JPH04312853A - How to form nozzle rows in inkjet printers - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an inkjet nozzle array, which is used in the head section of an inkjet printer that prints by jetting ink droplets onto paper, etc. Regarding the manufacturing method.

0002

2. Description of the Related Art Up to now, ink jet nozzle arrays of various materials and shapes have been devised and manufactured. Among them, Applied Physics
Letters magazine, Volume 31, No. 2, 1977, 13
The inkjet nozzle array, in which each nozzle is formed in an inverted pyramid shape surrounded by four (111) planes, is formed by alkali anisotropic etching on a (100) silicon substrate, as described on page 5-137. It is ideal for inkjet printer heads that require high-definition printing due to its simple manufacturing process and good shape accuracy due to anisotropic etching. FIG. 5 shows the manufacturing process of the above-mentioned inkjet nozzle array. (100)
A mask pattern of an etching-resistant material (usually a silicon oxide film) corresponding to the inkjet nozzle array is formed on one surface 52 of the silicon substrate 51, and an etching-resistant material is formed on the entire surface of the other surface 53. An inkjet nozzle array was formed by etching a predetermined amount (here, until each nozzle penetrated).

0003

[Problem to be solved by the invention] As mentioned above (10
0) In an inkjet nozzle array using a silicon substrate, the angle formed by the (111) plane 69 forming the nozzle wall and the (100) plane 63 which is the surface of the silicon substrate is 54.7° as shown in FIG. be. That is, the ink discharge port 61
The opening width of the ink supply port 614 is W1, and the opening width of the ink supply port 614 is W1.
2. If the thickness of the silicon substrate is t, these relationships are expressed by the following equation.

0004

[Equation 1] W1 = W2-√2 t...(1) Here, when the nozzles are lined up with a certain pitch width, unless the design value of the pitch width is greater than or equal to W2, the nozzle will overlap with the adjacent nozzle, Formation by etching becomes impossible. In other words, from the above equation, when the nozzle opening width W1 is constant, the thickness t of the silicon substrate must be reduced in order to reduce the nozzle pitch width, that is, to increase the density of the nozzle array. There was a problem. However, there are limits to reducing the thickness of the silicon substrate.
Furthermore, as the silicon substrate becomes thinner, it becomes more likely to break, resulting in handling problems and lower yields.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and its object is to provide a high-density inkjet nozzle array using a (100) silicon substrate.

[0006]

[Means for Solving the Problems] A method for manufacturing an inkjet nozzle array of the present invention includes a process for manufacturing an inkjet nozzle array using a (100) silicon substrate as a constituent member. A mask pattern of an etching-resistant material for forming the inkjet nozzle array by etching is formed, one surface 12 of the silicon substrate 11 is etched by a predetermined amount, and then one surface 12 of the silicon substrate 11 is etched again. An etching-resistant material is formed on the other surface 13 of the silicon substrate 11, at least at a portion corresponding to a portion where the inkjet nozzle array is formed, and then an etching-resistant material is not formed on the other surface 13 of the silicon substrate 11. It is characterized by applying a predetermined amount of etching to the area. Or, in the manufacturing process of the inkjet nozzle row, (100)
A mask pattern of an etching-resistant mask material for forming the inkjet nozzle rows by etching is formed on one surface 22 of the silicon substrate 21, and at least the inkjet nozzle rows are formed on the other surface 23 of the silicon substrate 21. It is characterized in that no etching-resistant material is formed on the corresponding portions, and then a predetermined amount of etching is performed on both sides of the silicon substrate 21. Further, the method is characterized in that the etching is anisotropic etching using an alkaline solution.

[0007]

[Example] Example 1: The present invention will be explained in detail below based on an example. FIG. 1 is a manufacturing process diagram of an inkjet nozzle array according to the present invention. First, both sides of a (100)-oriented silicon wafer are mirror-polished to form a silicon substrate 11 with a thickness of 280 microns (FIG. 1(a)).
1 was subjected to heat treatment at 1100 degrees Celsius for 4 hours in an O2 and water vapor atmosphere, and a thickness of 1 was formed on both sides of the silicon substrate 11.
Micron SiO2 films 14 and 15 were formed (Fig. 1
(b)). The SiO2 film is used as an etching resistant material. One side 12 of silicon substrate 11
A photoresist pattern 16 having a photomask pattern 26 as shown in FIG. 2 transferred thereon was formed on the SiO2 film 14 formed above. As for the dimensions of the figure in FIG. 2, the square 26 corresponding to the inkjet nozzle has a side of 80 microns, and the distance between the centers of adjacent squares, that is, the nozzle pitch, is 84.7 microns. 84.7 microns is 300
Corresponds to dpi (dots per inch). other side 13
After applying a photoresist to the entire surface of the SiO2 film 15 formed thereon, the silicon substrate 11 is immersed in a hydrofluoric acid etching solution, and only the SiO2 film 14 on one side 12 is partially etched and patterned. (Figure 1(c)
). Next, silicon was etched only on one surface 12 using an alkaline solution. As an alkaline solution, 7 degrees Celsius
A 20% by weight KOH aqueous solution at 0 degrees Celsius is used, and the etching rate of the (100) plane of silicon is 0.8 microns per minute. The etching time was set to 37 minutes and 30 seconds, and the etching was once terminated at an etching depth of 30 microns (FIG. 1(d)). Next, the silicon substrate 11 was heat-treated at 1100 degrees Celsius for 4 hours in an O 2 and water vapor atmosphere to form a 1 micron SiO 2 film on the surface where the etching recesses 110 were to be formed. A SiO2 film is originally formed on the surface other than the surface where the etching recess 110 is formed, and a total of 1 micron or more of Si is formed on these parts.
An O2 film is formed (FIG. 1(e)). Next, a SiO2 film 1 is formed on the other surface 13 of the silicon substrate 11.
5, a photoresist pattern in which a portion encompassing the entire concave portion 110 that will become an inkjet nozzle is formed by etching on one surface 12 when viewed from the vertical direction with respect to surfaces 12 and 13 of the silicon substrate 11; 1
7 is formed by transferring the photomask pattern 27 shown in FIG. Processed (
Figure 1(f)). Next, silicon etching was performed on the other side 13 of the silicon substrate 11 for 5 hours and 24 minutes using the above-mentioned alkaline etching solution, and silicon etching was completed at an etching amount of 259 microns, and finally, silicon etching was performed using a hydrofluoric acid etching solution. SiO2 as an etching mask
Films 14 and 15 were removed (FIG. 1(g)). In this embodiment, the design value of the hole diameter of the inkjet nozzle is 50 microns square. From formula (1), in order to make the hole diameter 50 microns square, the plate thickness t is calculated from the formula below:

[0008]

[Math. 2] t=(80-50)/√2=21 ・・・・・・(
2) It is 21 microns. That is, if the etching amount d1 of the other surface 13 is set to d1 = 280-21 = 259 (microns), an inkjet nozzle with a hole diameter of 50 microns can be formed. The thickness of the silicon in the inkjet nozzle array forming part obtained in this example is 21 microns, but the original thickness of 280 microns remains in other parts of the silicon substrate 11, and this part allows the inkjet nozzle array to be formed. is supported.

In the etching process for the other surface 13 described above, etching is performed to 259 microns, but when the etching reaches 240 microns midway, the other surface 13 is etched.
The etched surface is the bottom surface 112 of the etched recess 110.
When the through hole 111 is reached, a through hole 111 is formed, but by further etching to 259 microns, it is possible to form an inkjet nozzle with a square size of 50 microns, as calculated from equation (2). When the hole diameter dimensions of 48 nozzles in the completed inkjet nozzle row were measured, they were distributed from 48.3 to 51.5 microns, and the average value was 50.1 microns. That is, in this example, the nozzle pitch is 300
An inkjet nozzle array with a nozzle diameter of 50 microns dpi could be obtained. When this inkjet nozzle array was incorporated into an inkjet head and a printing test was conducted, good printing was obtained.

Embodiment 2: The second embodiment of the present invention will be explained in detail below. FIG. 3 is a manufacturing process diagram of an inkjet nozzle array according to the present invention. First, both sides of a (100)-oriented silicon wafer were mirror-polished to a thickness of 280 mm.
After forming a micron silicon substrate 31 (FIG. 3(a)), the substrate 31 is heated at 1 Celsius in an O2 and water vapor atmosphere.
Heat treatment was performed at 100 degrees for 4 hours to form 1 micron SiO2 films 34 and 35 on both sides of the silicon substrate 31 (FIG. 3(b)). As in Example 1, a silicon substrate 31
A photoresist pattern 36 having a photomask pattern 26 as shown in FIG. 2 transferred thereon was formed on the SiO2 film 34 formed on one surface 32 of the substrate. The pattern dimensions are the same as in Example 1. Next, a SiO2 film 35 on the other surface 33 of the silicon substrate 31 is coated with Si when viewed from a direction perpendicular to the surfaces 32 and 33 of the silicon substrate 31.
Photoresist pattern 36 formed on O2 film 34
A photoresist pattern 37 in which a portion encompassing the entire portion is missing is formed by transferring the photomask pattern 27 of FIG. 2 (FIG. 3(c)), and then the silicon substrate 3
1 was immersed in a hydrofluoric acid etching solution to remove the SiO2 film in the portion corresponding to the inkjet nozzle array (FIG. 3(d)).

Next, silicon was anisotropically etched using an alkaline solution. As in Example 1, a 20% by weight KOH aqueous solution at 70 degrees Celsius was used as the alkaline solution. When the silicon substrate 31 is immersed in the alkaline solution, etching progresses on both sides.

FIG. 4 is a diagram showing the state of one surface 32 of the silicon substrate 31 after 30 minutes of etching.
a) is a cross-sectional view, and FIG. 4(b) is a top view. One side 3
In the middle of the etching step 2, as shown in FIG. 4(a), a (111) plane 49 with an extremely slow etching rate appears and the area of the (100) plane 48 gradually becomes smaller. In the example, the (100) plane 48 disappears when the etching depth reaches 57 microns. At the stage of FIG. 4, the etching depth d2 is d2
= 30 x 0.8 = 24 (microns), (100)
Surface 48 is one side

[0013]

[Equation 3] It is a square of 80-24√2=46.2 (μm). Further, FIG. 3(e) also shows the state after 30 minutes of silicon etching. At this time, the other surface 33 of the silicon substrate 31 is also etched to a depth of 24 microns. Further etching was performed continuously, and silicon etching was completed in a total etching time of 5 hours and 24 minutes.
Finally, the SiO2 films 34 and 35, which serve as etching masks, were removed using a hydrofluoric acid etching solution (Fig. 3(f)
)). After 5 hours and 24 minutes of etching, the silicon was etched by 259 microns, and the thickness of the inkjet nozzle array part of the silicon substrate 31 was 21 microns, but the thickness of the other parts of the silicon substrate 31 remained 280 microns. The inkjet nozzle row is supported by this part. Etching on one side 32 of the silicon substrate 31 stops when the etching depth reaches 57 microns, but etching progresses further on the other side 33, resulting in an inkjet nozzle array formed on one side 32. When the etching recess 310 is reached and the etching progresses further, a through hole 311 is formed at the bottom of the etching recess 310, and the size of the through hole 311 is the same as that of the other surface 3.
It becomes larger as the etching progresses in step 3. In this example, the design value of the nozzle hole size was 50 microns square, and etching was performed for the same time as in Example 1, but the nozzle ejection opening size of the completed inkjet array was 48 microns square. The nozzle was measured from 51.3 to 53.
It was distributed between 8 microns and the average value was 52.5 microns. That is, in this example, it was possible to obtain an inkjet nozzle array with a nozzle pitch of 300 dpi and a nozzle diameter of 52.5 microns. The hole diameter is 2.5 microns larger than the design value of 50 microns, but this is because the end 313 of the through hole 311 was gradually etched as the etching progressed, and the hole diameter was enlarged. be. That is, according to this embodiment,

[0014]

[Formula 4] W1 = W2-√2 t...A hole diameter larger than that defined by (1) can be obtained. If a 50 micron square nozzle is desired, the 80 micron dimension of the square 26 corresponding to the inkjet nozzle in FIG. The diameter of the nozzle can be obtained. As mentioned above, in inkjet nozzles using (100) silicon substrates, there is a limit to increasing the density of the nozzles due to the limitation that the plate thickness cannot be made thinner when the nozzle hole diameter is constant. However, in this embodiment, since the pattern corresponding to the inkjet nozzle can be made smaller in order to obtain a constant nozzle hole diameter, the pitch can be made narrower by that amount. The hole diameter can be arbitrarily determined to some extent depending on the etching conditions. Further, when this inkjet nozzle array was incorporated into an inkjet head and a printing test was conducted, good printing was obtained.

The manufacturing process of the inkjet nozzle array described in Examples 1 and 2 is an extremely simple process without any difficulties in terms of process technology. Obtained by yield.

[0016]

[Effects of the Invention] As described above, according to the present invention, (1
00) It is possible to obtain a high-density inkjet nozzle array using a silicon substrate, and an inkjet head using such an inkjet nozzle array has the effect of enabling high-definition printing.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram of an inkjet nozzle array of the present invention.

FIG. 2 is a mask pattern diagram for forming inkjet nozzle rows by etching.

FIG. 3 is a manufacturing process diagram of the inkjet nozzle array of the present invention.

FIG. 4 is a sectional view and a top view of an inkjet nozzle array in a manufacturing process of the inkjet nozzle array of the present invention.

FIG. 5 is a manufacturing process diagram of a conventional inkjet nozzle array.

FIG. 6 is a diagram showing the dimensional relationship of inkjet nozzle arrays on a (100) silicon substrate.

[Explanation of symbols]

Claims (3)

[Claims] Claim 1: (100) In the manufacturing process of an inkjet nozzle array having a silicon substrate as a component, (100)
00) A mask pattern of an etching-resistant material for forming the inkjet nozzle array by etching is formed on one surface 12 of the silicon substrate 11, and a predetermined amount of etching is performed on the one surface 12 of the silicon substrate 11, and then An etching-resistant material is again formed on one surface 12 of the silicon substrate 11, and an etching-resistant material is formed on at least a portion of the other surface 13 of the silicon substrate 11 corresponding to a portion where the inkjet nozzle array is formed. First, a method for manufacturing an inkjet nozzle array, which comprises etching the other surface 13 of the silicon substrate 11 by a predetermined amount. 2. In the manufacturing process of the inkjet nozzle array, one surface 2 of the (100) silicon substrate 21
2, a mask pattern of an etching-resistant material for forming the inkjet nozzle array by etching is formed, and at least a portion of the other surface 23 of the silicon substrate 21 corresponding to the portion where the inkjet nozzle array is formed is coated with an etching-resistant material. A method for manufacturing an inkjet nozzle array, characterized in that no etching material is formed, and then a predetermined amount of etching is performed on both sides of the silicon substrate 21. 3. The method of manufacturing an inkjet nozzle array according to claim 1, wherein the etching is anisotropic etching using an alkaline solution.