JPH09216368A - Ink jet nozzle plate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce orifices and taper parts high in shape accuracy and to inexpensively provide an ink jet recording apparatus excellent in printing quality. SOLUTION: Orifices 2 are formed to the active layer 4 of an SOI substrate 1 by plasma etching and taper parts 3 are formed to the part corresponding to the support 5 of the SOI substrate 1 to form an ink jet nozzle plate. The taper parts 3 are formed by alkali anisotropic etching or by alkali anisotropic etching and plasma etching succeeding thereto. The SOI substrate having the active layer 4 formed thereto by a CVD method is used to form the ink jet nozzle plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet nozzle plate used in a head portion of an ink jet recording apparatus for ejecting ink droplets on paper or the like for printing, and a method for manufacturing the same, which nozzles are formed. Regarding

[0002]

2. Description of the Related Art Up to now, various types of ink jet recording apparatuses have been developed. Among them, an electrostatic ink jet recording apparatus proposed by the present applicant in JP-A-5-50601 is known. A face type ink jet head having nozzles formed on the surface of a substrate has been proposed as one method of the ink jet recording apparatus, which has characteristics of high printing quality and long life. Further, the applicant of the present invention has proposed a method of manufacturing an inkjet nozzle plate made of Si having a high density, that is, a small pitch between nozzles, which is an ejection port of an ink droplet, in Japanese Patent Laid-Open No. 4-312853. In the ink jet recording apparatus using these ink jet recording apparatuses or ink jet nozzle plates, higher printing quality and durability were obtained as compared with the conventional ink jet recording apparatuses, but, for example, the above-mentioned JP-A-4-312.
The inkjet nozzle plate proposed in Japanese Patent No. 853 has a variation of about ± 3 microns in the length of the orifice.

[0003]

Generally, the print quality in an ink jet recording apparatus is affected by variations in characteristics such as ink droplet size and ink ejection speed, and these characteristics are greatly affected by variations in fluid resistance of orifices. to be influenced. In order to obtain higher printing quality, the dimensional tolerances such as the diameter and length of the orifice become strict, and specifically, a processing accuracy of about ± 1 micron is required.

Therefore, the present invention solves the above problems, and an object of the present invention is to provide an ink jet nozzle plate which is required for an ink jet recording apparatus of high printing quality and has a small dimensional variation of each nozzle portion. Where it is. Another object of the present invention is to inexpensively provide an inkjet nozzle plate in which the dimensional variation of each part of the nozzle is small.

[0005]

An ink jet nozzle plate of the present invention is used in an ink jet recording apparatus, wherein the Si substrate is an SOI substrate, and the Si substrate is an SOI substrate.
A single or a plurality of orifices are formed in the active layer of the OI substrate so as to penetrate the active layer, and a tapered hole is formed at a position corresponding to the orifice of the support of the SOI substrate so as to penetrate the support. It is characterized in that it communicates with the tapered hole.

SOI (Silicon on Insu)
The “later) substrate is a Si substrate having a SiO ₂ layer in the substrate, which has been developed for the purpose of speeding up the LSI. The SOI substrate is generally made of SiO ₂ as a dielectric layer on a Si plate called a support having a thickness of several hundreds of microns.
A layer is formed, and a thin (0 to several microns) Si layer called an active layer is formed on the layer, and the thickness of the active layer is formed with extremely high accuracy (generally, the thickness is An accuracy of 0.01 micron) is used in the manufacture of LSI, but an integrated circuit is formed in the active layer. In the present invention, an SOI substrate is used, and an orifice, which is a hole for ejecting ink onto paper or the like, is formed in the active layer of the SOI substrate, so that the length of the orifice is equal to the thickness of the active layer. High shape accuracy can be achieved.

Further, the ink jet nozzle plate of the present invention is characterized in that the active layer of the SOI substrate is made of polycrystalline Si formed by a CVD method.

The SOI substrate is generally manufactured by a method called a bonding method. In this method, a SiO ₂ film is formed by a thermal oxidation method on either or both of the bonding surfaces of a Si substrate to be an active layer and a Si substrate to be a support, and then both substrates are bonded to form an active layer. Although such a Si substrate is processed into a desired thickness by a method such as polishing, the manufacturing cost is very high because it takes time for the steps such as bonding and polishing. In the present invention, Si formed by the CVD method on the support as an active layer
Since the layer is used as the active layer, there is an advantage that the manufacturing cost of the SOI substrate is low.

Further, the method for manufacturing an ink jet nozzle plate of the present invention is characterized in that the above-mentioned orifice is formed by plasma etching, and that the plasma etching uses a halogen-based gas.
The tapered hole is formed by plasma etching, and a fluorine-based gas is used in this plasma etching. Further, as a method of forming the tapered hole, it is characterized in that it is formed by alkali anisotropic etching.

In plasma etching, generally, etching with good shape accuracy can be performed by adjusting conditions such as type of etching gas, pressure, electric power for generating plasma. In particular, Si has a high vapor pressure of halides such as chlorides and fluorides, so that plasma etching using chlorine-based or fluorine-based gas
Although the etching rate is high and processing with good shape accuracy is possible, the depth of the orifice and the tapered hole is extremely small because the SiO ₂ layer in the SOI substrate acts as an etching stop layer in plasma etching. Can be formed with high precision. The tapered shape formed by alkali anisotropic etching is also suitable as the shape of the tapered hole of the inkjet nozzle, and as described above, the SiO ₂ layer in the SOI substrate is an etching stop layer even in alkaline anisotropic etching. Therefore, the depth of the tapered hole can be formed very accurately.

Further, the method for manufacturing an ink jet nozzle plate of the present invention is characterized in that the tapered hole is formed by plasma anisotropic etching after alkaline anisotropic etching. The shape of the tapered hole obtained by further plasma etching the tapered hole formed by alkali anisotropic etching is also suitable as the shape of the tapered hole of the inkjet nozzle.

[0012]

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1A is a perspective view of an ink jet nozzle plate according to the first embodiment of the present invention, showing a partial cross section. FIG. 1B shows A- in FIG.
It is an expanded sectional view of the nozzle part of A '. As shown in FIG. 1, the inkjet nozzle plate of this embodiment has a structure in which an orifice 2 is formed in an active layer 4 of an SOI substrate 1, and a tapered portion 3 is formed in a support body 5. Substrate 1 has Si thermal oxide film (SiO ₂ ) inside
The active layer 4 and the support 5 are electrically separated by the dielectric layer 6 which is
Are both made of Si single crystal. FIG. 2 shows a manufacturing process of the inkjet nozzle plate shown in FIG. Active layer 4
Of 15 μm, the thickness of the dielectric layer 6 is 0.1 μm, and the thickness of the support 5 is 100 μm.
The OI substrate 1 (both the crystal plane orientations of the active layer 4 and the support 5 are the (100) plane) is heat-treated at 1100 degrees Celsius for 4 hours in an oxygen atmosphere containing water vapor, and the SOI is obtained.
Thermal oxide films 8 and 9 having a thickness of 1.5 μm are formed on both surfaces of the substrate 1 (FIG. 2A). Then, the thermal oxide films 8 and 9 are subjected to a photoetching process to process the patterns corresponding to the orifices 2 and the tapered portions 3 (FIG. 2B). Next, the surface on which the thermal oxide film 8 is formed (the surface on the active layer side) is subjected to the first plasma etching treatment to form the orifice 2 (FIG. 2C). A halogen (fluorine, chlorine, bromine) -based gas is used for this plasma etching, and the conditions are such that holes perpendicular to the substrate surface are processed. , Processing that is almost vertical can be performed. Further, in the plasma etching process, the dielectric layer 6 is exposed when all the Si to be removed by etching is exposed and the etching is automatically terminated (etch stop), and the orifice length at that time is the active layer 4 Is processed to have the same thickness. That is, even if there is a variation in the etching rate of Si between the wafer and the batch during plasma etching, the variation is within the range of the thickness variation of the active layer 4 (± 0.
A nozzle having a fixed length of about 01 micron can be easily formed. In plasma etching using a halogen-based gas, the etching rate of SiO ₂ is much smaller than the etching rate of Si, so that etching can be stopped. Next, in order to form the tapered portion 3, the surface on which the tapered portion 3 is formed is subjected to the second plasma etching process. In this plasma etching, unlike the condition of the first plasma etching in which the orifice 2 is formed, it is possible to process the taper shape with a large amount of undercut by mainly using the fluorine-based gas (FIG. 2 (d). )). Taper part 3 as in orifice processing
Even in the above process, the plasma etching process automatically ends when the dielectric layer 6 appears on the bottom surface of the processed part, so that the taper part 3 can be processed very accurately. Finally,
The entire SOI substrate 1 is immersed in a hydrofluoric acid-based etching solution to remove the thermal oxide films 8 and 9 and the dielectric layer 6 between the orifice 2 and the taper portion 3 to complete an inkjet nozzle plate (see FIG. e)). In the ink jet nozzle plate of this embodiment, the processing accuracy of the nozzles (orifices 2 and taper portions 3), which are the flow paths of the ink liquid, is finished within ± 1 micron of the dimensional design value, that is, the flow of the ink liquid. As for the fluid resistance to, the variation between nozzles is very small, and when a print inspection was performed with an inkjet recording device assembled using this inkjet nozzle plate, there was a very large variation in the ink discharge amount and speed between nozzles. It was possible to provide an ink jet recording apparatus that is small and has excellent print quality. In this example, both the active layer 4 and the support 5 had the (100) plane orientation, but even if another surface such as (110) is used, the plane orientations of the active layer and the support may be different. Even with such a combination, the above effect does not change.

Next, another embodiment (second embodiment) of the present invention will be described in detail.

FIG. 3A is a perspective view of an ink jet nozzle plate according to the second embodiment of the present invention, showing a partial cross section. FIG. 3B shows AA ′ of FIG.
3 is an enlarged cross-sectional view of the nozzle portion of FIG. As shown in FIG. 3, the inkjet nozzle plate in this embodiment is an SOI substrate processed in the same manner as in the first embodiment of the present invention, but has a tapered portion 3a formed on the support 5a.
Is formed by crystal anisotropic etching using alkali. FIG. 4 shows a manufacturing process of the inkjet nozzle plate shown in FIG. The thicknesses of the active layer 4a, the dielectric layer 6a, and the support 5a are the same as those in the first embodiment of the present invention. However, the crystal plane orientations of the active layer 4a and the support 5a are (110 Surface) is formed with the thermal oxide films 8a and 9a in the same manner as in the first embodiment of the present invention (FIG. 4A), and then the orifice 2a and the tapered portion are formed on the thermal oxide films 8a and 9a, respectively. Three
A pattern corresponding to a is formed (FIG. 4B). At that time, the thermal oxide film 8a is half-etched by the hydrofluoric acid-based etching solution so as to leave a part (0.7 μm) in the thickness direction of SiO ₂ . The pattern of the thermal oxide film 9 is a pattern depending on the crystal orientation for forming the tapered portion 3a by wet alkaline anisotropic etching of Si. In the step of FIG. 4C, the crystal anisotropic etching using the above alkali is performed to form the tapered portion 3a. In this embodiment, a KOH aqueous solution having a concentration of 17% by weight is used as the alkaline solution at 80 ° C.
Etching was performed for a predetermined time by using the one that was heated once. The predetermined time is the time during which the thickest portion of the support 5a (average thickness in the present embodiment + 10 microns or less) can be penetrated by etching in one batch. In this case, in the thinner portion of the support 5a, overetching occurs, but as in the case of the first embodiment, the dielectric layer 6a appears automatically when the support 5a is completely etched, and automatically. It will be an etch stop. Next, the SOI substrate 1a is treated with a hydrofluoric acid-based etching solution to remove the thermal oxide film 8
A portion of a which is left by the half etching in the step of FIG. 4B is removed (FIG. 4D). Initially, the thickness of SiO _{2 in} this portion was 0.7 μm, but FIG.
In the step (c), it is about 0.3 micron,
The etching with the above-mentioned hydrofluoric acid-based etching solution is 0.
It suffices to perform the treatment for a time sufficient to remove 3 μm of SiO ₂ . Next, plasma etching of the surface on the thermal oxide film 8a side is performed in the same manner as in the first embodiment of the present invention to form the orifice 2a (FIG. 4 (e)). Finally, SO
The entire I substrate 1a is immersed in a hydrofluoric acid-based etching solution to remove the thermal oxide films 8a and 9a, and the inkjet nozzle plate is completed (FIG. 4 (f)). In the ink jet nozzle plate of this embodiment, the processing accuracy of the nozzles (orifices 2a and taper portions 3a), which are the flow paths of the ink liquid, is finished within ± 1 micron with respect to the dimensional design value as in the first embodiment. Therefore, the variation in the fluid resistance value is very small. In this embodiment, the active layer 4a and the support 5 are
Although a has a (110) plane orientation, other plane orientations such as (100) do not change the above effect.

Next, another embodiment (third embodiment) of the present invention will be described in detail.

FIG. 5A is a perspective view of an ink jet nozzle plate according to the third embodiment of the present invention, showing a partial cross section. FIG. 5B is A-A of FIG.
It is an expanded sectional view of the nozzle part of '. As shown in FIG. 5, the inkjet nozzle plate in this embodiment is an SOI substrate processed in the same manner as in the first embodiment of the present invention, but the tapered portion 3b formed on the support 5b is used.
Is formed by crystal anisotropic etching using alkali and plasma etching. FIG. 6 shows a manufacturing process of the inkjet nozzle plate shown in FIG. The thicknesses of the active layer 4b, the dielectric layer 6b and the support 5b are the same as in the first embodiment of the present invention S.
Thermal oxide films 8b and 9b are formed on the OI substrate 1b (however, the crystal plane orientation of the active layer 4b and the support 5b is the (100) plane) as in the case of the first embodiment of the present invention (see FIG. 6
(A)), the orifice 2 is formed in each of the thermal oxide films 8b and 9b.
A pattern corresponding to b and the tapered portion 3b is formed (FIG. 6B). At that time, the thermal oxide film 8b is half-etched by the hydrofluoric acid-based etching solution so as to leave a part (0.7 μm) in the thickness direction of SiO ₂ . The shape of the pattern corresponding to the tapered portion 3b is square, and the length of one side thereof is 110 microns, for example. Next, similar to the second embodiment of the present invention, wet alkaline anisotropic etching is performed for a predetermined time to form the inverted pyramid type hole 10b (FIG. 6C). Then, similarly to the first embodiment of the present invention, the dielectric layer 6b appears on the side of the thermal oxide film 9b by the plasma etching mainly using the fluorine-based gas under the condition that the amount of undercut is large. Processing is performed until the tapered portion 3b is formed (see FIG. 6).
(D)). Next, the SOI substrate 1b is treated with a hydrofluoric acid-based etching solution to remove the portion of the thermal oxide film 8b left by the half etching in the step of FIG. 6B (FIG. 6E). Initially the thickness of SiO _{2 in} this part is 0.7
Although it was micron, it was about 0.3 in the process of FIG.
Since the etching is performed using the hydrofluoric acid-based etching solution, it suffices to perform the treatment for a time sufficient to remove 0.3 μm of SiO ₂ . Next, the thermal oxide film 8
Similar to the case of the first or second embodiment of the present invention, the side b is subjected to S
Plasma etching is performed until the OI substrate 1b penetrates to form the orifice 2b (FIG. 6 (f)), and finally S
The entire OI substrate 1b is immersed in a hydrofluoric acid-based etching solution to remove the thermal oxide films 8b and 9b, and an inkjet nozzle plate is completed (FIG. 6 (g)). The ink jet nozzle plate in this embodiment is different from the first and second embodiments of the present invention (see FIG. 1B, FIG. 3B and FIG. 5).
(Compare (b)), aspect ratio of taper hole 3b (depth /
Since the planar dimension) can be increased, the range of selection of the flow path resistance value of the nozzle is expanded. Further, since the ratio of the plasma etching amount in the taper hole processing is reduced, the cost can be reduced. In the present embodiment, the active layer 4b has the (100) plane orientation, but other planes such as the (110) plane do not change the above effect.

Next, another embodiment (fourth embodiment) of the present invention will be described in detail.

The ink jet nozzle plate (not shown) in this embodiment is an SOI substrate processed in the same manner as in the first embodiment of the present invention, and the size, shape, processing process, etc. are the same as those of the first embodiment of the present invention. It is basically the same as the example.
The difference is that the active layer is not made of single crystal Si but made of polycrystalline Si formed by the CVD method. As described above, by forming the active layer by the CVD method,
In this embodiment, under the same conditions as in the case of the first embodiment of the present invention, a plasma etching process is performed on the active layer so that the processed surface can be made perpendicular to the SOI substrate surface. The etching rate, size, and shape in Fig. 1 hardly depend on the crystallinity of the material to be processed (whether it is single crystal or polycrystal), that is, the size and shape are the same as those of the first embodiment of the present invention. It is almost the same as the case of, and within the design standard of ± 1 micron is achieved. Therefore, the ink ejection characteristics of the ink jet head using the ink jet nozzle plate in this embodiment are excellent in print quality as in the case of the first embodiment of the present invention, and such an ink jet nozzle plate is used. It was possible to provide it at low cost.

[0020]

As described above, according to the present invention,
In an inkjet nozzle plate having a Si substrate as a constituent member, an SOI substrate is used, and by forming an orifice and a taper portion to be nozzles in an active layer of the SOI substrate and a support, a nozzle for an inkjet head with extremely high accuracy is provided. Therefore, it is possible to provide an inkjet head with high print quality.

Further, according to the present invention, the orifice is formed by plasma etching, and the tapered portion is formed by plasma etching or alkali anisotropic etching or alkali anisotropic etching followed by plasma etching. As a result, a highly accurate nozzle can be obtained, and thus an inkjet head with high print quality can be provided.

According to the present invention, the active layer is CV
By forming it by D, a highly accurate nozzle plate can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a partial cross section of an inkjet nozzle plate and an enlarged cross sectional view of a nozzle portion according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of an inkjet nozzle plate according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a partial cross section of an ink jet nozzle plate in another embodiment of the present invention and an enlarged cross sectional view of a nozzle portion.

FIG. 4 is a manufacturing process diagram of an inkjet nozzle plate according to another embodiment of the present invention.

5A and 5B are a perspective view showing a partial cross section of an ink jet nozzle plate and an enlarged cross sectional view of a nozzle portion according to still another embodiment of the present invention.

FIG. 6 is a manufacturing process diagram of an ink jet nozzle plate in still another embodiment of the present invention.

[Explanation of symbols]

 1, 1a, 1b SOI substrate 2, 2a, 2b Orifice 3, 3a, 3b Tapered part 4, 4a, 4b Active layer 5, 5a, 5b Support 6,6a, 6b Dielectric layer 8, 8a, 8b Thermal oxide film 9, 9a, 9b Thermal oxide film 10b Reverse pyramid type hole

Claims (8)

[Claims] 1. An S used in an ink jet recording apparatus,
In an inkjet nozzle plate having an i substrate as a constituent member, the Si substrate is an SOI substrate,
A single or a plurality of orifices are formed in the active layer of the substrate so as to penetrate the active layer, and a tapered hole is formed in the support of the SOI substrate at a position corresponding to the orifice so as to penetrate the support. The inkjet nozzle plate, wherein the orifice and the tapered hole are communicated with each other. 2. The inkjet nozzle plate according to claim 1, wherein the active layer of the SOI substrate is made of polycrystalline Si formed by a CVD method. 3. An ink jet recording apparatus, comprising:
In an inkjet nozzle plate manufacturing method using an i substrate as a constituent member, a Si substrate is used as an SOI substrate, and
A single or a plurality of orifices are formed in the active layer of the OI substrate by plasma etching so as to pass through the active layer, and the support is passed through the support at a location corresponding to the orifice. A method for manufacturing an inkjet nozzle plate, characterized in that a tapered hole is formed by plasma etching and the orifice and the tapered hole are communicated with each other. 4. An ink jet recording apparatus, comprising:
In an inkjet nozzle plate manufacturing method using an i substrate as a constituent member, a Si substrate is used as an SOI substrate, and
A single or a plurality of orifices are formed in the active layer of the OI substrate by plasma etching so as to pass through the active layer, and the support is passed through the support at a location corresponding to the orifice. A method for manufacturing an inkjet nozzle plate, characterized in that a tapered hole is formed by alkali anisotropic etching, and the orifice and the tapered hole are communicated with each other. 5. An S used in an ink jet recording apparatus,
In an inkjet nozzle plate manufacturing method using an i substrate as a constituent member, a Si substrate is used as an SOI substrate, and
A single or a plurality of orifices are formed in the active layer of the OI substrate by plasma etching so as to pass through the active layer, and the support is passed through the support at a location corresponding to the orifice. A method of manufacturing an inkjet nozzle plate, characterized in that a tapered hole is formed by plasma etching subsequent to alkali anisotropic etching, and the orifice and the tapered hole are communicated with each other. 6. The method for manufacturing an inkjet nozzle plate according to claim 3, wherein the active layer of the SOI substrate is formed by a CVD method. 7. The method of manufacturing an inkjet nozzle plate according to claim 3, wherein the method of manufacturing the orifice is plasma etching using a halogen-based gas. 8. The method of manufacturing an ink jet nozzle plate according to claim 3, wherein the method of manufacturing the tapered hole by plasma etching is plasma etching using a fluorine-based gas.