JP6229220B2 - Method for manufacturing liquid jet head - Google Patents

Description

The present invention relates to a printer manufacturing techniques, particularly directed to producing how the liquid jet head.

  Printers are common office equipment, and with increasing advances in printer technology, file processing speed and printing speed are gaining more and more attention. The liquid ejecting head is an important device of a printer, and ink droplets are printed on a print medium by a method of ejecting ink droplets to realize a printing process. The printing speed and print quality of the printer are determined by the accuracy of the ejection speed and ejection position of the ink droplets by the liquid ejection head.

  In order to achieve higher printing accuracy, a generally complicated ink flow path is formed inside the liquid ejecting head. As a result, the ink flows smoothly and accurately into the corresponding flow path. A conventional liquid ejecting head includes a base, an orifice plate, a pressure cavity, a pressure actuator, and the like. The pressure cavity is formed by stacking a plurality of thin plates after etching the plurality of thin plates. The plurality of thin plates are bonded using an adhesive in order to firmly bond each other. In the manufacturing process of the liquid ejecting head, the base part, the orifice plate, the pressure cavity, and the pressure actuator are independently processed to manufacture a semi-finished product. Then, the manufactured orifice plate is bonded to the semi-finished product using an adhesive.

  Conventional liquid jet heads mostly use an adhesive in the manufacturing process, and it is necessary to accurately position each member in the bonding process. Therefore, the manufacturing process is complicated and the production cycle is long. Extended and yield is low. Further, when the adhesive flows out of a predetermined area, a phenomenon that the ink flow path becomes narrow or blocked may occur. If the ejection holes in the orifice plate are blocked, the print quality and print accuracy are greatly reduced.

The present invention can solve the problem of poor print quality due to the complexity and the adhesive of the manufacturing process of a conventional liquid ejecting head, to provide a manufacturing how the liquid jet head.

Producing how the liquid jet head according to the present invention,
Forming a pressure actuator on the first surface of the base;
Etching a second surface of the base portion facing the first surface to form a groove;
Filling the concave groove with a first photoresist to form a sacrificial layer, and making the surface of the sacrificial layer the same as the height of the second surface of the base portion;
Forming an orifice plate on the second surface of the base and the surface of the sacrificial layer;
Developing the sacrificial layer using a first developer to remove the sacrificial layer and form a pressure cavity.
Forming a sacrificial layer by filling the concave groove with a first photoresist;
Spin-coating the first photoresist in the concave groove to form the sacrificial layer;
Planarizing the sacrificial layer such that the height of the surface of the sacrificial layer and the second surface of the base are the same;
Performing a drying process on the sacrificial layer;
Performing an exposure process on the sacrificial layer using a first mask so that the sacrificial layer is modified and easily dissolved in the first developer.

  According to the technical solution according to the present invention, the orifice plate and the base portion are integrally formed. Therefore, the problem that the manufacturing process of the conventional liquid ejecting head is complicated is solved, and the phenomenon that the ink flow path or the ejection hole is blocked by using the adhesive is avoided, and the printing quality and the printing accuracy are improved.

  In addition, a monolithic liquid jet head is formed by the technical solution according to the present invention. The mechanical strength of the liquid ejecting head is not affected by the number of pressure cavities, the etching accuracy can be increased according to the need for printing accuracy, the number of pressure cavities and ejection holes can be increased, and the yield can be increased. Improve to some extent.

FIG. 5 is a flowchart of a method for manufacturing a liquid jet head according to an embodiment of the present invention. FIG. 5 is a schematic configuration diagram in which a diaphragm is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. FIG. 5 is a schematic configuration diagram in which a piezoelectric element is formed in a method for manufacturing a liquid jet head according to an embodiment of the present invention. FIG. 5 is a schematic configuration diagram in which a protective layer is formed in the method of manufacturing a liquid jet head according to the embodiment of the invention. FIG. 4 is a schematic configuration diagram in which a concave groove is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. FIG. 5 is a flowchart for forming a sacrificial layer in the method of manufacturing a liquid jet head according to the embodiment of the invention. FIG. 5 is a schematic configuration diagram in which a sacrificial layer is formed in the method of manufacturing a liquid jet head according to the embodiment of the invention. FIG. 6 is a schematic configuration diagram for performing exposure processing on a sacrificial layer in the method of manufacturing a liquid jet head according to the embodiment of the present invention. FIG. 4 is a schematic configuration diagram in which a jet hole photoresist layer is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. FIG. 5 is a schematic configuration diagram for performing an exposure process on a jet hole photoresist layer in the method of manufacturing a liquid jet head according to the embodiment of the present invention. FIG. 5 is a schematic configuration diagram in which ejection holes are formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. FIG. 4 is a schematic configuration diagram in which a pressure cavity is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention.

<Implementation-shaped state>
FIG. 1 is a flowchart of a method for manufacturing a liquid jet head according to an embodiment of the present invention. As shown in FIG. 1, the method for manufacturing a liquid jet head includes the following steps.

  Step 10: Form a pressure actuator on the first surface of the base.

The pressure actuator may be a conventional piezoelectric element or film resistor in the prior art. When the piezoelectric element is used, the piezoelectric element is formed on the first surface of the base portion. By applying a voltage through the piezoelectric element, the piezoelectric element is deformed and pressure is applied to the surrounding ink, whereby the ink is ejected from the ejection holes and printed on the printing medium. When film resistance is used, film resistance is formed on the first surface of the base. By applying a pulse voltage signal to the film resistance, the film resistance is dissipated in heat, whereby the ink is heated to a certain temperature, and the volatile components in the ink are vaporized to form bubbles to form the bubbles. It blows and then ruptures by touching cold air and is printed on a print medium.

  Step 20: Etching is performed on the second surface of the base portion facing the first surface to form a groove.

  The concave grooves are used as pressure cavities to eject ink from the ejection holes by providing pressure to the ink. The size of the groove may be set based on the size of the pressure cavity.

  Step 30: Fill the concave groove with the first photoresist to form a sacrificial layer, and make the surface of the sacrificial layer the same as the height of the second surface of the base.

The method of manufacturing a liquid jet head according to the present exemplary form condition, it is necessary to form the orifice plate to the surface of the pressure cavity. That is, although the orifice plate having the ejection holes is formed on the second surface of the base portion, the difficulty of forming the orifice plate increases due to the presence of the concave groove. Therefore, as a solution of step 30, first, a sacrificial layer is formed in the concave groove, and then an orifice plate is formed on the surface of the sacrificial layer. After forming the orifice plate and the ejection holes, the sacrificial layer is removed to form a pressure cavity.

  Step 40: forming an orifice plate on the second surface of the base and the surface of the sacrificial layer.

  After step 30, the surface of the sacrificial layer is flush with the second surface of the base. Therefore, the orifice plate can be formed in the plane, and the orifice plate and the base portion are integrally formed.

  Step 50: The sacrificial layer is developed using a first developer to remove the sacrificial layer and form a pressure cavity.

  After forming the orifice plate, the first photoresist used in the sacrificial layer is subjected to development processing by selecting a corresponding developing material as the first developing solution, dissolving the sacrificial layer material, Form.

  According to the technical solution described above, the orifice plate and the base portion are integrally formed, and it is not necessary to use an adhesive. This solves the problem that the manufacturing process of the conventional liquid ejecting head is complicated and the printing quality is lowered due to the use of the adhesive.

  Hereinafter, a specific method for realizing each step described above will be described in detail with examples.

According to technical solution according to the present exemplary form condition, method of producing individually each member in the conventional liquid ejecting head is an alternative to the method of integrally molding the base part. The base portion may be a silicon substrate and has a thickness of less than 70 μm. Those skilled in the art may employ various technical solutions to reduce the thickness of the silicon substrate to 50 μm or less. As a result, the volume of the liquid ejecting head is reduced.

See FIG. 2 for step 10. FIG. 2 is a schematic configuration diagram in which a diaphragm is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. In this embodiment shaped condition, employing a piezoelectric element as a pressure actuator. First, the diaphragm 2 is formed on the first surface of the base portion 1. Specifically, the diaphragm 2 may be formed using a plasma-assisted chemical vapor deposition method. The material of the diaphragm 2 may be silicon nitride. The role of the diaphragm 2 is to convert the driving force generated by the piezoelectric element into deformation of the diaphragm 2. As a result, the liquid ink receives pressure and is ejected from the ejection holes.

  Thereafter, as shown in FIG. 3, the piezoelectric element 3 is formed on the surface of the diaphragm 2. FIG. 3 is a schematic configuration diagram in which piezoelectric elements are formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. The piezoelectric element includes a lower electrode layer, a piezoelectric layer, and an upper electrode layer that are sequentially formed. Specifically, a refractory metal such as platinum or titanium is employed to form a lower electrode layer on the surface of the diaphragm 2. Thereafter, a sputtering method is employed to deposit a lead zirconate titanate film on the lower electrode layer to form a piezoelectric layer. Finally, an upper electrode layer is formed on the surface of the piezoelectric layer by using a refractory metal such as platinum.

  Preferably, as shown in FIG. 4, a protective layer may be formed on the outer periphery of the piezoelectric element 3. FIG. 4 is a schematic configuration diagram in which a protective layer is formed in the method of manufacturing a liquid jet head according to the embodiment of the invention. Specifically, a silicon nitride film is deposited on the surface of the upper electrode layer as the protective layer 4 by employing a low pressure chemical vapor deposition method. The protective layer 4 covers the lower electrode layer, the piezoelectric layer, and the upper electrode layer to protect the piezoelectric element 3 from being damaged.

  See FIG. 5 for step 20. FIG. 5 is a schematic configuration diagram in which a concave groove is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. Specifically, a method such as wet etching or reactive ion etching is employed to form the concave groove 5 on the second surface of the base portion 1 as a pressure cavity. In FIG. 5, the upper surface of the base 1 is the first surface, and the lower surface of the base 1 is the second surface.

  Further, the liquid supply passage 6 may be formed on the side surface of the groove 5 by etching. Similarly, methods such as wet etching or reactive ion etching may be employed. The liquid supply passage 6 communicates with the concave groove 5 and penetrates the first surface of the base portion 1. As a result, the ink flows into the pressure cavity via the liquid supply passage 6.

After forming the concave groove, the orifice plate may be formed subsequently. The photoresist required for forming the orifice plate is a jelly-like substance and not a fixed shape. The surface of the groove is coated with a jelly-like substance. The jelly-like substance always flows into the groove. Thus, in this embodiment shaped state, first, filling the sacrificial layer in the groove, after the formation of the orifice plate, to remove the sacrificial layer. This realizes formation of an orifice plate on the surface of the pressure cavity. Hereinafter, specific implementation methods of Step 30, Step 40, and Step 50 will be described with examples.

  In step 30, the first photoresist may be a photodegradable photoresist or a photocrosslinked photoresist. Here, the property of the photodegradable photoresist is that the photodecomposition reaction occurs after UV irradiation and is denatured and easily dissolved in a specific solvent. The photodegradable photoresist may be a general positive photoresist in the prior art, or a negative photoresist having the characteristics of a photodegradable photoresist by mixing a specific substance. Also good. The photocrosslinking photoresist is solidified by irradiation with ultraviolet light. The photocrosslinking photoresist may be a general negative photoresist in the prior art, but some positive photoresists have characteristics of a photocrosslinking photoresist by mixing a specific substance. .

FIG. 6 is a flowchart for forming a sacrificial layer in the method of manufacturing a liquid jet head according to the embodiment of the invention. As shown in FIG. 6, step 30 specifically includes the following steps.

  Step 301: A first photoresist is spin-coated on the concave groove to form a sacrificial layer.

In the present exemplary type state (specifically, a polyimide material) typical positive photoresist in the prior may be adopted. The polyimide material is easily dissolved in a solvent such as potassium hydroxide KOH after being irradiated with ultraviolet light. A polyimide material is spin-coated in the groove 5 to fill the space of the groove 5 and form a sacrificial layer 7.

  Step 302: Planarize the sacrificial layer so that the surface of the sacrificial layer is flush with the second surface of the base.

  FIG. 7 is a schematic configuration diagram in which a sacrificial layer is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. As shown in FIG. 7, the surface of the first photoresist filled in the concave groove 5 in step 301 is the same height as the second surface of the base portion 1, and the first photoresist is formed to form the orifice plate. Is flattened.

  Step 303: Dry the sacrificial layer.

Depending on the material of the selected first photoresist, the jelly-like material is dried in an appropriate manner to form a solid. The polyimide material employed in the present embodiment form state is dried for 180 seconds at a temperature of 110-1 180 ° C.. In particular, when dried at a temperature of 125 ° C., the speed at which the material is converted from jelly to solid is the fastest.

  Step 304: Perform an exposure process on the sacrificial layer using the first mask. Thereby, the sacrificial layer is denatured and easily dissolved in the first developer.

FIG. 8 is a schematic configuration diagram for performing exposure processing on the sacrificial layer in the method of manufacturing a liquid jet head according to the embodiment of the present invention. As shown in FIG. 8, the first photoresist may be exposed after the coated first photoresist in the groove 5 is completely solid. For polyimide material employed in this embodiment shaped state, specifically, it may perform exposure employing a first mask 8. The first mask 8 may be a general mask, and its light transmittance may be set as follows. In the first mask, the portion corresponding to the groove 5 is totally transmitting light, and the portion other than the portion corresponding to the groove 5 is not transmitted. Using ultraviolet light with an exposure level of 11 mw / cm ² , the light transmitting part of the first mask 8 is transmitted, and the polyimide material in the groove 5 is irradiated to maintain the exposure time of 20 seconds. Polyimide undergoes a photochemical change due to light irradiation and changes to a substance that is easily dissolved in KOH.

  Other materials that are easily dissolved in a specific solvent by those skilled in the art may be adopted as the first photoresist. The sacrificial layer 7 is formed by coating in the groove 5 and the first photoresist is formed after the ejection holes are formed. May be dissolved.

  After forming the sacrificial layer 7 that is easily dissolved in a specific solvent in the above steps 301 to 304, an orifice plate is formed on the surface of the sacrificial layer 7 and the second surface of the base portion 1. In step 40, specifically, the following method may be adopted.

FIG. 9 is a schematic configuration diagram in which a jet hole photoresist layer is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. As shown in FIG. 9, first, a second photoresist is spin-coated on the second surface of the base portion 1 and the surface of the sacrificial layer 7 to form the ejection hole photoresist layer 9. Thereafter, an exposure process is performed on the ejection hole photoresist layer 9 to form ejection holes.

As the second photoresist, a conventional general negative photoresist (specifically, a photoresist SU8 (registered trademark: MicroChem) ) may be employed. The photoresist SU8 is solidified by irradiation with ultraviolet light. The photoresist SU8 itself is easily soluble in 1-methyl ether acetate propylene glycol ester.

  Thereafter, it is necessary to perform a drying process on the ejection hole photoresist layer 9. The blow hole photoresist layer is dried for 7 minutes at a temperature of 65-95 ° C. to convert the jelly-like material into a solid.

FIG. 10 is a schematic configuration diagram for performing an exposure process on the ejection hole photoresist layer in the method of manufacturing the liquid jet head according to the embodiment of the present invention. As shown in FIG. 10, an exposure process may be performed on the ejection hole photoresist layer 9 using the second mask 10 so that the portion irradiated with light in the ejection hole photoresist layer 9 is solidified. In the 2nd mask 10, the part corresponding to the position of an ejection hole does not permeate | transmit, and parts other than the part corresponding to the position of an ejection hole permeate | transmit all light. Exposure is performed for 90 seconds using ultraviolet light having an exposure level of 11 mw / cm ² , and then drying is performed at a temperature of 65 to 95 ° C. for 6 minutes. The ultraviolet light is transmitted through the portion of the second mask where light is totally transmitted, and irradiates the ejection hole photoresist layer 9. While the portion irradiated with light is solidified, the portion not subjected to light irradiation maintains the properties of the second photoresist itself and can be dissolved by the second developer to form ejection holes.

  As shown in FIG. 11, the part which has not received light irradiation is melt | dissolved by 1-methyl ether acetate propylene glycol ester. Therefore, the ejection hole 11 is formed by developing the ejection hole photoresist layer 9 using 1-methyl ether acetate propylene glycol ester as the second developer. FIG. 11 is a schematic configuration diagram in which ejection holes are formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention.

  Said 2nd developing solution is not limited to 1-methyl ether acetate propylene glycol ester, You may employ | adopt the other solution which can melt | dissolve SU8 substance.

One skilled in the art may employ a plurality of methods to form the orifice plate. For example, the second photoresist is coated on the second surface of the base portion 1 and the surface of the sacrificial layer 7 to form the ejection hole photoresist layer 9. Thereafter, all of the ejection hole photoresist layer 9 is exposed using ultraviolet light, the ejection hole photoresist layer 9 is solidified, and then ejection holes are formed by a method such as laser drilling and etching. A method other than the above may be adopted for forming the orifice plate, and the method is not limited to the method of the present embodiment.

FIG. 12 is a schematic configuration diagram in which a pressure cavity is formed in the method of manufacturing a liquid jet head according to the embodiment of the present invention. As shown in FIG. 12, step 50 may be performed after the orifice plate is formed. The sacrificial layer 7 is developed using KOH as the first developer to dissolve the exposed polyimide material, thereby forming the pressure cavity 12. Polyimide materials used in form condition, after passing through the exposure and development, are rapidly removed by the KOH developer, smoothness of the inner wall of the pressure cavity is ensured.

By adopting the above technical solution, a plurality of pressure cavities 12 can be formed in the base 1. The pressure cavities are evenly arranged, and by appropriately increasing the number of pressure cavities, printing accuracy is improved and the mechanical strength of the liquid ejecting head is not affected. A plurality of ejection holes are formed in the orifice plate. Each jet hole corresponds to one pressure cavity. The ink is ejected from the ejection holes by driving the pressure actuator, and the print medium is printed.

The technical solution of the present type condition is formed in a unitary structure with the orifice plate and the base portion, a problem manufacturing process of the conventional liquid ejecting head of complexity is solved, the ink flow path by using an adhesive or The phenomenon that the ejection holes are blocked is avoided, and the printing quality and printing accuracy are improved.

Moreover, the technical solutions according to the present exemplary form condition, by liquid jet head integral structure is formed, the mechanical strength of the liquid jet head is not affected by the quantity of pressure cavity, the needs of the printing precision Accordingly, the etching accuracy can be increased, the number of pressure cavities and ejection holes can be increased, and the yield can be improved to a certain extent.

< Reference form 1 >
A reference embodiment of the present invention provides a liquid ejecting head. The liquid ejecting head may be manufactured in an integrated structure by the method of manufacturing a liquid ejecting head according to the above embodiment. A pressure actuator is formed on the first surface of the base portion, an orifice plate is formed on the second surface of the base portion via a sacrificial layer, and then the sacrificial layer is removed to form a pressure cavity. By forming the orifice plate and the base portion in an integral structure, the problem that the manufacturing process of the conventional liquid ejecting head is complicated is solved, and the phenomenon that the ink flow path or the ejection hole is blocked by using the adhesive is avoided. Printing quality and printing accuracy are improved.

< Reference form 2 >
Another reference embodiment of the present invention provides a printing apparatus having a liquid jet head. The apparatus solves the problem that the orifice plate and the base are integrally formed, the manufacturing process of the conventional liquid jet head is complicated, and the printing quality is lowered due to the use of the adhesive, and the adhesive is used. As a result, the phenomenon that the ink flow path or the ejection hole is blocked is avoided, and the printing quality and printing accuracy are improved.

The last thing to be explained is as follows. The above embodiments are only intended to illustrate the technical solution according to the present invention, not to limit the present invention. It has been described in detail the present invention with reference to the implementation form described above, but those skilled in the art should understand the following points. Some or all of the technical solutions described in the implementation form of the above, can be modified or equivalent substitutions. These modifications and substitutions, the essence of corresponding technical solution is, does not depart from the scope of this onset bright technical solution.

DESCRIPTION OF SYMBOLS 1 Base part 2 Diaphragm 3 Piezoelectric element 4 Protective layer 5 Groove 6 Liquid supply path 7 Sacrificial layer 8 1st mask 9 Ejection hole photoresist layer 10 2nd mask 11 Ejection hole 12 Pressure cavity

Claims (9)

Forming a pressure actuator on the first surface of the base;
Etching a second surface of the base portion facing the first surface to form a groove;
Filling the concave groove with a first photoresist to form a sacrificial layer, and making the surface of the sacrificial layer the same as the height of the second surface of the base portion;
Forming an orifice plate on the second surface of the base and the surface of the sacrificial layer;
Look including a step of performing development processing on the sacrificial layer by using the first developing solution to form a pressure cavity and removing the sacrificial layer,
Forming a sacrificial layer by filling the concave groove with a first photoresist;
Spin-coating the first photoresist in the concave groove to form the sacrificial layer;
Planarizing the sacrificial layer such that the height of the surface of the sacrificial layer and the second surface of the base are the same;
Performing a drying process on the sacrificial layer;
A step of exposing the sacrificial layer to the sacrificial layer using a first mask so that the sacrificial layer is modified and easily dissolved in the first developer. Method. The first photoresist is a photolytic photoresist,
2. The method of manufacturing a liquid jet head according to claim 1 , wherein a portion of the first mask corresponding to the concave groove is a total light transmission. Forming an orifice plate on the second surface of the base and the surface of the sacrificial layer;
Spin-coating a second photoresist on the second surface of the base and the surface of the sacrificial layer to form an ejection hole photoresist layer;
The method for manufacturing a liquid jet head according to claim 2 , further comprising: performing an exposure process on the jet hole photoresist layer to form a jet hole. The second photoresist is a photocrosslinking photoresist,
The step of performing an exposure process on the ejection hole photoresist layer to form the ejection holes,
By performing an exposure process on the ejection hole photoresist layer using a second mask, a portion irradiated with light in the ejection hole photoresist layer is solidified, and is positioned at the position of the ejection hole in the second mask. A step in which the corresponding part does not transmit and the part other than the part corresponding to the position of the ejection hole completely transmits light;
4. The method of manufacturing a liquid jet head according to claim 3 , further comprising: performing development processing on the ejection hole photoresist layer using a second developer to form ejection holes. 5. Etching the second surface of the base portion facing the first surface to form a groove,
Etching a second surface of the base portion facing the first surface to form a groove;
By performing the etching on the side surface of the groove, according to claim 4, characterized in that it comprises a step of forming said groove and communicating and a liquid supply passage penetrating said first surface of said base portion A method for manufacturing a liquid jet head. The pressure actuator is a piezoelectric element;
Forming the pressure actuator on the first surface of the base,
Forming a diaphragm on the first surface of the base;
The method of manufacturing a liquid jet head according to claim 5 , further comprising: sequentially forming a lower electrode layer, a piezoelectric layer, and an upper electrode layer on the surface of the vibration plate. Forming the pressure actuator on the first surface of the base,
Further comprising forming a protective layer on a surface of the upper electrode layer;
The method of manufacturing a liquid jet head according to claim 6 , wherein the lower electrode layer, the piezoelectric layer, and the upper electrode layer are covered with the protective layer. The first photoresist method for manufacturing a liquid jet head according to any one of claims 1 to 6, characterized in that a polyimide. The second photoresist method for manufacturing a liquid jet head according to any one of claims 4-6, characterized in that a negative photoresist.

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