JP2001001530A - Manufacture for ink jet head, and ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure liquid chamber having an integrated structure of nozzles and channels and its manufacturing method, and provide a highly reliable and low-cost ink jet head by using a pressure liquid chamber having a nozzle integrated structure. SOLUTION: The ink jet head consists of a multilayer film pressure liquid chamber substrate 10, a diaphragm substrate 2 and a counter electrode substrate 30. An electrostatic attraction force is generated between a diaphragm 22 and a counter electrode 32 to shift the diaphragm 22, whereby the ink in a pressure liquid chamber 14 is pressured and discharged from a nozzle 15. In a method for forming the pressure liquid chambers 14 and nozzles 15 communicating with the pressure liquid chambers, a multilayer film including etching stop layers 12a, 12b and 12c is formed on a glass substrate 11a and etched, whereby the pressure liquid chambers 14 and nozzles 15 are formed (Figs. (I)-(P)). Thereafter, the multilayer film is anodically joined to the Si diaphragm substrate 20, and the glass substrate 11a and etching stop layer 12a are removed by etching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an ink jet head and an ink jet head manufactured by the method, and more particularly, to a method for manufacturing an on-demand ink jet head using a micromachining technique.

[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.

[0003] Since an electrostatic ink jet head can be manufactured by a wafer process, it is possible to manufacture a large number of elements which are easy to increase the density and have stable characteristics, and are based on a planar structure. For this reason, it has an advantage that the size can be easily reduced. For example, JP-A-2-289351, JP-A-5-50601, and JP-A-6-718.
Many structures are disclosed as disclosed in, for example, Japanese Patent Application Publication No. 82-82. In these electrostatic ink jet heads, parallel plate electrodes are formed at opposing positions of a diaphragm constituting a bottom surface of a liquid chamber, and an electrostatic attractive force acting between the diaphragm and the parallel plate electrode and a vibration of the diaphragm are generated. The ink is sucked into the liquid chamber by vibration due to rigidity, and the sucked ink is discharged.
The pressurized liquid chamber and the ink flow path are formed by anisotropically etching the Si substrate and then bonding to the nozzle plate.

[0004]

In an on-demand type ink jet printer, it is required to perform high-speed printing of 3 sheets / min or more with high image quality close to a silver halide photograph of 600 dpi or more. 6 / mm or more is naturally required, and more than 100 elements are required to be integrated into one chip. However, the price is going on at the same time as the high performance, and the price reduction including the mounting of the head is required.

In an electrostatic ink jet head of a system in which an electrostatic force is generated between a diaphragm and a counter electrode to deform the diaphragm and pressurize the liquid by the restoring force of the diaphragm to discharge the liquid, When the short side length of the diaphragm is shortened due to the demand for higher density, apparent diaphragm rigidity increases, and the deformation of the diaphragm tends to decrease. Therefore, a liquid chamber shape that enables effective use of the discharge pressure generated by the diaphragm is required. However, when trying to integrally mold the pressurized liquid chamber up to the nozzle part on a glass or Si substrate for the purpose of cost reduction,
The height of the liquid chamber and the nozzle length depend on the thickness of the substrate, and the thickness of the substrate is at least 400 in consideration of handling.
μm or more, which reduces the degree of freedom in designing the shape of the liquid chamber and the flow path. Therefore, a multilayer film including an etching stop layer is formed on the substrate, and after forming a pressurized liquid chamber and a nozzle by etching, it is joined to the diaphragm substrate,
By removing the substrate portion by etching, it was possible to solve the problem of handling, and at the same time, obtain a pressurized liquid chamber and a flow path having optimal shapes.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pressurized liquid chamber having a nozzle and a flow path integrally structured and a method of manufacturing the same which can be freely designed for a wafer process, and to provide a pressurized liquid chamber having a nozzle integrated structure. An object of the present invention is to provide a highly reliable and low-cost inkjet head by using the same.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for generating an electrostatic attraction between a diaphragm and a counter electrode, and displacing the diaphragm to restore ink in a pressurized liquid chamber by restoring force of the diaphragm. In the method of manufacturing an electrostatic ink jet head of a method of discharging the ink in the pressurized chamber, the method of manufacturing the pressurized liquid chamber and the ink flow path communicating with the pressurized liquid chamber includes the steps of: Forming a multilayer film including an etching stop layer, forming the pressurized liquid chamber and the ink flow path by etching the multilayer film, and then anodically bonding to the diaphragm substrate, and then etching the substrate by etching. It is characterized by being removed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing a main part of an example of an electrostatic ink jet head manufactured by a manufacturing method according to the present invention. As shown, it is composed of a multi-layer pressurized liquid chamber substrate 10 including an etching stop layer, a single crystal Si diaphragm substrate 20, and a counter electrode substrate 30. The multilayer film pressurized liquid chamber substrate 10 includes a Pyrex glass layer (nozzle section) 11, an etching stop layer 12, a Pyrex glass layer (pressurized liquid chamber section) 13, a pressurized liquid chamber 14, and a nozzle 15.
The pressurized liquid chamber 14 and the nozzle 15 are formed by etching a multilayer film including the etching stop layer 12. By sequentially patterning the etching stop layer when forming the multilayer film, the number of etching steps can be reduced. The diaphragm 20 is composed of a SiO ₂ layer 21 as an etching stop layer and a Si layer 22 as a diaphragm substrate.
It is formed by etching with H aqueous solution, TMAH, EPW hydrazine or the like. The control of the thickness of the diaphragm is determined by the control of the etching end point. The control of the etching end point includes an etch stop by a boron high concentration diffusion layer, an electrochemical etch stop by anodic oxidation of a phosphorus diffusion layer, and a SiO ₂ and Si Utilizing the difference in the etching rate, a method of stopping the etching at the SiO ₂ layer in the SOI substrate can be used. The counter substrate electrode 30 includes a Pyrex glass substrate 31, a counter electrode 32, an insulating film (surface protective layer) 33, and the like.
A gap is formed on the substrate 1 by dry etching or wet etching with buffered hydrofluoric acid, and a counter electrode 32 and an insulating film (surface protective film) 33 are formed in the gap by sputtering or the like and formed by patterning.

(Embodiment 1) FIGS. 2 (A) to 2 (H) and 3 (I) to 3 (Q) are process diagrams for explaining a method of manufacturing an ink jet head according to the first aspect. And the following steps (a) to (q). (A) First, a Pyrex glass substrate 31 is prepared (FIG. 2A), and (b) patterning is performed on the Pyrex glass substrate 31 using a negative resist 34 in order to form a gap between a diaphragm and a counter electrode (FIG. 2A). 2 (B)). (C) A gap 35 is formed by dry etching (FIG. 2C), and (d) a Pt film 3 is formed on the etching surface of the Pyrex substrate 31.
2. An SiO ₂ film 33 is formed by sputtering (FIG. 2)
(D)). (E) After lithography using the negative resist 36 (FIG. 2)
(E)), (f) The SiO ₂ insulating film 33 is etched with buffered hydrofluoric acid, and the Pt film 32 is etched back by sputtering to form the counter electrode 32 (FIG. 2 (F)). (G) The SOI substrate 20 'is anodically bonded to the Pyrex glass substrate 30 after the dry etching (FIG. 2 (G)). (H) The Si substrate 23 of the SOI substrate 20 'after the bonding is
Then, etching was performed with H, and the etching was stopped at the SiO ₂ layer 21 of the SOI substrate 20 ′, thereby completing the electrostatic actuator portion (FIG. 2 (H)).

(I) A Cr film 12a as an etching stop layer is formed on another Pyrex glass substrate 11a.
And a Pyrex glass film 11b as a nozzle layer,
A Cr layer 12b as an etching stop layer and a Pyrex glass film 11c as a liquid chamber layer are formed by sputtering.
The surface ends with a Cr film 12c to be used as a mask for wet etching with buffered hydrofluoric acid (FIG. 3 (I)). (J) The outermost Cr mask 12c is patterned to form a wet etching mask (FIG. 3 (J)). (K) The Pyrex glass layer 11c is etched with buffered hydrofluoric acid to form the pressurized liquid chamber 14. At this time, the etching is spontaneously stopped by the lower Cr film 12b (FIG. 3K). (L) Photolithography is performed on the Cr film 12b used as the etching stop layer to open a nozzle pattern 15 '(FIG. 3 (L)). (M) Etch 15 ″ the Cr film 12b (FIG. 3
(M)). (N) After etching the Cr film 12b, the nozzle layer Pyrex glass 11b is etched 15 with buffered hydrofluoric acid (FIG. 3 (N)). (O) The created multilayer liquid chamber is anodically bonded to the diaphragm 20 side of the electrostatic actuator created in step (h) (FIG. 3 (O)). (P) The Pyrex glass substrate 11a supporting the multilayer liquid chamber is etched and removed with buffered hydrofluoric acid (FIG. 3 (P)). (Q) Cr etching stop layer 12 remaining on multilayer film
a is removed by etching with hydrochloric acid (FIG. 3 (Q)).

As described above, the electrostatic ink jet head integrally formed with the nozzle and the flow path using the multilayer film shown in FIG. 1 was completed (however, the Pyrex glass 11 shown in FIG. 12 corresponds to the Cr layer 12b, and Pyrex glass 13 corresponds to 11c).

(Embodiment 2) FIGS. 4 and 5 are views for explaining an embodiment 2 of a method for producing an ink jet head according to claim 2, wherein steps (a) to (h) are described in this embodiment. FIGS. 2A to 2C show a manufacturing process of an electrostatic actuator portion of an inkjet head according to the first embodiment.
4 (A) to FIG.
(H)) only, and the description thereof is omitted.
Steps (I) to FIG. 5 (S) will be described.

(I) A Cr film 12a as an etching stop layer is formed on the Pyrex substrate 11a by sputtering (FIG. 5I). (J) An alkoxide having a composition shown as an example in Table 1 containing silicon tetraethoxide as a main component as a starting material,
Dissolve in methanol. A gel containing silica as a main component obtained by adding water and hydrolyzing with stirring is spin-coated or, after being adjusted to a higher viscosity, a doctor blade is applied to the Pyrex substrate to a desired thickness. Apply and dry at 110 ° C, then at 700 ° C for 3 hours, 8
A heat treatment is performed at 50 ° C. for 3 hours, and a Pyrex glass layer 11b corresponding to a nozzle portion is passed through a step of slow cooling and slow strain.
Was formed (FIG. 5 (J)).

[0014]

[Table 1]

(K) After the Cr film 12b is again formed by sputtering, the Pyrex glass 11c of the liquid chamber layer is formed by the same process as (j), and the Cr film 1 for the etching mask is formed.
2c was formed by sputtering to form a multilayer film for a nozzle, a flow path, and a liquid chamber (FIG. 5 (K)). (L) The Cr mask 12c on the outermost surface is patterned to form a wet etching mask (FIG. 5 (L)). (M) The Pyrex glass layer 11c is etched with buffered hydrofluoric acid to form the pressurized liquid chamber 14. At this time, the etching is spontaneously stopped by the lower Cr film 12b. (N) Cr film 12b used as an etching stop layer
Is subjected to photolithography to open a nozzle pattern 15 '(FIG. 5 (N)). (O) The Cr film 12b is etched (FIG. 5 (O)). (P) After etching the Cr film 12b, the nozzle layer Pyrex glass 11b is etched with buffered hydrofluoric acid to open the nozzle 15 (FIG. 5 (P)). (Q) The prepared multilayer liquid chamber 10 'is anodically bonded to the diaphragm substrate side of the electrostatic actuator prepared in the step (h) (FIG. 4 (H)) (FIG. 5 (Q)). (R) Pyrex substrate 11a supporting multilayer liquid chamber
Is etched and removed with buffered hydrofluoric acid (FIG. 5 (R)). (S) Cr etching stop layer 12 remaining on multilayer film
a is removed by etching with hydrochloric acid (FIG. 5 (S)).

As described above, an electrostatic ink jet head in which a nozzle and a flow path using a multilayer film are integrally formed is completed (however, 11 shown in FIG. 1 is 11b and 12 is 12b).
And 13 corresponds to 11c).

(Embodiment 3) FIGS. 6 and 7 are manufacturing process diagrams for explaining an embodiment of a method for manufacturing an ink-jet head according to claim 3, in which the steps (a) to (h) are performed in accordance with the present invention. FIG. 2A is a view showing a manufacturing process of an electrostatic actuator portion of an ink jet head according to the present invention.
2 (H) to FIG. 2 (H).
(H)) only, and the description thereof is omitted.
Steps (I) to FIG. 7 (S) will be described.

(I) A Cr film 12a as an etching stop layer is formed on the Pyrex substrate 11a by sputtering (FIG. 7I). (J) A Pyrex glass layer 11b corresponding to a nozzle portion is formed by sputtering or a sol-gel method (FIG. 7 (J)). (K) A Cr film 12b is formed as an etching stop layer by sputtering (FIG. 7K). (L) The pattern of the nozzle portion is patterned on the Cr film 12b by the negative resist 16, and an opening 15 'is formed by wet etching (FIG. 7 (L)). (M) A Pyrex glass layer 11c corresponding to the liquid chamber portion is formed by a sputtering method or a sol-gel method (FIG. 7 (M)). (N) A Cr film 12c as an etching mask is formed by sputtering (FIG. 7 (N)). (O) The pattern of the liquid chamber and the flow path is formed by applying photolithography 17 to the Cr film 12c and performing wet etching (FIG. 7 (O)). (P) The formed multilayer film is etched with buffered hydrofluoric acid. The channel and the liquid chamber portion 14 are formed by etching using the mask formed by the Cr film 12c, and the Pyrex glass layer 1 forming the liquid chamber portion is formed.
Pyrex glass layer 11 forming nozzle portion with 1c
b, the etching proceeds from the opening pattern 15 ′ formed in the etching stop layer 12 b between the nozzle 15 b and the nozzle 15.
Is opened, and the liquid chamber portion and the nozzle portion are integrally formed (FIG. 7 (P)). (Q) The prepared multilayer liquid chamber 10 'is anodically bonded to the Si diaphragm substrate side of the electrostatic actuator prepared in the step (h) (FIG. 6 (H)) (FIG. 7 (Q)). (R) Pyrex substrate 11a supporting multilayer liquid chamber
Is etched and removed with buffered hydrofluoric acid (FIG. 7 (R)). (S) Cr etching stop layer 12 remaining on multilayer film
a is removed by etching with hydrochloric acid (FIG. 7 (S)). As described above, an electrostatic inkjet head in which a nozzle and a flow path using a multilayer film are integrally formed is completed.

(Embodiment 4) FIGS. 8 and 9 are manufacturing process diagrams for explaining an embodiment of a method of manufacturing an ink-jet head according to claim 4, wherein steps (a) to (h) are described in the present embodiment. FIG. 2A is a view showing a manufacturing process of an electrostatic actuator portion of an ink jet head according to the present invention.
2 (H) to FIG. 2 (H), only the figures (FIGS. 8 (A) to 8 (H)) are shown, and the description thereof is omitted.
Steps (I) to FIG. 9 (S) will be described.

(I) A Cr film 12a as an etching stop layer is formed on the Pyrex substrate 11a by sputtering (FIG. 9 (I)). (J) A Pyrex glass layer 11b corresponding to a nozzle portion is formed by sputtering or a sol-gel method (FIG. 9 (J)). (K) A Cr film 12b is formed by sputtering as an etching stop layer (FIG. 9K). (L) On the Cr film 12b, the pattern of the nozzle portion and the side wall portion of the liquid chamber / flow path is patterned by the negative resist 18, and the pattern is formed by wet etching (FIG. 9 (L)). (M) The surface of the Cr film 12b is oxidized 12b '(FIG. 9)
(M)). (N) The Pyrex glass layer 11c corresponding to the liquid chamber portion is formed by the method shown in the step (j) of the second embodiment.
An etching mask for the film 12c was formed (FIG. 9).
(N)). (O) The formed multilayer film is etched with buffered hydrofluoric acid (FIG. 9 (O)). (P) The flow path and the liquid chamber portion 14 are formed by etching using the mask formed by the Cr film 12c, and etching is stopped between the Pyrex glass 11c forming the liquid chamber portion and the Pyrex glass 11b forming the nozzle portion. The etching proceeds according to the opening pattern formed in the layer 12b, the nozzle 15 is opened, and the liquid chamber portion and the nozzle portion are integrally formed (FIG. 9 (O)). (Q) The prepared multilayer liquid chamber is transferred to the step (h) (FIG. 8).
Anodically bonding the electrostatic actuator prepared in (H)) to the Si diaphragm substrate side (FIG. 9 (Q)). (R) Pyrex substrate 11a supporting multilayer liquid chamber
Is etched and removed with buffered hydrofluoric acid (FIG. 9 (R)). (S) Cr etching stop layer 12 remaining on multilayer film
"a" is removed by etching with hydrochloric acid (FIG. 9 (S)).

As described above, an electrostatic ink jet head in which a nozzle and a flow path using a multilayer film are integrally formed is completed. A Cr ₂ O ₃ layer is obtained by oxidizing the surface of the Cr film used for the etching stop layer in the nozzle portion and the liquid chamber portion. Cracks and the like are often observed due to volume shrinkage when the applied silica-based gel is densified, but Cr ₂ O ₃ used for the mold of a glass mold lens has poor wettability with glass, Since the stress due to shrinkage is selectively relieved at the contact surface with Cr ₂ O ₃ , it was confirmed that cracks and the like due to volume shrinkage were suppressed.

[0022]

According to the first aspect of the present invention, when the short side length of the diaphragm is shortened due to a demand for higher density, the apparent rigidity of the diaphragm increases, and the deformation of the diaphragm is increased. It tends to be smaller. Therefore, a liquid chamber shape that can effectively use the discharge pressure generated by the diaphragm is required. After forming a multi-layer film including an etching stop layer on the substrate, forming a pressurized liquid chamber and a nozzle by etching, bonding to the diaphragm substrate and etching away the substrate part, the pressurized liquid in the optimal shape is formed. A chamber and a flow path can be obtained, and a glass partition having a thickness of about several tens of μm can be handled. Further, by performing a wafer process up to dicing, further cost reduction can be achieved. .

(Advantage of the second aspect of the invention) The advantage of the nozzle-integrated pressurized liquid chamber using a multilayer film including an etching stop layer is that an optimum liquid chamber shape capable of responding to miniaturization of an ink jet head can be created, and It is a low cost process. The adoption of the sol-gel method results in a lower cost process.

(Effect of Claim 3) By patterning the etching stop layer in advance, it is possible to control the etching end point in the vertical direction, simplify the etching process, and perform the lithography process in a flat state. Therefore, the final dimensional accuracy can be improved.

(Effect of Claim 4) The advantage of using the sol-gel method is that a glass body can be obtained at a temperature lower than the melting point. By using a material with poor wettability with glass for the etching stop layer, it is possible to control where stress relaxation occurs, reduce the incidence of defects such as cracks, and shorten the stress relaxation time. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an inkjet head manufactured according to the present invention.

FIG. 2 is a manufacturing process diagram (diaphragm substrate portion and electrode substrate portion) of the inkjet head according to the first aspect of the present invention.

FIG. 3 is a manufacturing process diagram (liquid chamber nozzle substrate portion) of the ink jet head according to the invention of claim 1;

FIG. 4 is a manufacturing process diagram (diaphragm substrate portion and electrode substrate portion) of the inkjet head according to the invention of claim 2;

FIG. 5 is a manufacturing process diagram (liquid chamber nozzle portion) of the ink jet head according to the invention of claim 2;

FIG. 6 is a manufacturing process diagram (diaphragm substrate portion and electrode substrate portion) of the inkjet head according to the invention of claim 3;

FIG. 7 is a manufacturing process diagram (liquid chamber nozzle portion) of the inkjet head according to the invention of claim 3;

FIG. 8 is a manufacturing process diagram (diaphragm substrate portion and electrode substrate portion) of the inkjet head according to the invention of claim 4;

FIG. 9 is a manufacturing process diagram (liquid chamber nozzle portion) of the inkjet head according to the invention of claim 4;

[Explanation of symbols]

10: Multilayer pressurized liquid chamber substrate, 11: Pyrex glass layer (nozzle part), 12: etching stop layer, 13 ...
Pyrex glass layer (pressurized liquid chamber), 14: pressurized liquid chamber, 15: nozzle, 20: diaphragm substrate, 21: SiO ₂
Layer, 22: Si layer, 30: counter electrode substrate, 31: Pyrex glass substrate, 32: counter electrode, 33: insulating film (surface protective layer).

Claims (5)

[Claims] 1. A method for generating electrostatic attraction between a diaphragm and a counter electrode, displacing the diaphragm to pressurize ink in a pressurized liquid chamber by a restoring force of the diaphragm, In the method for manufacturing the pressurized liquid chamber and the ink flow path communicating with the pressurized liquid chamber in the electrostatic ink jet head that discharges the ink of the type, a multilayer film including an etching stop layer is formed on a substrate, Forming a pressurized liquid chamber and an ink flow path by etching a film, thereafter anodically bonding a diaphragm substrate, and removing the substrate by etching; 2. The method according to claim 1, wherein at least one of the multilayer films on the substrate is formed by a sol-gel method. 3. The method for manufacturing an ink jet head according to claim 1, wherein a part of the etching stop layer is patterned at a stage of forming a multilayer film. 4. The method for manufacturing an ink jet head according to claim 1, wherein Cr is used for at least one layer of the etching stop layer, and a part of the surface is oxidized to form a multilayer film. A method for manufacturing an ink jet head, comprising: 5. An ink jet head manufactured by the method according to claim 1.