JP2000263795A - Production of ink jet printing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an ink jet printing head equipped with an orifice plate having nozzle orifices or the like formed thereto in low cost with high accuracy. SOLUTION: A dry film resist 22 is laminated on the entire surface of a substrate to which heating resistors 13, a common electrode, individual wiring electrodes, a drive circuit electrode pad 15, a partition wall 18, ink supply grooves 16 and an ink feed port are formed and, after the excessive portion of the resist is removed by patterning, a conductive member (Ni membrane 23) is formed in a thickness of 0.1-1 μm by sputtering or vapor deposition and a photoresist material 24 is applied to the conductive member to be patterned so as to remain on the heating resistors 13 and the corresponding part of the electrode pad 15 and, thereafter, the exposed part of the Ni membrane 23 is electroplated with Ni in a thickness of 5-50 μm. Thereafter, the disused photoresist 24 and the dry film resist 22 are removed by peeling and a solvent and the Ni membrane 23 remaining on nozzle orifice parts 25 and the electrode pad part 15 is removed within a short time by dry etching to complete a printing head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an ink jet printer head having an orifice plate in which holes such as ink discharge nozzles are formed at low cost and in a desired shape with high precision.

[0002]

2. Description of the Related Art Conventionally, an ink jet printer has been used. In the printing method of the ink jet printer, ink droplets are ejected from ink ejection nozzles of an ink jet printer head, and the ink droplets are absorbed by a recording material such as paper or cloth to print (print) characters and images. It is what you do. This printing method is a printing method that generates less noise, does not require special fixing processing, can perform high-speed printing, and can perform full-color printing.

[0003] In the case of full-color printing, usually, three subtractive primary colors, yellow (yellow), magenta (red dye name) and cyan (greenish blue), are added to three color inks.
Printing is performed using four colors of ink to which black (black) used for black portions of characters and images is added. That is, a nozzle row dedicated to each color is arranged in the print head, and four color inks of yellow, magenta, cyan, and black are discharged from these nozzle rows while controlling the discharge amount of each color. Full-color printing is performed by mixing and absorbing each ink in one pixel of the material.

As a method of ejecting ink droplets from the nozzles described above, a pressure due to mechanical deformation is generated in a finely formed ink reservoir using an electromechanical transducer such as a piezo element. A method in which droplets are ejected from minute nozzles by repelling pressure, and a resistive heating element is arranged in a fine ink reservoir, and an electric pulse is applied to the resistive heating element so that the ink is heated and foamed at a high speed to grow the bubbles. There is a method of performing ejection by utilizing the method.

FIG. 4A is a plan view schematically showing an ink ejection surface of the above-described ink jet printer head (hereinafter, simply referred to as a print head), and FIG. It is a figure showing a silicon wafer manufactured. As shown in FIG. 1A, a print head 1 has a large number of ink discharge nozzles (hereinafter simply referred to as nozzles or orifices) 4 formed in a single row on an orifice plate 3 laminated on the uppermost layer of a chip substrate 2. And such a nozzle row 5 as a whole
Are formed in four rows.

On the upper surface of the chip substrate 2 where the orifice plate 3 is not stacked, a common electrode power supply terminal 6 for a heating resistor and a drive circuit terminal 7 for supplying power to a drive circuit, which will be described later, are provided. As shown in FIG. 1 (b), such a print head 1 is collectively formed on a chip substrate 2 partitioned on a silicon wafer 8 of at least 4 inches or more using an LSI forming technique and a thin film forming technique. Formed. Although FIG. 6A shows 36 orifices 4, 64, 128 or 256 ink ejection nozzles are actually formed in a line.

FIGS. 5A, 5B, and 5C show the print head 1 described above.
4A and 4B are schematic views showing a plan view and a cross-sectional view of a state of being formed on the chip substrate 2 of the silicon wafer 8 shown in FIG. . 3 (a), 3 (b) and 3 (c) show plan views in the upper part, the middle part is a sectional view taken along the line BB 'of the upper part (see FIG. 3 (a)), and the lower part is the CC in the upper part. 'A sectional view taken along the arrow (see FIG. 1 (a)). In addition, in the figures (a), (b) and (c), 64 (or 128 or 256) orifices or heating elements are replaced by five orifices or heating elements for convenience of illustration. It is shown as a representative. The middle part of FIG. 5 (c) is also an enlarged view taken along the line AA 'of FIG. 4 (a).

A method for manufacturing the print head 1 will be described with reference to FIGS. 5 (a), 5 (b) and 5 (c). First, as step 1, a drive circuit and its terminals are formed on a chip substrate of a silicon wafer by an LSI forming process, and an oxide film having a thickness of 1 to 2 μm is formed. Then, a resistive film made of Ta (tantalum) -Si (silicon) -O (oxygen) and an electrode film made of Ti / W are formed, and a pattern of a wiring portion is formed on the electrode film by photolithography. Has a fine heating resistor (heating element)
Is formed. In this step, the position of the heating resistor is determined.

FIG. 5A shows a state immediately after the steps 1 and 2 have been completed. That is, the common electrode 11 and the common electrode power supply terminal 6 (FIG. 4A)
), Individual wiring electrodes 12, a large number of (six as shown in the figure, six heating resistors), a driving circuit 14,
The drive circuit electrode pad 15 and the drive circuit terminal 7 (FIG. 4A)
See).

Subsequently, as a step 3, a partition member made of an organic material such as photosensitive polyimide is formed to a height of about 20 μm by coating in order to form an ink seal wall and ink reservoirs corresponding to the individual heating elements 13. After patterning this, heat of 300 to 400 ° C. is applied for 30 minutes.
Then, curing (dry curing, baking) for 10 to 60 minutes is performed, and a partition made of the photosensitive polyimide having a height of 10 μm is formed and fixed on the chip substrate. Further, in step 4, a groove-like ink supply groove is formed on the surface of the chip substrate by wet etching or sand blasting, and an ink supply hole communicating with the ink supply groove and opening on the lower surface of the chip substrate is formed. I do.

FIG. 5B shows a state immediately after Steps 3 and 4 are completed. That is, the elongated ink supply groove 16 and the ink supply hole 17 are formed, the common electrode 11 located on the left side of the ink supply groove 16, the right individual wiring electrode 12 is disposed, and A partition 18 (18, 18) is provided between the resistor 13 and the heating resistor 13.
18-1 and 18-2) are formed. Partition wall 18 laminated on the vicinity of the heating resistor 13 and the drive circuit portion
Are the parts 18-on the individual wiring electrodes 12 and the drive circuit 14.
If 1 is a comb body, a portion 18-2 extending between the respective heating resistors 13 has a shape corresponding to the teeth of the comb. As a result, the fine teeth of the comb are used as partition walls, and the finely divided sections where the heating resistors 13 are located at the roots between the teeth are formed as ink reservoirs 19 by the number of the heating resistors 13.

Thereafter, in step 5, an orifice plate of a polyimide film having a thickness of 10 to 30 μm is coated on one side with a very thin thermoplastic polyimide as an adhesive, for example, to a thickness of 2 to 5 μm. The orifice plate is adhered to the uppermost layer of the laminated structure by applying pressure while heating at 170 to 300 ° C. Then, Ni, Cu
Alternatively, a metal film such as Al having a thickness of about 0.5 to 1 μm is formed.

Further, as a step 6, the metal film on the orifice plate is patterned to form a mask for selectively etching the polyimide.
18 .mu.m.phi.
A large number of nozzles are formed at once by making a hole of μmφ. Also, openings are provided in the orifice plate portions corresponding to the terminal portions such as the power supply terminal 6 and the drive circuit terminal 7 described above. The holes can be formed by using an excimer laser or the like.

FIG. 5 (c) and FIG. 4 (a) show the state immediately after the above-described steps 5 and 6 have been completed. That is, the orifice plate 3 covers the entire area except for the power supply terminals 6 and 7, the ink reservoir 19 formed by the partition 18-2 covers the top, and the opening facing the ink supply groove 16. A fine partition portion having a height corresponding to a thickness (height) of 10 μm of the partition wall 18-2 having the discharge holes (nozzles) 4 individually above the portion is formed. In addition, an ink flow path 21 having a height of 10 μm is formed to connect the opening of the ink reservoir 19 and the ink supply groove 16.

Thus, a multi-color print head 1 having four nozzle rows 5 having 64 (or 128 or 256) nozzles 4 in one row is completed on a large number of silicon wafers 8. The processing up to this point is performed in a wafer state. Finally, in step 7, the silicon wafer is cut using a dicing saw or the like, divided into individual chip substrate units, die-bonded to a mounting substrate, and connected to terminals to form a print head in a practical unit. Is completed.

[0016]

As described above, the orifice plate 4 is first adhered to the uppermost layer of the chip substrate 2 and then the base pattern, that is, the heating resistor 1 is attached.
Processing the nozzle (orifice) 4 in accordance with the position of 3 has been considered to be a much more productive and practical method than laminating the orifice plate 4 on which the orifice 4 has been processed in advance. .

However, after the orifice plate is attached to the uppermost layer of the chip substrate, the nozzles are collectively opened by dry etching with strong anisotropy such as helicon wave dry etching, and the heat generated by the thin film immediately below the nozzles is generated. There is often a problem that the resistor is damaged, and the yield of the silicon wafer is reduced.

In the case of drilling by dry etching or the like, residues tend to remain. The presence of such a residue adversely affects the ejection of the ink from the nozzles, and also adversely affects the subsequent bonding of the electrode terminal portion.

Although the productivity is high and the practicability is high, the helicon wave etching apparatus and the ICP etching apparatus in the case of performing the dry etching for the above-described hole forming processing have a high equipment cost, so that the processing cost of the hole forming step is high. However, it also has a problem that it becomes expensive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances,
An object of the present invention is to realize a method of manufacturing an ink jet printer head including an orifice plate in which holes such as nozzles are formed in a desired shape at low cost and with high precision.

[0021]

According to the present invention, there is provided a method of manufacturing an ink-jet printhead, comprising the steps of: forming a plurality of heating elements on a substrate and partition walls for defining ink flow paths corresponding to the heating elements; An orifice plate forming step of forming an ink discharge nozzle in the orifice plate while forming an orifice plate laminated on the substrate via a partition.

The orifice plate forming step may include, for example, a step of laminating an electrode layer having a substantially flat upper surface on the substrate via the partition, and at least an ink discharge nozzle on the upper surface of the electrode layer. A step of selectively forming a plating resist film at a position corresponding to, a step of forming a plating layer of a predetermined thickness on the electrode layer by applying electroplating using the electrode layer as an electrode, and And removing the portion of the electrode layer facing the ink discharge nozzle to penetrate the ink discharge nozzle, and for example, as described in claim 3, Forming a base film of the electrode layer at least in a region excluding the partition so that the upper surface is substantially at the same height as the upper surface of the partition; and removing the base film after forming the plating layer. Further configured and a step. Preferably, the electrode layer is formed of the same material as the plating layer, for example.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A, 1B, 1C, and 1D are diagrams illustrating a first half of a process of a main part of a method of manufacturing an ink jet print head according to an embodiment.

FIG. 2A, FIG. 2B, FIG. 2C, and FIG.
FIG. 9 is a diagram illustrating the latter half of the process of the main part of the method of manufacturing the ink jet print head following FIG. These figures 1 (a)
2 (a) to 2 (d) and FIGS. 2 (a) to 2 (d), a method of manufacturing an ink jet print head will be described below.

First, FIG. 1 (a) shows a state immediately after the completion of the steps 3 and 4 shown in the middle part of FIG. 5 (b). Are given the same numbers as in FIG. 5 (b). That is, on the chip substrate 2 of the silicon wafer on which the drive circuit 14 is formed, the heating resistor 13 necessary for heating and foaming the ink is provided.
And a common electrode 11 electrically connected to the heating resistor 13.
And the individual wiring electrodes 12 and the drive circuit electrode pads 15 are patterned, and a partition 18 made of an organic material such as photosensitive polyimide is formed thereon by patterning.

Further, an ink supply groove 16 for supplying ink to each of the heating resistors 13 in common, and an ink supply hole 17 for supplying ink to the ink supply groove 16 from outside.
Is made by sandblasting. This is a production intermediate of a roof shooting type print head.

Next, as shown in FIG. 1 (b), a dry film resist 22 is laminated on the entire upper surface of the wafer, and the dry film resist 22 is supplied with ink as shown in FIG. 1 (c). Exposure and development are performed and patterning is performed so as to remain between the partition walls 18 and 18 from the groove 16 to the heating resistor 13, that is, in a concave portion where the partition wall 18 is not provided. The remaining resist film 22 becomes a base film for forming a plating electrode described later.

Then, as shown in FIG. 1 (d), a Ni electrode as a plating electrode made of a conductive member is formed on the entire surface of the resist film 22 and the partition 18 which are substantially flush with each other on the wafer. Are laminated. As a method for laminating such a thin film, it is possible to form a film to a thickness of about 0.1 to 1 μm by using various methods such as sputtering and vapor deposition.

The conductive member is not limited to Ni, and may be a member that functions as a common electrode for electroplating performed in a subsequent step and has good adhesion to the electroplated layer to be electrodeposited.
Other metals or conductive materials may be used. Here, in consideration of the adhesion between the conductive thin film and the electroplating layer, it is not always preferable that the conductive thin film and the electroplating layer be made of the same material. If an oxide film is easily formed on the surface, the adhesion may be deteriorated. In addition, good adhesion can be obtained as long as an intermetallic compound is easily formed even with dissimilar metals.

Subsequently, a photoresist material is applied on the entire surface of the Ni thin film 23 by spin coating or the like, and the photoresist material 24 is placed on the heating resistor 13 as shown in FIG. Exposure and development are performed and patterning is performed so as to remain in a portion above the electrode pad 15 of the drive circuit, that is, in a portion requiring holes.

Next, a plating layer 23-2 serving as an orifice plate is formed by electroplating using the thin film 23 as an electrode. In the electrolytic solution, a voltage is applied to the Ni thin film 23 serving as an electrode, and the same Ni plating layer 23-2 is laminated on the Ni thin film 23 as shown in FIG. As described above, the thickness of the first Ni thin film 23 is about 1 μm even when it is thick.
To a degree, a plating layer having a thickness of 5 μm to 50 μm can be laminated thereon by this electroplating. In this electroplating, a portion corresponding to a hole of a nozzle facing the heating resistor 13 and a portion corresponding to an electrode pad 15 serving as a terminal portion of an electrode of a drive circuit are covered with a photoresist 24. There is no plating.

The drive circuit 14 is made of a polyimide partition wall 1.
Since it is protected by the layer No. 8 and does not come into direct contact with the electrolytic solution, there is no risk of being affected by the electric solution. When there is a possibility that other components may be affected by the electric liquid, a protective film may be attached to the back surface of the chip substrate 2, that is, the back surface of the wafer.

As shown in FIG. 2B, after the plating layer 23-2 is formed to a predetermined thickness by this electroplating, the unnecessary photoresist 24 and the dry film resist 22 are removed. Peel and remove as shown in 2 (c). In this stripping, since a highly reactive chemical such as diethylene glycol ethyl ether is used as a stripping solvent for the etching photoresist 24, the resist film 22 can be stripped more easily. Therefore, the photoresist 24 for etching and the resist film 2
2 can be peeled off in the same step.

In the state shown in FIG.
3 and a portion of the electrode pad 15 which becomes the opening of the electrode of the drive circuit.
3 above the partition wall 18 and above the portion between the ink supply groove 16 and the heating resistor 13, the N thin film 23 and the Ni plating layer 23-2 formed by electroplating have a thickness of N.
An i-orifice layer 23-3 is formed.

Thereafter, the Ni thin film 23 remaining in the nozzle hole 25 and the electrode pad 15 is removed by light etching (simple etching that is performed in a short time without providing a resist film). This light etching time is
The thickness of the Ni thin film 23 to be etched is 0.2 μm
In the case of (1), the etching is performed by setting a time for etching a thin film having a thickness of 0.2 to 0.6 μm. As a result, the surface of the Ni orifice layer 23-3, which is not an etching target, is also etched since no resist film is provided, and the Ni orifice layer 2-3 is not etched.
3-3 becomes thinner by 0.2 μm to 0.6 μm.

The remaining Ni thin film is a thin film having a thickness of only 1 μm at most even if the thin film is thick.
The effect on the diameter of No. 3 is negligible and does not cause any practical problems.

Thus, as shown in FIG. 2D, the Ni orifice layer 23 shown in FIG.
The orifice plate 26 of Ni is thinned from above by an amount corresponding to the etching of the Ni thin film 23. The nozzle hole 25 is formed through a portion of the orifice plate 26 facing the heating resistor 13. With electrode pad 15
Are exposed to the outside and the roof shooting type print head 27 is completed.

As the material of the orifice plate, it is sufficient if the material has resistance to the applied ink. In this respect, Ni described above also has good adaptability. Further, the orifice plate is preferably capable of performing a water-repellent process for improving the cut when the ink is ejected, and in this case, a water-repellent plating layer, for example, a Ni-F-containing composite plating layer is formed as described above. It may be formed by the method described above.

The conductive thin film used as the plating electrode is not limited to the above-described method in which Ni is deposited by vapor deposition or sputtering, but may be formed by depositing another conductive metal or alloy, sputtering, or sputtering. You may make it apply | coat as a thin film by electroplating etc. In alloys, Sn-Ni,
Ni-Fe, Fe-Ni-Cr, Cu-Ni, Ni-M
n, Ni—Co and the like are preferable.

The conductive thin film is not limited to a metal film formed by a thin film forming process, but may be made of graphite powder, silver powder, copper powder, brass powder, Al powder, etc. It can also be formed by directly applying to the surface.

Although it has been described that the effect on the diameter of the nozzle hole 23 can be neglected in the short-time etching in which the thickness of 1 μm is etched, the arrangement density of the nozzles is small, the hole diameter of the nozzle is small, and the nozzle hole 23 is high. Accuracy is required,
If the effect cannot be neglected even with an etching thickness of 1 μm, the pattern of the photoresist material 24 formed on the heating resistor 13 shown in FIG. 2A may be adjusted to be smaller in consideration of the amount to be etched. .

In order to form a temporary base for the conductive thin film (Ni thin film 23), a dry film resist 22 is laminated on the entire surface of the wafer in FIG. The target substrate is not limited to a dry film resist, and a liquid photoresist can be used.

FIG. 3 is a manufacturing process diagram when a liquid photoresist is used, and shows a process corresponding to FIG. 1B described above. As shown in the figure, in this case, the protective film 2 is formed on the back surface of the wafer (the back surface of the chip substrate 2 in the figure).
Paste 8 After the ink supply holes 17 are thereby closed, a liquid photoresist 29 is applied by a spin coating method or the like and solidified, and then the protective film 28 attached to the back surface of the wafer is peeled off. Then, FIG. 1 (c),
Processing can be performed in the same manner as in (d) and FIGS. 2 (a) to (d).

Further, in the above-described manufacturing method, a resist film or a photoresist is disposed as a base film of the plating electrode layer. However, this base film is omitted, and a metal film plate such as a metal foil is used as the plating electrode layer. An orifice plate equivalent to that of the above-described manufacturing method can also be formed by arranging it on a substrate via a partition as a plating electrode and performing electroplating in the same manner as described above.

[0045]

As described above in detail, according to the present invention, the holes such as the ink discharge nozzles are formed while forming the orifice plate on the substrate on which the heating elements and the partition walls are formed.
It is possible to manufacture an ink jet printer head having an orifice plate in which ink discharge nozzles, holes for connecting wiring electrodes, and the like are formed in a desired shape with high precision, in a short time, with good yield, and at low cost.

Further, since no residue is left as in the case of dry etching, troubles such as a trouble in an ink flow path and a trouble in electrode connection do not occur. Manufacturing becomes possible.

[Brief description of the drawings]

FIGS. 1A, 1B, 1C, and 1D are diagrams illustrating a first half of a process of a main part of a method of manufacturing an ink jet print head according to an embodiment.

FIGS. 2 (a), (b), (c), and (d) are views showing the latter half of the main steps of the method for manufacturing an ink jet print head.

FIG. 3 is a manufacturing process diagram when a liquid photoresist is used.

FIG. 4A is a plan view schematically showing an ink ejection surface of an ink jet printer head, and FIG. 4B is a diagram showing a silicon wafer on which a print head is manufactured.

FIGS. 5A, 5B, and 5C are a plan view and a cross-sectional view illustrating a method of manufacturing a conventional inkjet printer head in the order of steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet printer head (print head) 2 Chip substrate 3 Orifice plate 4 Ink discharge nozzle (nozzle, orifice) 5 Nozzle array 6 Common electrode power supply terminal 7 Drive circuit terminal 8 Silicon wafer 11 Common electrode 12 Individual wiring electrode 13 Heating resistor 14 Drive circuit 15 Electrode pad of drive circuit 16 Ink supply groove 17 Ink supply hole 18 (18, 18-1, 18-2) Partition wall 19 Ink reservoir 21 Ink flow path 22 Dry film resist (base film) 23 Ni thin film ( Conductor film) 23-2 Plating layer 23-3 Orifice layer 24 Photoresist material 25 Nozzle hole 26 Orifice plate 27 Roof shooting printhead 28 Protective film 29 Liquid photoresist

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2C057 AF24 AF93 AG07 AG14 AG92 AG93 AP02 AP13 AP22 AP34 AP52 AP54 AP55 AP60 AQ02 BA04 BA13

Claims (4)

[Claims] A step of forming, on a substrate, a plurality of heating elements and a partition for partitioning an ink flow path corresponding to each of the heating elements; and forming an orifice plate laminated on the substrate via the partition. And an orifice plate forming step of forming an ink discharge nozzle in the orifice plate. 2. The method according to claim 1, wherein the step of forming the orifice plate includes the step of laminating an electrode layer having a substantially flat upper surface on the substrate via the partition wall, and selectively forming at least a position on the upper surface of the electrode layer corresponding to an ink discharge nozzle. Forming a plating resist film on the electrode layer, performing electroplating using the electrode layer as an electrode to form a plating layer having a predetermined thickness on the electrode layer, removing the plating resist film, 2. The method according to claim 1, further comprising: removing a portion of the layer facing the ink discharge nozzle to penetrate the ink discharge nozzle. 3. The step of forming an orifice plate includes the steps of: forming a base film of the electrode layer in a region on the substrate except at least the partition so that an upper surface of the base layer is substantially flush with an upper surface of the partition; 3. The method of manufacturing an ink jet print head according to claim 1, further comprising the step of: removing after forming the plating layer. 4. The method according to claim 2, wherein the electrode layer is formed of the same material as the plating layer.