JP7134831B2 - Manufacturing method of liquid ejection head - Google Patents

Description

The present invention relates to a method of manufacturing a liquid ejection head.

One example of a liquid ejection head that ejects liquid is an inkjet recording head used in an inkjet printing method that ejects small ink droplets and deposits them on a recording medium such as paper.

With the recent development of recording technology, the array density of ejection openings for ejecting liquid has been increased, and the shape of the ejection openings and the flow paths communicating with them has been improved in liquid ejection heads such as inkjet recording heads. High definition is required.

Japanese Patent Application Laid-Open No. 2002-200000 discloses a method of manufacturing an inkjet recording head, in which a nozzle layer is formed of a resin that can be patterned by photolithography on a silicon substrate on which ejection energy generating elements are provided in advance.

Further, in Patent Document 2, a liquid supply port for supplying a liquid is formed prior to a nozzle layer, and after the substrate (substrate) surface side of the liquid supply port is closed with a tape or the like, the inside of the liquid supply port is filled with a filler. is disclosed, followed by forming a nozzle layer.

JP-A-6-286149 JP-A-2002-326363

Here, in the manufacturing method in which the liquid supply port is formed prior to the nozzle layer described in Patent Document 2, the following phenomenon may occur. That is, when the filler filled in the liquid supply port dries and shrinks due to hardening, peeling may occur at the adhesive surface between the tape attached to the substrate surface side and the filler. When the filler peels off from the tape or the like, a gap is formed in the vicinity of the substrate surface side in the liquid supply port. Since the nozzle layer is formed using the mold material that forms the flow path in a state where the gap exists, the mold material sometimes gets into the gap. In addition, when the mold material enters the gap, the film thickness distribution of the mold material formation and the nozzle layer formation may be affected with the part as a starting point. In addition, when the degree of peeling of the filler is large, the molding material may go around to the back side of the substrate through the peeled portion in the liquid supply port, making it impossible to form a desired nozzle.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide the following in a method of manufacturing a liquid ejection head in which a nozzle layer is formed in a state in which a filler is filled in the liquid supply port after forming the liquid supply port. In other words, an object of the present invention is to provide a method for manufacturing a liquid ejection head that suppresses the occurrence of gaps due to peeling of the filler on the surface side of the substrate on which the nozzle layer is formed, and can easily form the nozzle layer in a desired shape. to do.

The present invention has been made in view of the above problems, and has the following features.
That is, a nozzle layer having an ejection port for ejecting a liquid and a flow channel communicating with the ejection port, an energy generating element for generating energy for ejecting the liquid from the ejection port, and an energy generating element communicating with the flow channel. A method for manufacturing a liquid ejection head having an element substrate having a liquid supply port for supplying liquid and an adhesion improving layer disposed between the nozzle layer and the element substrate, the method comprising:
forming the adhesion improving layer on a first surface of a substrate having a first surface and a second surface facing each other and on which the energy generating element is arranged; forming the liquid supply port penetrating through the surface of the liquid supply port, covering the opening of the liquid supply port on the first surface side with a tape, and filling the liquid supply port from the second surface side with a filler and covering at least the opening bottom of the liquid supply port on the first surface side with the filler; removing the tape; and the first surface of the substrate filled with the filler. forming the nozzle layer; and removing the filler to allow the flow path and the liquid supply port of the nozzle layer to communicate,
The adhesion improving layer is composed of an organic film, is formed on the first surface by extending from the opening end of the liquid supply port onto the substrate, and forms at least a contact portion between the nozzle layer and the element substrate. A liquid characterized by having a covering first portion and a second portion extending from the opening end of the liquid supply port to a position covering at least a portion near the opening end of the opening. A method for manufacturing an ejection head.

Further, the present invention provides a nozzle layer having an ejection port for ejecting a liquid, a flow path communicating with the ejection port, an energy generating element for generating energy for ejecting the liquid from the ejection port, and the flow path. an element substrate having a liquid supply port communicating with the channel and supplying liquid; and an adhesion improving layer disposed between the nozzle layer and the element substrate and covering at least a contact portion between the nozzle layer and the element substrate. A method for manufacturing a liquid ejection head having
The substrate has a first surface and a second surface facing each other, and the first surface on which the energy generating element is arranged has an opening on the first surface side and is composed of an organic film. forming an adhesion improving layer; and forming the liquid supply port penetrating from the first surface to the second surface in the substrate on which the adhesion improving layer is formed, provided that the formed liquid supply port a liquid supply port forming step of exposing at least a part of the open end portion of the adhesion improving layer in the opening of the port on the first surface side; and the opening of the liquid supply port on the first surface side. filling the liquid supply port with a filler from the second surface side, and covering at least the opening bottom of the liquid supply port on the first surface side with the filler; removing the tape; forming the nozzle layer on the first surface of the substrate filled with the filler; and connecting the liquid supply ports.

According to the present invention, in a manufacturing method for forming a nozzle layer in a state in which a filler is filled in a liquid supply port, generation of a gap due to peeling of the filler on the surface side of the substrate on which the nozzle layer is formed is suppressed, and a desired gap is formed. It is possible to provide a method for manufacturing a liquid ejection head that can easily form a nozzle layer having a shape of .

1 is a schematic plan view (top view) of a liquid ejection head obtained by one embodiment of the present invention; FIG. 1A and 1B are schematic cross-sectional views of a liquid ejection head obtained according to an embodiment of the present invention, where (a) is a longitudinal cross-sectional view and (b) is a lateral cross-sectional view; FIG. 4 is a diagram for explaining the state of a filler filled in a liquid supply port, (a) being a diagram relating to a conventional method, and (b) being a diagram relating to an embodiment of the present invention; It is process sectional drawing for demonstrating each process in one Embodiment of this invention. FIG. 5 is a diagram for explaining the shape of an adhesion improving layer in multiple embodiments of the present invention;

As described above, in the conventional method of forming the nozzle layer after forming the liquid supply port, the filler peeled off from the tape attached to the surface of the substrate, resulting in the formation of gaps. As shown in FIG. 3A, such a gap 6a tends to be conspicuous at the open end of the liquid supply port 5. As shown in FIG. This is because the opening end portion of the liquid supply port 5 tends to be coated with the filler 6 thicker than the other portions, so that the curing shrinkage of the filler 6 increases accordingly, and the substrate 1 and the tape 7 are separated from each other. This is probably because the filler 6 is easily peeled off from the adhesive surface (adhesive surface).

On the other hand, according to the present invention, by arranging an adhesion improving layer having a specific structure and configuration between the nozzle layer and the element substrate having the liquid supply port formed thereon, it is possible to suppress the peeling of the filler described above. . Therefore, it is possible to suppress the occurrence of gaps near the substrate surface side in the liquid supply port due to peeling of the filler. Influences on the layer thickness distribution can be easily avoided.

<Liquid ejection head>
The liquid discharge head obtained by the present invention can be installed in printers, copiers, facsimiles having communication systems, and industrial recording devices combined with various processing devices. In the following description, the description may focus on the ink jet recording head as the liquid ejection head, but the present invention is not limited to this form.

The liquid ejection head obtained from the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a schematic plan view (top view) of a liquid ejection head obtained according to an embodiment of the present invention, omitting the illustration of a nozzle layer. 2 is a schematic cross section of the liquid ejection head shown in FIG. More specifically, FIG. 2(a) is a cross-sectional view of the head taken along the longitudinal direction, more specifically along the line AA' shown in FIG. 1, and FIG. 2 is a cross-sectional view when the head is cut along the direction, more specifically, the BB' line shown in FIG. 1. FIG.

As shown in these figures, the liquid ejection head (for example, an inkjet recording head) includes a substrate (element substrate 10) having energy generating elements 2, a nozzle layer 9 disposed on the substrate 1, an element substrate 10 and and an adhesion improving layer 3 disposed between the nozzle layers 9 .

(element substrate)
The element substrate 10 includes, as shown in FIG. and a liquid supply port (common flow path) 5 that communicates with and supplies liquid. A liquid supply port 5 is formed in the central portion of the substrate 1 (chip).

As the substrate 1 used for the element substrate 10, for example, a wafer (silicon substrate) made of single crystal silicon with crystal orientation (100) can be used. The substrate 1 has two opposing surfaces, the surface on which the nozzle layer 9 is arranged is hereinafter referred to as a first surface 1a, and the surface opposite to the first surface 1a is referred to as a second surface 1b. .

The energy generating element 2 arranged on the first surface 1a is not particularly limited, and for example, an electrothermal conversion element (heating resistor element, heater element) that boils a liquid, or an element that pressurizes a liquid by volume change or vibration. An element (piezo element, piezoelectric element) or the like can be used. The number and arrangement of the energy generating elements can be appropriately selected according to the structure of the liquid ejection head to be manufactured. can be provided.

The liquid supply port 5 penetrates the substrate 1 (element substrate 10) in a direction perpendicular to the substrate surface, that is, from the first surface 1a to the second surface 1b of the substrate 1, and penetrates the substrate (element substrate 10). It is open on two opposite sides of the substrate). Although the shape of the liquid supply port is not particularly limited, for example, as shown in FIG. 2, the opening area may be tapered from the second surface 1b toward the first surface 1a. The opening shape of the liquid supply port is also not particularly limited. For example, as shown in FIG. It can be a shape such as a rectangular shape (rectangular) having a shape. However, the shape of the opening of the liquid supply port may be any other shape, such as a rectangle with four corners rounded or chamfered.

The liquid supply port 5 can be formed using, for example, a through laser guide hole and anisotropic etching. For example, when single crystal silicon is used as the substrate 1, the liquid supply port 5 can be formed by anisotropic etching using an alkaline solution on the substrate in which the through laser guide hole is formed in advance. can. In anisotropic etching, etching progresses along the crystal plane of silicon, so that a substantially rectangular opening can be obtained.

Further, the substrate 1 may have a protective film (not shown) for protecting the energy generating element 2 from liquid, a drive circuit (not shown), and the like.

(nozzle layer)
The nozzle layer 9 has ejection openings 11 for ejecting liquid for recording an image on a recording medium such as paper, and flow paths 12 communicating with the ejection openings. The ejection port 11 is for ejecting a liquid, and can be formed, for example, above the energy generating element 2 (upper portion in the figure) as shown in FIG. 2(b). The number and arrangement of ejection openings can also be set as appropriate. In the liquid ejection head shown in FIG. The ejection port arrays are arranged one by one on both sides of the liquid supply port 5 .

The flow path 12 can be a space surrounded by the element substrate 10, the nozzle layer 9, and the adhesion improving layer 3, and can be used as a liquid chamber for holding liquid in this space.

The nozzle layer 9 can be formed by a photolithographic technique using a photosensitive resin or the like, and may be composed of one layer. It may be composed of a plurality of layers including

(Adhesion improving layer)
The adhesion improving layer 3 is arranged between the nozzle layer 9 and the element substrate 10, as shown in FIG. The adhesion improving layer 3 is composed of an organic film, and the material forming the adhesion improving layer (organic film) can be appropriately set according to the filler, tape, and substrate material used, and is not particularly limited. However, it is preferable to appropriately select a material that can ensure adhesion to the filler 6, which will be described later, or at least a material that has better adhesion to the filler 6 than the tape 7 to be used. For example, the adhesion improving layer can be formed using a resin composition containing a resin (thermoplastic resin) or the like, or a photosensitive resin composition containing a photosensitive resist or the like.
The adhesion improving layer may be selected according to the resistance of the liquid (ink solvent) used, for example, thermoplastics such as trade names: HL-1200CH and HPC-5020 (both manufactured by Hitachi Chemical). Resin can be used. As the photosensitive resist, for example, product names: PR-1000D1 and SU-8 (both manufactured by Nippon Kayaku Co., Ltd.) can be used.

When forming the adhesion improving layer, first, the material for forming the adhesion improving layer is applied to the first surface of the substrate 1 by a spin coating method, a slit method, or the like to form a coating film. Then, on the coating film, a patterned photoresist pattern is produced using a photolithographic technique, and the coating film is dry-etched using this pattern as a mask to form an adhesion improving layer in a desired shape. can be done. When the material for forming the adhesion improving layer itself has photosensitivity, the adhesion improving layer can be formed by directly patterning a coating film of this material using a photolithographic technique.

Although the thickness of the adhesion improving layer 3 can be set as appropriate, it should be 1.0 μm or more from the viewpoint of step absorption of the protective film on the substrate 1 or the like, and 3.0 μm or less from the viewpoint of the flatness of the nozzle layer 9 . is preferred.

1 and 2, the adhesion improving layer 3 includes a first portion 3a and a second portion 3b on the first surface 1a.
The first portion 3 a is a portion that extends from the opening end of the liquid supply port 5 onto the substrate and covers at least the contact portion between the nozzle layer 9 and the element substrate 10 .
The second portion 3b is formed by extending from the opening end of the liquid supply port to a position covering at least a portion of the vicinity of the opening end in the opening.

As described above, the liquid ejection head obtained by the present invention has the adhesion improving layer 3 at a position covering the vicinity of the opening of the opening end of the liquid supply port, as shown in FIG. 3(b). Therefore, peeling of the filler 6 from the substrate 1 and the tape 7 can be easily suppressed as compared with the conventional liquid ejection head shown in FIG. Therefore, when the nozzle layer is formed in a state in which the filler is filled in the liquid supply port, the formation of a gap due to the peeling of the filler on the first surface side is suppressed, and the nozzle layer having a desired shape can be easily formed. can do. 3A and 3B are diagrams for explaining the state of the filler filled in the liquid supply port, FIG. 3A being a diagram relating to a conventional method, and FIG. is.

Here, in the liquid ejection head obtained by the first embodiment of the present invention shown in FIGS. It is formed in the part that covers the part. The second portion 3b is formed on the first surface 1a to cover the vicinity of the opening end in the opening from the longitudinal opening end of the liquid supply port 5 having a rectangular opening shape. When the shape of the opening on the first surface of the liquid supply port has a longitudinal direction and a lateral direction (for example, a rectangle), the filling is closer to the longitudinal opening end than the lateral opening end. It is easier to peel off the filler that is used. Therefore, by forming the adhesion improving layer (second portion 3b) at a position covering the vicinity of the opening end in the longitudinal direction, peeling of the filler can be efficiently suppressed.

The distance from the longitudinal opening end covered by the second portion is not particularly limited, and can be appropriately set according to the filling amount of the filler and the amount of shrinkage. However, it is preferred that this distance is less than or equal to 200 μm. By covering the portion at a distance of 200 μm or less from the opening end in the longitudinal direction of the liquid supply port with the adhesion improving layer, the filler and the adhesion improving layer can be brought into closer contact, and the filler can be easily peeled off. can be suppressed. This distance is preferably 50 μm or more from the viewpoint of adhesion to the filler, and more preferably 150 μm or less from the viewpoint of print quality.

Note that, as shown in FIG. 1, of the ejection ports 11 arranged on both sides of the liquid supply port 5 in the lateral direction, liquid is ejected to the portion where the second portion 3b of the adhesion improving layer is arranged. A plurality of dummy nozzles (dummy ejection ports) 13 are arranged. By arranging the dummy nozzles, it is possible to further improve the flatness of the nozzle layer.

5(a) to 5(c) show schematic partial plan views of liquid ejection heads obtained from a plurality of embodiments of the present invention. Note that the nozzle layer 9 is omitted in these figures, and the first portion 3a of the adhesion improving layer 3 is formed at the same position as in the first embodiment described above.

In the liquid ejection head obtained from the second embodiment of the present invention shown in FIG. 5(a), the second portion 3b is a corner of the longitudinal direction of the liquid supply port whose opening shape on the first surface is rectangular. It is formed so as to cover the vicinity of the opening of the part. In this way, by arranging the second portion 3b near (only) the corners of the liquid supply port where the filling amount of the filler tends to increase, the state where the adhesion improving layer covers the liquid supply port is further reduced. can effectively suppress the peeling of the filler. As a result, it is possible to further increase the degree of freedom in nozzle design, such as improving refillability.
At this time, from the viewpoint of the balance of the liquid supply, the liquid supply port should be covered so that the distance from the apex of the corners of the liquid supply port to the corners of the liquid supply port is 50 μm or less so that the center of the liquid supply port in the lateral direction is evenly left and right. It is preferred to form the second portion in the In FIG. 5(a), with respect to each corner of liquid supply ports adjacent in the width direction, the base is half the length of the liquid supply ports in the width direction on the first surface. 1, a right-angled triangular second portion 3b having a height equal to the length from the open end in the longitudinal direction is formed. The shape of the second portion 3b is not particularly limited as long as it can be arranged near the corner of the liquid supply port. For example, the shape of the opening in the vicinity of the longitudinal end of the liquid supply port not covered by the second portion 3b (V-shaped in FIG. 5A) may be U-shaped or Y-shaped. .

Also, in the liquid ejection head obtained by the third embodiment of the present invention shown in FIG. A collecting hole 14 is formed. Foreign matter contained in the liquid supplied to the liquid supply port can be collected by the foreign matter collection hole 14 . The shape and arrangement of the foreign matter collection holes can be appropriately set. The foreign matter collection hole 14 can be a hole (for example, circular) that penetrates the adhesion improving layer 3 . Moreover, the arrangement may be, for example, arranged at random in the second portion, or may be arranged at regular intervals. FIG. 5B shows an example in which a plurality of foreign matter collecting holes 14 are arranged in the adhesion improving layer covering the vicinity of the inside of the open end of the liquid supply port in the lateral direction. From the viewpoint of collecting foreign matter, the (average) hole diameter of the foreign matter collecting holes 14 is preferably equal to or smaller than the diameter of the discharge port 11 .

In the liquid ejection head obtained by the fourth embodiment of the present invention shown in FIG. 5(c), as in the first embodiment, the portion covering the vicinity of the opening of the opening end in the longitudinal direction of the liquid supply port forming the second part. Along with this, a second portion is also formed in a portion that covers the vicinity of the inside of the opening of the opening end in the lateral direction of the liquid supply port. In other words, in the fourth embodiment, the second portion is formed from the open end of the liquid supply port to the entire periphery near the open end in the opening. As a result, peeling of the filler can be suppressed all around the opening end of the liquid supply port, in FIG. 5C, near the opening end in both the longitudinal direction and the lateral direction. The distance from the opening end of the liquid supply port in the lateral direction in the second portion 3b is 14% of the length (opening) of the liquid supply port in the lateral direction on the first surface. Preferably covered by two parts.

<Method for Manufacturing Liquid Ejection Head>
A method for manufacturing a liquid ejection head according to the present invention includes the following steps.
- The step of forming the above-described adhesion improving layer 3 on the first surface 1a of the substrate having the first surface 1a and the second surface 1b facing each other and on which the energy generating element 2 is arranged (formation of the adhesion improving layer process).
- A step of forming the liquid supply port 5 penetrating from the first surface 1a to the second surface 1b (liquid supply port forming step).
A step of covering the opening on the first surface side of the liquid supply port 5 with the tape 7 (covering step).
A step of filling the liquid supply port with the filler 6 from the second surface side and covering at least the opening bottom of the liquid supply port 5 on the first surface side with the filler 6 (filling step).
- A step of removing the tape 7 (tape removing step).
- A step of forming a nozzle layer on the first surface of the substrate 1 filled with the filler 6 (nozzle forming step).
• A step of removing the filler 6 (from the inside of the liquid supply port) to allow the passage 12 of the nozzle layer and the liquid supply port 5 to communicate with each other (filler removal step).

The order of these steps is not particularly limited, and may be performed sequentially, or a plurality of steps (for example, nozzle formation step and filler removal step) may be performed in parallel. A step of curing the filler (curing step) may be provided between the filling step and the tape removing step.
Each step will be described in detail below with reference to FIG. In addition, FIG. 4 is a process cross-sectional view for explaining each process in the first embodiment of the present invention. In FIG. 4, the substrate (head) in each process is shown on the right side of the drawing as a cross-sectional view taken along the line AA' shown in FIG. It is shown in a cross-sectional view when cut.

<<First Embodiment>>
(Adhesion improving layer forming step)
First, a substrate having the energy generating elements 2 arranged on the first surface 1a is prepared. For example, in the same way as a normal semiconductor device, a substrate (for example, a silicon substrate) 1 is provided with an energy generating element (for example, a heater element) 2, a protective film (not shown) for protecting this element, and a drive circuit (not shown). form etc. These formations can be formed, for example, by a multilayer wiring technique using a photolithography technique.

Subsequently, as shown in FIG. 4A, an adhesion improving layer 3 having an opening on the first surface side and made of an organic film is formed on the first surface 1a of the substrate. In the first embodiment, as shown in FIGS. 1, 2 and 4(g), the adhesion improving layer includes a first portion covering the contact portion between the nozzle layer and the element substrate, and a longitudinal portion of the liquid supply port. and a second portion arranged at a position covering the vicinity of the opening end in the opening from the opening end in the direction. In FIG. 4A, the adhesion improving layer 3 is not formed on the surface (upper side of the figure) of the energy generating element 2. As shown in FIG.

Specifically, as described above, the adhesion improving layer forming material (resin composition) is applied onto the substrate 1 by a spin coating method, a slit method, or the like to form a coating film. Next, a resist pattern is formed on the coating film using a normal positive resist or the like, and using this pattern as an etching mask, dry etching is performed to form the adhesion improving layer 3 covering the above-described specific portion. As described above, when the adhesion improving layer forming material has photosensitivity, the adhesion improving layer 3 may be formed by directly patterning the coating film.

(Liquid supply port forming step)
Next, as shown in FIGS. 4B and 4C, a liquid supply port 5 penetrating the substrate 1 (from the first surface to the second surface) is formed in the substrate on which the adhesion improving layer 3 is formed. Form. At this time, at least part of the open end portion of the adhesion improving layer 3 is exposed in the opening on the first surface side of the formed liquid supply port. Here, the shape of the opening on the first surface forms a rectangular liquid supply port having a longitudinal direction and a lateral direction. to expose the open end portion (and its vicinity) of the

The method for forming the liquid supply port is not particularly limited, and a method known in the field of liquid ejection heads can be used as appropriate. However, from a cost and processing time (takt) point of view, it is preferable to form the liquid supply ports using (through-laser) pilot holes and anisotropic etching.
Specifically, as shown in FIG. 4B, the substrate 1 is irradiated with a laser to form a through laser guide hole 4 penetrating through the substrate 1 . The number, shape, arrangement, and the like of the guide holes 4 can be appropriately set according to the shape of the liquid supply port to be manufactured, the material of the substrate 1 used, and the like.
Subsequently, as shown in FIG. 4C, using an etching pattern (not shown) formed on the second surface 1b of the substrate as a mask, an alkaline solution (eg, tetramethylammonium hydroxide (TMAH) solution) or the like is used. Anisotropic etching is performed to form the liquid supply port 5 . At this time, the etching pattern can be produced using a resin having resistance to metals and alkalis.

(Coating process)
Subsequently, the opening of the liquid supply port 5 on the first surface side is covered with the tape 7 . By attaching the tape 7 on the substrate, specifically, the first surface of the substrate 1, the surface of the adhesion improving layer 3, and the like, the filler 6 to be filled in the liquid supply port in a later step is applied to the nozzle layer. can be prevented from entering the part forming the In principle, the tape 7 is attached before filling the filler 6 and peeled off after filling. Although the material of the tape 7 is not particularly limited, for example, a heat-curable or ultraviolet radiation-curable tape for the semiconductor industry can be used. It should be noted that it is preferable to apply the tape 7 in a vacuum state from the viewpoint of suppressing inclusion of air bubbles.

(Filling process)
Subsequently, as shown in FIG. 4(d), the liquid supply port 5 whose opening on the first surface side is covered with the tape 7 is filled with a filler from the second surface 1b side. The filling amount of the filler is not particularly limited, but at least the first surface 1a side of the liquid supply port 5 should be Allow the opening bottom to be covered with filler 6 . From the viewpoint of strength, it is preferable to fill the first surface side with the filler with a thickness of 2 to 8% of the thickness (from the first surface to the second surface) of the liquid supply port.
Although the filler 6 is not particularly limited, it is preferable to use a material that has solvent resistance and can be easily removed because it needs to be removed in a post-process. For example, polyvinyl alcohol (PVA) can be used. The filler 6 can be filled into the liquid supply port from the second surface 1b by a screen printing method or a dispensing method.

(Curing process)
In order to harden (stabilize) the filler 6 filled in the liquid supply port to which the tape 7 is attached, the substrate filled with the filler can be baked using a hot plate or the like. At this time, as described above, the filler 6 near the opening end (especially in the longitudinal direction) of the liquid supply port of the conventional configuration shown in FIG. Due to the fact that the tape 7 is reinforced, the curing shrinkage is large, and the adhesive surface of the substrate 1 and the tape 7 may be peeled off.
On the other hand, the adhesion improving layer 3 having the configuration of the present invention shown in FIG. As a result, it is possible to improve the adhesion between the filler 6 and the adhesion improving layer 3 and to suppress peeling due to cure shrinkage of the filler 6 .

(Tape removal process)
Next, the tape 7 is peeled off from the substrate. The peeling method can be appropriately selected according to the type of tape used. For example, the tape can be peeled off from the substrate by irradiating the tape with ultraviolet light or applying heat.

(Nozzle forming step and filler removing step)
Subsequently, a nozzle layer is formed on the first surface 1 a of the substrate filled with the filler 6 .
First, as shown in FIG. 4( e ), above the liquid supply port 5 filled with the filler 6 and the adhesion improving layer 3 (above the figure), a mold for the flow path 12 (including the foaming chamber) and A mold member 8 is formed. Specifically, after applying a mold-forming material such as a photosensitive resin material on the substrate by a spin coating method or the like, patterning is performed using a photolithographic technique to form the mold material 8 . As the resin used for the mold material 8, for example, positive deep-UV resist ODUR (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) can be used.

Subsequently, as shown in FIG. 4F, a material for forming a nozzle layer is applied onto the substrate on which the mold material 8 is formed by using a spin coating method or the like, and then exposure and development are performed to form a discharge port. 11 is formed. For example, SU-8 (trade name, manufactured by Nippon Kayaku Co., Ltd.) and EHPE-3150 (trade name, manufactured by Daicel Corporation), which are negative resists, can be used as the nozzle layer forming material.

Next, as shown in FIG. 4(g), the filler 6 and the mold material 8 filled in the liquid supply port are removed to form the flow path 12, and the flow path 12 and the liquid supply port 5 are communicated. Let These removal methods are not particularly limited, and can be appropriately set according to the materials used.

As described above, it is possible to obtain a liquid ejection head in which the vicinity of the opening end in the opening from the opening end in the longitudinal direction of the liquid supply port is covered by the adhesion improving layer. In the first embodiment, it is possible to suppress the peeling of the filler in the longitudinal direction, which is particularly prone to peeling. Therefore, it is possible to easily manufacture a liquid ejection head having a nozzle layer of a desired shape.

<<Second Embodiment>>
In the second embodiment of the present invention, as shown in FIG. 5A, the second portion 3b of the adhesion improving layer 3 is configured to cover the vicinity of the opening at the corner of the liquid supply port 5 . In other words, in the liquid supply port forming step, a rectangular liquid supply port whose opening shape on the first surface has a longitudinal direction and a lateral direction is formed, and the corners of the ends of the liquid supply port in the longitudinal direction are filled with liquid. The open end portion (and the vicinity thereof) of the adhesion improving layer 3 is exposed in a portion. As a result, the adhesion improving layer 3 can be selectively arranged in the vicinity of the corner where the amount of the filler 6 applied is large. Therefore, the area of the adhesion improving layer 3 covering the liquid supply port 5 can be minimized, and the degree of freedom in nozzle design can be increased, such as improving refillability.

<<Third Embodiment>>
In the third embodiment of the present invention, as shown in FIG. 5(b), the second portion 3b of the adhesion improving layer 3 covers the vicinity of the opening of the opening end in the longitudinal direction of the liquid supply port, It is configured to have minute foreign matter collecting holes 14 . In other words, in the liquid supply port forming step, minute foreign matter collection holes are formed in the adhesion improving layer exposed in the opening on the first surface side of the liquid supply port. As a result, it is possible to prevent the filler from peeling in the vicinity of the opening end in the longitudinal direction, which tends to peel off, and to collect foreign matter contained in the liquid in the liquid supply port by the foreign matter collecting hole 14 .

<<Fourth Embodiment>>
In the fourth embodiment of the present invention, as shown in FIG. 5(c), the second portion of the adhesion improving layer 3 covers the entire periphery from the opening end of the liquid supply port to the vicinity of the opening end in the opening. Configuration. In other words, in the liquid supply port forming step, the open end portion (and the vicinity thereof) of the adhesion improving layer is exposed in the opening inner portion of the entire circumference of the open end portion on the first surface side of the formed liquid supply port. This makes it possible to suppress peeling of the filler 6 at the open ends in both the longitudinal direction and the lateral direction of the liquid supply port.

[Example 1]
First, a silicon wafer having a diameter of 200 mm and a thickness of 725 μm on which a heater element as the energy generating element 2 and a drive circuit (not shown) were formed was prepared as the substrate 1 .
Next, a material for forming an adhesion improving layer was applied onto the first surface of the substrate by spin coating to form a coating film. At that time, the spin rotation speed was adjusted to form a coating film having a dry film thickness (thickness from the first surface 1a of the substrate) of 2 μm. A thermoplastic resin, trade name: HL-1200CH (manufactured by Hitachi Chemical Co., Ltd.), was used as the adhesion improving layer forming material.

Subsequently, after the coating film was dried and cured, a positive photosensitive resist serving as an etching mask was formed on the coating film. Further, an etching mask was formed by exposing and developing the photosensitive resist into a predetermined shape. As a positive photosensitive resist, trade name: THMR-iP5700 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used. The coating film was patterned into a predetermined shape by dry etching using a fluorocarbon _- based gas CF4 through an etching mask to form an adhesion improving layer 3 shown in FIG. 4(a). . As shown in FIGS. 1 and 2, the adhesion improving layer 3 covers the contact portion between the nozzle layer 9 and the element substrate 10, and also closes the opening of the liquid supply port 5 in the longitudinal direction. formed to cover the

Next, as shown in FIG. 4B, a plurality of guide holes 4 penetrating through the substrate 1 were formed by irradiating a laser as a penetrating pattern for forming a liquid supply port.

After that, as shown in FIG. 4(c), anisotropic etching was performed using an etchant through an etching mask (not shown) formed on the second surface 1b of the substrate 1. As shown in FIG. At this time, an oxide film was used as an etching mask, a TMAH solution having a liquid temperature of 80° C. and a mass concentration of 25% was used as an etchant, and the etching time was 3 hours. Thus, a tapered liquid supply port 5 was formed in which the openings on the first and second surfaces were rectangular, and the opening area decreased from the second surface to the first surface of the substrate. The adhesion improving layer 3 was formed so as to cover a portion of the prepared liquid supply port which was 200 μm or less from the open end in the longitudinal direction.

Next, a tape 7 was attached to the first surface of the substrate 1 to cover the opening of the liquid supply port 5 on the first surface side. As the tape (adhesive for the tape), an ultraviolet curable tape for the semiconductor industry was used, and the tape was attached in a vacuum atmosphere of about 90 Pa.

Subsequently, as shown in FIG. 4(d), the liquid supply port of the substrate 1 to which the tape is attached is filled with the filler 6 from the second surface side by a dispensing method. The open bottom was covered with filler. As the filler 6, a PVA aqueous solution with a viscosity of 1000 CP (1 Pa·s) was used. After that, baking was performed at 60° C. for 5 minutes. Further, when the filling amount of the filler was measured, it was found that a portion of the liquid supply port with a depth of 50 μm from the first surface 1a was filled with the filler. As described above, since the adhesion improving layer 3 is also arranged in the vicinity of the inside of the opening of the liquid supply port in the longitudinal direction, even when the filler cures and shrinks, the opening in the longitudinal direction does not reach the opening. There was no peeling of the filler at the edges. Further, in this example, the filler did not peel off at the opening end in the lateral direction.

Further, the tape 7 was peeled off from the substrate 1 by irradiating the tape 7 with ultraviolet rays at 200 mJ/mm ² .

Next, as shown in FIG. 4E, a mold material forming material was applied onto the substrate by spin coating, and then patterned by photolithography to form a mold material 8 that serves as a mold for the flow path. As described above, since the filler does not peel off at the opening end of the liquid supply port, the mold member forming material does not enter the inside of the liquid supply port, etc., and the mold member 8 having a desired shape can be formed. was made.
A positive deep-UV resist ODUR (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. was used as the mold material. At that time, the spin rotation speed was adjusted so that the film thickness (maximum thickness from the first surface of the substrate) after coating of the mold material forming material was 15 μm, and the baking temperature after coating was 120° C. The baking time was 3 minutes.

Next, as shown in FIG. 4F, a material for forming a nozzle layer was applied onto the substrate by spin coating, and then patterned by photolithography to form ejection ports 11. Next, as shown in FIG. EHPE-3150 (trade name, manufactured by Daicel Corporation) was used as the material for forming the nozzle layer. The number of revolutions when applying the nozzle layer forming material by spin coating was adjusted so that the thickness of the nozzle layer to be produced was 30 μm from the first surface of the substrate, the baking temperature after application was 150° C., and the baking time was 150° C. was 60 minutes.

Next, as shown in FIG. 4(g), the filler 6 filled in the liquid supply port and the molding material 8 formed as a flow path mold including the foaming chamber were removed. Since PVA, which is the material of the filler 6, is water-soluble, the filler 6 was removed by washing with warm water. Further, the mold material 8 was dissolved and removed by immersing the substrate in a cleaning liquid (trade name: Lucklean MC, manufactured by Hayashi Pure Chemical Industries).
By removing the filler 6 and the mold material 8 in this manner, the flow path 12 and the liquid supply port 5 are communicated with each other, and the liquid ejection head (nozzle chip) according to the first embodiment of the present invention is completed. .
In Example 1, since the filler did not peel off at the opening end of the liquid supply port, a nozzle layer with a desired shape could be formed.
The peeling of the filler was confirmed by observing the cut surface using a SEM (Scanning Electron Microscope) (manufactured by JEOL Ltd.).

[Example 2]
As shown in FIG. 5(a), the second part 3b of the adhesion improving layer covers the vicinity of the inside of the opening at the corner of the longitudinal end of the liquid supply port 5. Thus, a liquid ejection head according to the second embodiment of the present invention was manufactured. At this time, the second portion 3b of the adhesion improving layer was formed so as to cover at least a portion at a distance of 50 μm or less from the vertex of the corner portion of the longitudinal end portion of the liquid supply port. In Example 2, since the adhesion improving layer is arranged near the inside of the opening at the corner of the liquid supply port 5 where the amount of the filler 6 applied is large, the area covered by the adhesion improving layer within the liquid supply port can be reduced. , improved refillability, and increased freedom in nozzle design.

[Example 3]
As shown in FIG. 5(b), the third embodiment of the present invention is manufactured in the same manner as in Example 1 except that minute foreign matter collecting holes 14 are provided in the second portion 3b of the adhesion improving layer. Such a liquid ejection head was produced. The (average) diameter of the foreign matter collecting holes was 10 μm, and a plurality of foreign matter collecting holes were arranged in the vicinity of both ends of the opening in the lateral direction of the liquid supply port.
Foreign matter contained in the liquid in the liquid supply port was able to be collected by the foreign matter collection hole 14 .

[Example 4]
As shown in FIG. 5(c), in the same manner as in Example 1, except that the second portion 3b of the adhesion improving layer covers the entire periphery of the opening near the opening end of the liquid supply port. A liquid ejection head according to the fourth embodiment of the present invention was produced. The adhesion improving layer was formed so as to cover a portion at a distance of 150 μm or less from the longitudinal opening end of the liquid supply port and a portion at a distance of 18 μm or less from the lateral opening end of the liquid supply port. Therefore, peeling of the filler could be easily suppressed in the entire vicinity of the opening end of the liquid supply port 5 .

Reference Signs List 1 Substrate 1a First surface 1b Second surface 2 Energy generating element 3 Adhesion improving layer 3a First portion 3b Second portion 4 (Penetrating laser) Guide hole 5 Liquid supply port 6 Filling agent 7 Tape 9 Nozzle layer 10 Element substrate 11 (Liquid) Ejection port 12 (Liquid) Flow path 14: foreign matter collecting hole

Claims (15)

a nozzle layer having an ejection port for ejecting a liquid and a flow path communicating with the ejection port;
an element substrate having an energy generating element that generates energy for ejecting liquid from the ejection port; and a liquid supply port that communicates with the flow path and supplies the liquid;
an adhesion improving layer arranged between the nozzle layer and the element substrate;
A method for manufacturing a liquid ejection head having
forming the adhesion-enhancing layer on a first surface of a substrate having a first surface and a second surface facing each other and having the energy generating element disposed thereon;
forming the liquid supply port penetrating from the first surface to the second surface;
covering an opening of the liquid supply port on the first surface side with a tape;
a step of filling the liquid supply port with a filler from the second surface side, and covering at least the opening bottom portion of the liquid supply port on the first surface side with the filler;
removing the tape;
forming the nozzle layer on the first surface of the substrate filled with the filler;
removing the filler to allow the flow path and the liquid supply port of the nozzle layer to communicate;
has
The adhesion improving layer is composed of an organic film, is formed on the first surface by extending from the opening end of the liquid supply port onto the substrate, and forms at least a contact portion between the nozzle layer and the element substrate. A liquid characterized by having a covering first portion and a second portion extending from the opening end of the liquid supply port to a position covering at least a portion near the opening end of the opening. A method for manufacturing an ejection head. an opening shape of the liquid supply port on the first surface has a longitudinal direction and a lateral direction;
2. The method of manufacturing a liquid ejection head according to claim 1, wherein said second portion is formed by extending from the longitudinal opening end of said liquid supply port to a position covering the vicinity of the opening end in said opening. 3. The method of manufacturing a liquid ejection head according to claim 2, wherein said second portion is formed so as to cover a portion having a distance of 200 [mu]m or less from said opening end in the longitudinal direction. the shape of the opening of the liquid supply port on the first surface is a shape having a longitudinal direction and a lateral direction and corners;
2. The method of manufacturing a liquid ejection head according to claim 1, wherein the second portion is formed so as to cover the vicinity of the opening at the corner of the longitudinal end of the liquid supply port. The liquid ejection head according to any one of claims 1 to 4, wherein the second portion is formed so as to cover the entire periphery from the open end of the liquid supply port to the vicinity of the open end in the opening. manufacturing method. 6. The method of manufacturing a liquid ejection head according to claim 1, wherein the second portion has minute foreign matter collection holes. 7. The method of manufacturing a liquid ejection head according to claim 1, wherein the adhesion improving layer is made of a material containing a thermoplastic resin. 8. The method of manufacturing a liquid ejection head according to claim 1, wherein the adhesion improving layer is made of a photosensitive material. The method for manufacturing a liquid ejection head according to any one of claims 1 to 8, wherein the filler contains polyvinyl alcohol. 10. The method of manufacturing a liquid ejection head according to claim 1, wherein the liquid supply port is formed using a through-laser guide hole and anisotropic etching. a nozzle layer having an ejection port for ejecting a liquid and a flow path communicating with the ejection port;
an element substrate having an energy generating element that generates energy for ejecting liquid from the ejection port; and a liquid supply port that communicates with the flow path and supplies the liquid;
an adhesion improving layer disposed between the nozzle layer and the element substrate and covering at least a contact portion between the nozzle layer and the element substrate;
A method for manufacturing a liquid ejection head having
The first surface of the substrate having first and second surfaces facing each other and on which the energy generating element is arranged has an opening on the first surface side and is composed of an organic film. forming an adhesion improving layer;
The substrate on which the adhesion improving layer is formed is formed with the liquid supply port penetrating from the first surface to the second surface, provided that the formed liquid supply port is on the first surface side. a liquid supply port forming step of exposing at least part of the open end portion of the adhesion improving layer in the opening;
covering an opening of the liquid supply port on the first surface side with a tape;
a step of filling the liquid supply port with a filler from the second surface side, and covering at least the opening bottom portion of the liquid supply port on the first surface side with the filler;
removing the tape;
forming the nozzle layer on the first surface of the substrate filled with the filler;
removing the filler to allow the flow path and the liquid supply port of the nozzle layer to communicate;
A method of manufacturing a liquid ejection head, comprising: In the liquid supply port forming step, a liquid supply port having an opening shape on the first surface having a longitudinal direction and a lateral direction is formed, and the opening inner portion of the open end portion of the liquid supply port in the longitudinal direction is provided with the liquid supply port. 12. The method of manufacturing a liquid ejection head according to claim 11, wherein the open end portion of the adhesion improving layer is exposed. In the liquid supply port forming step, the opening shape of the first surface has a longitudinal direction and a lateral direction, and a liquid supply port having corners is formed, and the corners of the ends in the longitudinal direction of the liquid supply port are formed. 12. The method of manufacturing a liquid ejection head according to claim 11, wherein the open end portion of the adhesion improving layer is exposed in the inner portion of the opening. 11. The opening end portion of the adhesion improving layer is exposed in the opening inner portion of the entire circumference of the opening end portion of the formed liquid supply port on the first surface side in the liquid supply port forming step. 14. The method for manufacturing a liquid ejection head according to any one of 13. 15. The liquid ejection according to any one of claims 11 to 14, wherein the adhesion improving layer exposed in the opening of the liquid supply port on the first surface side has minute foreign matter collection holes formed therein. How the head is made.

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