JPH11320874A - Ink-jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a process time for parts at an ink-jet head and reduce process costs with securing accuracy of the parts requiring the process accuracy. SOLUTION: In a p-type or n-type low concentration single crystal silicon substrate 2, n-type impurities are diffused in a high concentration when the silicon substrate 2 is the p-type or p-type impurities are diffused in a high concentration when the silicon substrate is the n-type, thereby forming a pn junction. After a glass substrate 1 is anodically united to the side of the single crystal silicon substrate 2 where the impurities are diffused, the side of a low concentration is electrochemically etched, whereby a diaphragm 2a is formed. The diaphragm 2a is provided with a part 22 of a vibration plate and a part of a larger thickness than the vibration plate which is formed by deepening the pn junction partly. The nozzle 22 is formed at the thicker part. The thicker part is set correspondingly to a position where a liquid chamber 11 is to be separated. An orifice 12 is set at a part of the liquid chamber 11 immediately below the nozzle 22, thereby reducing the thickness of the thicker part by a flow passage resistance of the orifice 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a micromachining technique, and an ink jet head used for a head for an on-demand type ink jet printer.

[0002]

2. Description of the Related Art Ink-jet printers have become very popular in recent years as low-cost and compact full-color printers. The reasons for this include the development of low-cost, high-density, high-performance inkjet heads that can be mounted on low-cost machines, as well as the development of glossy paper for lowering the price of dedicated paper and achieving photographic image quality. However, the speed of full-color printing is inferior to the printing speed of several ppm in the A4 size of a laser printer, and demand for higher density of the head is expected. For example, Japanese Patent Application Laid-Open No. 3-288649 discloses a liquid ejecting head in which a nozzle portion is formed including a flow path resistance portion by using a silicon process by employing an edge shooting configuration. Further, there are many embodiments in which the nozzle is engraved by dry etching on another Si thin plate constituting a liquid chamber different from the diaphragm, but there is no configuration example in which the nozzle is provided on the same diaphragm as the diaphragm.

[0003] Japanese Patent Application No. 9-1960 filed by the present applicant
In No. 70, by forming a cap on a glass substrate and performing anodic bonding in the thickness state of a commercially available wafer, there is no risk of deformation of the Si wafer due to a high electric field at the time of bonding, and diffusion depth by electrochemical etching after bonding. It is disclosed that a diaphragm corresponding to the above can be obtained. However, in this prior art, it is difficult to control the surface roughness of the diaphragm on the liquid chamber side, and it is difficult to use anodic bonding for joining the liquid chambers.

[0004]

In the prior art, the process of forming the electrostatic actuator and the liquid chamber by highly reliable anodic bonding is performed on a glass substrate whose etching rate by dry etching is slower than that of Si. It was complicated due to the necessity of drilling through holes. Generally, a configuration is used in which three layers of a vibration plate of Si, a liquid chamber penetrating a glass substrate, and a nozzle plate of a silicon or metal plate are laminated. In this configuration, there are various problems such as controllability of the positional relationship between the three layers and control of the bonding method depending on differences in the thermal expansion coefficients of the respective layers. On the other hand, in the prior art, there is an example in which a through hole for a nozzle is formed by using a dry etching process on a diaphragm itself constituting a liquid chamber. Since it is necessary to maintain the right angle direction, it is necessary to be located at the center of the short side (deflection direction) of the diaphragm, and it is necessary to control the nozzle position with high accuracy. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in the related art, and an object of the present invention is to provide an ink jet head that can solve the above problems.

[0005]

According to a first aspect of the present invention, there is provided a low-concentration single-crystal silicon substrate having an n-type impurity when the silicon substrate is p-type and a p-type impurity when the silicon substrate is n-type. In the ink-jet head, a pn junction is formed by diffusing the silicon substrate at a high concentration, a glass substrate is anodically bonded to the impurity diffusion side of the silicon substrate, and a diaphragm is formed by electrochemically etching the low concentration side. The diaphragm is formed in a portion having a thickness greater than the diaphragm and the diaphragm formed by partially increasing the depth of the pn junction, and a nozzle is formed in the portion having the thickness. An inkjet head.

According to a second aspect of the present invention, in the ink jet head according to the first aspect, the portion having the thickness, in which the nozzle is formed, is formed corresponding to the divided position of the divided liquid chamber, and is located immediately below the nozzle. An ink jet head, wherein an orifice serving as a flow path resistance portion at the time of ink ejection is provided in a liquid chamber portion.

According to a third aspect of the present invention, in the ink-jet head according to the second aspect, a multi-value expression is enabled by weighting the volume of the divided liquid chamber. It is.

The invention according to claim 4 is based on claims 1, 2, and 3.
The liquid-jet head according to any one of the above, wherein a liquid chamber is formed on the anodic bonding surface side of the glass substrate before electrochemical etching.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction and manufacturing method of the present invention will be described with reference to embodiments. FIG. 1 is a sectional view of a configuration example of an electrostatic ink jet head according to claim 1 of the present invention. In the figure,
1 is a liquid chamber glass substrate for forming a liquid chamber and a flow path;
Is a Si substrate for forming the diaphragm 2a, 3 is a glass electrode substrate, 11 is a liquid chamber, 12 is an orifice portion formed between the liquid chamber and a flow path, 13 is an ink flow path, 22 is a nozzle, and 31 is a nozzle. These are a counter electrode and an extraction electrode provided on the glass electrode substrate 1. Next, a method for manufacturing an ink jet head according to the present invention will be described. First, a Cr film was formed on the Pyrex glass 1 by sputtering, and the liquid chamber and the ink flow path were patterned with a negative resist to form a mask with the Cr film. Isotropic etching is performed using buffered hydrofluoric acid to form a liquid chamber 11 and an ink channel 13 as shown in FIG. Adjustment of the resistance of the ink flow path 13 can be controlled by changing the pattern width by using two parameters of the etching depth and the flow path width.

Next, a mask having a grid-like pattern arranged on a Si substrate 2 having a medium resistance at a position corresponding to the fluid resistance portion formed on the glass substrate 1 is used to form an n-type substrate in the case of a p-type substrate. Type impurity is p in the case of an n-type substrate.
-Impurity of type impurity is implanted and drive diffusion is performed. Thereafter, similarly, in the case of a p-type substrate, an n-type impurity is
In the case of a mold substrate, an impurity profile as shown in FIG. 3 was obtained by ion-implanting p-type impurities into the entire surface of the same surface and performing drive diffusion. After anodically bonding the etched surface of the glass substrate 1 after the etching and the impurity diffusion surface of the Si substrate 2 after the impurity diffusion, a reverse bias is applied to the pn interface in a KOH aqueous solution to perform the etching, thereby performing p-type etching. The diaphragm 2a having a shape corresponding to the impurity diffusion profile was formed by utilizing the fact that etching was stopped at the n-junction surface (electrochemical etch stop).

Next, the diaphragm 2a is patterned by photolithography, and the diaphragm 2a above the liquid chamber 11 of the glass substrate 1 is dry-etched to a depth corresponding to the gap with the electrode 31 to form a gap. A through hole 22 for a nozzle is formed in a grid-like thick portion 21 provided on the diaphragm 2a by patterning by photolithography and dry etching. A Cr film is formed on both surfaces of the electrode glass substrate 3 by sputtering, patterning is performed with a negative resist to form a window in the nozzle portion 21 on the diaphragm 2a, a Cr mask is formed, and etching is performed from both surfaces with buffered hydrofluoric acid. Thereby, the through hole 32 is formed. On this substrate, a counter electrode and a lead electrode 31 are formed of a metal such as platinum or rhodium. Next, the diaphragm 2a and the glass substrate for electrode 3 are anodically bonded, and the liquid chamber side glass substrate 1 is bonded.
As shown in FIG. 1, after dicing up to the diaphragm 2a, dicing for separating each chip is performed, whereby the electrostatic ink jet head according to claim 1 can be manufactured.

According to the above-described embodiment, the parts required to be subjected to precision processing are technically established on anodically bonded Si substrate by controlling a diffusion profile by impurity diffusion, anisotropic processing by dry etching, and the like. It is possible to process with high precision by using the process described above, and on the other hand, for processing a glass substrate that requires processing of a deep groove or through hole, for example, wet etching using a Cr mask can be used. An element can be formed while achieving both cost reduction and controllability. Further, by determining the gap between the counter electrode and the Si diaphragm at two points in the chip, it is possible to reduce variations in elements in the chip and in the wafer and to form a high-quality inkjet head.

FIG. 4 shows the structure of an electrostatic ink jet head according to a second aspect of the present invention. The configuration of the three layers of the liquid chamber glass substrate 1, the diaphragm Si substrate 2, and the electrode glass substrate 3 is the same as that of the electrostatic ink jet head according to claim 1, but a nozzle (through hole) opened in the diaphragm 2a.
The orifice 12 was provided immediately below 22. By adopting this configuration, the required thickness of the diaphragm 22 of the nozzle portion 21 can be reduced in consideration of the fluid resistance of the orifice 12. Therefore, the processing time by dry etching can be reduced, and the nozzle shape can be stabilized.

FIG. 5 shows the structure of an electrostatic ink jet head according to a third aspect of the present invention. The three-layer structure of the liquid chamber glass substrate 1, the diaphragm Si substrate 2, and the electrode glass substrate 3 is the same as that of the electrostatic ink jet head according to claim 2, but the liquid chamber 1 is formed by the nozzle 22 and the orifice 12.
By dividing 1 and weighting the volume ratio of the divided liquid chambers, an ink jet head capable of multi-value expression sharing the nozzle 22 was completed.

According to a fourth aspect of the present invention, as shown in FIGS. 1, 3 and 4, an electrostatic ink jet head is constructed by anodically bonding a Si substrate 2 to a liquid chamber side substrate 1 and then performing electrochemical bonding. The diaphragm 2a is formed by etching. As a result, the liquid chamber substrate 1 can be anodic-bonded to the polished surface, and a highly reliable ink jet head having a sealed liquid chamber is completed.

[0016]

According to the first aspect of the present invention, a portion requiring precision processing is technically established on a silicon substrate anodically bonded, such as control of a diffusion profile by impurity diffusion and anisotropic processing by dry etching. It can be manufactured with high precision by using the prepared process.

In the electrostatic ink jet head according to the second aspect of the invention, by providing an orifice immediately below the nozzle opened in the diaphragm, the required thickness of the nozzle portion can be reduced by the flow path resistance of the orifice, and the penetration by dry etching can be achieved. The working time of the hole forming process can be shortened and the processing cost can be reduced.

In the electrostatic ink jet head according to the third aspect, the liquid chamber is divided by the nozzles and the orifices, and the volume ratio of the divided liquid chambers is weighted, so that the multi-value expression that shares the nozzles can be realized. .

In the electrostatic ink jet head according to the fourth aspect, a diaphragm is formed by electrochemical etching after the Si substrate is anodically bonded to the liquid chamber side substrate. As a result, the liquid chamber substrate can be anodic-bonded to the polished surface, and a decrease in the yield due to a bit defect caused by poor bonding of the liquid chamber can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an electrostatic ink jet head according to the present invention.

FIGS. 2A and 2B are diagrams showing a liquid chamber and an ink flow path in the embodiment of the electrostatic inkjet head shown in FIG. 1; FIG. 2A is a plan perspective view, and FIG. FIG.

FIG. 3 shows the S of the electrostatic inkjet head shown in FIG.
It is a top perspective view of an i substrate.

FIG. 4 is a sectional view showing another embodiment of the electrostatic ink jet head of the present invention.

FIG. 5 is a sectional view showing another embodiment of the electrostatic ink jet head of the present invention.

[Explanation of symbols]

1 ... glass substrate, 2 ... Si substrate, 2a ... diaphragm,
3 ... Glass electrode substrate, 11 ... Liquid chamber, 12 ... Orifice part, 13 ... Ink flow path, 21 ... Diaphragm nozzle part,
22: Nozzle (through hole), 23: Diaphragm diaphragm part, 31: Counter electrode and lead electrode, 32: Through hole.

Claims (4)

[Claims] 1. A pn junction comprising a low-concentration single-crystal silicon substrate, wherein an n-type impurity is diffused at a high concentration when the silicon substrate is p-type, and a p-type impurity is diffused at a high concentration when the silicon substrate is n-type. Is formed, and a glass substrate is anodically bonded to the impurity diffusion side of the silicon substrate, and then the diaphragm is formed by electrochemically etching the low concentration side of the silicon substrate. In the inkjet head, the diaphragm is connected to the diaphragm and the pn junction. An ink jet head comprising: a portion having a thickness greater than the diaphragm formed by partially increasing the depth; and a nozzle being formed in the portion having the thickness. 2. The ink jet head according to claim 1, wherein the portion having the thickness where the nozzle is formed is formed corresponding to the divided position of the divided liquid chamber, and the ink is formed in the liquid chamber portion immediately below the nozzle. An ink jet head provided with an orifice serving as a flow path resistance portion at the time of ejection. 3. The ink jet head according to claim 2, wherein a weight of the divided liquid chamber is weighted to enable multi-value expression. 4. The ink jet head according to claim 1, wherein a liquid chamber is formed on the side of the anodic bonding surface of the glass substrate before electrochemical etching. Ink jet head.