatically driven ink jet head disclosed in Japanese Patent Application Laid-Open No. 5-50601 proposed by the present applicant. The ink jet head 1C uses an electrostatic force acting between the opposing electrodes to vibrate the vibration plate 8 instead of the piezoelectric element 9, thereby discharging ink droplets.

That is, the ink head 1C also forms an ink supply path by joining the first and second silicon single crystal substrates 20 and 3 °. In the figure, portions corresponding to the above-described examples are denoted by the same reference numerals. A third substrate (electrode glass) 40 is bonded to the back surface of the second silicon single crystal substrate 30, and a groove is formed on the surface of the third substrate 40 facing the diaphragm 8. 40 a is formed, and an individual electrode layer 40 b is formed in the groove 40 a while maintaining a predetermined gap with respect to the diaphragm 8. By applying a driving voltage between the second silicon single crystal substrate 30 on which each diaphragm 8 is formed and each individual electrode 40b, each diaphragm 8 functioning as a common electrode and each individual electrode Electrostatic force is generated between the electrodes 40b, whereby the diaphragm 8 vibrates, the volume of the ink cavity 5 fluctuates, and ink droplets are ejected.

The first silicon single crystal substrate 20 of the ink jet head 1C of this example has a groove 4D for forming an ink nozzle, a groove 7D for forming an orifice, and a groove 7D for forming an ink inlet. A groove 11D is formed. On the other hand, in the second silicon single crystal substrate 30, a groove 5D for forming a cavity and a groove 6D for forming an reservoir are formed.

The first silicon single crystal substrate 20 has a (100) crystal plane orientation of the substrate surface 20a on the bonding side, and the first silicon single crystal substrate 20 has a (100) crystal plane orientation. The crystal plane orientation of the substrate surface 30a is defined as the (110) crystal plane. ing.

In the first and second silicon single crystal substrates 20 and 30 in this example, each groove can be formed by wet-crystal anisotropic etching in the same manner as in each of the above-described embodiments.

Here, in the second silicon single crystal substrate 30, the depth dimension of the groove 5 D for ink cavities is precisely controlled, and the diaphragm 8 defining the bottom surface is accurately targeted. In order to set the etching rate, an etch stop layer may be formed by doping boron or the like on the back surface of the substrate, and then etching may be performed after a short time.

FIG. 7 shows an etching method for this purpose. Referring to this figure, the thickness of the second single crystal silicon substrate 30 used was set to 180 microns. The groove 5D for ink cavities as a deep groove formed on this substrate is, for example, a width of 108 microns, a length of 3.6 millimeters and a depth of 178 microns, and has a common ink reservoir. The shallow groove 6D has a width of 1.5 millimeters, a length of 3.0 millimeters and a depth of 160 microns.

In order to form the grooves 5D and 6D having such a shape, the single crystal silicon substrate 30 may be etched as follows.

First, as shown in FIG. 7 (A), boron is uniformly doped at a high concentration on the back surface of the silicon single crystal substrate 30 to form an etch stop layer 32 having a thickness of 2 to 3 μm. . Further, a SiO 2 film 33 was formed on the surface of the silicon substrate 30.

Next, as shown in FIG. 7 (B), the Sio2 film 33 is etched with hydrofluoric acid while the Sio3 33 is subjected to a predetermined masking, and the deep groove 5 is etched. The opening 35 is formed by removing the portion that becomes D, and the shallow groove 6 D is subjected to half-etching to form a Si 2 having a width of 200 μm or less. A plurality of thin film portions 37 were formed.

After forming the mask pattern in this manner, the concentration is 35% and the temperature is 80. Etching was performed with an aqueous solution of potassium hydroxide C for about 20 to 30 minutes. As a result, as shown in FIG. 7 (C), only the portion where the deep groove 5D was formed was etched by about 80 to 90 microns.

Thereafter, the entire substrate was etched again with hydrofluoric acid to remove the thin three odor portion 37 of Si02. As a result, the other Si 02 film 33 becomes thinner as a whole. This state is shown in FIG. 7 (D).

Thereafter, etching was performed again using a potassium hydroxide aqueous solution having a concentration of 35% and a temperature of 80 ° C. for about 20 to 30 minutes. As a result, as shown in FIG. 7 (E), the portion where the deep groove 5D was formed was etched by about 165 to 170 microns, and the part where the shallow groove 6D was formed was etched by about 80 to 90 microns. .

Thereafter, etching was performed for about 40 to 50 minutes using an aqueous solution of hydrating hydroxide at 80 ° C. at a concentration of 2 to 5% as an etching solution. As a result, as shown in FIG. 7 (F), in the portion where the deep groove 5D is formed, a groove having a depth reaching the etch stop layer 32 formed on the back side of the silicon substrate is formed, and the other shallow groove 6D is formed. At the formation portion of, etching proceeded in the lateral direction, and a wide groove was formed.

As described above, also in the ink jet head 1C of the present embodiment, the ink nozzle 4, the orifice 7, and the ink supply port can be formed with high accuracy, as in the first embodiment. Further, the thickness of the diaphragm 8 can be formed with high accuracy. Therefore, it is possible to suppress variations in the ink ejection characteristics of each ink nozzle, and to realize an ink jet head capable of performing printing with high print quality. Industrial applicability As described above, the present invention relates to an ink jet head having first and second silicon single crystal substrates each having an ink cavity, an orifice, and an ink reservoir formed by bonding the first silicon substrate to each other. The single-crystal substrate is subjected to wet-crystal anisotropic etching or dry-etching on the substrate surface on the bonding side to form an ink nozzle and a groove for forming an orifice. On the substrate, a groove for forming an ink cavity and a groove for forming an ink reservoir are formed by performing wet crystal anisotropic etching on the surface of the substrate on the bonding side. I have to.

Therefore, in the inkjet head of the present invention, relatively small-sized ink nozzles and grooves for forming orifices are formed in the first silicon single crystal substrate, and relatively large-sized ink cavities are formed. And a groove for forming an ink reservoir is formed in the second silicon single crystal substrate. As a result, compared to the case where the groove for forming the ink supply passage is etched only on one of the substrates, it is easier to control the etching conditions for forming the groove of each dimension. Good etching becomes easy.

Further, in the present invention, when dry etching is used to form an ink nozzle and a groove for forming an orifice in the first silicon single crystal substrate, wet crystal anisotropic etching is performed. In general, these parts can be formed with higher accuracy than in the case of employing.

Further, in the inkjet head of the present invention, when a groove is formed on the first silicon single crystal substrate by using wet-crystal anisotropic etching, the first silicon single crystal substrate is formed as the first silicon single crystal substrate. The substrate surface on the bonding side has a (100) plane orientation or a (110) plane orientation, preferably a (100) crystal plane. As a result, both side walls in the width direction of the formed orifice forming groove are defined by the (111) crystal plane. It is possible to accurately set the cross-sectional area of the groove to a target value. As a result, variations in the fluid resistance of the orifice can be suppressed, and the ink ejection characteristics can be improved. Furthermore, in the present invention, as the second silicon single crystal substrate, one having a (110) plane orientation of the substrate surface on the bonding side is used. If a plurality of grooves for ink cavities are formed by performing anisotropic etching from the substrate surface with this crystal plane orientation, each ink cavity can be formed with high precision and high density, making it easy to increase the nozzle pitch. Can respond to.

In addition to the above, in the partition wall between the groove for forming each of the ink cavities in the second silicon single crystal substrate and the groove for forming the ink reservoir, the groove for forming the orifice is formed. The wall portions located at both ends in the longitudinal direction can be defined by the (111) crystal plane. The length of the orifice is precisely defined by the (1 1 1) crystal plane. As described above, since the length of the orifice can be made with high accuracy, the variation in the fluid resistance of the orifice can be suppressed, and the ink ejection characteristics can be improved.

Claims

The scope of the claims

1. a plurality of ink nozzles, an ink cavity communicating with each ink nozzle, a common ink reservoir for supplying ink to each ink cavity, and an orifice communicating each ink cavity with the ink reservoir. A diaphragm defining the bottom surface of each of the ink cavities of

A first and a second silicon single crystal substrate on which the ink cavities, the orifices, and the ink reservoir are formed by being bonded to each other;

The first silicon single crystal substrate has a first groove for forming the orifice on the surface of the substrate on the bonding side,

The second silicon single crystal substrate includes a second groove for forming the ink cavity and a third groove for forming the ink reservoir formed on the surface of the substrate on the bonding side. Preparation

An ink jet head, wherein the shape of the first groove is defined by a wall surface formed by a (111) crystal plane.

2. In Claim 1, the crystal plane orientation of the substrate surface on the bonding side of the first silicon single crystal substrate is (100) plane orientation or (1).

:)) An ink jet head characterized by a plane orientation.

3. The ink jet head according to claim 2, wherein the crystal orientation of the substrate surface on the bonding side of the second silicon single crystal substrate is a (110) plane orientation. De.

4. The partition according to claim 3, wherein a partition wall between the groove for forming each of the ink cavities and the groove for forming the ink reservoir in the second silicon single crystal substrate is: An ink jet head, characterized in that the wall portions located at both ends in the longitudinal direction of the groove for forming the orifice are (111) crystal planes.

5. The first silicon single crystal substrate according to claim 1, wherein the first silicon single crystal substrate includes a fourth groove for forming the ink nozzle on a surface of the substrate on a bonding side thereof, and a shape of the fourth groove. An ink jet head, wherein is defined by a wall surface formed by a (111) crystal plane.

6. The method according to claim 1, further comprising an ink intake port communicating with the ink reservoir, wherein the first silicon single crystal substrate has the ink intake port on a substrate surface on a bonding side thereof. An ink jet head comprising: a fifth groove to be formed, wherein the shape of the fifth groove is defined by a wall surface formed by a (111) crystal plane.

7. a plurality of ink nozzles, ink cavities communicating with the respective ink nozzles, a common ink reservoir for supplying ink to the respective ink cavities, and an orifice communicating the respective ink cavities with the ink reservoir, A method of manufacturing an ink head having a diaphragm defining a bottom surface of each ink cavity of the above.

Prepare a first silicon single crystal substrate with a (100) or (1 10) crystal plane orientation on the substrate surface,

Wet crystal anisotropic etching on the substrate surface of the first silicon single crystal substrate Forming at least the groove for forming the orifice so that the crystal plane orientation of the wall surface becomes the (111) crystal plane.

Prepare a second silicon single crystal substrate with a (100) or (1 10) crystal plane orientation of the substrate surface,

Performing a wet crystal anisotropic etching on the substrate surface of the second silicon single crystal substrate to form a groove for forming the ink cavity and a groove for forming the ink reservoir;

By bonding the substrate surfaces of the first and second silicon single crystal substrates to each other, the ink nozzle, the ink cavity, the ink reservoir, and the orifice communicating the ink cavity and the ink reservoir are formed. A method for manufacturing an inkjet head, comprising:

8. The partition wall according to claim 7, which separates a groove for forming each of the ink cavities and a groove for forming the ink reservoir in the second silicon single crystal substrate. The groove for ink cavity and the groove for ink reservoir are etched so that the wall portions located at both ends in the longitudinal direction of the orifice in (1) are (111) crystal planes. Inkjet manufacturing method.

9. In Claim 7, the surface of the first silicon single crystal substrate is subjected to wet-crystal anisotropic etching, and the crystal plane orientation of the wall surface becomes (111) crystal plane. Thus, a method for manufacturing an ink jet head, wherein the groove for forming the ink nozzle is formed.

10. In claim 9, the ink nozzle is formed by performing dry etching from a back side of a surface on which the groove for forming the ink nozzle is formed. A method for producing an ink jet head.

11. The method according to claim 7, wherein the surface of the first silicon single crystal substrate is subjected to wet crystal anisotropic etching, and the crystal plane orientation of the wall surface is set to (111) crystal plane. A method for manufacturing an ink jet head, comprising forming a groove for forming an ink intake port communicating with the ink reservoir.

12. The method according to claim 7, wherein an etch stop layer is formed on a back surface of the substrate surface before performing wet-crystal anisotropic etching on the substrate surface of the second silicon single crystal substrate. A method for producing an ink jet head.