JP2009119725A - Ink jet recording head and method of manufacturing ink jet recording head - Google Patents

Abstract

To improve the ejection characteristics of an ink jet recording head more stably and more, and to further improve the reliability associated with a recovery mechanism. In addition, to achieve higher image quality, an ink jet recording head capable of more stable and more reliable ejection amount modulation is provided.
A first foaming chamber and a channel forming layer for limiting an ink channel communicating with the first foaming chamber and a sacrificial layer for covering the first foaming chamber and a sacrificial layer for covering the first foaming chamber and a sacrificial layer are flattened, and a low-sensitivity resist layer is formed thereon. And the layer of a high sensitivity resist is formed in this order. Next, an area other than the second foaming chamber is exposed with an exposure amount that simultaneously exposes both resists, and an area other than the area that becomes the ink discharge port is exposed with an exposure amount that only the high-sensitivity resist is exposed. Then, the flow path forming layer, the low sensitivity resist layer in the region serving as the second foaming chamber, and the high sensitivity resist layer in the region serving as the ink discharge port are removed.
[Selection] Figure 1i

Description

  The present invention relates to an ink jet recording head that forms an image by ejecting ink from an ejection port.

  The inkjet recording head is a device that prints an image of a predetermined hue by ejecting minute droplets of printing ink to a desired position on a recording sheet. Such ink jet recording heads are roughly classified into two types according to the ink droplet ejection mechanism. One of them is a thermally driven ink jet recording head that generates bubbles in ink using a heat source and ejects ink droplets by the expansion force of the bubbles. The other one is a piezoelectric drive type ink jet recording head that uses a piezoelectric body and ejects ink droplets by pressure applied to the ink by deformation of the piezoelectric body.

  An ink jet recording head in an ink jet recording method generally includes a fine discharge port for discharging print droplets, a liquid channel communicating with the discharge port, and a liquid discharge energy generating unit provided in a part of the liquid channel It has. The ink jet recording head can be roughly divided into two forms depending on the positional relationship between the liquid discharge energy generating portion and the discharge port. That is, a so-called edge shooter type ink jet head in which the bubble growth direction and the discharge direction are different (substantially perpendicular) and a so-called side shooter type ink jet head in which the bubble growth direction and the discharge direction are substantially the same.

Of these two forms, a manufacturing method described in Patent Document 1 will be described as a manufacturing method of a side shooter type ink jet recording head. This manufacturing method is characterized in that the distance between the ink discharge pressure generating element and the orifice can be set with a very high accuracy in a short and reproducible manner and has the following steps in order to enable high-quality recording.
(1) forming an ink flow path pattern with a dissolvable resin on a substrate (base) on which an ink discharge pressure generating element is formed;
(2) A coating resin containing a solid epoxy resin at room temperature is dissolved in a solvent, and this is solvent-coated on the soluble resin layer, thereby forming an ink flow path wall on the soluble resin layer. Forming a coating resin layer;
(3) forming an ink discharge port in the coating resin layer above the ink discharge pressure generating element;
(4) A step of eluting a soluble resin layer.
Hereinafter, this manufacturing method will be described in detail with reference to FIGS.

  First, as shown in FIG. 4a, an ink flow path pattern 3 is formed on a substrate 1 including an ink discharge energy generating element 2 with a soluble resin. Thus, a desired number of ink discharge energy generating elements 2 such as electrothermal conversion elements or piezoelectric elements are arranged on the substrate 1. Then, the ink ejection energy generating element 2 applies ejection energy for ejecting ink droplets as a recording liquid to the ink liquid, and recording is performed.

  For example, when an electrothermal conversion element is used as the ink ejection energy generating element 2, the element heats the nearby recording liquid, thereby causing a change in state in the recording liquid and generating ejection energy. For example, when a piezoelectric element is used as the ink ejection energy generating element 2, ejection energy is generated by mechanical vibration of this element.

  These elements 2 are connected to control signal input electrodes (not shown) for operating these elements. In general, various functional layers such as a protective layer are provided for the purpose of improving the durability of the ejection energy generating element 2, but it is of course possible to provide such a functional layer.

  Next, as shown in FIG. 4b, a coating resin layer 4 is further formed on the ink flow path pattern 3 formed of a soluble resin by a spin coating method, a roll coating method, or the like.

  Next, as shown in FIG. 4c, the ink discharge port 5 is formed by performing pattern exposure on the coating resin layer 4 through a mask. Since the covering resin layer 4 is formed of a negative resist, a portion where the ink discharge port is formed is shielded with a mask (of course, a portion where electrical connection is made is also shielded (not shown)). The pattern exposure can be appropriately selected from ultraviolet rays, deep-UV light, electron beams, X-rays and the like according to the photosensitive region of the photocationic polymerization initiator to be used. Next, the pattern-exposed photosensitive coating resin layer 4 is developed using an appropriate solvent to form an ink discharge port 5.

  Next, an opening (ink supply port) 7 for supplying ink is formed. At this time, as shown in FIG. 4d, the protective member 6 such as cyclized rubber is used to protect the surface of the silicon substrate on which the nozzle is formed, so that the nozzle member produced above is not damaged, After the ink supply port 7 is formed, it may be removed. Any method can be used for forming the ink supply port 7 as long as it can form a hole in the substrate 1. For example, it may be formed by mechanical means such as a drill, or light energy such as laser may be used. Further, a resist pattern or the like may be formed on the substrate 1 and chemically etched.

  Finally, as shown in FIG. 4e, the soluble resin forming the ink flow path pattern 3 is eluted with a solvent. Elution is easily performed by immersing the substrate in a solvent or wiping the solvent with a spray. Moreover, elution time can be further shortened by using ultrasonic waves or the like together.

  Electrical connection (not shown) for driving the ink supply member and the ink discharge pressure generating element 2 is performed on the substrate 1 formed with the ink flow path and the ink discharge port thus formed. Thus, an ink jet recording head is formed.

Patent Document 2 discloses a method of manufacturing a monolithic ink jet recording head including the following steps.
(A) forming a heater for heating ink on the substrate and an electrode for supplying current to the heater;
(B) applying a negative photoresist on the substrate on which the heater and the electrode are formed, and then patterning the photoresist by a photolithography process to form a flow path forming layer that limits an ink flow path;
(C) forming a sacrificial layer on the substrate on which the flow path forming layer is formed so as to cover the flow path forming layer;
(D) planarizing the upper surfaces of the flow path forming layer and the sacrificial layer through a chemical mechanical polishing (CMP) process;
(E) After applying a negative photoresist on the flow path forming layer and the sacrificial layer, patterning it by a photolithography process to form a nozzle layer having a nozzle;
(F) forming an ink supply port on the substrate;
(G) removing the sacrificial layer;

  However, in the manufacturing method to which the semiconductor manufacturing method is applied, basically, the shape change in the vicinity of the ink flow path and the ejection port is limited to the change in the two-dimensional direction parallel to the element substrate. In other words, since the photosensitive material is used for the ink flow path and the ejection port mold, the photosensitive material layer cannot be partially multilayered. Therefore, a desired pattern with a change in the height direction cannot be obtained in a mold such as an ink flow path, and the shape in the height direction from the element substrate is uniformly limited. As a result, it becomes an impediment to the ink flow path design for realizing high-speed and stable ejection.

  On the other hand, Patent Document 3 discloses a method of controlling the processing depth of a resin film by partially changing the opacity by using a laser mask when excimer laser processing of a liquid flow path structure. By this method, the shape of the ink flow path is changed in a three-dimensional direction, that is, an in-plane direction parallel to the element substrate and a height direction from the element substrate. Control of the depth direction in such laser processing is possible in principle. However, the excimer laser used for these processes differs from the excimer laser used for semiconductor exposure, and a high-brightness laser is used in a wide band, which suppresses variations in illuminance within the laser irradiation surface and stabilizes the laser illuminance. It is very difficult to realize. In particular, in a high-quality inkjet recording head, non-uniform discharge characteristics due to variations in the processing shape between the discharge nozzles are recognized as image unevenness, and it is a major issue to improve processing accuracy. Furthermore, it is often impossible to form a fine pattern due to the taper attached to the laser processed surface.

U.S. Pat. No. 6,057,077 discloses a novel polymer orifice fabrication method that does not require a Ni orifice plate or barrier interface material to make a multi-material sandwich of photoimageable layers on a substrate. In U.S. Pat. No. 6,057,049, direct imaging polymer orifices typically comprise two or more layers of negative working photoresist material with slightly different dissolution rates. The dissolution rate is based on the various materials of each layer having different molecular weights, physical compositions, or optical densities. In an exemplary method using two layers, a “slow” photoresist is applied to the substrate that requires an electromagnetic energy of 500 millijoule / cm ² strength for cross-linking. In a fluid jet printhead, the substrate is composed of a semiconductor material that has a stack of thin film layers applied to its surface. A “fast” photoresist, which requires an electromagnetic energy of just 100 millijoules / cm ² for crosslinking, is added over the layer of slow photoresist. After curing, the photoresist layer of the substrate is exposed through the mask to a very high intensity of at least 500 millijoules / cm 2 to form a fluid well chamber. The strength is high enough to cross-link both the upper and lower layers. The photoresist layer of the substrate is then exposed to low intensity electromagnetic energy of 100 millijoules / cm ² through another mask to form an orifice chamber. It is important that the second exposure intensity be low enough so that the lower orifice layer of the slow photoresist under the orifice opening does not crosslink. In U.S. Patent No. 6,047,049, a slow photoresist can be made from a fast photoresist with no dye or a small amount of dye by adding an optical dye (such as orange # 3, ~ 2% weight) to the transparent polymer material. It is disclosed. However, in Patent Document 4, an ink flow path is formed with a “slow” photoresist, and an orifice including an ejection port is formed with a “fast” photoresist. Therefore, the following two points must be satisfied in order to satisfy the functions of the inkjet head that have been required recently.
(1) High-speed refilling property: In other words, after the droplets fly from the orifice, the ink is refilled in the nozzle (up to the ejection port) as soon as possible.
(2) Making flying droplets smaller: In other words, not only the ejection port size is reduced, but also the orifice layer is made as thin as possible, thereby providing an ink ejection energy generating element (hereinafter referred to as a heater). To shorten the distance of the discharge port. However, it has been found that if the entire orifice layer is made thin, the orifice is broken when the discharge port is deformed or when the wafer is cut into chips.
(3) Densification of nozzles: In other words, when droplets are made smaller, the dot size formed by one droplet becomes smaller, and it is necessary to increase the number of droplets driven per pixel. For this reason, it is necessary to further increase the refill frequency (time for repeatedly ejecting droplets) or to dispose many nozzles at the same time per unit area by arranging nozzles at high density.

In order to achieve both of the above three points, it is necessary to increase the cross-sectional area of the ink flow path as much as possible and to reduce the thickness of the orifice as much as possible. However, if the nozzles are arranged at high density, it is necessary to increase the thickness of the flow path in order to increase the cross-sectional area of the ink flow path. This is difficult with the technique disclosed in Patent Document 4. That is, with this technique, the orifice layer can be thinned as a whole, but only the orifice layer around the discharge port cannot be thinned. In addition, when forming nozzles with high density, a low-sensitivity resist layer and a high-sensitivity resist layer are formed at the same exposure amount at the same time. In order to accurately control the photosensitive area in the thickness direction and in the lateral direction, many restrictions arise.
JP-A-6-286149 JP 2005-205916 A Japanese Patent Laid-Open No. 10-291317 JP 11-314371 A

  Therefore, according to the present invention, a plurality of ejection energy generating elements (hereinafter referred to as heaters) are arranged at high density and bonded onto a substrate for driving the heaters to form an ink flow path and an ink ejection port. The present invention relates to an ink jet recording head. An object of the present invention is to provide an ink jet recording head that stably ejects small ink liquid and enables high-speed refill (easy flow of ink from an ink supply port to an ink flow path). It is.

  Furthermore, in order to meet the market demand for high image quality in recent years, in order to achieve high resolution and printed matter with small droplets, the ink jet recording heads are arranged in high density and from the discharge port. It is necessary to fly a minute droplet. For this purpose, the ink flow path becomes a finer capillary, and in order to constantly and stably fill the interior with ink, a recovery mechanism provided in the recording apparatus provides a recovery means such as suction or pressurization. It has been. At that time, it is important to refresh the inside of the ink flow path more stably, easily, and so as not to leave residual bubbles. An object of the present invention is to achieve recovery means more stably and more easily even in an ink flow path arranged at a higher density.

  In addition, when changing the ink discharge port size for each column and discharging different ink volumes from the plurality of ink discharge ports arranged on the surface, more stable and better discharge characteristics can be obtained. Provided is an ink jet recording head capable of achieving ejection amount modulation while maintaining the same.

  Furthermore, the present invention provides an ink jet recording head in which recovery means can be taken more stably and more easily even with an ink jet recording head having a plurality of ink outlets arranged in a plane and having different sizes for each column. There is.

  However, in Patent Document 2, the shape change in the vicinity of the ink flow path and the ejection port is limited to a change in a two-dimensional direction parallel to the element substrate. Further, in Patent Document 4, when the ink discharge port is exposed and then developed and the resist in the unexposed portion is removed, the resist in the unexposed portion corresponding to the ink flow path is also removed at the same time. For this reason, when the thermally crosslinked negative resist is subsequently thermally cured, the “fast” photoresist in the upper layer hangs down to the ink flow path side formed by the “slow” photoresist in the lower layer. There was a problem.

  The present invention has been made in view of the above problems, and aims to more stably and improve the ejection characteristics of an ink jet recording head and to further improve the reliability associated with the recovery mechanism. It is what. It is another object of the present invention to provide an ink jet recording head that can perform discharge amount modulation more stably and more reliably in order to achieve higher image quality.

The present invention is an ink jet recording head in which a plurality of ink flow paths and a plurality of ink discharge ports are provided on a substrate provided with an ink discharge energy generating element,
(A) forming an ink discharge energy generating element for heating ink and an electrode for supplying a current to the ink discharge energy generating element on a substrate;
(B) A first negative photosensitive resist is applied on the substrate on which the ink ejection energy generating element and the electrode are formed, and the first negative photosensitive resist is patterned by a photolithography process. Forming a flow path forming layer that limits the first foaming chamber and the ink flow path communicating with the first foaming chamber;
(C) forming a sacrificial layer on the substrate on which the flow path forming layer is formed so as to cover the flow path forming layer;
(D) polishing the sacrificial layer by CMP until the flow path forming layer is exposed, and planarizing the upper surface of the flow path forming layer and the sacrificial layer;
(E) On the flow path forming layer and the sacrificial layer, a second negative photosensitive resist is applied to form a low-sensitivity resist layer, and subsequently, on the low-sensitivity resist layer, the first Applying a third negative photosensitive resist having a higher sensitivity than the negative photosensitive resist 2 to form a high-sensitivity resist layer;
(F) Exposing a region other than the second foaming chamber communicating with the first foaming chamber with an exposure amount capable of simultaneously exposing the second negative photosensitive resist and the third negative photosensitive resist. And a process of
(G) exposing a region other than the region serving as an ink discharge port with an exposure amount capable of exposing only the third negative photosensitive resist;
(H) forming an ink supply port on the substrate;
(I) a step of removing the sacrificial layer, the low-sensitivity resist layer in the region serving as the second foaming chamber, and the high-sensitivity resist layer in the region serving as the ink discharge port. It is.

According to the present invention, the following items can be obtained.
(1) Since the main process for manufacturing the ink jet recording head is based on the photolithography technique using a photoresist or the like, the discharge port of the liquid flow path structure of the liquid discharge head and the ink flow path have a desired pattern, It can be formed very easily. Furthermore, it is possible to easily process a large number of liquid ejection heads having the same configuration at the same time.
(2) It is possible to partially change the thickness of the liquid flow path structure material layer and the thickness of the ink flow path, the inkjet speed is high, the landing accuracy is extremely high, and the ink refill speed is high. Since the recording head can be manufactured, high-quality recording can be performed at high speed.
(3) A liquid discharge head of a high density multi-array nozzle can be obtained by simple means.

  In this description, as an application example of the present invention, an inkjet recording method will be described as an example. However, the scope of the present invention is not limited to this, and in addition to biochip creation and electronic circuit printing, drugs It can also be applied to a liquid discharge head for medical use for discharge.

  A method for manufacturing the ink jet recording head of the present invention will be described. Hereafter, each manufacturing process in the manufacturing method of this invention is demonstrated with reference to FIG.

  First, as shown in FIG. 1a, a substrate 10 having a plurality of ink discharge energy generating elements 11 is prepared. As the substrate, a silicon substrate can be used. For example, a CZ substrate manufactured by Mitsubishi Materials Corporation having a thickness of 625 μm and a size of 6 inches (Φ150 mm) can be used. A P—SiO film and a P—SiN film, which are membrane films, may be formed.

  An electrode (not shown) for supplying a current to the ink discharge energy generating element 11 is formed on the surface of the substrate 10. Further, on the surface of the substrate 10, a pattern of HIMA (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is an adhesion improving layer, is formed by a photolithography process, and the same material is used on the back side. A pattern of (trade name, manufactured by Hitachi Chemical Co., Ltd.) is formed.

  Next, as shown in FIG. 1b, a first negative photosensitive resist is applied onto the substrate 10, patterned by a photolithography process, and communicated with the first foaming chamber and the first foaming chamber. A flow path forming layer 14 for limiting the ink flow path is formed. The first negative photosensitive resist to be applied is preferably a photocurable composition containing a cationically polymerizable compound and a photocationic polymerization initiator. For example, a photosensitive material mainly composed of an epoxy resin described in Japanese Patent No. 3143307 can be used, and it is preferably used as a coating resist after being dissolved in an aromatic solvent such as xylene. The flow path forming layer 14 formed by exposing and developing the first negative photosensitive resist (photolithography process) limits the ink flow path communicating with the first foam chamber and the first foam chamber. It becomes an ink flow path wall. Since the first negative photosensitive resist has negative characteristics, a photomask (not shown) that does not irradiate light to a portion that becomes an ink flow path is applied during exposure.

  The thickness of the flow path forming layer 14 is preferably 5 μm or more and 30 μm or less.

  Next, as shown in FIG. 1C, a sacrificial layer 12 is formed by applying a positive resist layer containing, for example, PMIPK (polymethylisopropenyl ketone) on the substrate on which the flow path forming layer 14 is formed. A positive resist for coating mainly composed of PMIPK is commercially available from Tokyo Ohka Kogyo Co., Ltd. under the trade name “ODUR-1010”, for example. The sacrificial layer 12 can be formed by a general-purpose spin coating method. At this time, the sacrificial layer 12 is formed so as to cover the entire flow path forming layer 14 and to be thicker than the flow path forming layer 14 even in a region where the flow path forming layer 14 does not exist. The sacrificial layer 12 may be formed by a spin coating method using a positive resist containing a copolymer of methacrylic acid ester and methacrylic acid (for example, PMMA copolymer). These positive resists are ionizing radiation decomposing positive resists that are decomposed and solubilized by irradiation with ionizing radiation.

  Next, as shown in FIG. 1d, the upper surface of the flow path forming layer 14 and the sacrificial layer 12 is planarized by polishing until the flow path forming layer 14 is exposed while the sacrificial layer 12 is scraped off by a CMP process. In the CMP process, for example, a trade name “MAT ARW-681MS” manufactured by MAT can be used. At this time, the upper surfaces of the flow path forming layer 14 and the sacrificial layer 12 are polished to the desired height of the ink flow path by the CMP process, so that the upper surfaces of the flow path forming layer 14 and the sacrificial layer 12 are made the same height.

  Next, as shown in FIG. 1e, the low sensitivity resist layer 15 is formed on the flow path forming layer 14 and the sacrificial layer 12, and then the high sensitivity resist layer 16 is formed on the low sensitivity resist layer 15. To do. The low sensitivity resist layer 15 is formed by applying a second negative photosensitive resist by spin coating. The high sensitivity resist layer 16 is formed by applying a third negative photosensitive resist having higher sensitivity than the second negative photosensitive resist by a spin coating method.

  As the second negative photosensitive resist, for example, a photocurable composition containing a cationic polymerizable compound, a photo cationic polymerization initiator, and a photo cationic polymerization inhibitor or an optical dye can be used.

  The cationically polymerizable compound is a compound in which compounds can be bonded to each other using a cation addition polymerization reaction. For example, a solid epoxy compound described in Japanese Patent No. 3143307 can be suitably used. Examples of the epoxy compound include a reaction product of bisphenol A and epichlorohydrin having a molecular weight of at least about 900, a reaction product of bromosphenol A and epichlorohydrin, a reaction of phenol novolac or o-cresol novolac and epichlorohydrin. And polyfunctional epoxy resins having an oxycyclohexane skeleton described in JP-A-60-161973, JP-A-63-221121, JP-A-64-9216, and JP-A-2-140219. Can be mentioned. These 1 type (s) or 2 or more types can be used. In these epoxy compounds, a compound having an epoxy equivalent of 2000 or less, more preferably 1000 or less, is preferably used. This is because if the epoxy equivalent exceeds 2000, the crosslinking density decreases during the curing reaction, the Tg of the cured product or the heat distortion temperature may decrease, and problems may occur in adhesion and ink resistance. is there.

  Examples of the cationic photopolymerization initiator include aromatic iodonium salts, aromatic sulfonium salts [J. POLYMER SCI: Symposium No. 56 383-395 (1976)] and SP-150 and SP-170 (both are trade names) marketed by Asahi Denka Kogyo Co., Ltd., and the like. In addition, the cationic photopolymerization initiator can promote the cationic addition polymerization reaction by using a reducing agent in combination with heating (the crosslink density is improved as compared with a single cationic photopolymerization). However, when a photocationic polymerization initiator and a reducing agent are used in combination, the reducing agent is selected so that it becomes a so-called redox type initiator system that does not react at room temperature and reacts at a certain temperature or higher (preferably 60 ° C. or higher). There is a need. As such a reducing agent, copper triflate (copper trifluoromethanesulfonate (II)) is most suitable in consideration of the copper compound, particularly reactivity and solubility in the epoxy resin. A reducing agent such as ascorbic acid is also useful. Further, as described later, the crosslinking density can be increased by a post-process for heating the coating resin layer after the exposure / PEB / development process of the coating resin layer as described later. This is particularly effective when a higher crosslinking density (high Tg) is required, such as an increase in the number of nozzles (high-speed printability) and the use of non-neutral ink (improvement of water resistance of the colorant).

  As a usage-amount of a photocationic polymerization initiator, 0.5-10.0 mass% is preferable with respect to a cation polymeric compound.

  It is possible to appropriately add additives and the like to the photocurable composition as necessary. For example, a flexibility-imparting agent may be added for the purpose of lowering the elastic modulus of the epoxy resin, or a silane coupling agent may be added to obtain further adhesion to the substrate.

  Furthermore, a photocationic polymerization inhibitor can be added to this photocurable composition. This cationic photopolymerization inhibitor reduces the curability of the photocurable composition and is formed at the interface between the positive resist layer (solid layer) and the negative resist layer (nozzle forming material layer) described above. The compatible layer prevents the cured layer from being formed by the exposed light. The photocationic polymerization inhibitor may be any substance that can provide the desired curing characteristics and scum generation prevention effect in the light irradiation part, and can reduce the function of the acid catalyst. Substance is used. As the basic substance, a compound that can serve as a proton acceptor, that is, a basic substance having an unshared electron pair can be preferably used. A nitrogen-containing compound having an unshared electron pair is a compound that acts as a base with respect to an acid and is effective for preventing the formation of scum. Specific examples include compounds containing atoms such as nitrogen, sulfur, and phosphorus, and representative examples include amine compounds. Specifically, amines substituted with 1 to 4 carbon pyridoxyalkyl groups such as diethanolamine, triethanolamine, triisopropanolamine; pyrimidine compounds such as pyrimidine, 2-aminopyrimidine, 4-aminopyrimidine; pyridine And pyridine compounds such as methylpyridine; aminophenols such as 2-aminophenol and 3-aminophenol; Moreover, you may use these basic substances in mixture of 2 or more types.

  The amount of the photocationic polymerization inhibitor used is preferably 0.01 to 100% by mass, more preferably 0.1 to 20% by mass, based on the photocationic polymerization initiator.

  In addition, an optical dye can be added to the photocurable composition. As the optical dye, acridine orange which is an acridine pigment, acid orange (represented by the following chemical formula (10)) or the like is used. However, the material is not particularly limited to the above materials as long as it is an optical dye having an effect of inhibiting photocationic polymerization.

  What is necessary is just to add the quantity used as 20 mass% or less in a photocurable composition as the usage-amount of an optical dye. By adding this dye, the amount of electromagnetic energy required is greater than the non-dye mixed material that crosslinks the material, so adding an amount of 0.1-2% by weight in the photocurable composition Is preferred.

  The pre-baking conditions after applying the second negative photosensitive resist can be, for example, 100 ° C. and 6 minutes. The temperature at this time is preferably 90 to 120 ° C., and the time is preferably 3 minutes or more. However, if baking is performed at a temperature exceeding 120 ° C., cracks, wrinkled patterns, and the like may occur on the coating layer. Moreover, if it is less than 90 degreeC, the residual rate of a solvent will increase in a coating layer, and a compatible layer will be formed between the highly sensitive photocurable composition layers applied after that, and a desired shape will be formed. May be difficult to do. In addition, if the baking time is 3 minutes or more, the curing of the present invention can be satisfied without any problem. However, if the baking time is too long, the production tact surface or the cracked or wrinkled pattern on the coating layer described above may be used. Since problems occur, 10 minutes or less is preferable.

  The film thickness of the low sensitivity resist layer 15 formed of the second negative photosensitive resist is preferably 3 μm or more and 20 μm or less.

  As the third negative photosensitive resist, a resist having higher sensitivity than the second negative photosensitive resist may be selected. For example, a photocurable composition containing a cationic polymerizable compound and a photo cationic polymerization initiator. Can be used. The cationically polymerizable compound and the photocationic polymerization initiator used here can be selected from the materials described above. Moreover, it may be the same as or different from the cationically polymerizable compound and the photocationic polymerization initiator used as the second negative photosensitive resist.

  The pre-baking conditions after applying the third negative photosensitive resist can be, for example, 70 ° C. and 150 seconds. The temperature at this time is preferably 60 ° C. or more and less than 90 ° C., and the time is preferably less than 3 minutes. However, usually a minimum baking time of 1 minute or more is required. If it is less than 1 minute, the solvent evaporation is extremely small, and the wafer sticks to the cassette, or the resist (age bead portion) that rises around the wafer has fluidity around the wafer and returns. May occur.

  The film thickness of the high-sensitivity resist layer 16 formed of the third negative photosensitive resist is preferably 2 μm or more and 50 μm or less.

  Further, as described in JP-A No. 2000-326515, a water-repellent coating (not shown) can be formed on the high-sensitivity resist layer 16 using a photosensitive water-repellent material. The water repellent coating can be formed by a laminating method.

  Next, as shown in FIG. 1f, the second foaming chamber communicates with the first foaming chamber with an exposure amount capable of simultaneously exposing the second negative photosensitive resist and the third negative photosensitive resist. Expose other areas. Note that the photomask in FIG. 1f is an image, and in the case of a projection exposure apparatus, the mask is projected onto the resist pattern. Projection exposure machines used at this time include Canon's MPA600 Super (product name), which is an equal magnification type projection exposure machine, and step exposure machines such as FPA-3000i5 + and FPA-3000GMR (both are trade names). Is suitable.

  When a water-repellent film (not shown) is formed on the high-sensitivity resist layer 16, the second negative photosensitive resist of the low-sensitivity resist layer 15 and the third negative of the high-sensitivity resist layer 16 are used. Type photosensitive resist and the photosensitive water-repellent material of the water-repellent coating can be exposed simultaneously.

  Next, as shown in FIG. 1g, a region other than the ink discharge port is exposed with an exposure amount capable of exposing only the third negative photosensitive resist. Note that the photomask in FIG. 1g is an image, and in the case of a projection exposure apparatus, the mask is projected onto the resist pattern. As the projection exposure machine used at this time, the same one as described above is suitable.

  When a water-repellent film (not shown) is formed on the high-sensitivity resist layer 16, a third negative photosensitive resist of the high-sensitivity resist layer 16, a photosensitive water-repellent material of the water-repellent film, and Can be exposed simultaneously.

  Here, the exposure amount obtained by simultaneously exposing the second negative photosensitive resist and the third negative photosensitive resist in the previous step, and the exposure amount obtained by exposing only the third negative photosensitive resist in the subsequent step. The ratio (exposure amount ratio) to is preferably 6: 1 or more. The larger the exposure amount ratio, the more accurately the shape of the ink discharge port can be formed. From the viewpoint of securing an exposure amount for exposing only the third negative photosensitive resist, the exposure amount ratio is preferably 20: 1 or less.

  Next, as shown in FIG. 1h, a protective layer 19 made of cyclized isoprene is applied on the high-sensitivity resist layer 16 in order to protect the high-sensitivity resist layer 16 from an alkaline solution. As a material constituting the protective layer 19, for example, a material marketed under the name “OBC” by Tokyo Ohka Kogyo Co., Ltd. can be used.

  Thereafter, the ink supply port 20 is formed in the substrate 11. For example, the ink supply port 20 can be formed by immersing the silicon substrate 11 in a tetramethylammonium hydride (TMAH) 22 wt% solution at 83 ° C. for 16 hours. Next, the P-SiO film and the P-SiN film, which are membrane films, can be removed continuously.

  Finally, as shown in FIG. 1 i, after removing the protective layer 19, the sacrificial layer 12, the low-sensitivity resist layer in the region that becomes the second foaming chamber 17, and the high-sensitivity resist layer in the region that becomes the ink discharge port 18 are formed. Remove. For example, in the case of a protective layer made of the trade name “OBC”, the protective layer 19 can be removed by immersing the substrate in xylene. Thereafter, the entire surface is exposed to light having a wavelength of 330 nm or less, and the material of the sacrificial layer 12 which is the mold material of the liquid flow path is decomposed into low molecular weight compounds, which can be removed with a solvent. The low-sensitivity resist layer in the region to be the second foaming chamber 17 and the high-sensitivity resist layer in the region to be the ink discharge port 18 are preferably developed with an aromatic solvent such as xylene. Alternatively, a mixed solution of NMP and IPA can also be used.

  Thus, as shown in FIG. 1i, the substrate 10, the plurality of ink discharge energy generating elements 11, the ink discharge ports 18, the second foaming chamber 17, the first foaming chamber, the ink flow path, and the common ink supply An ink jet recording head having a mouth is formed. In the substrate 10, a plurality of ink discharge energy generating elements 11 are arranged in a row, and an ink supply port including a through hole extending along the arrangement direction of the ink discharge energy generating elements 11 is formed. The second foaming chamber 17 communicates with the ink discharge port 18, the first foaming chamber communicates with the second foaming chamber 17 and the ink channel, and the ink channel communicates with a common ink supply port. Yes. The ink droplets are ejected from the ink ejection port 18 by the energy from the ink ejection energy generating element 11.

  FIG. 2 is a top view of the nozzle arrangement for one color constituting the ink jet recording head in which the ink flow path 22 is formed with respect to the ink discharge energy generating element 11. As shown in FIG. 2, the ink flow path 22 disposed on both sides of the common ink supply port disposed in the center, the first foaming chamber communicating with the ink flow path 22, and the first foaming chamber communicated with each other. The second foaming chamber and the ink discharge port 18 communicating with the second foaming chamber are formed. An ink discharge energy generating element 11 is disposed in the first foam chamber. With such an arrangement, the ink supplied from the common ink supply port is filled into the first foaming chamber, the second foaming chamber, and the ink discharge port 18 through the ink flow path. Then, bubbles generated in the ink discharge energy generating element 11 grow in the first bubble chamber, the second bubble chamber, and the ink flow path, and on the recording medium (not shown) via the ink discharge port. Then, the ink droplets fly to form a print image.

  The ink jet recording head manufactured as described above is mounted on the ink jet head unit having the form shown in FIG. 3, and good image recording is possible by performing ejection and recording evaluation. As a form of the inkjet head unit, as shown in FIG. 3, for example, a TAB film 214 is provided on the outer surface of a holding member that detachably holds an ink tank 213 to exchange recording signals with the recording apparatus main body. Yes. The ink jet recording head 212 is connected to the electrical wiring by the electrical connection lead 215 on the TAB film 214.

Example 1
As described in the above embodiment, the processes up to the state shown in FIG. At this time, the thickness of the flow path forming layer 14 and the sacrificial layer 12 formed by the CMP process was 15 μm.

  Next, as shown in FIG. 1e, a second negative photosensitive resist is applied by spin coating to form a low-sensitivity resist layer 15 having a thickness of 5 μm, and then a third negative photosensitive resist is formed. A high-sensitivity resist layer 16 having a thickness of 5 μm was formed by application by spin coating.

  As the second negative photosensitive resist, a photocurable composition in which an optical dye (acid orange, 2% by mass) is mixed with a fast crosslinking polymer such as a photoimageable epoxy or a photoimageable polymer. Using. By adding the dye in this manner, the amount of electromagnetic energy required to crosslink is greater than the non-dye mixed material. As the third negative photosensitive resist, a photocurable composition comprising a fast cross-linking polymer such as a photoimageable epoxy or a photoimageable polymer was used. Examples of the photoimageable epoxy include SU8 (trade name) developed by IBM. Examples of the photoimageable polymer include OCG (trade name) which is commonly known in the industry.

Next, as shown in FIG. 1f, a ^second bubbling chamber communicating with the first bubbling chamber is formed at an exposure amount of 600 mJ / cm ² using a projection exposure machine (product name: MPASuper600, manufactured by Canon). Exposed areas were exposed. In addition, this exposure amount is an exposure amount that can simultaneously expose the second negative photosensitive resist and the third negative photosensitive resist. Further, as shown in FIG. 1g, a region other than the region serving as the ink discharge port was exposed with a projection exposure machine (manufactured by Canon, trade name: MPASuper600) with an exposure amount of 100 mJ / cm ² . Note that this exposure amount is an exposure amount capable of exposing only the third negative photosensitive resist. The exposure ratio in this embodiment is 6: 1.

  Thereafter, as described in the above embodiment, an ink jet recording head having the configuration shown in FIG. 1i was formed. The shape in the vicinity of the ink discharge port of the obtained ink jet recording head was formed with high accuracy.

(Example 2)
As described in the above embodiment, the processes up to the state shown in FIG. At this time, the thickness of the flow path forming layer 14 and the sacrificial layer 12 formed by the CMP process was 12 μm.

  Next, as shown in FIG. 1e, a second negative photosensitive resist is applied by spin coating to form a low-sensitivity resist layer 15 having a thickness of 3 μm. Subsequently, a third negative photosensitive resist is formed. A high-sensitivity resist layer 16 having a thickness of 10 μm was formed by application by spin coating.

As the second negative photosensitive resist,
EHPE-3150 (cationic polymerizable compound) 50 parts (Daicel Chemical Industries, trade name)
SP-172 (photo cationic polymerization initiator) 1 part (Asahi Denka Kogyo Co., Ltd., trade name)
・ A-187 (Silane coupling agent) 2.5 parts (Nippon Unica, trade name)
A photocurable composition obtained by adding 0.01 mol% of SP-172 (trade name) to triethanolamine as a photocationic polymerization inhibitor and dissolving it in 50 parts of xylene as a coating solvent was used.

As the third negative photosensitive resist,
EHPE-3150 (cationic polymerizable compound) 50 parts (Daicel Chemical Industries, trade name)
SP-172 (photo cationic polymerization initiator) 1 part (Asahi Denka Kogyo Co., Ltd., trade name)
・ A-187 (Silane coupling agent) 2.5 parts (Nippon Unica, trade name)
Was used as a coating solvent and was dissolved in 50 parts of xylene.

Next, as shown in FIG. 1f, a ^second bubbling chamber communicating with the first bubbling chamber is formed with a projection exposure machine (manufactured by Canon, trade name: MPASuper600) at an exposure amount of 800 mJ / cm ^2. Exposed areas were exposed. In addition, this exposure amount is an exposure amount that can simultaneously expose the second negative photosensitive resist and the third negative photosensitive resist. Further, as shown in FIG. 1g, a region other than the region serving as the ink discharge port was exposed with a projection exposure machine (manufactured by Canon, trade name: MPASuper600) with an exposure amount of 100 mJ / cm ² . Note that this exposure amount is an exposure amount capable of exposing only the third negative photosensitive resist. The exposure ratio in this embodiment is 8: 1.

  Thereafter, as described in the above embodiment, an ink jet recording head having the configuration shown in FIG. 1i was formed. The shape in the vicinity of the ink discharge port of the obtained ink jet recording head was formed with high accuracy.

(Example 3)
As described in the above embodiment, the processes up to the state shown in FIG. At this time, the thickness of the flow path forming layer 14 and the sacrificial layer 12 formed by the CMP process was 14 μm.

  Next, as shown in FIG. 1e, a second negative photosensitive resist is applied by spin coating to form a low-sensitivity resist layer 15 having a thickness of 10 μm, and then a third negative photosensitive resist is formed. A high-sensitivity resist layer 16 having a thickness of 2 μm was formed by application by spin coating.

As the second negative photosensitive resist,
EHPE-3150 (cationic polymerizable compound) 50 parts (Daicel Chemical Industries, trade name)
SP-172 (photo cationic polymerization initiator) 1 part (Asahi Denka Kogyo Co., Ltd., trade name)
・ A-187 (Silane coupling agent) 2.5 parts (Nippon Unica, trade name)
In addition, 0.1 mol% of SP-172 (trade name) as a photocationic polymerization inhibitor and 2 parts of an optical dye orange acid having an effect of inhibiting photocationic polymerization were added as a coating solvent. A photocurable composition dissolved in 50 parts of xylene was used.

As the third negative photosensitive resist,
EHPE-3150 (cationic polymerizable compound) 50 parts (Daicel Chemical Industries, trade name)
SP-172 (photo cationic polymerization initiator) 1 part (Asahi Denka Kogyo Co., Ltd., trade name)
・ A-187 (Silane coupling agent) 2.5 parts (Nippon Unica, trade name)
Was used as a coating solvent and was dissolved in 50 parts of xylene.

Next, as shown in FIG. 1f, a ^second foaming chamber communicated with the first foaming chamber is formed at an exposure amount of 1600 mJ / cm ² using a projection exposure machine (product name: MPASuper600, manufactured by Canon). Exposed areas were exposed. In addition, this exposure amount is an exposure amount that can simultaneously expose the second negative photosensitive resist and the third negative photosensitive resist. Furthermore, as shown in FIG. 1g, a region other than the region serving as the ink discharge port was exposed with a projection exposure machine (manufactured by Canon, trade name: MPASuper600) with an exposure amount of 80 mJ / cm ² . Note that this exposure amount is an exposure amount capable of exposing only the third negative photosensitive resist. The exposure ratio in this embodiment is 20: 1.

  Thereafter, as described in the above embodiment, an ink jet recording head having the configuration shown in FIG. 1i was formed. The shape in the vicinity of the ink discharge port of the obtained ink jet recording head was formed with high accuracy.

It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a figure for demonstrating the manufacturing process in the method of this invention. It is a top view of the inkjet recording head manufactured by the method of this invention. FIG. 3 is a schematic perspective view of an ink jet recording head unit on which an ink jet recording head manufactured by the method of the present invention is mounted. It is a figure for demonstrating the manufacturing process in the conventional method. It is a figure for demonstrating the manufacturing process in the conventional method. It is a figure for demonstrating the manufacturing process in the conventional method. It is a figure for demonstrating the manufacturing process in the conventional method. It is a figure for demonstrating the manufacturing process in the conventional method.

Explanation of symbols

10: substrate 11: ink ejection energy generating element 12: sacrificial layer 14: flow path forming layer 15: low sensitivity resist layer 16: high sensitivity resist layer 17: second foaming chamber 18: ink ejection port 19: protective layer 20: Ink supply port

Claims (9)

An ink jet recording head in which a plurality of ink flow paths and a plurality of ink discharge ports are provided on a substrate provided with an ink discharge energy generating element,
(A) forming an ink discharge energy generating element for heating ink and an electrode for supplying a current to the ink discharge energy generating element on a substrate;
(B) A first negative photosensitive resist is applied on the substrate on which the ink ejection energy generating element and the electrode are formed, and the first negative photosensitive resist is patterned by a photolithography process. Forming a flow path forming layer that limits the first foaming chamber and the ink flow path communicating with the first foaming chamber;
(C) forming a sacrificial layer on the substrate on which the flow path forming layer is formed so as to cover the flow path forming layer;
(D) polishing the sacrificial layer by CMP until the flow path forming layer is exposed, and planarizing the upper surface of the flow path forming layer and the sacrificial layer;
(E) On the flow path forming layer and the sacrificial layer, a second negative photosensitive resist is applied to form a low-sensitivity resist layer, and subsequently, on the low-sensitivity resist layer, the first Applying a third negative photosensitive resist having a higher sensitivity than the negative photosensitive resist 2 to form a high-sensitivity resist layer;
(F) Exposing a region other than the second foaming chamber communicating with the first foaming chamber with an exposure amount capable of simultaneously exposing the second negative photosensitive resist and the third negative photosensitive resist. And a process of
(G) exposing a region other than the region serving as an ink discharge port with an exposure amount capable of exposing only the third negative photosensitive resist;
(H) forming an ink supply port on the substrate;
(I) a step of removing the sacrificial layer, the low-sensitivity resist layer in the region serving as the second foaming chamber, and the high-sensitivity resist layer in the region serving as the ink discharge port. .   2. The method of manufacturing an ink jet recording head according to claim 1, wherein the first negative photosensitive resist is a photocurable composition containing a cationically polymerizable compound and a photocationic polymerization initiator.   The sacrificial layer is an ionizing radiation decomposing positive resist containing polymethylisopropenyl ketone, or an ionizing radiation decomposing positive resist containing a copolymer of methacrylic acid ester and methacrylic acid. A method of manufacturing an ink jet recording head according to claim 1 or 2.   The second negative photosensitive resist is a photocurable composition containing a cationically polymerizable compound, a photocationic polymerization initiator, and a photocationic polymerization inhibitor or an optical dye. 4. A method for producing an ink jet recording head according to any one of items 1 to 3.   The inkjet recording according to any one of claims 1 to 4, wherein the third negative photosensitive resist is a photocurable composition containing a cationically polymerizable compound and a photocationic polymerization initiator. Manufacturing method of the head.   6. The method of manufacturing an ink jet recording head according to claim 1, wherein the ratio of the exposure amount in the step (f) and the exposure amount in the step (g) is 6: 1 or more. .   The method of manufacturing an ink jet recording head according to claim 1, wherein the low-sensitivity resist layer has a thickness of 3 μm or more and 20 μm or less.   8. The method of manufacturing an ink jet recording head according to claim 1, wherein the high-sensitivity resist layer has a thickness of 2 to 50 [mu] m.   An ink jet recording head manufactured by the method for manufacturing an ink jet recording head according to claim 1.

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