JP2000318169A - Manufacture of ink jet printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for ink jet printer head having high thermal energy efficiency and excellent in cavitation durability. SOLUTION: A photomask 46 has a forming pattern 47 including a pectinate cut exposing patterns 47a corresponding to barrier walls to be formed, and a plurality of process patterns 47b formed at respective corner parts of the forming pattern 47. A light shielding pattern is formed at the root of a pectinate pattern corresponding to a section barrier wall over the entire length in the widthwise direction. It is a pattern not appearing on a formed barrier wall and provided to form a part for releasing a developer standing at the corner part of a section part when developing is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an ink jet printer head having excellent cavitation durability.

[0002]

2. Description of the Related Art In recent years, ink jet printers have been widely used. Printers using the ink jet system include a thermal ink jet system in which ink droplets are ejected by the force of air bubbles, and a piezo system in which ink droplets are ejected by deformation of a piezoresistive element (piezoelectric element).

[0003] In these methods, a process in which ink as a color material is formed into ink droplets and directly ejected toward recording paper requires a lower printing energy as compared with an electrophotographic system using a toner as a powdery printing material. It is easy to colorize by mixing ink, and it is possible to reduce the size of printing dots, so that high image quality is achieved, the amount of ink used for printing is not wasted, and cost performance is excellent. This is the printing method used.

There are two types of thermal ink jet systems depending on the direction in which ink droplets are ejected. That is, there is a configuration that discharges in a direction parallel to the heating surface of the heating element, and a configuration that discharges in a direction perpendicular to the heating surface of the heating element.

FIGS. 6 (a), 6 (b) and 6 (c) show a structure in which ink is ejected in a direction parallel to the heat generating surface of the heat generating element.
(e) and (f) each schematically show a configuration in which ink is ejected in a direction perpendicular to the heating surface of the heating element. As shown in FIG. 1A or FIG. 1D, a heating element 2 is formed on a silicon substrate 1, and an orifice plate 3 is disposed above the heating element 2 with a predetermined gap. An orifice (ink discharge nozzle) 4 is formed on the side of the heating element 2 in a), and facing the heating element 2 in FIG. The heating element 2 is connected to an electrode (not shown), and the ink 5 is always supplied to the ink flow path in which the heating element 2 is provided.

In order to discharge ink droplets from the orifice 4, first, as shown in FIG. 1B or FIG. 1E, the heating element 2 is caused to generate heat by energizing according to image information. Generate nuclear bubbles on top. The nuclear bubbles coalesce and grow into a film bubble 6, and the film bubble 6 expands adiabatically and further grows to push out the surrounding ink, whereby the ink 5 'is pushed out from the orifice 4, and the pushed out ink 5 'is ejected from the orifice 4 toward the paper surface as an ink droplet 7, as shown in FIG. Thereafter, the film bubbles are shrunk by the heat of the surrounding ink, and finally disappear. Then, it waits for the next heating element 2 to be heated. This series of steps is performed instantaneously.

[0007] A structure in which ink droplets are ejected in a direction perpendicular to the heating surface of the heating element is called a roof shooter type thermal ink jet printer head.
It is known that power consumption is extremely small as compared with a configuration in which ink droplets are ejected in a direction parallel to a heating surface of a heating element. As a method of manufacturing a thermal ink jet printer head for full color in this type, a method of monolithically forming a plurality of heating elements, individual driving circuits, and orifices collectively by using a silicon LSI forming technique and a thin film forming technique. There is.

According to this method, for example, 10 mm × 15
Resolution is 360dp on a chip substrate of about mm
If the head is i (dot / inch), 128 heating elements, drive circuits and orifices can be formed, and if the resolution is 720 dpi, 256 heating elements, drive circuits and orifices are formed. can do.

By the way, the boiling phenomenon which appears in the above-mentioned processes 1 to 4 is a so-called film boiling phenomenon. The film boiling phenomenon occurs when an object heated to a high temperature, such as quenching of iron, is immersed in a liquid, and when the surface temperature of the object in contact with the liquid is rapidly increased. The film boiling phenomenon used in the method is based on the latter method of "rapidly increasing the surface temperature of an object in contact with a liquid". The phenomenon that occurs when the bubbles disappear in the film boiling phenomenon is called cavitation.

FIGS. 7 (a) and 7 (b) are diagrams schematically showing the process of growth and extinction of bubbles in the ejection of the ink droplets.
FIG. 1A shows a heating element 9 experimentally set in an open pool 8 having a water depth of 1 mm (millimeter) and the process of bubble growth and extinction caused by the heating element 9 from 0 to 6 μs (microsecond).
It is shown every μs. FIG. 3B shows the timing of energizing the heating element 9.

As shown in FIG. 1A, the heating element 9 is heated in 0 to 1 .mu.s, and a plurality of nuclear bubbles are integrated in 1 to 2 .mu.s, thereby ejecting ink droplets in 2 to 3 .mu.s. A film bubble is generated, and the contraction of the film bubble has already started in 3 μs. Until the film bubbles disappear in 6 μs, a destructive force based on an action called cavitation is generated as shown by arrows a-1, a-2, and a-3 in FIG. It is said that the destructive force due to the cavitation acts as a force for peeling the heating element 9 from the installation surface, and the impact force reaches 1000 ton / cm ² in the case of the above-mentioned open pool having a depth of 1 mm. The area of the heating element of the thermal ink jet head is about 40 μm × 40 μm. When converted by this area ratio, the impact force is about 16 kg (kilogram).

FIG. 8A is a plan view showing the structure of a roof-shooter type thermal ink jet printer head (hereinafter simply referred to as an ink jet printer head), and FIG. 8B is a plan view of FIG. A 'cross-sectional view, same figure
(c) is a view showing a photomask for forming a partition for partitioning the heat-generating element disposition portion. In addition, FIG.
The uppermost orifice plate is shown in perspective. In addition, in practice, a large number of heating elements are used as an example to make it easy to understand.
Only one is shown.

As shown in FIGS. 1A and 1B, an ink jet printer head 10 has an LSI
, A heating circuit 14 composed of a thin film 13 of a heating resistor, an individual wiring electrode 15 connecting the heating element 14 and the driving circuit 12, and a common power supply electrode 16 are formed. Are laminated. The heating elements 14 and the individual wiring electrodes 15 are arranged in the same number as the orifices 18 as ink discharge nozzles formed later.

An orifice plate 19 is laminated from above, and an ink flow path 21 having a height of about 10 μm corresponding to the thickness of the partition wall 17 is provided between the heating element 14 and a common ink supply groove (not shown). It is formed. Thereafter, the orifice 18 for discharging ink is formed on the orifice plate 19.

The partition 17 is a seal partition (not shown) for sealing the ink disposed on the common power supply electrode 16 below the ink flow path 21 (below the drawing).
And a partition wall 17b disposed on the individual wiring electrode 15 above and a partition wall 17b extending from the seal partition wall 17a between the heating elements 14 to partition the heating elements 14. ing. The heating element 14 is disposed in a partition 22 formed by the partition 17 formed by the seal partition 17a and the partition 17b and forming a pressurized chamber.

In general, when the partition 22 is formed by patterning the thin film of the partition wall material by photolithography, a photomask 23 shown in FIG. 1C is used. An opening pattern (hereinafter, referred to as an exposure pattern) for transmitting light formed in the photomask 23 is formed of a negative photosensitive resin (a type in which a portion irradiated with light is cured) as a partition material. As shown in FIG. 4C, a comb-shaped notch 24 having a flat cross section corresponding to the comb-shaped partition 17 is formed, and a corner 25 corresponding to the root of the comb tooth is substantially formed. It is formed so as to form a right angle.

[0017]

However, it has been found that the shape of the cross section of the partition wall 17 formed by using the photomask 23 is not exactly formed according to the shape of the molding pattern of the photomask 23. That is, as shown in FIG. 8 (a), the corners, which are the roots of the teeth of the partition wall 17 having a comb-like flat cross section, are not at right angles according to the forming pattern of the photomask 23. By design, the corners that should bend at right angles are rounded as if the corners were intentionally padded. In other words, the corner is the partition 2
It is approaching inside 2. As a result, the cavitation damage described below occurs in the heating element 14.

FIGS. 9 (a), 9 (b) and 9 (c) show 3 μs shown in FIG.
FIG. 9 (d), (e), and (f) show again the process in which the largest grown film bubble during the period from 5 μs to 5 μs contracts to the state immediately before disappearance. FIG. 9B is a view showing a process of shrinkage of a film bubble actually occurring in the above-mentioned section 22 corresponding to (b) and (c). As shown in FIGS. 5A and 5B and FIGS. 5D and 5E, the film bubble 6-1 which has reached the maximum and has finished ejecting ink contracts to the film bubble 6-2.

Further, when the state of the shrinkage bubble 6-3 immediately before the disappearance is reached, if the partition 22 shown in FIG. 5 (f) becomes like the partition 22 'shown in FIG. If the two corners corresponding to the root of the tooth are perpendicular, the same figure (c)
The shrinking bubble 6-3 shown in FIG. 7 is divided into two as shown in a section 22 'shown in FIG. Therefore, the cavitation breaking force acts on the retracted position of the shrinking bubble, but in the example shown in FIG. 3 (g), the cavitation breaking force is exposed at the corner of the partition 22 '. Works on the surface of the chip substrate and does not substantially act on the heating elements that are out of the retracted position.The surface of the chip substrate is a silicon oxide film, which is resistant to the destructive force of cavitation. There is no problem because it is strong.

However, the partition 22 shown in FIG.
Then, as described above, since the corner of the section is protruding inward, the corner cannot be the retraction position of the bubble, so that the contracted bubble 6-3 does not split into two but remains united. ,
It retreats to the center of the bottom (back side) of the partition 22. Then, in a state where a part of the heating element 14 is applied to the surface of the side portion 26 located on the inner side of the partitioning portion 22, the cavitation breaking force acts on this retraction position. As a result, cavitation damage occurs at the side 26 located on the inner side of the partition 22 of the heating element 14. Since the destructive force of the cavitation acts on the heating element 14 every time the ink is ejected, there is a problem that the life of the heating element 14, that is, the life of the inkjet printer head 10 is significantly shortened.

In order to solve this problem, a method of providing a cavitation damage preventing layer on the surface of the heating element is generally employed to prevent the above-mentioned cavitation damage occurring on the heating element.

However, in the method of providing the cavitation damage preventing layer on the surface of the heating element, although the damage of the heating element can be prevented, the provision of the cavitation damage preventing layer makes it impossible for the heating element to come into direct contact with the ink. Among them, the efficiency of the thermal energy contributing to the generation of film bubbles becomes extremely low, that is, a problem occurs that the thermal energy is reduced to approximately 10% according to experiments.

SUMMARY OF THE INVENTION The object of the present invention is to provide
An object of the present invention is to provide a method of manufacturing an ink jet printer head including a heating element having good thermal energy efficiency and excellent cavitation durability.

[0024]

According to a method of manufacturing an ink jet printer head of the present invention, a plurality of heating elements for generating thermal energy for ejecting ink, and the plurality of heating elements are separated from each other to form a partition. A partition wall surrounding at least three directions around each of the heat generating elements in a rectangular shape so as to form a bubble, and generating a bubble by each of the heat generating elements to apply pressure to the ink and discharge the ink in a predetermined direction. A step of uniformly applying a photosensitive resin on the substrate on which the heating element is formed;
An exposure step of irradiating the applied photosensitive resin with light through a photomask having a predetermined molding pattern, and a shape of a partition wall for isolating the light-irradiated photosensitive resin from each of the heating elements. And a developing step of developing the photomask used in the exposing step, the corners of the pattern corresponding to the partition walls, for flowing the developer stagnating near the corners A process pattern is provided which does not appear in the shape of the formed partition wall.

The process pattern may be, for example,
As described, it is a rectangular pattern formed over the entire length in the width direction at the corner of the formed pattern, and when the width of the rectangular pattern is d and the height of the partition is h, "0 .2.h <d <h ".

In the above process pattern, for example, when a circle is formed and the radius of the circle is defined as r and the height of the partition is defined as h, the following formula is obtained. r <
0.8 · h ”. For example, as described in claim 4, a square is formed and one corner of the square corresponds to a corner of the partition of the forming pattern. It may be formed so as to overlap the corner portion, and for example, as described in claim 5, a triangular shape is formed, and one side of the triangle overlaps a corner portion corresponding to a corner of the partition of the molding pattern. It may be formed as follows.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a), 1 (b) and 1 (c) are diagrams showing a method of manufacturing an ink jet printer head according to an embodiment in the order of steps, each showing a state of being formed on a silicon chip substrate in a series of steps. 1 schematically shows a schematic plan view and a cross-sectional view. In these figures, for convenience of explanation, only one print head of the full color inkjet printer head (the same as the configuration of the monochrome inkjet head) is shown. A plurality of (usually four) heads are formed on a single substrate (silicon chip). FIG. 3C shows orifices as 36 ink ejection nozzles. Actually, there are 64, 128, and 256 orifices, etc. of the model of the printer main body to be mounted and the design policy. Are formed in large numbers.

FIGS. 2 (a), (b) and (c) are shown in FIG. 1 (a), (b) and
2 (a), 2 (b) and 2 (c), the middle section of FIG. 2 (a), 2 (b) and 2 (c) is a sectional view taken along the line BB 'of the upper section (FIG. 2 (a)). )), And the lower part is a cross-sectional view taken along the line CC ′ of the upper part (see FIG. (A)). In addition, FIG.
The cross-sectional views shown in the middle section of (b) and (c) are FIGS. 1 (a), (b) and
It is the same as the sectional view shown below (c). FIG.
(a), (b), and (c) show 64 pieces, 1 piece for convenience of illustration.
28 or 256 orifices are represented by 5 orifices.

First, a basic manufacturing method will be described. First, as a step 1, a drive circuit and its terminals are formed on a silicon substrate of 4 inches or more by an LSI forming process, and an oxide film having a thickness of 1 to 2 μm is formed. Using Ta (tantalum)-
A heating resistor film made of Si (silicon) -O (oxygen) and an electrode film made of W-Au or the like are formed. Then, a pattern of a wiring portion is formed on the electrode film by photolithography, and a fine pattern of a heating portion is formed on the heating resistor film. In this step, the position of the heat generating portion is determined.

FIGS. 1 (a) and 2 (a) show a state immediately after the above steps 1 and 2 are completed. That is, a common electrode 31, a common electrode power supply terminal 32 (see FIG. 1A), an individual wiring electrode row 33 'composed of individual wiring electrodes 33, and a heating resistor film are formed on the chip substrate 30 by patterning. A heating element array 34 'including a large number of heating elements 34, a driving circuit 35, and a driving circuit terminal 36 (see FIG. 1A) are formed.

Subsequently, in step 3, the individual heating elements 3
In order to form an ink supply path corresponding to No. 4, a partition member made of an organic material such as photosensitive polyimide is formed to a height of about 20 μm by coating, and this is formed by a photolithography technique. After patterning into a partition shape, 300 ° C ~ 4
Cure (dry hardening, applying heat of 00 ° C for 30 to 60 minutes)
Baking) to form and fix a 10 μm-high partition wall made of the photosensitive polyimide on the chip substrate. Further, in step 4, a groove-like common ink supply path is formed on the surface of the chip substrate by wet etching or sand blasting or the like, and an ink supply hole communicating with this common ink supply path and opening on the lower surface of the substrate is formed. I do.

FIGS. 1 (b) and 2 (b) show a state immediately after the above steps 3 and 4 are completed. That is, the groove-shaped common ink supply path 37 and the ink supply holes 38
Are formed on the common electrode 31 located on the left side of the common ink supply channel 37 and the seal partition 39-1 for sealing ink inside the portion where the individual wiring electrode 33 on the right is disposed. , 39-2 are formed, and a partition wall 39-3 extending from the seal partition wall 39-2 and partitioning each of the heat generating elements 34 is formed between the heat generating elements 34.

The seal partition wall 39-2 and the partition partition wall 39-3 have a shape corresponding to the teeth of a comb if the seal partition wall 39-2 is a so-called comb body. Section 4 having a rectangular cross section formed between the teeth and the teeth
The heating element 34 is arranged in one.

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 structure, that is, the partition wall by applying pressure while heating at 380 to 300 ° C. Subsequently, a metal film such as Ni, Cu, or 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 polyimide, and then the orifice plate is dry-etched by a helicon wave or the like to form the metal film. A plurality of nozzle holes (orifices) are formed at once by making holes of 31 μmφ to 38 μmφ according to the mask.

FIGS. 1 (c) and 2 (c) show the process 5 described above.
And the state immediately after the end of step 6. That is, the orifice plate 42 covers the entire area except the common power supply terminal 32 and the drive circuit terminal 36, and the partition wall 3
The partitioning portion 41 formed by 9-3 is also covered with fine pressure of a height corresponding to the thickness (height) 10 μm of the partition wall 39 (39-1, 39-2, 39-3). The opening is directed toward the common ink supply path 37 as a chamber. In addition, an ink flow path 43 having a height of 10 μm, which connects the openings of the partitioning portions 41 and the common ink supply path 37, is formed.

An orifice 44 is formed on the orifice plate 42 at a portion facing the heating element 34 by dry etching. Thereby, 64 pieces, 13 pieces
A mono-color inkjet head 45 having seven or 346 orifices 44 in one row is completed.

In this manner, attaching the orifice plate 42 and then machining the orifice 44 in accordance with the pattern of the base, that is, the position of the heating element 34, is better than attaching the orifice plate 42 in which the orifice 44 has been machined in advance. A much more productive and practical method. In the case of dry etching, the mask is N
By using a metal film such as i, Cu, or Al, a selectivity between the resin and the metal film of about 100 can be obtained. Therefore, it is sufficient to form a mask with a metal film of 1 μm or less in order to etch a 38 to 31 μm polyimide film.

The processing up to this point is performed in the state of a silicon wafer. Finally, as a step 7, the silicon wafer is cut along a scribe line using a dicing saw or the like, divided into individual chip substrate units, die-bonded to a mounting substrate, and connected to terminals. A practical unit of the inkjet printer head is completed.

As described above, the mono-color ink jet printer head 45 having the one row of orifices 44 is a monochromatic ink jet head by itself. However, in full-color printing, the three primary colors of subtractive color mixing, namely yellow ( Y), magenta (M), and cyan (C), plus black (Bk) dedicated to black portions of characters and images, and a total of four colors of ink are required.
Therefore, at least four rows of orifices are required.
According to the above-described manufacturing method, it is possible to form a full-color ink jet printer head by monolithically forming four rows of mono color ink jet printer heads. It is possible to accurately arrange the semiconductor devices by the semiconductor manufacturing technology described above.

In step 3 of the above-described basic manufacturing method, the seal partition 39 is formed in a conventional manner.
When the partition wall 39 is formed by forming the seal partition wall 39-2 and the partition partition wall 39-3 together with -1, the corner portion of the partition wall 39 which should be bent at a right angle in the design protrudes inward. As described above, there is a problem that resistance to cavitation damage is weakened.

In view of the above, the present applicant has pursued a cause in which the corner of the partition wall 39 which should be bent at a right angle in the above-described design protrudes inward. As a result, it was found that the flow of the developing solution when developing the partition wall pattern stayed at the corner of the partition wall 39.

In the method of manufacturing an ink jet printer head according to the present invention, the sealing in the above step 3 is performed so that the stagnation of the developing solution at the corners of the molding pattern is eliminated and the corners of the partition 41 are formed at right angles. Partition wall 3
In the step of forming the partition 9-2 and the partition wall 39-3, that is, the step of forming the partition 41, a specially devised method is used.

FIG. 3 is a view showing an example of a photomask forming pattern used for the negative photosensitive resin according to the present invention used in the above-mentioned step 3 in the present embodiment. The photomask 46 shown in the figure allows an exposure pattern 47a cut out in a comb shape corresponding to the partition to be formed and a developing solution stagnating near the corner of the partition to be formed at the time of development. For this reason, a plurality of process patterns 47 respectively formed at each corner of the above-mentioned formation pattern
b. The process pattern 47b is a light-shielding pattern formed at the base of the comb-tooth pattern corresponding to the partition wall 39-3 (see FIG. 2B) so as to fill the cutout pattern over the entire length in the width direction thereof. This is a pattern that does not appear on the partition walls.

When the width of the process pattern 47b of the molding pattern 47 is d and the height of the partition wall formed by using the photomask 46 is h, “0.2 · h <
d <h ”, more preferably“ 0.4 · h <d <0.6 ·
h ”. When the photomask 46 is developed after being exposed, a gap corresponding to the width d is temporarily formed between the seal partition wall 39-2 and the partition partition wall 39-3. The gap is so small as to be negligible at the stage of completion of the development, and the partition 39 having the gap eliminated to such an extent that there is no problem is obtained at the stage after the curing step by firing. A 90-degree bend is formed at the corner of the partition wall 39.

FIG. 4A is a view showing the shape of a partition 41 obtained by forming a seal partition 39-2 and a partition 39-3 using a photomask 46 having the above-described forming pattern 47. (B), (c), and (d) are diagrams for explaining the action of cavitation acting on the heating element 34 in the configuration of the partition.

As shown in FIG. 5A, the partition 41 in the present embodiment is formed by bending two inner corners at right angles. As a result, as shown in FIG. 4B, the largest film bubble 51a that has finished discharging ink is formed as shown in FIG.
As shown in FIG. 8C, when the contracted portion gradually shrinks from the ink inlet 52 side of the partitioning portion 41 to reach the state of the contracted film bubble 6-3 just before disappearance shown in FIG. ), 2
Divided into two contracted membrane bubbles 51c 'and 51c "
Each of the two corners of the inner portion of the heating element 34 retreats at right angles, and no film bubbles exist on the heating element 34 any longer.

Therefore, at this time, the contracted film bubble 51
Even if the cavitation breaking force acts on the retraction positions of c ′ and 51 ″, the breaking force only acts on the silicon oxide film exposed at the corners of the partition 41, and the heating element 34
Does not act on As a result, the life of the heating element 34 is extended, and an ink jet head having excellent durability can be obtained.

The photomask forming pattern is shown in FIG.
For example, even if a process pattern that individually protrudes outside the corner of the light-shielding pattern corresponding to the corner at the back of the partition is obtained, the same good partition wall development result as described above can be obtained. It is something that can be done.

FIGS. 5 (a), 5 (b) and 5 (c) are diagrams each showing another example of a photomask forming pattern. First, FIG.
In the photomask 48 shown in FIG. 5, the molding pattern 49 is continuous with a corner portion 49-1 corresponding to a corner portion of the partition wall 39 separating the heating element 34 by the seal partition wall 39-2 and the partition partition wall 39-3 described above. A process pattern 49b protruding outside the corner portion 49-1 is provided.

The process pattern 49b of the photomask 48 shown in FIG. 7A forms a missing circle, and the radius of the missing circle is r. When the height of the partition wall 39-3 is h, the relationship of “0.2 · h <r <0.8h”, more preferably “0.4 · h <r <0.6 · h” is satisfied. Is formed.

Similarly, the process pattern 51 of the photomask 50 shown in FIG. 3B is also formed in the same manner as described above, and is continuous with the corner 51-1 corresponding to the corner of the partition to be formed. 51b. However,
In this example, the process pattern 51b forms a quadrangle, and one corner of the quadrangle is defined by the partition 41 of the molding pattern 51.
Is formed so as to overlap with a corner portion 51-1 corresponding to the corner portion.

In the photomask 52 shown in FIG. 9C, the process pattern 53b of the forming pattern 53 forms an isosceles triangle, and the base of the isosceles triangle is a corner of the partition of the forming pattern 53. Is formed so as to overlap with the corner portion 53-1 corresponding to. Process pattern 53b
Is formed in this manner, the corners of the partition walls obtained by exposing and developing using this are formed at right angles.

As described above, in each case, the process pattern 49b, 51b or 53b is
9, 51 or 53, the corner portion 49-1, 51-1 or 53-1 corresponding to the corner portion of the partition portion 41, followed by the corner portion 49.
-1, 51-1 or 53-1 is a light-shielding pattern protruding to the outside of the partition wall. Further, a relief portion which is depressed outside is formed. Thereby, the photomask 48 (or the photomask 50)
Or 52) using the seal partition wall 39-2 and the partition partition wall 3
When 9-3 is developed, the stagnation of the developing solution is
Pattern 49b forming the relief at the corner of
(Or the process pattern 51b of the molding pattern 51 and the process pattern 53c of the molding pattern 53) only occur in the inner part, and the original corner part 49-1 (or the corner part 51) is formed.
In (-1, 53-1), the fluidity of the developer is maintained well, and the shape of the partition 41 obtained by this development is such that the two inner corners form a right angle.

The photolithography process for developing the partition walls is as follows. This means that the partition height is 1
In this case, a photosensitive polyimide is used as a photosensitive resin serving as a partition wall material.

1. Substrate pretreatment (dehydration treatment): On a hot plate, 270 ° C, 3 minutes. 2. Photosensitive resin coating: spin coating, 1500 rpm,
30 seconds. 3. Drying of photosensitive resin: 100 ℃ on hot plate, 1
00 seconds, and on a hot plate at 120 ° C. for 100 seconds.

4. Pattern printing: G-line (405 nm wavelength) of a mercury lamp is 400 m by a mask contact.
J / cm ² irradiation. 5. Pattern development: While rotating at 3000 rpm on a rotating body, cyclopentanone is sprayed at a flow rate of 70 ml / min for 60 seconds, and then washed with a cellosolve acetate-based rinsing liquid.

6. Photoresin baking: oxygen concentration 1000p
Baking is performed at 350 ° C. for 2 hours in an atmosphere of pm or less. 7. Pretreatment for pasting the top plate: Immediately before pasting the top plate, it is treated with an oxygen plasma generator for 5 minutes.

In the above embodiment, a negative photosensitive resin is used as the photosensitive resin. However, the present invention is not limited to this, and the present invention can be applied to a case where a positive photosensitive resin is used as the photosensitive resin. Of course.

[0060]

As described above in detail, according to the present invention, a pattern for forming a photomask used for exposure in a photolithography process for forming a partition wall is formed at a corner of a partition where a heating element is arranged. By providing a process pattern that serves as a refuge for the stagnant developer in the corresponding corner, the partition can be developed so that the corner of the partition becomes a right angle. The extinguishing positions can be dispersed at the corners of the partition, so that the cavitation breaking effect can be prevented from exerting on the heating element disposed at the center of the partition, thereby providing a heating element having excellent cavitation durability. It is possible to manufacture a long-life inkjet printer head provided with the above.

Since the cavitation can be prevented from acting on the heating element in this way, there is no need to provide a cavitation damage prevention layer on the heating element surface. It becomes possible to manufacture a printer head.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are a schematic plan view and a cross-sectional view schematically illustrating a method of manufacturing an ink jet printer head according to an embodiment in the order of steps.

FIGS. 2 (a), (b), and (c) show enlarged plan views of FIGS. 1 (a), (b), and (c) in the upper part, respectively, and show BB 'of the upper part in the middle part;
It is a figure which shows a sectional arrow view and shows the CC 'sectional arrow view of an upper stage in the lower stage.

FIG. 3 is a view showing an example of a photomask forming pattern used in a manufacturing process 3 according to the present invention.

FIG. 4 (a) is a view showing the shape of a partition obtained by forming a partition using the photomask according to the present invention, (b), (c),
(d) is a diagram for explaining the action of cavitation acting on the heating element in the partition.

FIGS. 5 (a), (b), and (c) are diagrams respectively showing another example of a forming pattern of a photomask according to the present invention used in manufacturing step 3. FIG.

FIGS. 6A, 6B, and 6C are diagrams schematically showing a configuration in which ink is ejected in a direction parallel to a heating surface of a heating element, and FIGS.
(e), (f) is a figure which shows typically the thing of the structure which discharges ink in the direction perpendicular | vertical to the heating surface of a heating element.

FIGS. 7A and 7B are diagrams schematically showing a process of growth and disappearance of bubbles related to ejection of ink droplets.

FIG. 8A is a plan view showing a configuration of a conventional roof shooter type thermal inkjet printer head, and FIG.
FIG. 3A is a cross-sectional view taken along the line AA ′, and FIG. 3C is a view showing a mask pattern for forming a partition for partitioning the heat-generating element disposition portion.

FIGS. 9 (a), (b), and (c) are views again showing the process in which the largest grown film bubble contracts to a state immediately before disappearance, (d), (e),
(f) is a diagram showing the process of film bubble contraction actually occurring in the compartment corresponding to (a), (b) and (c).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Heating element 3 Orifice plate 4 Orifice 5 Ink 5 'Extruded ink 6 Film bubble 7 Ink drop 8 Open pool 9 Heating element 11 Chip substrate 12 Drive circuit 13 Thin film 14 Heating element 15 Individual wiring electrode 16 Common power supply electrode Reference Signs List 17 partition 18 orifice 19 orifice plate 21 ink flow path 22 partitioning part 23 pattern mask 24 U-shaped cutout part 25 corner part 26 back side part 30 chip substrate 31 common electrode 32 common electrode power supply terminal 33 individual wiring electrode 34 Heating element 35 Drive circuit 36 Drive circuit terminal 37 Common ink supply path 38 Ink supply hole 39 Partition 39-1, 39-2 Seal partition 39-3 Partition partition 41 Partition section 42 Orifice plate 43 Ink flow path 44 Orifice 45 Monocolor Inkjet printer Head 46, 48, 50, 52 photomask 47,49,51,53 molding pattern 49-1,51-1,53-1 corner portions 47b, 49b, 51b, 53b process patterns 52 ink inlet

Claims (5)

[Claims] 1. A plurality of heating elements for generating thermal energy for ejecting ink, and at least three directions around each heating element are rectangular in order to form a partition by separating the plurality of heating elements individually. A method of producing an ink jet printer head that generates bubbles by each of the heating elements, applies pressure to the ink, and discharges the ink in a predetermined direction, wherein a photosensitive layer is formed on the substrate on which the heating elements are formed. A step of uniformly applying a resin, an exposure step of irradiating the applied photosensitive resin with a light through a photomask having a predetermined molding pattern, and a step of applying the light-irradiated photosensitive resin to the photosensitive resin. A developing step of developing each heating element into a shape of a partition wall for isolating the heating elements, wherein the forming pattern of the photomask used in the exposure step is a pattern of a pattern corresponding to the partition wall. A process pattern for flowing a developer stagnating in the vicinity of the corner portion, wherein the process pattern does not appear in the shape of the formed partition wall. . 2. The process pattern is a rectangular pattern formed over the entire length in the width direction at a corner of the forming pattern, wherein the width of the rectangular pattern is d, and the height of the partition is h. When performing, “0.2 · h <d <h”
2. The method according to claim 1, wherein the ink jet printer head is formed so as to satisfy the following relationship. 3. The process pattern forms a missing circle, where r is the radius of the missing circle and h is the height of the partition wall.
2. The method for manufacturing an ink jet printer head according to claim 1, wherein said ink jet printer head is formed so as to satisfy a relationship of "0.2.h <r <0.8.h". 4. The process pattern according to claim 1, wherein the process pattern has a quadrangular shape, and one corner of the quadrangular shape is formed so as to overlap a corner portion corresponding to a corner of the partition of the molding pattern. A manufacturing method of the ink jet printer head described in the above. 5. The process pattern according to claim 1, wherein the process pattern forms a triangle, and one side of the triangle is formed so as to overlap a corner corresponding to a corner of the partition of the molding pattern. A manufacturing method of the ink jet printer head described in the above.