JP5224771B2 - Manufacturing method of recording head substrate - Google Patents

Description

The present invention relates to a manufacturing method of the recording head board.

  A substrate constituting a recording head (sometimes referred to as an “inkjet head”) used in an ink jet recording method (liquid discharge recording method) for recording by discharging a recording liquid such as ink is generally as follows. It has a special structure.

  That is, an ejection port from which a recording droplet (hereinafter referred to as “droplet” or “ink droplet”) is ejected, a supply port to which a recording liquid is supplied, an ink flow path that connects the ejection port and the supply port, and ink An energy generating element is provided in the flow path. In general, the energy generating element is disposed near the end of the ink flow path immediately below the ejection port, and such a region is called a “foaming chamber” or the like, and may be distinguished from other regions of the ink flow channel. .

  As a manufacturing method of a recording head substrate having the above structure, for example, the following method is known.

  A through hole for supplying ink is formed on a substrate on which a heater as an energy generating element and a driver circuit for driving the heater are formed, and then a pattern forming a wall of an ink flow path is formed with a negative resist. . Next, the plate on which the discharge ports are formed is bonded to the substrate by electroforming or excimer laser processing.

  In another method, an ink flow path structure plate is formed by forming an ink flow path and a discharge port by excimer laser processing on a resin film (usually polyimide is preferably used) coated with an adhesive layer. Next, the formed ink flow path structure plate and the substrate are bonded together by applying hot pressure.

  Here, in order to achieve high image quality recording, it is necessary to enable ejection of minute ink droplets. To enable ejection of minute ink droplets, a heater and an ejection port that affect the ejection amount The distance between must be as short as possible. Specifically, it is necessary to reduce the height of the ink flow path, to reduce the volume of the foaming chamber, or to reduce the size of the ejection port. That is, in order to manufacture a recording head substrate capable of discharging minute ink droplets by the conventional manufacturing method, it is necessary to reduce the thickness of the ink flow path structure plate laminated on the substrate. However, it is extremely difficult to process a thin-film ink flow path structure plate with high accuracy and to bond it to a substrate.

  In order to solve the above problems, Patent Document 1 discloses a method for manufacturing a recording head substrate as follows. In the manufacturing method disclosed in Patent Document 1, an ink flow path mold is patterned with a photosensitive material on a substrate on which an energy generating element is formed, and then coated on the substrate so as to cover the mold pattern. A resin layer is formed. Next, after forming a discharge port communicating with the mold of the ink flow path in the coating resin layer, the mold pattern (photosensitive material) is removed. In the present specification, the manufacturing method disclosed in Patent Document 1 may be referred to as a “casting method”.

  In the manufacturing method disclosed in Patent Document 1, a positive resist that is easy to remove is used as the photosensitive material. In addition, since this manufacturing method employs a photolithography method used in semiconductor manufacturing, it is possible to perform very fine processing with extremely high accuracy with respect to the formation of ink flow paths, discharge ports, and the like.

  Next, recording dots or dots formed by ink droplets landing on the surface of the recording medium will be described. As a method of expressing gradation smoothly and making graininess inconspicuous, there are a dot density control method for controlling the number of recording dots per unit area, a dot diameter control method for controlling the size of recording dots, and combinations thereof. is there.

  For example, a conventional ink jet recording apparatus is provided with two ejection port arrays for ejecting light ink droplets and dark ink droplets respectively, and the light to middle portions of the image are expressed by light recording dots. Some parts are expressed from dark to dark recording dots. In short, there is one that controls the size of the recording dots in a pseudo manner.

  However, in order to form a light-colored recording dot and a dark recording head, separate ink tanks containing inks having different densities are required, resulting in an increase in cost. Therefore, there has been proposed a recording method in which nozzles for ejecting ink droplets of different sizes are provided, and the bright portion to the intermediate portion of the image are expressed by small-diameter recording dots, and the intermediate portion to the dark portion are expressed by large-diameter recording dots. Yes. In this case, it is necessary to supply the same ink from the same ink tank to each ejection port because the recording dots having different sizes need to have the same color.

  However, when a large number of ink flow paths are connected to the same supply port, the flow of ink generated when each discharge port discharges and refills ink droplets affects the other discharge ports (in this specification, This effect is sometimes referred to as “crosstalk”). When crosstalk occurs, fluctuations occur in the liquid level of the ejection port that is not ejecting, the amount of ink droplets ejected from the ejection port and the flying speed become unstable, and in the worst case, ejection may not be performed. is there.

  Furthermore, in order to connect a large number of ink flow paths to the same supply port, it is necessary to form the supply port widely (largely). One common method for forming supply ports is by crystal anisotropic etching. Here, when chemical etching using an alkaline solution is performed on a silicon wafer having crystal orientations of (100) plane and (110) plane from (100) plane and (110) plane, (111) plane The etching rate with respect to is extremely low with respect to other crystal planes. Therefore, the etching proceeds with selectivity depending on the crystal orientation, and anisotropy is obtained between the depth direction and the width direction of the etching.

  For example, when etching is started from the (100) plane for silicon having a crystal orientation of the (100) plane, the etching is started because the depth is geometrically determined by the width at which the etching is started. The width of the supply port can be controlled by the width. Specifically, an inner side surface that becomes narrower with an inclination of 54.7 ° in the depth direction from the etching start surface is obtained.

  Therefore, when the supply port is formed by etching the substrate from the back surface to the front surface, the supply port on the substrate surface is considered by considering the thickness of the substrate and the opening width of the supply port on the back surface of the substrate (back surface opening width). The opening width (surface opening width) can be controlled.

  As described above, it is necessary to form a large supply port in order to arrange a large number of ink flow paths at the same supply port, but more precisely, it is necessary to form a supply port having a wide surface opening width. . And it should be understood from the above description that in order to increase the front surface opening width, it is necessary to increase the back surface opening width beyond that. However, widening the opening width of the back surface, and the adhesion area between the recording head substrate and the supporting member that supports the recording head substrate are reduced, and defects such as color mixing with other color inks are likely to occur. Further, when the width of the supply port is widened, a large amount of silicon in the substrate can be removed by etching, so that the wall of the supply port becomes thin and the strength of the entire substrate is lowered. When the substrate strength decreases, the recording head substrate is likely to be deformed or warped due to a tensile stress or the like generated by another thin film laminated on the substrate.

  For these problems, Patent Document 2 discloses a method of widening the front surface opening width without increasing the back surface opening width. Specifically, a method of performing a two-stage etching process on a substrate is disclosed. In this method, the first etching is performed by crystal anisotropic etching, and the second etching is performed by dry etching, thereby forming the supply port having the first and second common liquid chambers. In dry etching, etching is performed perpendicularly to the substrate, so that the expansion of the opening width of the entire supply port can be suppressed.

Furthermore, in Patent Document 2, an independent supply port is formed by performing an etching process on a thin film on which an insulating layer made of TEOS, SiN, or SiC, a wiring such as TaAl or Al, or a heater member is formed. Is disclosed.
Japanese Examined Patent Publication No. 6-45242 US Pat. No. 6,534,247

  However, a thin film on which an insulating layer made of TEOS, SiN, or SiC, a wiring such as TaAl or Al, a heater member, or the like is formed is generally formed by a CVD method or a sputtering method. Therefore, each film thickness is 1 [μm] or less, and the total thickness is only a few [μm]. When an independent supply port is formed for such a thin film, since the strength of the film itself is insufficient, deformation or breakage may occur due to damage during dry etching or tensile stress from the upper layer resist.

  The present invention has been made in view of the above problems, and provides a recording head substrate in which a plurality of supply ports corresponding to each flow path and a common supply port that communicates with the supply ports are provided inside the substrate. For the purpose.

The recording head substrate manufacturing method of the present invention communicates with each of the first supply port to which the liquid is supplied, the plurality of second supply ports communicating with the first supply port, and each of the second supply ports. A plurality of channels, a plurality of outlets communicating with each channel, and a liquid supplied from the first supply port and distributed to each channel via each second supply port are discharged from each outlet. A recording head substrate having a plurality of energy generating elements that generate energy for generating the recording head substrate. In the manufacturing method of the recording head substrate of the present invention, the substrate is directed from the back side, which is the back side of the surface on which the energy generating element is provided, to the surface side, which is the side on which the energy generating element is provided. Then, a first etching step is performed in which etching is performed by crystal anisotropic etching halfway in the thickness direction to form a recess corresponding to the first supply port. Furthermore, using the structure corresponding to the pattern of the flow path formed on the surface of the substrate as the etching stop layer, etching the substrate from the bottom of the recess toward the substrate surface by dry etching until reaching the stop layer , A second etching step of forming a plurality of holes corresponding to the second supply port; Etching by dry etching is performed from a position apart from the intersection line between the bottom surface of the recess and the side surface of the recess among the bottom surface of the recess, and the second supply port is from the intersection line between the bottom surface of the recess and the side surface of the recess. It is formed at a spaced position.

  According to the present invention, both a plurality of supply ports corresponding to each flow path and a common supply port communicating with the supply ports are formed inside the substrate, and the recording head has high strength and is less likely to be deformed or warped. A substrate is realized.

Next, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 to FIG. 8 are schematic cross-sectional views showing the respective steps of the method for manufacturing a recording head substrate according to the present embodiment. Hereinafter, each step will be described in order.
(Ink channel forming process)
As shown in FIG. 1, a photo-disintegrating positive resist layer 2 is formed on the surface of a substrate 1 provided with an energy generation element (not shown). As the substrate 1, a substrate made of glass, ceramic, metal or the like on which an energy generating element for discharging a liquid (ink in this example) is used is used. As the energy generating element, an electric heat generating element, a piezoelectric element, or the like is used, but is not limited thereto. Further, when an electric heat generating element is used as the energy generating element, a protective film (not shown) may be formed for the purpose of mitigating impact during ink foaming or reducing damage from the ink.

  Examples of the resist coating method for forming the photodisintegrating positive resist layer 2 include a spin coating method, a direct coating method, and a laminate transfer method, but are not limited thereto. As the photodegradable positive resist, a resist having a photosensitive wavelength region near 290 [nm] such as polymethyl isopropenyl ketone (PMIPK) or polyvinyl ketone is generally used. Alternatively, a resist having a photosensitive wavelength region near 250 [nm] is used, such as a polymer compound composed of methacrylic acid ester units such as polymethyl methacrylate (PMMA). However, the photo-disintegrating positive resist is not limited to the resist.

  After forming the photodisintegrating positive resist layer 2, a predetermined region of the resist layer 2 is removed by a photolithography process including exposure and development processes to form an ink flow path pattern. Specifically, the photodisintegrating positive resist layer 2 is irradiated with ionizing radiation through a quartz mask 3 on which an ink flow path pattern is drawn. As the ionizing radiation, those containing a wavelength range around 290 [nm] or 250 [nm], which is a photosensitive wavelength range of a photo-disintegrating positive resist, are used. As a result, a main chain decomposition reaction occurs in the region of the photodisintegrating positive resist layer 2 irradiated with the ionizing radiation, and the solubility of the region in the developer is selectively improved. Therefore, the structure 4 corresponding to the ink flow path pattern can be formed by developing the photodisintegrating positive resist layer 2 irradiated with the ionizing radiation (see FIG. 2).

  The developer is not particularly limited as long as it is a solvent that dissolves the exposed area with improved solubility and does not dissolve the unexposed area. Generally, methyl isobutyl ketone or propylene glycol monomethyl ether acetate is used. It is possible to use. Further, from the viewpoint of preventing cracks during development, a glycol ether having 6 or more carbon atoms that can be mixed with water at an arbitrary ratio, a nitrogen-containing basic organic solvent, a developer containing water, and the like are preferably used. For example, as a developing solution for PMMA used as a resist in X-ray lithography, a developing solution having a composition disclosed in Japanese Patent Publication No. 3-10089 can be suitably used.

  Next, as shown in FIG. 2, a negative resist layer 5 for forming an ink flow path wall is formed on the photodisintegrating positive resist layer 2 (structure 4). As the negative resist for forming the negative resist layer 5, a resist utilizing a reaction such as cation polymerization or radical polymerization can be used, but is not limited thereto. Taking a negative resist using a cationic polymerization reaction as an example, the cations generated from the photocationic initiator contained in the negative resist cause a cation polymerizable monomer or polymer contained in the negative resist between the molecules. It hardens as polymerization and crosslinking proceed. Examples of the photocation initiator include aromatic iodonium salts and aromatic sulfonium salts, and specific examples include SP-170 and SP-150 (both trade names) manufactured by Asahi Denka Kogyo Co., Ltd.

  Further, as the monomer or polymer capable of cationic polymerization, those having an epoxy group, a vinyl ether group, or an oxetane group are suitable, but are not limited thereto. Examples include alicyclic epoxies such as bisphenol A type epoxy resin, novolac type epoxy resin, Aron Oxetane OXT-211 (trade name, manufactured by Toa Gosei Co., Ltd.), Celoxide 2021 (trade name, manufactured by Daicel Chemical Industries, Ltd.) Resin. Moreover, monoepoxides having a linear alkyl group such as AOE (trade name, manufactured by Daicel Chemical Industries, Ltd.) can also be mentioned. Furthermore, the polyfunctional epoxy resin described in Japanese Patent No. 3143308, for example, EHPE-3150 (trade name, manufactured by Daicel Chemical Industries, Ltd.), etc., exhibits very high cationic polymerizability, and has a high crosslinking density when cured. Indicates. Accordingly, a cured product having excellent strength can be obtained, which is particularly preferable as a resist for forming the negative resist layer 5.

  It is also preferable to include a glycol-based compound in the negative resist in order to improve coating properties such as film uniformity during coating film formation. Examples thereof include compounds such as diethylene glycol dimethyl ether and triethylene glycol methyl ether, but the present invention is not limited to these.

  By applying the negative resist as described above onto the photodegradable positive resist layer 2 (structure 4) by a method such as a spin coat method, a direct coat method, or a laminate transfer method, the negative resist layer 5 is formed. Form.

  Next, an ink repellent layer (not shown) is formed on the negative resist layer 5 as necessary. In this case, it is desirable that the ink repellent layer has a crosslinkable photosensitivity like the negative resist layer 5. It is also important that the negative resist layer 5 is not compatible. The ink repellent layer can be formed by a method such as a spin coating method, a direct coating method, or a laminate transfer method.

  Thereafter, as shown in FIG. 3, a hole 6 to be a discharge port 6a (FIG. 11) is formed in a predetermined portion of the negative resist layer 5 later. In this step, the negative resist layer 5 is irradiated with light after shielding the region that will later become the discharge port 6a (FIG. 11), and the non-shielded region of the negative resist layer 5 is cured. If an ink repellent layer is formed, the ink repellent layer is also cured at the same time. In any case, the hole 6 corresponding to the discharge port pattern is formed by developing after light irradiation. As the developing solution for the negative resist layer 5 and the ink repellent layer, the exposed portion can be completely removed without dissolving the exposed portion, and the photodisintegrating positive resist layer 2 disposed therebelow. A developing solution that does not dissolve is optimal. For example, methyl isobutyl ketone or a mixed solvent of methyl isobutyl ketone / xylene can be used.

The reason why it is necessary not to dissolve the photodisintegrating positive resist layer 2 is as follows. That is, in general, a plurality of recording head substrates are formed on a single wafer, and the recording head substrates are cut into individual pieces. The positive resist layer 2 is desirably dissolved and removed after the cutting step.
(First etching step (first supply port forming step))
Next, a first etching step is performed on the substrate 1 to form a first supply port (common supply port). Specifically, the substrate 1 is etched halfway in the thickness direction from the back side to the front side to form a common supply port. As an etching method for forming the common supply port, anisotropic etching, laser processing, dry etching and the like are generally used, but are not limited thereto.

  As an example, a method for forming a common supply port by anisotropic etching will be described on the assumption that the substrate 1 is a Si substrate having a specific crystal orientation. In order to perform crystal anisotropic etching, a Si substrate having a crystal orientation of (100) plane or (110) plane and parallel to the plane direction is used as the substrate 1. The thickness of the substrate 1 is selected in consideration of the strength required for the completed recording head substrate and the etching efficiency in anisotropic etching described later.

  First, as shown in FIG. 4, an etching resistant protective film 7 (for example, OBC (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd.) is formed on the negative resist layer 5 on the substrate surface.

  Thereafter, as shown in FIG. 5, an etching resistant film 8 is formed on the back surface of the substrate. As the material of the etching resistant film 8, a polyether amide resin having excellent resistance to an etching solution and a dry etching gas to be used later and having good adhesion to silicon oxide on the surface is preferably used. When using a polyether resin, there is a method in which a solvent is coated using an appropriate solvent, and the film is formed by heating to 60 to 350 [° C.], more preferably 320 to 350 [° C.] to volatilize the solvent. Available. According to the solvent method, a liquid polyetheramide resin can be easily and uniformly coated. The heating temperature during the film formation of the polyetheramide resin is preferably 230 [° C.] or higher, which is the glass transition temperature of the polyetheramide resin. Further, it is preferably 400 [° C.] or less, which is the temperature at which the polyetheramide resin is thermally decomposed. For example, HIMAL HL-1200 (trade name) manufactured by Hitachi Chemical Co., Ltd. can be used.

  Next, as shown in FIG. 6, a pattern corresponding to the common supply port 9 a (FIGS. 11 and 12) is formed in the etching resistant film 8. The patterning method can be selected according to the material of the etching resistant film 8. When a polyetheramide resin film is provided as the etching resistant film 8, a first photosensitive material is applied on the polyetheramide resin film, and a desired pattern is formed by exposure and development. Thereafter, the polyether amide resin film is etched using the first photosensitive material layer as an etching mask, and then the photosensitive material is removed.

  Next, as shown in FIG. 7, the substrate 1 is anisotropically provided halfway in the thickness direction of the substrate 1 through the etching resistant film 8 in which a pattern corresponding to the common supply port 9 a (FIGS. 11 and 12) is formed. Etching is advanced to form a recess 9 that will later become a common supply port 9a. As the anisotropic etching solution, an etching solution made of an aqueous solution of potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide or the like, which is an alkaline etching solution, is used. Further, by immersing in an etching solution while heating, it is possible to dissolve only an exposed portion that is not covered with the etching-resistant film 8 with anisotropy, whereby the common supply port 9a (FIGS. 11 and 12). ) Can be formed. In addition, although it is desirable to use crystalline anisotropic etching for wet etching, it is not limited to this.

In anisotropic etching, selectivity occurs in the progress of etching depending on the crystal orientation, and anisotropy is obtained between the depth direction and the width direction of the etching. Therefore, by adjusting the etching start width, Is determined geometrically. Therefore, by considering the thickness of the substrate 1 and the etching start width, the opening width W1 of the recess 9 on the substrate surface, that is, the width of the common supply port 9a (FIGS. 11 and 12) can be easily controlled. The opening width W2 of the recess 9 on the back surface of the substrate that is the etching start surface is selected according to the desired characteristics of the recording head substrate, the thickness of the substrate 1, and the like.
(Second etching step (second supply port forming step))
Next, a second etching step is performed on the substrate 1 to form a plurality of second supply ports (independent supply ports) communicating with the first supply port (common supply port).

  First, as shown in FIG. 8, an etching resistant film 10 is formed on the back surface of the substrate including the inner surface of the recess 9. As the material of the etching resistant film 10, a material that is excellent in resistance to an etching solution and a dry etching gas used later and that can be uniformly coated with a thin film on an inclined surface (inner surface of the recess 9) is preferable. . For example, novolak resin derivatives and naphthoquinonediazide derivatives are preferable materials. However, the material is not limited to a specific material as long as the material can form a thin film that functions as an etching-resistant film even with a thickness of several micrometers. For example, AZ-P4620 (trade name) manufactured by AZ Electronic Materials can be used.

  In addition, as a method for forming the etching resistant film 10, a film forming method such as a spin coating method, a dip coating method, or a spray coating method can be used, but the spray coating method is preferable from the viewpoint of coverage with an inclined surface. In the spray coating method, a uniform thin film can be formed on the inclined surface by spraying the etching resistant solution in a mist form. Furthermore, if the etching resistant film 10 is formed while the substrate 1 is heated, the solvent in the film forming material attached to the inclined surface evaporates instantaneously, thereby avoiding the occurrence of liquid dripping or pooling on the inclined surface. A more uniform etching resistant film 10 can be formed. The heating temperature of the substrate 1 is preferably 40 [° C.] to 120 [° C.]. At this time, a more uniform etching resistant film 10 is formed by controlling the spray amount, spray pressure, substrate heating temperature, baking temperature and time after spraying, and the like according to the vapor pressure, viscosity, dilution rate, etc. of the film forming material. can do.

  Next, as shown in FIG. 9, a pattern of independent supply ports 11 a (FIGS. 11 and 12) is formed in the etching resistant film 10. As a forming method, a second photosensitive material is applied on the etching resistant film 10, and the applied second photosensitive material is exposed and developed. For the exposure, proximity exposure, mirror projection exposure, or stepper exposure can be used. Furthermore, when developing a pattern, it can be immersed in a developing solution by a dipping method or a spray coating method. Further, when the concave portion 9 is about 500 [μm], a method of applying ultrasonic waves or a spray method is used in order to circulate the developer in the concave portion 9 so that the developer is uniformly touched in the surface. It is preferable.

  Thereafter, as shown in FIG. 10, etching is performed using the etching resistant film 10 as a mask to form the holes 11 corresponding to the independent supply port pattern. As the etching of the substrate 1, dry etching such as ECR, ICP, or RIE can be used. In order to form the hole 11 having a depth of 50 [μm] or more perpendicular to the substrate 1, it is preferable to use an ICP etcher composed of a Bosch process in which etching and deposition are repeated. At this time, an insulating layer made of TEOS, SiN, or SiC installed on the upper portion, a thin film on which wiring such as TaAl or Al, a heater member, or the like is laminated can be simultaneously etched. Etching can be completed using a previously formed resist layer as a stop layer. In this example, etching can be completed by using the photodisintegrating positive resist layer 2 (structure 4) constituting the ink flow path pattern as a stop layer.

  Next, the etching resistant film 10 is removed as necessary. At this time, the protective film 7 on the substrate surface side plays a role of protecting the photodisintegrating positive resist layer 2 (structure 4) and the ink repellent layer from the etching solution. However, the formation of the protective film 7 is not essential.

  Thereafter, the photodisintegrating positive resist layer 2 (structure 4) is removed through the hole 11 and the recess 9 communicating with the hole 11, and the hole 6 (FIG. 3), the hole 11 and the recess 9 are communicated. In this step, the photodisintegrating positive resist layer 2 (structure 4) is irradiated with ionizing radiation, and the photodisintegrating positive resist layer 2 (structure 4) undergoes a decomposition reaction, whereby the solubility in the removal liquid is increased. To improve. As the ionizing radiation, the same ionizing radiation as that used in the patterning of the photodisintegrating positive resist layer 2 (structure 4) can be used. However, since the purpose of this step is to form the ink flow path by removing the photodisintegrating positive resist layer 2 (structure 4), the entire surface of the ionizing radiation can be irradiated without passing through a mask. it can. Thereafter, the photodegradable positive resist layer 2 (structure 4) is completely removed using a developer similar to the developer used for patterning the photodegradable positive resist layer 2 (structure 4). It is possible. In this step, it is not necessary to consider the patterning property, and a solvent that can dissolve the photodisintegrating positive resist layer 2 (structure 4) and does not affect the negative resist layer 5 and the ink repellent layer can be used.

  Through the above steps, the recording head substrate shown in FIGS. 11 and 12 is completed. In the completed recording head, the hole 6 becomes the discharge port 6a, and the space after the photodisintegrating positive resist layer 2 (structure 4) is removed becomes the ink flow path 4a. In other words, the ink flow path wall is formed by the negative resist layer 5. Moreover, the said hole 11 becomes the independent supply port 11a as a 2nd supply port, and the said recessed part 9 becomes the common supply port 9a as a 1st supply port. The ink flow path 4 a extends in a direction parallel to the surface of the substrate 1, and each independent supply port 11 a extends in a direction orthogonal to the surface of the substrate 1. The liquid (ink in this example) supplied to the common supply port 9a is distributed to each ink flow path 4a via each independent supply port 11a. The distributed ink is ejected from each ejection port 6a by the energy generated by the energy generating element provided in a part (foaming chamber) of the ink flow path 4a. As shown in the drawing, the extending directions of the ink flow path 4a and the independent supply port 11a are orthogonal to each other. Due to the difference in the extending direction, the direction in which the ink flows in the ink flow path 4a is orthogonal to the direction in which the ink flows in the independent supply port 11a. In this example, the ink flow paths 4a and the short ink flow paths 4a having a relatively long overall length are alternately formed along the arrangement direction of the ejection ports 6a. Furthermore, the diameter of the ejection port 6a communicating with the ink channel 4a having a relatively short overall length is larger than that of the ejection port 6a communicating with the ink channel 4a having a long overall length.

  From the description so far and FIGS. 11 and 12, it can be seen that both the independent supply port 11 a and the common supply 9 a are formed inside the substrate 1. In this regard, in the manufacturing method described in Patent Document 2, a supply port corresponding to the independent supply port 11a is formed in a thin film different from the substrate. However, this thin film has a thickness of only a few [μm]. Therefore, there is a possibility that deformation or breakage may occur due to damage by the etching gas or stress from the laminated resist material.

  On the other hand, in the recording head substrate of the present invention in which both the independent supply port and the common supply are formed inside the substrate and the recording head substrate manufactured by the manufacturing method of the present invention, the substrate strength is high, and the manufacturing method described in Patent Document 2 The above-mentioned problems of the substrate manufactured by the above are solved.

  However, in order to stop the anisotropic etching in the substrate, an etching start width (corresponding to the opening width W2 shown in FIG. 7) necessary to obtain a desired etching end width (opening width W1 shown in FIG. 7) is conventionally set. The advantage of the manufacturing method described in Patent Document 2 that it can be made narrower is maintained. Therefore, not only the strength of the substrate is improved, but also the adhesion area between the substrate and the supporting member that supports the substrate is widened, the adhesion reliability is improved, and color mixing with other inks can be prevented.

  Further, the length of the wall of the independent supply port (depth of the independent supply port) is the same as the depth of digging the substrate by the second etching process, and the wall of the independent supply port is a silicon crystal that is a substrate material. It is constituted by. Therefore, it has sufficient strength even when compared with a conventional thin film subjected to vapor deposition.

  In other words, the strength of the wall of the independent supply port is proportional to the depth of digging by the second etching process on the substrate. That is, the strength of the independent supply port wall increases as the depth of excavation increases. However, the longer each individual supply port (the deeper), the greater the flow resistance that occurs when ink flows through the independent supply port. Further, since each independent supply port communicates with the ink flow path corresponding to each discharge port, it is necessary to form the same number of independent supply ports as the number of discharge ports, and the width of each independent supply port is limited. The In addition to the various circumstances described above, the present inventors have conducted extensive research in consideration of stress relaxation from the resist forming the ink flow path wall. ) Found the conclusion that: That is, the length in the extending direction of the ink channel (ink channel length (CH)) and the length in the extending direction of the independent supply port (independent supply port length (CC)) are (CH) <( CC).

In the embodiment of the present invention already described, the ink flow path length (CH) and the independent supply port length (CC) are defined so that the above relationship is established.
(Example 1)
In this example, the recording head substrate was manufactured by the manufacturing method according to the above embodiment.

  First, as a substrate 1 shown in FIG. 1 and the like, a silicon substrate on which an electrothermal conversion element (heater) as an energy generating element and a driver and a logic circuit for driving the element were prepared.

Next, polymethylisopropenyl ketone (trade name ODUR-1010, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was adjusted on the substrate 1 so as to have a resin concentration of 20 [wt%] and applied by spin coating. Then, pre-baking is performed at 120 [° C] for 3 minutes on a hot plate and then at 150 [° C] for 30 minutes in an oven purged with nitrogen, and a photodisintegrating positive resist layer having a film thickness of 15 [μm] 2 (FIG. 1 etc.) was formed. Next, on the photo-disintegrating positive resist layer 2, using a Deep-UV exposure apparatus UX-3000 (trade name) manufactured by Ushio Inc., 18000 [mJ Deep-UV light was irradiated at an exposure dose of / cm ² ]. After that, development is performed with a nonpolar solvent, methyl isobutyl ketone (MIBK) / xylene (Xylene) = 2/3 solution, and rinsing is performed using xylene. The ink flow path pattern (structure 4) shown was formed.

  Thereafter, a negative resist was applied on the structure 4 to form a negative resist layer 5 shown in FIG. A resist solution having the following composition was used for the negative resist.

・ EHPE-3150 (trade name, manufactured by Daicel Chemical Industries, Ltd.) 100 parts by weight ・ HFAB (trade name, manufactured by Central Glass Co., Ltd.) 20 parts by weight ・ A-187 (trade name, manufactured by Nihon Unicar Co., Ltd.) 5 parts by weight・ SP170 (trade name, Asahi Denka Kogyo Co., Ltd.) 2 parts by weight ・ Xylene 80 parts by weight More specifically, a resist solution having the above composition is applied by spin coating, and is applied at 90 [° C.] on a hot plate at 3 ° C. A negative resist layer 5 of 20 [μm] (on a flat plate) was formed by performing pre-baking for a minute. Further, an ink repellent layer (not shown) made of a resin having the following composition having photosensitivity was formed on the negative resist layer 5 by a laminating method.

・ EHPE-3150 (trade name, manufactured by Daicel Chemical Industries, Ltd.) 35 parts by weight ・ 2,2-bis (4-glycidyloxyphenyl) hexafluoropropane 25 parts by weight ・ 1,4-bis (2-hydroxyhexafluoroisopropyl) ) 25 parts by weight of benzene ・ 16 parts by weight of 3- (2-perfluorohexyl) ethoxy-1,2-epoxypropane ・ A-187 (trade name, manufactured by Nihon Unicar) 4 parts by weight ・ SP170 (trade name, Asahi 1.5 parts by weight • 200 parts by weight of diethylene glycol monoethyl ether Next, using a mask aligner MPA600FA (manufactured by Canon Inc.), through a mask on which the pattern of the discharge ports 6a (FIGS. 11 and 12) is drawn And pattern exposure with an exposure amount of 3000 [mJ / cm ² ].

  Next, PEB is performed at 90 [° C.] for 180 seconds, developed with a solution of methyl isobutyl ketone / xylene = 2/3, and rinsed with xylene to form the hole 6 shown in FIG. did.

  Next, a hole 9 serving as a common supply port 9a was formed on the back surface of the substrate 1 by a first etching process. First, OBC (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to the entire surface of the ink repellent layer to form the protective film 7 shown in FIG.

  Next, a polyetheramide resin (HIMAL (trade name) manufactured by Hitachi Chemical Co., Ltd.) was applied to the back surface of the substrate 1 to form an etching resistant film 8 shown in FIG.

Next, a photosensitive positive resist (OFPR-800 (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied on the entire surface of the etching resistant film 8 as a first photosensitive material. Furthermore, the shape (slit shape) of the common supply port 9a (FIGS. 11 and 12) was applied to the applied positive resist using a Deep-UV exposure apparatus UX-3000 (trade name) manufactured by USHIO INC. A pattern was formed. Next, using a mixed gas of CF ₄ and O ₂ , chemical dry etching was performed on the photosensitive positive resist to form a pattern of the common supply port 9a in the etching resistant film 8 (FIG. 6). That is, an etching mask corresponding to the shape of the common supply port 9a was formed.

  Next, anisotropic etching is performed on the substrate 1 by immersing it in an aqueous solution of tetramethylammonium hydroxide at 80 [° C.] using the etching resistant film 8 as an etching mask, and the recess 9 shown in FIG. Formed. In the anisotropic etching, the immersion time was calculated by calculating the etching rate so that the substrate 1 remained about 100 [μm]. Note that the etching resistant film 8 serving as an etching mask may be formed in advance when the substrate 1 is prepared.

  Next, the etching mask (etching resistant film 8) was removed. Thereafter, a photosensitive positive resist layer (etching-resistant film 10 shown in FIG. 8 and the like) was formed on the surface subjected to anisotropic etching using a spray coater (manufactured by Evey Group). As a photosensitive positive resist, AZ-P4620 (manufactured by AZ Electronic Materials (trade name)) was used. By applying while heating the substrate chuck so that the temperature of the substrate 1 is kept at 60 [° C.] at the time of spray coating, the photosensitive positive resist is uniformly applied to the inclined inner surface and the edge portion of the recess 9. Applied.

Next, the etching resistant film 10 was exposed through a mask of the supply port pattern with an exposure amount of [1000 mJ / cm ² ] using an exposure machine manufactured by Evey Group. Next, shower development was performed using an AZ-400K remover to form a fine independent supply port pattern in the etching resistant film 10 (FIG. 9). That is, an etching mask corresponding to the shape of the independent supply port 11a (FIGS. 11 and 12) was formed.

  Next, using the etching resistant film 10 as an etching mask, the substrate 1 is etched to the surface photodisintegrating positive resist layer 2 (structure 4) by a Bosch process using AMS200 (manufactured by ALCATEL). The hole 11 shown in FIG.

Next, after removing the protective film 7 with xylene, the entire surface is exposed with an exposure amount of 7000 [mJ / cm ² ] from above the ink repellent layer using a Deep-UV exposure device UX-3000 (trade name) manufactured by USHIO. The structure 4 forming the ink flow path pattern was solubilized. Thereafter, the structure 4 was removed by immersion in methyl lactate while applying ultrasonic waves.

  In addition, each pattern was formed so that the completed ink flow path 4a and the independent supply port 11a might become arrangement | positioning as shown in FIG.

When a recording head using the recording head substrate manufactured as described above was mounted on a printer and ejection and recording evaluation were performed, stable printing was performed, and the obtained printed matter was of high quality. .
(Comparative Example 1)
In order to confirm the effect of the present invention, a recording head substrate to be compared was manufactured as follows. The immersion time of the first etching process (anisotropic etching) in Example 1 was extended to form an opening reaching the substrate surface. Thereafter, an etching-resistant mask is formed on the back surface of the substrate including the inner surface of the opening in the same manner as in Example 1, and an independent supply port made of a thin film for forming an insulating film, wiring, or the like is formed by performing a dry etching process on the mask. Formed. The other steps are the same as in the first embodiment.

  In the recording head substrate manufactured as described above, deformation that appears to be caused by the stress of the negative resist forming the ink flow path wall was observed at the independent supply port made of the thin film.

It is typical sectional drawing which shows the state in which the photodisintegrating positive type resist layer was formed in the board | substrate surface side. It is typical sectional drawing which shows the state in which the structure and the negative resist layer were formed in the board | substrate surface side. It is typical sectional drawing which shows the state in which the hole corresponding to a discharge outlet was formed in the board | substrate surface side. It is typical sectional drawing which shows the state in which the protective film was formed in the board | substrate surface side. It is typical sectional drawing which shows the state in which the etching-resistant film was formed in the board | substrate back surface side. It is typical sectional drawing which shows the state in which the common supply port pattern was formed in the etching-resistant film. It is typical sectional drawing which shows the state after the 1st etching process was implemented with respect to the board | substrate. It is typical sectional drawing which shows the state in which the etching-resistant film was formed in the board | substrate back surface side. It is typical sectional drawing which shows the state in which the independent supply port pattern was formed in the etching resistant film. It is typical sectional drawing which shows the state after the 2nd etching process was implemented with respect to the board | substrate. FIG. 3 is a schematic cross-sectional view illustrating an example of an embodiment of a recording head substrate of the present invention. FIG. 2 is a schematic top view illustrating an example of an embodiment of a recording head substrate of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Photodisintegrating positive resist layer 4a Ink flow path 6 Hole 6a Ejection port 8, 10 Etching resistant film 9 Recess 9a Common supply port 11 Hole 11a Independent supply port

Claims (11)

A first supply port through which a liquid is supplied; a plurality of second supply ports communicating with the first supply port; a plurality of flow paths communicating with each of the second supply ports; A plurality of discharge ports communicating with the channel, and energy for discharging the liquid supplied from the first supply port and distributed to the flow paths via the second supply ports from the discharge ports A plurality of energy generating elements for generating a recording head substrate,
Crystal anisotropic from the back side, which is the back side of the surface on which the energy generating element is provided, to the middle of the thickness direction from the back side, which is the side on which the energy generating element is provided. A first etching step of forming a recess corresponding to the first supply port by etching by reactive etching;
Using the structure corresponding to the flow path pattern formed on the surface of the substrate as the etching stop layer, the substrate is dried from the bottom of the recess toward the surface of the substrate until the stop layer is reached. Etching by etching to form a plurality of holes corresponding to the second supply port, and
Etching by the dry etching is performed from a position apart from the intersection line between the bottom surface of the recess and the side surface of the recess, of the bottom surface of the recess, and the second supply port includes the bottom surface of the recess and the recess A method of manufacturing a recording head substrate, wherein the recording head substrate is formed at a position separated from a line of intersection with the side surface of the recording head substrate. In the first etching step, the first photosensitive material is applied to the back surface of the substrate, and the applied first photosensitive material is exposed and developed to form the first supply port. Forming a corresponding etching mask,
In the second etching step, a second photosensitive material is applied to the back surface of the substrate including the bottom surface of the concave portion, and the applied second photosensitive material is exposed and developed, 2. The method of manufacturing a recording head substrate according to claim 1, further comprising a step of forming an etching mask corresponding to the shape of the second supply port. Wherein in the second etching step, according to claim 1 or claim 2, wherein the performing etching using the resist layer which is previously formed on the surface of the substrate to form the flow path as the stop layer Manufacturing method of recording head substrate. Method of manufacturing a recording head substrate according to any one of claims 1 to 3 depth of etching by the first etching step is characterized in that deeper than the depth of etching by the second etching step. Method of manufacturing a recording head substrate according to any one of claims 1 to 4 the depth of etching by the second etching step is characterized in that it is 50 [[mu] m] or more.   3. The method of manufacturing a recording head substrate according to claim 2, wherein the second photosensitive material is applied by spray coating. The method of manufacturing a recording head substrate according to claim 6, wherein the second photosensitive material is applied while heating the substrate. 8. The method of manufacturing a recording head substrate according to claim 7, wherein the second photosensitive material is applied while the substrate is heated to 40 [° C.] to 120 [° C.]. The back surface of the substrate, method of manufacturing a recording head substrate according to any one of claims 1 to 8, wherein the crystal orientation is (100) plane. The direction in which the liquid flows in the flow path and the direction in which the liquid flows in the second supply port are orthogonal to each other, and the length of the second supply port in the direction in which the liquid flows is to be longer than the length in the flow direction the liquid in the flow path, to any one of claims 1 to 9, characterized in that to form the said plurality of flow passages said second supply port The manufacturing method of the recording head board | substrate of description. The plurality of channels are composed of a plurality of channels having different lengths in the flow direction of the liquid,
For all of the plurality of flow paths, the length of the second supply port in the flow direction of the liquid is longer than the length of the flow path in the flow direction of the liquid. method of manufacturing a recording head substrate according to claim 1 0, characterized by forming said a road second feed port.

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