JP2005186622A - Heating resister, substrate for liquid ejection head, having the heating resister, liquid ejection head, and manufacturing method for liquid ejection head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating resister and the like, which can bring about a high-quality recorded image over a long period of time. <P>SOLUTION: The heating resistor 1005, which is provided in the liquid ejection head for ejecting a liquid from an ejection port by using thermal energy, is composed of FeSiN which comprises 15-30 at% Fe, 35-60 at% Si and 10-50 at% N, based on a composition ratio, and wherein the composition ratio of Fe, Si and N reaches 100 at% or approximate 100 at%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a liquid that records or prints characters, symbols, images, and the like by ejecting a functional liquid such as ink onto a recording medium including paper, plastic sheets, cloth, articles, and the like. The present invention relates to a heat generating resistor of a discharge head (hereinafter also referred to as “inkjet head” or “recording head”), a liquid discharge head substrate having the heat generating resistor, a liquid discharge head, and a method for manufacturing the same.

  An ink jet recording apparatus using this type of ink jet head (recording head) has a feature that a high-definition image can be recorded at high speed by ejecting ink as fine droplets from an ejection port at high speed. doing. In particular, an electrothermal converter is used as an energy generating means for generating energy used for ejecting ink, and ink is ejected using the foaming of ink generated by the thermal energy generated by the electrothermal converter. In recent years, the inkjet recording apparatus has attracted attention because it is suitable for high-definition and high-speed recording of images, and miniaturization and colorization of recording heads and recording apparatuses (see, for example, Patent Document 1 and Patent Document 2). .

  FIG. 1 is a schematic plan view showing a general configuration of a main part of a substrate of a recording head used for ink jet recording as described above. FIG. 2 is a schematic cross-sectional view of the ink jet recording head substrate 2000 cut along the line XX ′ corresponding to the ink flow path of FIG.

  As shown in FIG. 1, the inkjet recording head is provided with a plurality of ejection ports 1001, and an electrothermal conversion element 1002 that generates thermal energy used to eject ink from each ejection port 1001. Each ink channel 1003 is provided on the substrate 1004. The electrothermal conversion element 1002 mainly includes a heating resistor 1005, an electrode wiring 1006 for supplying power to the heating resistor 1005, and an insulating film 1007 for protecting them.

  Each ink flow path 1003 is a substrate in which a top plate on which a plurality of flow path walls 1008 are integrally formed is aligned with the electrothermal conversion element 1002 and the like on the substrate 1004 by means of image processing or the like. It is formed by bonding to 1004. Each ink channel 1003 has an end opposite to the ejection port 1001 communicating with the common liquid chamber 1009, and ink supplied from an ink tank (not shown) is stored in the common liquid chamber 1009. .

  The ink supplied to the common liquid chamber 1009 is guided to each ink flow path 1003 from here, and is held in the vicinity of the ejection port 1001 by forming a meniscus. At this time, by selectively driving the electrothermal transducer 1002, the ink on the heat acting surface is rapidly heated and boiled using the generated thermal energy, and the ink is ejected by the impact force generated at that time. .

  Referring to FIG. 2, an ink jet recording head substrate 2000 includes a silicon substrate 2001, a heat storage layer 2002 made of a thermal oxide film, an interlayer film 2003 made of an SiO film or SiN film that also functions as a heat storage function, a heating resistance layer 2004, Al, Protecting the protective film 2006 from chemical and physical shocks caused by heat generation of the metal wiring 2005 made of Al-Si, Al-Cu, etc., the protective layer 2006 made of SiO film, SiN film, etc., and the heating resistance layer 2004 The anti-cavitation film 2007 is laminated. On a part of the upper surface of the ink jet recording head substrate 2000, a heat acting portion 2008 of the heating resistance layer 2004 is formed.

A heating resistor used for such a recording head is required to have the following characteristics.
(1) It has excellent thermal responsiveness and can eject ink instantaneously.
(2) The resistance value change is small with respect to the driving operation performed at high speed and continuously, and the foaming state of the ink can be stabilized.
(3) Excellent heat resistance and thermal stress, long life and high reliability.

  As a heating resistor that satisfies these requirements, Patent Document 3 discloses a configuration in which TaN is used as a material for the heating resistor.

Characteristics stability of TaN film constituting the heating resistor, in particular the rate of change in resistance when subjected to long-term repeated recording operation there is a strong correlation between the composition of the TaN film, a tantalum nitride containing among others TaN _{0.8 hex} The configured heating resistor has a low resistance change rate when repeated recording operations are performed over a long period of time, and has excellent ejection stability.

  By the way, as described above, in recent years, in an ink jet recording apparatus, higher functions such as high image quality and high speed recording have been increasingly required.

  Among these, for high image quality, it is possible to improve image quality by reducing the size of the heater (heating resistor) and making it smaller (reducing the discharge amount per dot). It is. For high-speed recording, high-speed recording can be realized by driving the heater with a shorter pulse than before and increasing the drive frequency.

  However, the sheet resistance value of the heater (heating resistor) needs to be increased in order to drive the heater at a high frequency with a configuration in which the heater size is reduced in order to cope with higher image quality as described above.

  FIG. 3 is a diagram for explaining the relationship between various driving conditions depending on the difference in heater size. FIG. 3A shows the relationship between the sheet resistance value and current value of the heating resistor with respect to the driving pulse width when the heater size is changed from large (A) to small (B) when the driving voltage is constant. Show. FIG. 3B shows the sheet resistance value and current value of the heating resistor with respect to the drive voltage when the heater size is changed from large (A) to small (B) when the drive pulse width is constant. Showing the relationship. 3A and 3B, the solid line indicates the sheet resistance value, and the broken line indicates the current value.

As can be seen from FIG. 3, in order to drive the heater under the same conditions as before when the heater size is reduced, it is necessary to increase the sheet resistance value. In addition, in terms of energy, the method of driving by increasing the sheet resistance value and increasing the driving voltage reduces the current value, so that energy saving can be achieved. In particular, in the case of a configuration in which a plurality of heating resistors are arranged, the effect is increased.
U.S. Pat. No. 4,723,129 U.S. Pat. No. 4,740,796 JP 07-125218 A

However, the specific resistance value of HfB ₂ , TaN, TaAl, TaSiN or the like conventionally used for the material of the heating resistor of the ink jet recording head as described above is about 200 to 800 [μΩ · cm]. Considering the stable production of the heating resistor and the stability of the liquid ejection characteristics, the thickness of the heating resistor that can be formed is limited to about 400 mm, and when the above materials are used, The limit of the sheet resistance value obtained is about 200 [Ω / □]. Therefore, it is difficult to obtain a sheet resistance value higher than that using the above materials.

  For these reasons, conventionally, there has been no heat generating resistor for an ink jet recording head that has excellent thermal responsiveness by short pulse driving and has a high sheet resistance value. Furthermore, if the heater size is reduced and small ink droplets are ejected in order to increase the definition of the recorded image, the current value increases when a conventional heating resistor is used, resulting in increased heat generation. As a result, energy consumption increases.

  SUMMARY OF THE INVENTION The main object of the present invention is to solve the problems described above with respect to a heating resistor provided in a conventional liquid discharge head, and to obtain a high-quality recorded image over a long period of time. An object of the present invention is to provide a liquid discharge head substrate, a liquid discharge head, and a manufacturing method thereof.

  Another object of the present invention is to reduce the size of the ejected liquid droplets in order to achieve high definition of the recorded image, and to perform liquid droplets even when high speed driving is performed to achieve high speed recording. It is an object to provide a heating resistor, a liquid discharge head substrate having the heating resistor, a liquid discharge head, and a method for manufacturing the same.

  As described above, the heater (heating resistor) for the inkjet head is required to have a higher resistance. The fastest way to increase the resistance of the heating resistor is to apply a new material capable of realizing it to the heating resistor. Therefore, the present inventors have conducted literature surveys such as academic reports, technical books, and other reports. As a result, when a heating resistor is configured using a material such as CrSiN or CrSiON, the heating resistor can be increased in resistance and heat can be generated. It came to know that resistance could be given durability. And when the characteristics (high resistance and durability) of these materials were evaluated, the results were very good, so we have already made proposals for configuring heating resistors using materials such as CrSiN or CrSiON. Yes.

  By the way, the above-mentioned materials that are excellent for application to heaters for inkjet heads can be summarized as follows. A material system in which nitrogen is bonded to metal silicide, such as TaSiN and CrSiN, is used as a material for such heaters. It turns out that it is excellent. From these viewpoints, as a result of further investigation on the physical properties such as specific resistance of the metal silicide, it has been predicted that FeSi is excellent as a heater material for an ink jet head.

β-FeSi ₂ has an orthorhombic crystal structure, and its specific resistance is 1000 [μΩ · cm]. Thus, the specific resistance of β-FeSi ₂ is very large even as a metal silicide alone, and there is a possibility that the specific resistance can be further increased by bonding nitrogen to this material. However, it is necessary to check whether such materials have the desired durability. Therefore, an FeSiN film was actually formed using an FeSi target, and its characteristics were evaluated. FIG. 4 is a graph showing the results of evaluating the characteristics.

  The graph of FIG. 4 represents the correlation between the nitrogen partial pressure and the specific resistance when the FeSiN film is formed by sputtering. As can be seen from this graph, the specific resistance of the FeSiN film is about 2000 [μΩ · cm] when the nitrogen partial pressure is 5%, and the specific resistance can be increased by increasing the nitrogen partial pressure. is there. Further, when the TCR (resistance temperature coefficient) of the film formed at a nitrogen partial pressure of 12.5% was evaluated, it was found to be as small as about +90 [ppm / ° C.]. From these facts, it was found that the FeSiN film is very excellent in durability even when the specific resistance is high.

  Therefore, in order to achieve the above object, the heat generating resistor of the present invention is a heat generating resistor provided in a liquid discharge head that discharges liquid from a discharge port using thermal energy. Fe is 15 to 30 at% and Si is 35. It is characterized by having a composition ratio of ˜60 at% and N of 10 to 50 at%, and these are 100 at% or almost 100 at%.

  The heating resistor of the present invention has a positive TCR characteristic and a very small value, so that it can maintain a desired durability even when driven with a short pulse width. Moreover, according to the said structure, the sheet resistance value of a heating resistor becomes comparatively large.

  The substrate for a liquid discharge head according to the present invention is a substrate for a liquid discharge head provided with a heating resistor that generates thermal energy used for discharging a liquid from a discharge port. It has a composition ratio of ˜30 at%, Si of 35 to 60 at%, and N of 10 to 50 at%, and these are 100 at% or almost 100 at%.

  In addition, this heat generating resistor thin film contains other elements in the extent of traces other than the above-mentioned atoms, that is, the total amount of Fe, Si and N is almost 100 as long as the desired characteristics are not impaired. %. For example, the ratio of the total number of atoms of Fe, Si and N (Fe + Si + N) to the total number of atoms constituting the material is preferably 99.5 atomic% or more, and more preferably 99.9 atomic% or more.

  That is, the surface and the inside of the thin film sometimes take in the gas in the reaction region, but the effect is not reduced by the incorporation of a small amount of gas such as Ar on the surface or inside. Examples of such impurities include at least one element selected from C, B, Na, and Cl, including Ar.

  The liquid discharge head of the present invention includes a discharge port for discharging a liquid, a plurality of heating resistors of the present invention that generate thermal energy used to discharge the liquid, and the heating resistor. A liquid flow path communicating with the discharge port.

  Since the liquid discharge head of the present invention includes the heating resistor of the present invention that can maintain the desired durability even when driven with a short pulse width, it provides a high-quality recorded image over a long period of time. Is possible. Further, the heating resistor of the present invention has a relatively large sheet resistance value, and is suitable for reducing the size of the ejected droplets in order to achieve high definition of the recorded image. Therefore, heat generation can be suppressed when high-speed driving is performed in order to realize high-speed recording, and it is possible to stably discharge droplets while improving energy efficiency.

  The method of manufacturing a liquid discharge head according to the present invention is a mixed gas composed of nitrogen gas, oxygen gas, and argon gas, which generates the thermal energy used for discharging the liquid. The method includes a step of forming by reactive sputtering in an atmosphere, and a step of forming a liquid flow path communicating with the discharge port so as to correspond to the heating resistor.

  Furthermore, it may be configured to further include a step of performing a heat treatment on the heating resistor, and further, the step of performing a heat treatment on the heating resistor includes heat energy used for discharging liquid to the heating resistor. It is good also as a structure made | formed by applying the electric pulse which produces | generates the same thermal energy.

When the heat generating resistor is subjected to heat treatment, a metal silicide composed of FeSi ₂ is generated in FeSiN constituting the heat generating resistor. Since this intermetallic compound (FeSi ₂ ) is thermally stable and has a small TCR, the durability of the heating resistor can be improved. For this reason, the composition ratio of Fe and Si is preferably close to 1: 2 as in the present invention.

  As described above, according to the present invention, there are provided a heating resistor, a liquid discharge head substrate having the heating resistor, a liquid discharge head, and a method for manufacturing the same that enable high-quality recorded images to be obtained over a long period of time. Can be provided.

  In addition, according to the present invention, it is possible to reduce the size of the ejected droplets in order to achieve high definition of the recorded image, and to stabilize the droplets even when high-speed driving is performed to achieve high-speed recording. Thus, it is possible to provide a heating resistor, a liquid discharge head substrate having the heating resistor, a liquid discharge head, and a method for manufacturing the same.

  Hereinafter, embodiments of the present invention will be described in detail based on a plurality of examples. However, the present invention is not limited only to each example described below, and can be applied to a resistor thin film used for other applications as long as the object of the present invention can be achieved. It is.

  The configuration of the main part of the inkjet substrate and the base body thereof according to the present embodiment is the same as that shown in FIGS. 1 and 2, and therefore, in the present embodiment, those configurations will be described with reference to FIGS. 1 and 2. explain.

  The heating resistor 2004 can be manufactured using various film forming methods, but is generally formed by a magnetron sputtering method using a radio frequency (RF) power source or a direct current (DC) power source as a power source. .

  FIG. 5 is a diagram showing an outline of a sputtering apparatus capable of forming the heat generating resistance layer 2004.

  In FIG. 5, reference numeral 4001 denotes a target made of FeSi prepared in advance with a predetermined composition, reference numeral 4002 denotes a flat magnet, reference numeral 4011 denotes a shutter for controlling film formation on the substrate, and reference numeral 4003 denotes a substrate 4004 in a film formation chamber 4009. A supporting substrate holder 4006 indicates a power source connected to the target 4001 and the substrate holder 4003.

  Further, in FIG. 5, reference numeral 4008 denotes an external heater provided so as to surround the outer peripheral wall of the film formation chamber 4009. This external heater 4008 is used to adjust the atmospheric temperature in the film forming chamber 4009. On the back surface of the substrate holder 4003, an internal heater 4005 for controlling the temperature of the substrate is provided. The temperature control of the substrate 4004 is preferably performed using an external heater 4008 in combination.

  The heating resistor layer 2004 is formed using the sputtering apparatus shown in FIG. 5 as follows.

First, the exhaust valve 4007 is opened, and the inside of the film forming chamber 4009 is exhausted to a pressure of 1 × 10 ⁻⁵ to 1 × 10 ⁻⁶ Pa using an unillustrated exhaust pump. Next, a mixed gas composed of argon gas, nitrogen gas, and oxygen gas is introduced into the film formation chamber 4009 from the gas inlet 4010 via a mass flow controller (not shown). At this time, the internal heater 4005 and the external heater 4008 are adjusted so that the temperature of the substrate 4004 and the atmospheric temperature in the film formation chamber 4009 become predetermined temperatures.

  Next, power is applied from the power source 4006 to the target 4001 to cause sputtering discharge, and the shutter 4011 is adjusted to form a thin film (a heating resistor layer 2004) on the substrate 4004. Note that when the flat magnet 4002 is rotated during the film formation, high-density plasma and γ electrons are distributed on the target 4001 side, so that thermal and physical damage given to the substrate 4004 is alleviated.

In the above description, the method of forming the heating resistor by the reactive sputtering method using the alloy target made of FeSi has been described.
(1) Examples Regarding Heating Resistors Next, examples in which the heating resistor film of the present invention is produced under various film forming conditions by the above-described film forming method using the apparatus shown in FIG. 5 will be described.

(Example 1)
Referring to FIG. 2, in this example, as described above, a heat storage layer 2002 having a film thickness of 1.8 μm is formed on a silicon substrate 2001 by thermal oxidation, and SiO 2 is further formed on the heat storage layer 2002. ₂ was deposited to a thickness of 1.2 μm by a plasma CVD method to form an interlayer film 2003 that also serves as a heat storage layer. Next, an FeSiN film having a thickness of 400 mm was formed on the interlayer film 2003 as the heating resistor layer 2004. The gas flow rates at this time were 76 sccm for Ar gas and 4 sccm for N ₂ gas. In this embodiment, the target 4001 (see FIG. 5) is made of Cr ₃₂ Si ₆₈ , and the power supplied from the power source 4006 (see FIG. 5) to the target 4001 is 400 W. Further, the substrate temperature during film formation was set to 200 ° C.

  Further, an Al—Cu film having a thickness of 5500 mm was formed by a sputtering method as the metal wiring 2005 for heating the heating resistor layer 2004 by the heat acting portion 2008. Then, the Al—Cu film was patterned by photolithography to form a heat acting portion 2008 having a size of 15 μm × 40 μm from which the Al—Cu film was removed.

  Further, as the protective film 2006, a SiN film was formed to a thickness of 1 μm by plasma CVD. In this example, the substrate temperature at this time was set to 400 ° C., and the substrate temperature was maintained for about 1 hour, and the heat treatment was also performed.

  Finally, a Ta film having a thickness of 2000 mm was formed as the anti-cavitation layer 2007 by sputtering to obtain a substrate 2000 of this example. The sheet resistance value of the heating resistance layer 2004 in the base body 2000 obtained in this example was 450 [Ω / □]. Further, the TCR characteristic of the heat generation resistive layer 2004 was about +20 [ppm / ° C.]. The composition ratio of FeSiN constituting the heat generating resistive layer 2004 was 23 at% for Fe, 46 at% for Si, and 31 at% for N.

[Comparative Example 1]
A substrate of Comparative Example 1 was obtained in the same manner as in Example 1 except that the heating resistance layer 2004 was changed as follows.

That is, in this comparative example, the target 4001 (see FIG. 5) was made of Ta, and a TaN _0.8 film having a thickness of 1000 Å was formed as the heating resistor layer 2004 by a reactive sputtering method using a Ta target. In this comparative example, a mixed gas composed of argon gas and nitrogen gas was used, and the gas flow rates at that time were 64 sccm for Ar gas, 16 sccm for N ₂ gas, and 20% partial pressure of nitrogen gas. The power supplied from the power source 4006 (see FIG. 5) to the target 4001 was 350 W, and the substrate temperature during film formation was 200 ° C.

  The sheet resistance value of the heating resistance layer 2004 in the base body 2000 obtained by this comparative example was 25 [Ω / □].

<Evaluation 1>
Using an inkjet head (recording head) having a substrate manufactured according to Example 1 and Comparative Example 1, a foaming voltage Vth necessary for generating bubbles for ejecting ink to a heating resistor (heater) 1005 is measured. did. Then, the current value flowing through the heating resistor 1005 was measured when the heating resistor 1005 was driven with a driving pulse width of 2 μsec using a voltage 1.2Vth which is 1.2 times the foaming voltage Vth as a driving voltage.

  As a result, in Example 1, the foaming voltage Vth was 32 V and the current value was 35 mA, while in Comparative Example 1, the foaming voltage Vth was 9.9 V and the current value was 120 mA. From this result, when the substrate of Example 1 and the substrate of Comparative Example 1 are compared, the current value of Example 1 is about 1/4 or less compared to Comparative Example 1. Since an actual recording head has a large number of heating resistors 1005 that are driven simultaneously, it can be easily understood that the power consumption of Example 1 is much smaller than that of Comparative Example 1 and an energy saving effect is obtained.

  Further, the heating resistor 1005 of Example 1 and Comparative Example 1 was driven under the conditions that the driving frequency was 15 kHz, the driving pulse width was 1 μsec, and the driving voltage was 1.2 times the foaming voltage Vth (1.2 Vth), and the breakage occurred. Thermal stress durability evaluation by pulse was performed.

As a result, in Comparative Example 1, the heating resistor 1005 broke when the number of pulses was 6.0 × 10 ⁷ , whereas in Example 1, the heating resistor 1005 was reached until the number of pulses reached 3.0 × 10 ^9. Did not break. From this, it can be seen that the substrate 2000 of this example has good durability even when the drive pulse width is shortened.

(Example 2)
A substrate of Example 2 was obtained by manufacturing in the same manner as in Example 1 except that the heating resistance layer 2004 was changed as follows.

In other words, in this example, the target 4001 (see FIG. 5) was made of Fe ₃₂ Si ₆₈ . In this embodiment, the gas flow rate when forming the FeSiN film as the heating resistor layer 2004 to a thickness of 400 mm was 71 sccm for Ar gas and 8 sccm for N ₂ gas. The power supplied from the power source 4006 (see FIG. 5) to the target 4001 was 400 W, and the substrate temperature during film formation was 200 ° C.

  The sheet resistance value of the heating resistance layer 2004 in the base body 2000 of this example obtained in this way was 950 [Ω / □], and the TCR characteristic was +35 [ppm / ° C.]. The composition ratio of FeSiN constituting the heat generating resistive layer 2004 was 21 at% for Fe, 42 at% for Si, and 37 at% for N.

<Evaluation 2>
The substrate 2000 produced in Example 2 was evaluated in the same manner as the evaluation 1 described above. As a result, in the base body 2000 of Example 2, the foaming voltage Vth was 35 V and the current value was 23 mA. Further, in the heat stress durability evaluation by the break pulse, the heating resistor 1005 did not break until the number of pulses reached 2.0 × 10 ⁹ .

From this result, it can be seen that, similarly to the result of Evaluation 1, the base body 2000 of Example 2 has low power consumption and excellent energy saving effect. It can also be seen that the base body 2000 of Example 2 also has good durability even when the drive pulse width is shortened.
(2) Examples relating to inkjet head substrate Further, in order to evaluate the characteristics of the inkjet head substrate as a heating resistor, the sputtering apparatus shown in FIG. An ink jet head having a heating resistor layer 2004 made of a FeSiN film formed by the same film forming method as the above method was prepared, and its characteristics were evaluated.

(Example 3)
Referring to FIG. 2, in this embodiment, a simple silicon substrate 2001 or a silicon substrate 2001 on which a driving integrated circuit is already formed is used as the substrate of the ink jet head substrate 2000. When a simple silicon substrate 2001 is used, a heat storage layer 2002 made of SiO ₂ and having a thickness of 1.8 μm is formed thereon by thermal oxidation, sputtering, CVD, or the like. Similarly, in the case of using a silicon substrate 2001 on which an integrated circuit is formed, a heat storage layer 2002 made of SiO ₂ and having a thickness of 1.8 μm is formed thereon during the manufacturing process.

Next, an interlayer film 2003 made of SiO ₂ and having a thickness of 1.2 μm was formed on the heat storage layer 2002 by sputtering or CVD. Next, an FeSiN film was formed on the interlayer film 2003 as the heating resistance layer 2004. The gas flow rate at this time was set to 76 sccm for Ar gas and 4 sccm for N ₂ gas, as in Example 1. In this embodiment, the target 4001 (see FIG. 5) is made of FeSi, and the power supplied from the power source 4006 (see FIG. 5) to the target 4001 is 120 W. Further, the substrate temperature during film formation was set to 400 ° C. This is to accelerate the crystallization of the film by very slowing the film formation rate. For this reason, the substrate temperature was set to a relatively high value of 400 ° C.

  Further, as the metal wiring 2005, an Al film was formed to a thickness of 5500 mm by a sputtering method. Then, the Al film was patterned by photolithography to form a heat acting portion 2008 having a size of 20 μm × 30 μm from which the Al layer was removed.

  Further, as the protective film 2006, a SiN film was formed to a thickness of 1 μm by plasma CVD. Next, as a cavitation-resistant layer 2007, a Ta film is formed to a thickness of 2300 mm by a sputtering method, and patterning is performed by a photolithography method, thereby producing an inkjet head substrate 2000 as shown in FIG. An ink jet recording head (see FIG. 1) provided with the ink jet head substrate 2000 was produced.

An SST test was conducted using the ink jet head thus produced. Here, in the SST test, a pulse signal having a driving frequency of 15 kHz with a driving pulse width of 1 μsec is given to the heating resistor 1005 to obtain a foaming start voltage Vth for starting ink discharge, and then the applied voltage is changed from Vth to 0.05 V. It was increased every time, and 1 × 10 ⁵ pulses were applied at a driving frequency of 15 kHz until the heating resistor 1005 was disconnected, and the breaking voltage Vb at the time of disconnection was obtained. The ratio between the foaming start voltage Vth and the breaking voltage Vb is referred to as a breaking voltage ratio Kb (= Vb / Vth). The break voltage ratio Kb is an index indicating the heat resistance of the heating resistor 1005. The larger the value, the better the heat resistance of the heating resistor 1005. As a result of evaluating the ink jet head of this example, 1.65 was obtained as the numerical value of Kb.

Next, a heat pulse endurance test (CST test) was performed when the drive voltage Vop was 1.3 Vth. The CST test is performed by applying a pulse to the heating resistor 1005 in an empty state where the ink jet head is not filled with ink (liquid). In this CST test, a pulse signal having a driving frequency of 15 kHz with a driving pulse width of 1 μsec is continuously applied to the heating resistor 1005 by 1.0 × 10 ⁹ pulses, and the initial resistance value of the heating resistor 1005 is R0. The resistance value change rate ΔR / R0 when the resistance value after application was R was determined (where ΔR = R−R0). As a result, the resistance value change rate ΔR / R0 was + 2.6%.

Example 4
Referring to FIG. 2, in the present embodiment as well, as in the third embodiment, a simple silicon substrate 2001 or a silicon substrate 2001 on which a driving integrated circuit is already formed is used as the substrate of the inkjet head substrate 2000. When a simple silicon substrate 2001 is used, a heat storage layer 2002 made of SiO ₂ and having a thickness of 1.8 μm is formed thereon by thermal oxidation, sputtering, CVD, or the like. Similarly, in the case of using a silicon substrate 2001 on which an integrated circuit is formed, a heat storage layer 2002 made of SiO ₂ and having a thickness of 1.8 μm is formed thereon during the manufacturing process.

Next, an interlayer film 2003 made of SiO ₂ and having a thickness of 1.2 μm was formed on the heat storage layer 2002 by sputtering or CVD. Next, an FeSiN film was formed on the interlayer film 2003 as the heating resistance layer 2004. The gas flow rate at this time was set to 76 sccm for Ar gas and 4 sccm for N ₂ gas, as in Example 1. In this embodiment, the target 4001 (see FIG. 5) is made of FeSi, and the power supplied from the power source 4006 (see FIG. 5) to the target 4001 is 350 W. Further, the substrate temperature during film formation was set to 200 ° C.

  Further, as the metal wiring 2005, an Al—Si film was formed to a thickness of 5500 mm by a sputtering method. Then, the Al—Si film was patterned by photolithography to form a heat acting portion 2008 having a size of 20 μm × 30 μm from which the Al—Si layer was removed.

  Further, as the protective film 2006, a SiN film was formed to a thickness of 1 μm by plasma CVD. In this example, the substrate temperature at this time was set to 400 ° C., and the substrate temperature was maintained for about 1 hour, and the heat treatment was also performed.

  Next, as a cavitation-resistant layer 2007, a Ta film is formed to a thickness of 2300 mm by a sputtering method, and patterning is performed by a photolithography method, thereby producing an inkjet head substrate 2000 as shown in FIG. An ink jet recording head (see FIG. 1) provided with the ink jet head substrate 2000 was produced.

An SST test was conducted using the ink jet head thus produced. Here, in the SST test, a pulse signal having a driving frequency of 15 kHz with a driving pulse width of 1 μsec is given to the heating resistor 1005 to obtain a foaming start voltage Vth for starting ink discharge, and then the applied voltage is changed from Vth to 0.05 V. It was increased every time, and 1 × 10 ⁵ pulses were applied at a driving frequency of 15 kHz until the heating resistor 1005 was disconnected, and the breaking voltage Vb at the time of disconnection was obtained. As a result of evaluating the ink jet head of this example, 1.75 was obtained as the numerical value of the breaking voltage ratio Kb (= Vb / Vth).

Next, a heat pulse endurance test (CST test) was performed when the drive voltage Vop was 1.3 Vth. The CST test is performed by applying a pulse to the heating resistor 1005 in an empty state where the ink jet head is not filled with ink (liquid). In this CST test, a pulse signal having a driving frequency of 15 kHz with a driving pulse width of 1 μsec is continuously applied to the heating resistor 1005 by 1.0 × 10 ⁹ pulses, and the initial resistance value of the heating resistor 1005 is R0. The resistance value change rate ΔR / R0 when the resistance value after application was R was determined (where ΔR = R−R0). As a result, the resistance value change rate ΔR / R0 was + 2.1%.

(Example 5)
In this example, an ink jet head substrate 2000 was produced in the same manner as in Example 4 except that the heating resistance layer 2004 (see FIG. 2) was formed under the conditions shown in Example 2. Then, an SST test and a CST test were performed in the same manner as in Example 4 using the inkjet head substrate 2000.

In this embodiment, before performing these tests, as a heat treatment of the heating resistor 1005 (see FIG. 1), a pulse signal having a drive voltage Vop of 1.4 Vth, a drive pulse width of 1 μsec, and a drive frequency of 15 kHz is 1 0.0 × 10 ³ pulses were applied. When the heat generating resistor 1005 is subjected to heat treatment, a metal silicide composed of FeSi ₂ is generated in FeSiN constituting the heat generating resistor 1005. Since the intermetallic compound (FeSi ₂ ) is thermally stable and has a small TCR, the durability of the heating resistor 1005 can be improved. For this reason, the composition ratio of Fe and Si is preferably close to 1: 2 as in the present invention.

  As a result of the SST test, 1.65 was obtained as the numerical value of the breaking voltage ratio Kb in this example. As a result of the CST test, the resistance value change rate ΔR / R0 was + 3.3%.

(Examples 6 to 10 and Comparative Examples 2 to 4)
An ink jet head was prepared in the same manner as in Example 1 except that the heat generating resistance layer as shown in Table 1 below was formed, and the characteristics thereof were evaluated. The evaluation results are listed in Table 1.

  When Examples 6 to 10 and Comparative Examples 2 to 4 are compared, the values of the breaking voltage ratio Kb by the SST test are almost the same as those of Examples 6 to 10 and Comparative Examples 2 to 4, and the resistance value change by the CST test The rate is smaller in Examples 6 to 10, and the TCR (resistance temperature coefficient) is smaller in Examples 6 to 10. Thus, according to Examples 6-10, the inkjet head provided with the heating resistance layer which has the characteristic better than Comparative Examples 2-4 was able to be produced comprehensively.

It is a schematic plan view which shows the general structure of the board | substrate principal part of the recording head used for inkjet recording. FIG. 2 is a schematic cross-sectional view of an ink jet recording head substrate taken along line X-X ′ at a portion corresponding to the ink flow path of FIG. 1. It is a figure for demonstrating the relationship of the various drive conditions by the difference in heater size. It is a graph which shows the result of having evaluated the characteristic of the FeSiN film | membrane actually formed into a film using the FeSi target. It is a figure which shows the outline | summary of the sputtering device which can form into a heating resistance layer shown in FIG.

Explanation of symbols

1001 Discharge port 1002 Electrothermal conversion element 1003 Ink flow path 1004 Substrate 1005 Heating resistor 2000 Ink jet head substrate

Claims (6)

In the heating resistor provided in the liquid discharge head that discharges liquid from the discharge port using thermal energy,
A heating resistor having a composition ratio of 15 to 30 at% for Fe, 35 to 60 at% for Si, and 10 to 50 at% for N, and becomes 100 at% or almost 100 at%. In a liquid discharge head substrate provided with a heating resistor that generates thermal energy used to discharge liquid from the discharge port,
The heating resistor has a composition ratio of Fe of 15 to 30 at%, Si of 35 to 60 at%, and N of 10 to 50 at%, and these are 100 at% or almost 100 at%. A substrate for a liquid discharge head. A discharge port for discharging liquid;
Generates thermal energy used to discharge the liquid, Fe has a composition ratio of 15 to 30 at%, Si of 35 to 60 at%, and N of 10 to 50 at%. Or a heating resistor of approximately 100 at%,
A liquid flow path provided with the heating resistor and communicating with the discharge port;
A liquid discharge head. Generates thermal energy used to discharge the liquid, Fe has a composition ratio of 15 to 30 at%, Si of 35 to 60 at%, and N of 10 to 50 at%. Alternatively, a step of forming a heating resistor of approximately 100 at% by a reactive sputtering method in a mixed gas atmosphere composed of nitrogen gas, oxygen gas, and argon gas;
Forming a liquid flow path communicating with the discharge port so as to correspond to the heating resistor;
A method of manufacturing a liquid discharge head, comprising:   The method of manufacturing a liquid discharge head according to claim 4, further comprising a step of performing a heat treatment on the heating resistor.   The step of applying a heat treatment to the heating resistor is performed by applying an electric pulse to the heating resistor that generates the same thermal energy as that used for discharging a liquid. Manufacturing method of the liquid discharge head.

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