JP3133171B2 - Method of manufacturing inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an ink-jet head for performing recording by discharging ink droplets.

In an ink jet head, since the ink in a pressure chamber is ejected from a nozzle, it is necessary to form the nozzle diameter uniformly so that the size of the ink droplet does not vary.

[0003]

2. Description of the Related Art Conventionally, in order to form a nozzle, for example, as shown in FIG. 8, a single crystal silicon wafer 51 is subjected to wet anisotropic etching from both sides.
The through-hole was used as the nozzle 52.

[0004]

The speed of the etching process is greatly affected by the temperature of the etching solution. Therefore, it is desirable that the temperature of the etching liquid is always a predetermined constant temperature during the etching process. However, since the above-described processing of the hole of the nozzle requires a processing time of several hours, it is inevitable that the temperature of the etching solution fluctuates during the processing.

As a result, the ratio of the depth of the etching process from both surfaces to the single crystal silicon wafer 51 varies, the nozzle diameter varies, and the size of the ink droplet varies depending on the nozzle, thereby deteriorating the recording quality. Was causing it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing an ink jet head which can form a nozzle hole uniformly and accurately by double-sided etching.

[0007]

In order to achieve the above-mentioned object, a method of manufacturing an ink jet head according to the present invention is described with reference to FIG. , 3 between which the buffer layer 2 having a lower etching rate than that of the single-crystal silicon wafers 1, 3 is sandwiched, and these are integrally brought into close contact with each other. Etching is performed from both sides of the single crystal silicon wafers 1 and 3 to form holes 5 and 6 whose bottoms reach the buffer layer 2 respectively. The nozzle holes 7 are formed by etching from the side.

The buffer layer 2 may be a layer of silicon dioxide deposited on one surface of the two single-crystal silicon wafers 1 and 3. In this case, the buffer layer 2 is It is preferable to deposit only a thickness corresponding to the nozzle length.

A plurality of nozzle plates 10 having a plurality of nozzle holes 7 may be manufactured from the buffer layer 2 and two single-crystal silicon wafers 1 and 3 sandwiching the buffer layer 2.

[0010]

When holes 5 and 6 whose bottoms reach buffer layer 2 are formed by etching from both surfaces of two single-crystal silicon wafers 1 and 3 integrated with buffer layer 2 interposed therebetween, the etching rate is increased. Is not etched, and the bottoms of the holes 5 and 6 both stop at the surface of the buffer layer.

Therefore, each etching depth is the thickness of the single-crystal silicon wafers 1 and 3 as a raw material, and is not affected by the etching rate or the like. Does not vary,
The exact bottom diameter as expected is obtained.

Next, the buffer layer 2 is etched from the side where the bottom diameter of the holes 5 and 6 is small, so that the nozzle hole 7 having the same diameter as the bottom diameter of the hole 5 or 6 having the smaller bottom diameter. Formed on layer 2.

[0013]

An embodiment will be described with reference to the drawings. In FIG. 2, reference numeral 1 denotes a single-crystal silicon wafer, and a silicon dioxide (SiO ₂ ) layer 2 is deposited on the surface of the single-crystal silicon wafer 1 by thermal oxidation to a thickness (for example, 1 μm) corresponding to the nozzle length.

The silicon dioxide layer 2 has a much lower etching rate than the single crystal silicon wafer 1 and serves as a buffer layer during etching. Hereinafter, this layer is referred to as a buffer layer 2. The buffer layer 2 may be made of any material having a lower etching rate than that of the single crystal silicon wafer 1, and may be made of silicon nitride, polycrystalline silicon, a metal thin film, or the like.

Next, as shown in FIG. 3, another single-crystal silicon wafer 3 is joined to the buffer layer 2. In this case, since the buffer layer 2 is silicon dioxide, by heating in a vacuum at, for example, 1100 ° C. for about 30 minutes,
Both are directly joined without using an adhesive or the like.

Next, as shown in FIG. 4, wet etching is performed on both surfaces of the single crystal silicon wafers 1 and 3 integrated with the buffer layer 2 therebetween, for example, using potassium hydroxide to reach the buffer layer 2. I do.

At this time, holes 5 and 6 formed by etching from both sides are aligned with each other at the center, and the diameter d of the bottom of one hole 5 facing buffer layer 2 is
The required diameter (for example, 50 μm) of the nozzle diameter and the diameter D of the bottom of the other hole 6 are formed to be larger than that.

At this time, each single-crystal silicon wafer 1, 3
Etching depth of the material single crystal silicon wafers 1, 3
Since the thickness itself is not affected by the etching rate or the like, even if the etching temperature fluctuates during the etching process, the bottom diameters d and D do not vary, and the exact bottom diameters d and D are as planned. Is obtained.

When the single crystal silicon wafers 1 and 3 are etched as described above, the buffer layer 2 also comes into contact with the etching solution. However, the buffer layer 2 has a very low etching rate, and can be said to be completely intact. Not as etched. Note that a dry etching process such as a reactive ion etching process may be performed instead of the wet etching process.

Next, as shown in FIG. 1, the buffer layer 2 is etched with hydrogen fluoride or the like, for example, for 3 minutes from the surface of the bottom portion facing the buffer layer 2 where the diameter d is small. By this processing, the buffer layer 2 has a predetermined diameter d.
A nozzle hole 7 (for example, 50 μm) is formed to penetrate.

The nozzle plate 10 formed as described above
Are connected to the ink flow path 21 and the pressure chamber 2 as shown in FIG.
An ink jet head can be obtained by bonding to the single crystal silicon wafer 20 on which 2 is formed. 23 is a piezoelectric element.

Although one ink jet head requires one nozzle plate 10 in which a large number of nozzle holes 7 are formed, as shown in FIG. 6, in this embodiment, a large number of nozzle plates 7 are provided. The above-described etching process is performed on a set of large single-crystal silicon wafers 1 and 3 on which the nozzle plate 10 can be formed, and is cut to obtain the nozzle plates 10 one by one.

FIG. 7 is an enlarged view of the portion A shown in FIG. 6, and shows the positional relationship of the nozzle hole 7 with respect to the ink flow path 21 and the pressure chamber 22.

[0024]

According to the method of manufacturing an ink jet head of the present invention, the bottom diameter of an etching hole formed in a single crystal silicon wafer is not affected by an etching temperature or the like, and is equal to the bottom diameter of a buffer layer. Since the nozzle hole is formed, the diameter of the nozzle hole can be formed uniformly and accurately without variation.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view showing a manufacturing process of an embodiment.

FIG. 2 is a partially enlarged sectional view showing a manufacturing process of the embodiment.

FIG. 3 is a partially enlarged sectional view showing a manufacturing process of the example.

FIG. 4 is a partially enlarged sectional view showing a manufacturing process of the example.

FIG. 5 is a partially enlarged sectional view showing a manufacturing process of the example.

FIG. 6 is an overall plan view showing a manufacturing process of the example.

FIG. 7 is a partial plan view showing a manufacturing process of the example.

FIG. 8 is a partially enlarged sectional view showing a conventional manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single crystal silicon wafer 2 Buffer layer 3 Single crystal silicon wafer 5 Hole 6 Hole 7 Nozzle hole

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-49275 (JP, A) JP-A-4-125159 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/135

Claims (3)

(57) [Claims] 1. A buffer layer (2) having an etching rate lower than that of said single crystal silicon wafer (1, 3) is sandwiched between two single crystal silicon wafers (1, 3).
These are integrally brought into close contact with each other, and etching is performed from both surfaces of the two single-crystal silicon wafers (1, 3) integrated with the buffer layer (2) interposed therebetween. After forming the holes (5, 6) reaching 2), the buffer layer (2) is etched from the side having the smaller bottom diameter of the holes (5, 6) to form the nozzle holes (7). A method for manufacturing an ink jet head, comprising: 2. The buffer layer (2) is a layer of silicon dioxide deposited on one surface of the two single crystal silicon wafers (1, 3) by a thickness corresponding to a nozzle length. A method for manufacturing an ink jet head according to claim 1. 3. A plurality of nozzle plates (10) having a plurality of nozzle holes (7) are manufactured from the buffer layer (2) and two single-crystal silicon wafers (1, 3) sandwiching the buffer layer (2). The method for manufacturing an ink jet head according to claim 1.