JP2005186360A - Element substrate for liquid discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an element substrate for a liquid discharge head which can eliminate a deformation such as a warpage of the substrate and simplify a manufacturing process for the element substrate. <P>SOLUTION: In this element substrate 1 for a liquid discharge head, the element substrate 1 with a plurality of heating resistors 5a is plurally formed on a metallic substrate 2, then this metallic substrate 2 is cut along a cutting line 9 and thereby, so many discrete pieces of the element substrate 1 are obtained. In addition, a regenerative layer 4 which effectively transfers a heat energy generated by each heating resistor 5a to a recording liquid by inhibiting the emission of the heat energy from the metallic substrate 2, is segmentally coated per element substrate 1 along the cutting line 9 instead of coating the layer 4 across the entire surface of the metallic substrate 2. Consequently, the substrate 1 is free from any deformation such as a warpage of the substrate 1 by minimizing a total stress on each area, so that a stress correction coating film need not be formed on the back of the substrate 1 as is the case with a conventional element substrate. Thus the process simplification and the curtailment of working time/material cost can be achieved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an element substrate for a liquid discharge head that performs recording on a recording medium by discharging liquid as droplets from a fine discharge nozzle.

  A liquid discharge head used in a liquid discharge recording method (inkjet method) is positioned in a plurality of liquid flow paths that constitute a plurality of fine discharge nozzles (orifices) for discharging a liquid such as ink and in each liquid flow path. Liquid by applying a drive signal corresponding to the recording information to the discharge energy generating element and applying the discharge energy to the liquid in the liquid flow path where the discharge energy generating element is positioned. Is ejected as flying droplets from a fine ejection nozzle, and recording is performed on a recording medium.

  Among these types of liquid discharge heads, a liquid discharge head that discharges liquid using thermal energy has a plurality of heating resistors (electrothermal conversion elements) as discharge energy generating elements and a plurality of discharge nozzles arranged at high density. Therefore, it is possible to perform recording at a high resolution, and it is advantageous in that it can be easily downsized. A liquid discharge head using this type of thermal energy uses a substrate in which a plurality of heating resistors are arranged in a line at a high density and a common heat storage layer or insulating layer is laminated on the plurality of heating resistors. The configuration is common.

A typical configuration example of such a liquid discharge head is schematically shown in FIG. In FIG. 3, reference numeral 102 denotes a metal substrate such as aluminum, 103 denotes an inorganic film such as SiO _2, or an insulating layer formed of a heat-resistant resin such as polyimide or polyether amide, and 104 denotes a heat energy of the metal substrate. The heat storage layer is formed on the insulating layer 103 in order to prevent it from being discharged through the heat storage layer 102. On the heat storage layer 104, a plurality of heat generating resistor layers 105 and these heat generating resistor layers 105 are provided. An electrode wiring layer 106 and the like for supplying electric power to each are arranged. Further, an element substrate 101 is manufactured by laminating an electric insulating layer 107 and a protective layer 108 thereon, and a top plate member 110 having a liquid flow path 109 constituting a discharge nozzle is provided on the element substrate 101. A liquid discharge head is configured.

  As described above, in the element substrate 101 on which the plurality of heating resistors formed by the heating resistor layer 105 and the electrode wiring layer 106 are arranged, the thermal energy for discharging the liquid generated by the heating resistor passes through the substrate 102. As a means for efficiently transferring thermal energy to the liquid in the liquid flow path 109, the heat storage layer 104 has a heating resistor as a means of preventing the discharge energy from being lowered and inferior printing quality from being released. Is provided on the entire surface of the substrate 102. The material of the heat storage layer 104 is not particularly limited as long as it is an insulator and has a large heat capacity. The heat storage layer 104 minimizes the release of heat energy through the substrate 102 and efficiently converts the heat energy into a liquid. So that it can be supplied.

It should be noted that a process by vacuum film formation is usually indispensable for the production of the element substrate of the liquid discharge head, and the formation of a heat storage layer is no exception. That is, the heat storage layer is usually formed on the entire surface of the substrate using sputtering, CVD (chemical vapor deposition), or the like.
JP-A-5-338174

By the way, in the above-described prior art and the like, a plurality of element substrates are formed on one substrate, and finally, each element substrate is cut along a cutting line of the substrate to cut out individual liquids. An element substrate for a discharge head is manufactured. For this reason, the substrate size naturally increases. In addition, since the heat storage layer is formed on the entire surface of the substrate having a large area, and a high-stress SiO ₂ film, SiN film, SiON film, or the like is used as the heat storage layer, the substrate is the sum of the large area and the high stress. The apparatus is greatly warped and deformed, and there has been a problem that the apparatus used in the subsequent process for manufacturing the liquid discharge head is not compatible with the apparatus, such as being unable to hold the substrate by suction.

  In order to avoid this problem, it has been essential to balance the stress by forming the same film on the back surface of the substrate with the same film thickness. In this way, forming the same film on the back surface of the substrate to correct the deformation of the substrate due to the film stress of a large area requires the material, processing time, labor cost for that, and leads to high cost, It took a double effort.

  Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and is a liquid ejection that can eliminate the deformation of the substrate and the like, and can simplify the manufacturing process of the element substrate. An object of the present invention is to provide a head element substrate.

  In order to achieve the above object, the element substrate for a liquid discharge head according to the present invention has a plurality of heating resistor arrays for generating thermal energy for discharging a liquid formed on the substrate and the thermal energy generated by each heating resistor. Forming a heat storage layer on the substrate for efficiently transferring the liquid to the liquid, and forming the element substrate for a liquid discharge head on the substrate by separating the plurality of element substrates by cutting the substrate. The heat storage layer is provided separately for each element substrate.

  In the element substrate for a liquid discharge head according to the present invention, it is preferable that the heat storage layer is divided by a cutting line for separating the heat storage layer into individual element substrates by cutting the substrate.

  In the element substrate for a liquid discharge head according to the present invention, it is preferable that the heat storage layer is provided only corresponding to a region where the heating resistor is formed.

  According to the element substrate for a liquid discharge head of the present invention, a plurality of element substrates are formed with a heat storage layer for suppressing the release of heat energy generated by the heating resistor from the substrate and efficiently transmitting the heat energy to the liquid. When forming on a substrate to be embedded, by providing each element substrate separately, stress can be reduced, and deformation such as warpage of the substrate can be suppressed to a level that does not cause any problem in flowing the substrate to a subsequent process. be able to. Further, unlike the prior art, it is not necessary to provide a stress correction film on the back surface of the substrate, the process can be simplified, the processing time and material cost can be reduced, and the cost can be reduced.

  Furthermore, in a long element substrate, by providing a heat storage layer only under the heating resistor, stress can be reduced and deformation of the substrate can be suppressed.

  Further, when cutting out each element substrate from the substrate, the life of the cutting blade can be extended by not providing the heat storage layer on the cutting line of the substrate, and the cost can be reduced also from this aspect.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram for explaining a liquid discharge head element substrate according to an embodiment of the present invention. FIG. 1A is a schematic plan view before cutting out a plurality of element substrates. (B) is sectional drawing which fractures | ruptures and shows the state in which the thermal storage layer of the element substrate was formed along the AA line of (a), The same (c) is the AA line of (a). It is sectional drawing of the element substrate shown broken along.

In FIGS. 1A to 1C, reference numeral 2 denotes a metal substrate such as aluminum. On the metal substrate 2, a plurality of liquid discharge head element substrates 1 each having a heating resistor array are fabricated. These element substrates 1 are finally cut out along the cutting lines 9 and separated into individual element substrates 1. Reference numeral 3 denotes an insulating layer in which SiO ₂ is formed on the entire surface of the metal substrate 2, and this insulating layer 3 electrically completely insulates the metal substrate 2 from the heating resistor layer 5 and the electrode wiring layer 6 to be formed later. The thinner the film thickness, the better from the viewpoint of stress. Reference numeral 4 denotes a heat storage layer for preventing heat energy from being released through the metal substrate 2 and suppressing heat leakage. This heat storage layer 4 is formed after the insulating layer 3 is formed, as shown in FIG. (A) thru | or (c), it forms so that it may be divided | segmented by the cutting line 9, ie, it may not form into a film in the part of the cutting line 9. As shown in FIG. Such a heat storage layer 4 can be formed by covering the portion of the cutting line 9 with a metal mask and forming a heat storage layer on the portion other than the cutting line 9 by sputtering or the like (so-called mask deposition). . As described above, the heat storage layer 4 in the present embodiment is not provided on the entire surface of the metal substrate 2 but is provided separately for each element substrate 1. The heat storage layer 4 is provided in order to suppress heat leakage, and the film thickness is desirably 2 μm or more. The material and film thickness of the heat storage layer can be determined according to desired characteristics, and the most commonly used materials include SiO ₂ , SiN, SiON, etc., and the film thickness depends on the material. Since it changes, it is necessary to set individually according to the application.

  In FIG. 1C, reference numeral 5 denotes a heating resistor layer for forming the heating resistor 5a serving as an ejection energy generating element, and 6 denotes an electrode wiring layer for supplying electric power to each heating resistor 5a. These are formed by sequentially forming a film and patterning each by a photolithography process. Reference numerals 7 and 8 denote an insulating layer and a protective layer which are laminated so as to electrically isolate and protect the plurality of heating resistors 5a formed by the heating resistor layer 5 and the electrode wiring layer 6.

  Next, the element substrate for a liquid discharge head according to the present embodiment will be described more specifically along the manufacturing process.

First, an insulating layer 3 is formed by depositing SiO ₂ with a thickness of 500 mm on the entire surface of an aluminum metal substrate 2 having a size of 300 mm × 200 mm and a thickness of 3.5 mm. The insulating layer 3 is preferably thin from the viewpoint of stress because the metal substrate 2 and the wiring to be formed later only need to be completely electrically insulated. Further, the film thickness of about 500 mm is a level with no particular problem from the viewpoint of warping (deformation) of the substrate. The film formation of SiO ₂ is not limited to sputtering, and may be a CVD method, and is not particularly limited as long as insulation performance is obtained.

Then, after forming the SiO ₂ film as the insulating layer 3, forming a SiO ₂ as a heat storage layer 4. This heat storage layer 4 is not provided on the entire surface of the substrate 2 but is divided by a cutting line 9 of the substrate 2 for cutting out each element substrate 1 as shown in FIGS. 1 (a) and 1 (b). In other words, it is formed so that no film is formed on the portion of the cutting line 9. The portion of the cutting line 9 is covered with a metal mask, and a heat storage layer is formed on the portion other than the portion of the cutting line 9 by sputtering (so-called mask deposition is performed). A state in which the heat storage layer 4 is thus formed is illustrated in FIG. The method for forming the heat storage layer 4 is not particularly limited as in the case of the insulating layer 3. The heat storage layer 4 is provided to suppress heat leakage, and is set to a film thickness of 3 μm in the present embodiment. As the heat storage layer 4, in addition to SiO _2, SiN, can be used such as SiON, a thickness is to be set individually by the heat capacity of the material.

  Thereafter, a plurality of heating resistor layers 5 for forming the heating resistors 5a and a plurality of electrode wiring layers 6 for supplying power to the heating resistors 5a are sequentially formed, and each pattern is formed by a photolithography process. As a result, the heating resistor 5a is formed. Thereafter, an insulating layer 7 and a protective layer 8 are appropriately formed on the plurality of heating resistor layers 5 and the electrode wiring layer 6. This state is illustrated in FIG.

  After a plurality of element substrates 1 are produced on the substrate 2 in this way, each element substrate 1 is cut by cutting with a cutting blade (not shown) along the cutting line 9 of the substrate 2 and cutting each element substrate 1. can get. Thereafter, a top plate member having a liquid flow path as shown by a two-dot chain line in FIG. 1C is provided for each element substrate 1 to complete a liquid discharge head.

  As described above, in the plurality of element substrates 1 manufactured on the metal substrate 2, the heat storage layer 4 is divided at the cutting line 9, so that the area of the heat storage layer 4 can be reduced and divided. In addition, the total stress in each area can be kept small. Therefore, the heat storage layer 4 can be formed at a level at which deformation such as warpage of the substrate does not occur.

  As a result, in the manufacturing process of the liquid discharge head, it is possible to prevent the substrate holding due to suction, which has been a problem in the past when flowing the substrate in the subsequent process, from becoming defective, and to flow without causing trouble in the manufacturing process. Thus, the heating resistor layer, the electrode wiring layer, and the like can be formed with high yield. At the same time, since it is not necessary to form a stress correction film on the back surface of the substrate, the manufacturing process can be simplified, the material can be reduced, and the film formation cost can be reduced. Moreover, since the heat storage layer is not provided on the cutting line of the substrate, the cutting blade used for cutting each element substrate is not damaged, and the life of the cutting blade can be extended.

  Next, a liquid discharge head element substrate according to another embodiment of the present invention will be described with reference to FIGS.

  FIG. 2 is a view for explaining an element substrate for a liquid discharge head according to another embodiment of the present invention. FIG. 2 (a) is a schematic plan view before cutting out a plurality of element substrates. The same (b) is sectional drawing which fractured | ruptures and shows the state which formed the thermal storage layer of the element board | substrate along the BB line of (a), (c) is the BB line of (a). It is sectional drawing of the element substrate shown fractured | ruptured along.

  In the present embodiment, the heat storage layer is provided only under the region of the heating resistor of the element substrate. With this configuration, the area of the heat storage layer can be extremely small, and the element substrate is long. This is particularly effective for the scale.

In FIGS. 2A to 2C, reference numeral 12 denotes a metal substrate such as aluminum having a size of about 200 mm × 300 mm and a thickness of 3.5 mm. Each of the metal substrates 12 has a heating resistor array. A plurality of long element substrates 11 are produced, and these element substrates 11 are finally cut out along a cutting line 19 and separated into individual long element substrates 11. Reference numeral 13 denotes an insulating layer in which SiO ₂ is formed on the entire surface of the metal substrate 12 with a film thickness of 500 mm. This insulating layer 13 electrically connects the metal substrate 12 and the heating resistor layer 15 and the electrode wiring layer 16 to be formed later. It is preferable that the film thickness is thinner from the viewpoint of stress. Reference numeral 14 denotes a heat storage layer for preventing thermal energy from being released through the metal substrate 12, and is provided only under the region where the heating resistor 15a is formed. In the present embodiment, SiN is used as the heat storage layer 14 and is formed to a thickness of 1.5 μm by the CVD method. In forming the heat storage layer 14, mask deposition is performed so that the heat storage layer 14 is formed only below the formation region of the heating resistor 15a. In other words, a mask obtained by etching a metal into a slit shape was used, and the size of the slit was 500 μm × 260 mm. Since the heat storage layer 14 formed in this way is provided only below the region where the heating resistor 15a is formed, even if it is 260 mm long, the total stress does not increase so much, and the substrate warps (deforms). ) Is at a level that does not cause any problems in the subsequent processes.

  In FIG. 2C, reference numeral 15 denotes a heating resistor layer for forming the heating resistor 15a serving as an ejection energy generating element, and 16 denotes an electrode wiring layer for supplying power to each heating resistor 15a. These are sequentially formed, and each is formed by patterning by a photolithography process. 17a and 17b are insulating layers for electrically separating the plurality of heating resistor layers 15 and the electrode wiring layers 16 and the plurality of heating resistors 15a, and 18 is for protecting the heating resistor layers 15 and the electrode wiring layers 16. It is a protective layer.

  After the plurality of element substrates 11 are formed on the metal substrate 12, each element substrate 11 is obtained by cutting each element substrate 11 by cutting with a cutting blade (not shown) along the cutting line 19 of the metal substrate 12. It is done. Then, by providing a top plate member having a liquid flow path (not shown) for each element substrate 11, a liquid discharge head is completed.

  In the liquid discharge head element substrate of the present embodiment formed in this way, the heat storage layer 14 is provided only in the region where the heating resistor 15a is formed. Is not so large, and warping (deformation) of the substrate does not become a problem in the subsequent process. A substrate manufactured in this manner can smoothly flow through the subsequent steps without forming a stress correction film on the back surface of the substrate, and can form a heating resistor layer, an electrode wiring layer, and the like with high yield. As in the above-described embodiment, the film formation cost can be reduced by simplifying the manufacturing process, reducing the material, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the element substrate for liquid discharge head by one embodiment of this invention, (a) is a schematic plan view before cutting out several element substrate, (b) is an element substrate. It is sectional drawing which fractures | ruptures and shows the state in which the thermal storage layer was formed along the AA line of (a), (c) is a cross section of the element substrate shown fractured along the AA line of (a) FIG. FIG. 5 is a diagram for explaining an element substrate for a liquid discharge head according to another embodiment of the present invention, wherein (a) is a schematic plan view before cutting out a plurality of element substrates, and (b) is an element substrate. It is sectional drawing which fractures | ruptures and shows the state in which the thermal storage layer of (a) was formed along the BB line of (a), (c) of the element substrate shown to fracture | rupture along the BB line of (a) It is sectional drawing. It is a fragmentary sectional view showing a part of a conventional element substrate for a liquid discharge head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 (For liquid discharge heads) Element substrate 2 Metal substrate 3 Insulating layer 4 Thermal storage layer 5 Heating resistor layer 5a Heating resistor 6 Electrode wiring layer 7 Insulating layer 8 Protective layer 9 Cutting line 11 (For liquid discharge head) Element substrate 12 Metal substrate 13 Insulating layer 14 Heat storage layer 15 Heating resistor layer 15a Heating resistor 16 Electrode wiring layer 17a, 17b Insulating layer 18 Protective layer 19 Cutting line

Claims (3)

A plurality of heating resistor arrays that generate thermal energy for discharging liquid are formed on the substrate and a heat storage layer is formed on the substrate to efficiently transmit the thermal energy generated by each heating resistor to the liquid, In an element substrate for a liquid discharge head constituted by separating the plurality of element substrates individually by cutting the substrate,
The element substrate for a liquid discharge head, wherein the heat storage layer formed on the substrate is provided separately for each element substrate.   2. The element substrate for a liquid discharge head according to claim 1, wherein the heat storage layer is divided by a cutting line for separating the heat storage layer into individual element substrates by cutting the substrate.   2. The element substrate for a liquid discharge head according to claim 1, wherein the heat storage layer is provided only corresponding to a region where the heating resistor is formed.

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