JPH0852874A - Thin film heating element for inkjet recording head and composite substrate for inkjet recording head provided with the same heating element - Google Patents

Abstract

(57) [Abstract] [Purpose] A thin film heating element for an ink jet recording head, which has a larger specific resistance and a smaller temperature coefficient of resistance than conventional heating elements, and is excellent in abrasion resistance and oxidation resistance. Provide a composite substrate for an inkjet recording head using a heating element. A heating element which contains 50 to 80 mol% of at least one carbide of a group IVa element of Ti, Zr and Hf, and has a basic component of the balance of 20 to 50 mol% of silicon carbide. Al coated on the surface of crystal substrate
_A composite substrate for an ink jet recording head is obtained by arranging it through an insulating layer such as ₂ O ₃ or SiO ₂ .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film heating element for an ink jet recording head for jetting a liquid by utilizing thermal energy for recording, and a composite substrate for an ink jet recording head provided with the heating element.

[0002]

2. Description of the Related Art A heating element for an ink jet recording head is S
A structure having an electrically insulating layer such as SiO ₂ on an i substrate, a heating element layer disposed on the substrate, further having an electrically insulating layer such as SiO ₂ thereon, and having a protective layer thereon. Has become.

As a material for forming a heating element for an ink jet recording head, it is necessary to have a large specific resistance and a small temperature coefficient of resistance, and since it is used at a high temperature, it has sufficient oxidation resistance and is resistant to other members. It is necessary to combine abrasion resistance for contact.

Conventionally, Japanese Patent Laid-Open Publication No. 54-59936 discloses that TaAl and Zr are used as heat generating materials used at high temperatures.
B ₂ , Ta ₂ N, W, Ni, Cr, SnO ₂ or Pd
-Ag-based, Ru-based,
A Si diffusion resistor, a semiconductor PN bond, etc. are formed by vapor deposition or sputtering, and an oxidation resistant layer such as SnO ₂ , Si ₃ N ₄ or the like is formed by sputtering on the surface of the heat generating material to prevent oxidation. Further, there is disclosed that a wear resistant layer such as Ta ₂ O ₅ is formed by sputtering to prevent wear due to mechanical sliding.

Further, in JP-A-4-12861 and JP-A-4-12862, HfB ₂ is used as a thin film heating element for an ink jet recording head, and as a protective film for improving its wear resistance. , Ta-Si-C
There is disclosed a composite substrate for an ink jet recording head provided with the coating layer.

[0006]

However, the conventional exothermic material has a small temperature coefficient of resistance at room temperature to 400 ° C. and a small change in resistance value, but a specific resistance of 250 to 300 μΩ · cm. The temperature rise rate is too small to use. If it is at least 450 μΩ · cm or more, a sufficient temperature rising rate cannot be obtained. Also, the specific resistance is 2500
If it exceeds μΩ · cm / ° C., temperature control is performed with a small current, and temperature control becomes difficult. Therefore, it is necessary to set the temperature to 2500 μΩ · cm / ° C. or less. In addition, TaSiO ₂ , CrSi
Although there are some such as O _{2 which} have a large specific resistance and a high rate of temperature rise, ink jet recording which operates at high speed due to a large variation in resistance value of 100 μΩ / ° C. in the operating temperature range of room temperature to 400 ° C. Response is poor as a head for
There is a problem that it can not be controlled with high accuracy, wear resistance is not sufficient, and because oxidation resistance is poor, a protective film for improving wear resistance and oxidation resistance is required, and durability as a heat generating material is also required. It wasn't enough. Furthermore, when applied to a color printer, multi-colored ink is used, so it is necessary to have a structure with an ink jet recording head, and in order to make it compact, a simple oxidation-resistant layer and abrasion-resistant layer are omitted. A structured structure has been required.

The object of the present invention is that the specific resistance is as large as 450 μΩ · cm or more, the temperature rising rate is large, and the temperature coefficient of resistance is as small as 5 μΩ · cm / ° C. or less as compared with the conventional heating element, and the resistance value is high even at high temperature. Another object of the present invention is to provide a thin film heating element for an inkjet recording head, which is excellent in abrasion resistance and oxidation resistance, and a composite substrate for an inkjet recording head using this heating element.

[0008]

A thin film heating element for an ink jet recording head according to the present invention contains 50 to 80 mol% of at least one kind of carbide of a group IVa element as a basic component,
The balance is formed of a thin film of 20 to 50 mol% of silicon carbide.

Further, the composite substrate for an ink jet recording head according to the present invention has the above-mentioned structure through an insulating layer such as a Si single crystal, Al ₂ O ₃ , AlN or SiO ₂ substrate coated with Al ₂ O ₃ or SiO _2. It is characterized in that a thin film heating element composed of basic components is provided. The thin film heating element for an ink jet recording head of the present invention is made of Si, Al ₂ O ₃ , Al
0.5% by sputtering, ion plating or plasma CVD method on the surface of N, SiO ₂ etc.
An insulating layer such as Al ₂ O ₃ or SiO ₂ having a thickness of up to 1.5 μm is deposited, and each element of IVa group elements such as Ti, Zr, and Hf and Si or their carbides is used as a target, or within these targets. B, Al ₂ O ₃ , Er ₂ O ₃ or H
Sputtering with a target containing fO ₂ as a target, or plasma CV using a halide of the above element, an organometallic compound, or a hydrocarbon such as methane as a raw material
A thin film heating element having a film thickness of 0.1 to 0.2 μm can be manufactured by D or the like. In particular, when the plasma CVD method is used, a dense film having good adhesion can be obtained.

If the thickness of the heating element is smaller than 0.1 μm, the uniformity of the thickness cannot be maintained, and uneven heat generation easily occurs.
If it is larger than 2 μm, peeling tends to occur. From the standpoint of step coverage of the insulating film mounted on this, 0.1-0.2
μm is preferred. Further, if the layer thickness of the insulating layer is thinner than 0.5 μm, the insulating effect is small, and if it is thicker than 1.5 μm, peeling easily occurs.

When the heating element of the present invention is formed into a film by the sputtering method, B and Al other than B are used as a sintering aid for the target material.
₂ O ₃ , Er ₂ O ₃ and HfO ₂ can also be used, and since these sintering aids are contained in the film, they serve to improve the oxidation resistance of the heating element. Part of the SiC of this heating element is B, Al ₂ O
It may be replaced with ₃ , Er ₂ O ₃ or HfO ₂ .

In the composition of the heating element of the present invention, SiC
Up to 10 mol% of B, Al ₂ O ₃ , HfO ₂ or Er
By substituting at least one of ₂ O ₃ for not only the required electrical characteristics but also the wear resistance and the oxidation resistance, a heat generating element having excellent wear resistance and an ink jet recording head composite using the heat generating element can be obtained. A substrate can be obtained. The displacing agent B, Al ₂ O ₃ , Er ₂ O ₃ or HfO ₂ is 10
If it exceeds mol%, the hardness may be lowered and the wear resistance may be deteriorated. Therefore, the amount of substitution with respect to SiC is preferably 10 mol% or less.

[0013]

In the present invention, IVa such as Ti, Zr, Hf, etc.
The carbide of the group element contributes to increasing the melting point and hardness of the heating element. 50 to 8 of at least one kind of IVa group element carbide
The reason for limiting the content to 0 mol% is that if the content is less than 50 mol%, the specific resistance becomes larger than 2500 μΩ · cm, and a minute current must be used to control the heat generation temperature, which causes a problem. When it exceeds, the specific resistance becomes smaller than 450 μΩ · cm, it is necessary to generate heat with a large current, and the temperature rising rate becomes slow, so that the response speed becomes slow, which is not preferable.

Among the contents of the group IVa carbide of the present invention, the optimum content of the group IVa carbide having a sufficiently large specific resistance and a small temperature coefficient of resistance is 60 mol% or more and 70 mol% or less.
The following are preferred.

Further, silicon carbide has an effect of improving not only oxidation resistance but also wear resistance. If the content of silicon carbide is less than 20 mol%, sufficient oxidation resistance and wear resistance will be obtained. If it exceeds 50 mol%, not only the specific resistance exceeds 2500 μΩ · cm, but also the temperature coefficient of resistance increases, and the resistance value increases as the temperature rises, resulting in unstable heat generation at high temperature. , It is difficult to control the heat generation temperature and stable printing cannot be performed. Although the temperature coefficient of resistance is small and the change in specific resistance with time is small even if the number of pulses of the pulse current is increased, the life is long, but the heating element and the substrate of the present invention have small temperature coefficient of resistance and change with time in specific resistance. Has a long life.

[0016]

EXAMPLE A SiO ₂ insulating film with a thickness of 1 μm was formed on the surface of a Si single crystal substrate by a sputtering method, and then output was ₂ KW.
Sputtering was performed using a target having the elemental composition shown in Table 1, Table 2 and Table 3 under the conditions of an Ar pressure of 15 × 10 ⁻³ Torr and a substrate target distance of 50 mm, and a film thickness was formed on the insulating film. A film having a composition of 0.1 μm shown at the left end of the table was obtained. As a result of X-ray photoelectron spectroscopy analysis of this film, it was found that C was almost bonded to Ti and Si, and a slight amount of free carbon and B were present. In this example, B was used as the sintering aid, but those using Er ₂ O ₃ , HfO ₂ or Al ₂ O ₃ as the sintering aid were Er ₂ O instead of B above. ₃ ,
It was found that HfO ₂ or Al ₂ O ₃ was present in the film.

[0017]

[Table 1]

[Table 2]

[Table 3] As a result of measuring the specific resistance of the obtained film by the 4-probe method, it was about 49
5 to 2170 μΩ · cm, and the temperature coefficient of resistance was 0.11 to 3.82 μΩ · cm / ° C. In the examples of the present invention shown in Table 1, Table 2 and Table 3, the case where only one kind of IVa group carbide is contained is shown. However, this IVa group carbide is partially contained by other IVa group elements. Even if replaced, the same electrical characteristics are exhibited. For example, SiC-25TiC obtained by partially replacing the TiC component of the SiC-50TiC film with ZrC or HfC.
-25ZrC and SiC-25TiC-25HfC have a specific resistance of 2080 and 2100 μΩ · cm, respectively, and a temperature coefficient of resistance of 3.65 and 3.68 μΩ · cm / ° C., respectively.
Met. SiC-30TiC-30ZrC-20Hf
C also showed similar electrical characteristics.

The larger the atomic number of the group IVa element to be replaced, the larger the specific resistance and the temperature coefficient of resistance tended to become.

The compositions of the targets used here are shown in Table 1, Table 2 and Table 3.
Rather than the Si or IVa group element being present in the form of carbide,
It is preferable to use a dense sintered body or a CVD deposited body in which these elements and the sintering aid component are present in a free state and uniformly dispersed, in view of the sputtering rate.

Further, although the unit-type sputtering apparatus is used here, a multi-element type sputtering apparatus can use a target of a single element, and the film composition can be easily controlled to be fine.

As a comparative example, a conventional heating element was formed by forming a SiO ₂ insulating film on the surface of a Si single crystal substrate and then using a sputtering apparatus to coat a 100 nm-thick HfB ₂ film as in the case of the example. Although a Si single crystal substrate was used here, similar electrical characteristics were exhibited even when Al ₂ O ₃ , AlN or SiO ₂ was used as the substrate.

As a result of measuring the specific resistance and the temperature coefficient of resistance of the obtained heating element, the specific resistance was 100 μΩ · cm and the temperature coefficient of resistance was 150 μΩ · cm / ° C.

By comparing this example with the comparative example, the heating element of the present invention is easy to control the temperature, has good responsiveness such as temperature rising / falling and is suitable as a heating element for an ink jet recording head required for high speed operation. 3 compared to conventional heating elements
It became clear that it could be operated more than twice as fast. As described above, the heating element of the present invention can be operated three times or more as fast as the conventional heating element, and the electric characteristics of the heating element do not change with time, and are twice as high as those of the conventional heating element. The life has been extended.

Although the HfB ₂ film of the conventional heating element has oxidation resistance, HfO ₂ formed on the surface of the heating element is soft at high temperatures, and is easily abraded by mechanical abrasion. Therefore, the surface of the heating element of the present invention can be operated in the state of being covered with an electric insulating film, which leads to a compact head. It is valid.

As examples of the present invention, Table 1, Table 2 and Table 3 show the method of forming a thin film by the sputtering method, but it can be formed by the plasma CVD method. For example, when forming a thin film of SiC-50TiC in the embodiments of the present invention,
A Si substrate is placed in a reaction vessel of a high frequency plasma CVD apparatus, and SiH ₄ , TiCl ₄ , and CH ₄ gases are introduced therein at flow rates of 20, 20, and 40 cc / min, respectively, and the pressure is 0.9 Torr. By coating at a temperature of 450 to 700 ° C. and an output of 100 W, a thin film having the same composition can be formed. The film formed by the plasma CVD method has a dense structure, and a film having particularly excellent oxidation resistance and the like can be obtained. For the other films, the films shown in Table 1, Table 2 and Table 3 can be synthesized by using a gas such as ZrCl ₄ , HfCl ₄ or the like as a raw material gas in combination with the above gas. The electrical characteristics are the same as those formed by the sputtering method.

[0026]

The present invention has the following effects.

(1) Specific resistance is 490 to 2200 μΩ · c
In m, the absolute value of the temperature coefficient between room temperature and 400 ° C. is less than 5 μΩ · cm / ° C., and a heating element excellent in toughness, oxidation resistance and wear resistance can be obtained.

(2) By using this heating element, an ink jet recording head having a long life can be obtained.

(3) By adjusting the composition of the heating element, the temperature coefficient of the specific resistance can be made negative or the absolute value thereof can be made small, the fluctuation of the resistance value at high temperature is small, and the temperature can be accurately measured. Controllable and stable ink supply.

(4) A printer using the composite substrate for an ink jet recording head of the present invention can be operated at a speed three times or more that of a conventional product.

(5) In the heating element of the present invention, the change in resistance with time is 2% or less, and the life of the head is extended twice or more that of the conventional product.

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[Procedure amendment]

[Submission date] August 29, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 6

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

However, the conventional exothermic material has a small temperature coefficient of resistance at room temperature to 400 ° C. and a small change in resistance value, but a specific resistance of 250 to 300 μΩ · cm. The heating rate is too small to be used , and a sufficient heating rate cannot be obtained unless it is at least 450 μΩ · cm or more. Also, the specific resistance is 2500μ
If it exceeds Ω · cm / ° C, temperature control is performed with a small current, and it becomes difficult to control the temperature. Therefore, it is necessary that the temperature be 2500 μΩ · cm / ° C or less. In addition, TaSiO ₂ , CrSiO
There is one large heating rate in the specific resistance as ₂ large, 1 temperature coefficient of resistance at the use temperature range of ordinary temperature to 400 ° C.
The resistance value is large, such as 00 μΩ · cm / ° C, and the responsiveness is poor as an inkjet recording head that operates at high speed, and there is a problem that it cannot be controlled with high precision, and the abrasion resistance is not sufficient and the oxidation resistance is also high. Since it is also inferior, a protective film for improving wear resistance and oxidation resistance is required, and durability as a heat generating material is not sufficient. Furthermore, since it uses multicolored ink when applied to a color printer,
It is necessary to have a structure in which an ink jet recording head is provided side by side, and a compact structure in which an oxidation resistant layer and a wear resistant layer are omitted has been required for downsizing.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Further, silicon carbide has an effect of improving not only oxidation resistance but also wear resistance. If the content of silicon carbide is less than 20 mol%, sufficient oxidation resistance and wear resistance will be obtained. If it exceeds 50 mol%, not only the specific resistance exceeds 2500 μΩ · cm, but also the temperature coefficient of resistance increases, and the resistance value increases as the temperature rises, resulting in unstable heat generation at high temperatures. However, it is difficult to control the heat generation temperature and stable printing cannot be performed. Although the temperature coefficient of resistance is small and the change in specific resistance with time is small even if the number of pulses of the pulse current is increased, the life is long, but the heating element and the substrate of the present invention have small temperature coefficient of resistance and change with time in specific resistance. Has a long life.

Claims (7)

[Claims] 1. An ink jet characterized in that the basic component is formed by a thin film containing 50 to 80 mol% of at least one kind of carbide of group IVa element, and the balance of 20 to 50 mol% of silicon carbide. Thin film heating element for recording head. 2. The thin film heating element for an ink jet recording head according to claim 1, wherein the group IVa elements are Ti, Zr and Hf. 3. B and Er ₂ containing 10 mol% or less of silicon carbide.
_{3. The} thin film heating element for an ink jet recording head according to claim 1 or _2, which is substituted with O ₃ , Al ₂ O ₃ or HfO ₂ . 4. A ceramic thin plate heating element having a basic component containing 50 to 80 mol% of at least one kind of carbides of Group IVa elements, and the balance of 20 to 50 mol% of silicon carbide through a surface of a ceramic plate. A composite substrate for an ink jet recording head, characterized in that 5. The composite substrate for an ink jet recording head according to claim 4, wherein the group IVa element is Ti, Zr, or Hf. 6. B and Er ₂ containing 10 mol% or less of silicon carbide.
The composite substrate for an ink jet recording head according to claim 4 or 5, which is substituted with O ₃ , Al ₂ O ₃ or HfO ₂ . 7. The ceramic substrate is made of Si, Al ₂ O ₃ ,
7. The composite substrate for an inkjet recording head according to claim 4, which is AlN or SiO ₂ .