JPH0726200B2 - Sputtering target, film resistor formed using the same, and thermal printer head - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a sputtering target that can easily and uniformly form a film resistor that has high resistivity and excellent heat resistance, corrosion resistance, etc., a film resistor formed using the sputtering target, and a thermal printer head that uses the film resistor.

BACKGROUND ART Conventionally, as a recording device built into a facsimile, a copying machine, a ticket vending machine, etc., taking advantage of advantages such as low noise and low maintenance,
Thermal transfer type recording devices using thermal printer heads are in use. In such thermal printer heads, the film resistors that generate heat and melt the printing medium are:
Tantalum nitride has traditionally been widely used as a stable material. Ta-N films are produced by reactive sputtering of a Ta target in an _N2 atmosphere, and the higher the N content, the higher the resistivity. However, when used as a heating element, _Ta2N has generally been used due to its reliability and stability.

However, the resistivity of Ta ₂ N itself is about 200 μΩcm, and even if efforts are made to increase the resistance by making the film very thin and elongated, there is a limit to the upper limit.
To obtain a resistance value of 200 Ω using ₂ N, the film must be long and narrow with a length-to-width ratio of 2:1 and the film thickness must be limited to about 20 nm. Making the film this thin makes it difficult to control the film thickness during manufacturing, reducing the reproducibility and uniformity of the resistance value, and also increases the power density, making it more susceptible to breakdown.

To overcome these drawbacks, attempts have been made to increase the resistance by forming the film resistor into a meandering shape and increasing the effective length per unit area, but the higher the resolution of the thermal printer head, the more advanced the patterning technology required, which leads to lower yields.Furthermore, the reactive sputtering method used for manufacturing is a very small amount of reactive gas introduced into the vacuum chamber, and strict manufacturing management is required to control this.

On the other hand, in Japanese Patent Laid-Open No. 52-109947, a high resistivity film is obtained using a target in which a heating resistor such as TiC is embedded in the recesses of a quartz disk. Although this has excellent oxidation resistance at high temperatures, it has the disadvantages of being difficult to control the film composition and of being prone to large variations in sheet resistance within the substrate.

Therefore, the application of cermet thin films that can obtain high resistivity is being considered.
For example, Ta- _SiO2 resistive films are formed by multi-target sputtering using a Ta target and _{an SiO2} target.
Because the sputtering angle is significantly different from that of Si, subtle differences in sputtering conditions can easily cause variations in the composition of the target and the film, making it difficult to control the film composition. Furthermore, for the reasons mentioned above, the composition within the film is likely to be non-uniform, which can easily cause variations in the sheet resistance within the film, resulting in poor reproducibility of the resistance value.

The present invention has been made in consideration of the above points, and aims to provide a sputtering target that has little compositional deviation from the target and is capable of forming a high-resistivity film with a uniform composition. Another object of the present invention is to provide a film resistor that has excellent heat resistance and corrosion resistance, and achieves high resistivity while suppressing variations in sheet resistance within the film. A further object of the present invention is to provide a thermal printer head that uses the above-mentioned film resistor to improve printing resolution and accommodate higher speeds, etc.

DISCLOSURE OF THE INVENTION The present inventors have conducted extensive research into film resistors used as heating elements in thermal printer heads, and have found that Nb-SiO ₂
The film resistors in this system have high resistance and excellent heat and corrosion resistance.
It has also been found that the reproducibility of the film composition of the Nb-- _SiO.sub.2 film resistor can be significantly improved by using a silicon oxide composite target containing Nb as an oxide or silicide.

The sputtering target of the present invention is characterized by containing an oxide of niobium or a composite oxide of niobium and tantalum and/or iron, and a silicide of niobium or a composite silicide of niobium and tantalum and/or iron, with the remainder consisting essentially of silicon oxide.

The film resistor of the present invention is a film resistor formed by sputtering using a sintered sputtering target containing an oxide of niobium and a silicide of niobium, with the balance consisting essentially of silicon oxide, and is characterized in that it is essentially composed of niobium, oxygen, and silicon; or a film resistor formed by sputtering using a sintered sputtering target containing a composite oxide of niobium and tantalum and/or iron, and a composite silicide of niobium and tantalum and/or iron, with the balance consisting essentially of silicon oxide, and is characterized in that it is essentially composed of niobium, at least one selected from tantalum and iron, oxygen, and silicon.

Furthermore, the thermal printer head of the present invention comprises an insulating substrate, a number of heating resistors provided on the insulating substrate, and electrodes connected to these heating resistors, wherein the heating resistors are formed by sputtering using a sintered sputtering target containing niobium oxide and niobium silicide, with the balance being substantially silicon oxide, and are film resistors substantially composed of niobium, oxygen, and silicon, or contain a composite oxide of niobium and tantalum and/or iron, and a composite silicide of niobium and tantalum and/or iron,
The film resistor is formed by sputtering using a sintered sputtering target with the remainder consisting essentially of silicon oxide, and is characterized by comprising a film resistor essentially composed of niobium, at least one selected from tantalum and iron, oxygen, and silicon.

As described above, the sputtering target of the present invention uses Nb as the metal component that is the main component of the target, and contains this Nb in the form of an oxide, a silicide, a composite oxide, or a composite silicide.
Since the sputtering angle between Nb and Si is similar, a sputtered film with little deviation in composition from the target can be obtained. In addition, since Nb is uniformly dispersed in the target in the form of compounds such as oxides and silicides, it is possible to make the film composition of the obtained film uniform.

The sputtering target of the present invention can be, for example,
This is obtained by reactive sintering a mixture of Nb powder or Nb alloy powder and silicon oxide powder. The composition ratio of silicon oxide powder in the mixture is 15 mol% in molar ratio.
In other words, the sputtering target of the present invention is preferably a Nb powder or Nb containing silicon oxide in a molar ratio range of 15 mol % to 70 mol %.
It is preferable to use a material obtained by reactive sintering of alloy powder.

Here, the molar ratio of silicon oxide in the mixed powder is 15
The reason for limiting the range to 70 mol% is as follows: if the molar ratio of silicon oxide powder exceeds 70 mol%, the resulting sintered body becomes brittle, making it difficult to handle, and the uniformity of the resulting sputtered film decreases. Furthermore, the rate of resistance change during sputtering increases, making it difficult to control the resistance value of the resulting sputtered film and increasing the variation in sheet resistance. On the other hand, if the molar ratio of silicon oxide is less than 15 mol%, the resistivity of the resulting sputtered film decreases, reducing its effectiveness as a resistor.
A more preferable range of the molar ratio of silicon oxide in the mixed powder is 30 mol % to 60 mol %.

The sputtering target of the present invention comprises an oxide powder of Nb or a composite oxide powder of each component in an Nb alloy,
It can also be obtained by sintering a mixed powder consisting of Nb silicide powder or composite silicide powder of each component in a Nb alloy and silicon oxide powder. In this case, the amount of each powder is not particularly limited, but it is preferable to determine the composition ratio according to the mixed powder for reaction sintering described above.

The mixed powder is generally sintered by hot pressing, but it may also be sintered under atmospheric pressure after hot isostatic pressing (HIP) or cold isostatic pressing (CIP).

The starting material for Nb is not limited to Nb powder, but Nb alloy powder can also be used as described above. Such Nb alloys include Nb-M alloys (M represents tantalum and/or iron), specifically:
Nb-Ta alloys, Nb-Fe alloys, etc. are used. In particular, Nb and Ta are often present in the same ore, although their contents differ. Therefore, using an alloy consisting of both metals is desirable from the viewpoint of the effort and cost required for refining.
When such Nb alloy powder is used, Nb exists in the target as a composite oxide or composite silicide with Ta or Fe. Even when Nb exists in the target in such a form, the above-mentioned effects can be similarly obtained.

The film resistor of the present invention is made of a film formed by sputtering using the sputtering target of the present invention, and basically has a Nb-SiO2 _- based composition, and is substantially composed of Nb-Si-O or Nb-M-Si-O. In addition, since the film itself is mainly amorphous, it has excellent oxidation resistance and heat resistance.
The film resistor is preferably a thin film having a thickness of 5 nm to 3000 nm. A more preferable range of the film thickness is 50 nm.
The thickness is preferably 100 nm to 200 nm, and more preferably 80 nm to 500 nm.

As described above, the film resistor contains silicon oxide as a resistive component and mainly contains Nb as a metal component, i.e., Nb
A film resistor substantially composed of Nb-Si-O or Nb-M-Si-O has high resistivity and excellent heat resistance and corrosion resistance.
For example, when used as a heating element in a thermal printer head, it can generate stable, high heat, thereby enabling excellent printing and recording. Furthermore, the density of Nb is about half that of Ta, and its price per unit weight is also roughly half that of Ta, making it extremely useful from the perspective of cost reduction. Furthermore, the film resistor of the present invention is formed using the sputtering target of the present invention, which has excellent sputtering characteristics (sputter emission angle, composition uniformity, etc.), and therefore has excellent adhesion to the substrate and little compositional deviation from the target, i.e., excellent film composition reproducibility and a uniform composition. Therefore, not only can high specific resistance be stably achieved, but also the variation in sheet resistance can be extremely reduced.

Considering that the film resistor of the present invention is used as a heating element, it is necessary for it to have a high resistivity, and the resistivity is preferably in the range of ^{10 2 μΩcm} to 10 ⁶ μΩcm. Such a high resistivity can be stably achieved by using the sputtering target of the present invention.
If the resistivity is less than 10 6 μΩcm, it cannot fully function as a high resistivity material. On the other hand, if the resistivity exceeds 10 ⁶ μΩcm, the resistivity of the film depends on the molar ratio of silicon oxide in the target, and as the proportion of silicon oxide in the sputtering target increases, the sintered target becomes brittle, and the stability of the resulting film resistance value decreases. The desirable range of resistivity is 3×10 ² μΩcm - 6×1
^0.5 μΩcm, and more preferably 3×10 ³ μΩcm to 6×10 3 μΩcm.
× 10 ⁴ μΩcm. Note that the specific resistance is the sheet resistance multiplied by the film thickness.

In addition, in order to enable a film resistor to always provide a stable high specific resistance, it is necessary to reduce the variation in sheet resistance. In the film resistor of the present invention, Nb is mainly used as the metal component, and the sputtering target of the present invention, which can realize a uniform film composition, is used, so the variation in sheet resistance can be reduced to 20
% or less. If the sheet resistance varies widely, when it is used in a thermal printer head, the amount of heat generated within the substrate varies widely, resulting in deterioration of printing characteristics. A more desirable sheet resistance variation is
The sheet resistance variation here is calculated using the following formula:

(Maximum resistance – Minimum resistance) / Average resistance x 100
The variation in the sheet resistance was determined by measuring the film resistance at the measurement points (indicated by x in the figure) shown in Figure 5 using a DC four-probe method (RESISTEST-8A, manufactured by Napson Co., Ltd.). These measurement points were determined for the film on substrate A.
Measurements were taken at the centre of as many complete 5mm square sections as possible.

The thermal printer head of the present invention utilizes a film resistor having the above-described characteristics as a heating element, and therefore can easily accommodate higher speeds and higher heat resistance, and furthermore, has excellent printing stability and resolution.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the relationship between the amount of _SiO2 in the target used and the film resistance in an Nb- _SiO2 -based film resistor produced in an embodiment of the present invention, in comparison with a conventional Ta- _SiO2- based film resistor. FIG. 2 is a graph showing the relationship between the substrate position and the variation in resistivity in an Nb- _SiO2 -based film resistor produced in an embodiment of the present invention, in comparison with a conventional Ta- _SiO2- based film resistor.
The figure is a cross-sectional view showing the schematic structure of a thermal printer head according to one embodiment of the present invention, FIG. 4 is a graph showing the rate of change in resistance when a heat pulse is applied to a thermal printer head using an Nb- _SiO2 -based film resistor prepared in one embodiment of the present invention as a heating element, in comparison with a conventional thermal printer head, and FIG. 5 is a diagram showing sheet resistance measurement points on a substrate.

MODES FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to examples.

Example 1 Nb powder having an average particle size of 3 μm and sufficiently dried silicon oxide powder having an average particle size of 1 μm were mixed in a molar ratio of Nb/SiO _x = 70/30.
The mixture was mixed in a ball mill in a vacuum for 18 hours. Then, this mixed powder was subjected to a pressure of 100 kg/ ^cm² in a vacuum hot press at 1400°C for 1 hour, and reactive sintering was carried out to obtain the desired sintered body. The components contained in this sintered body were analyzed by an X-ray microanalyzer and X-ray diffraction.
Identification by X-ray diffraction confirmed the presence of niobium oxide, niobium silicide, and silicon oxide.
The surface of the sintered body was ground by about 1 mm by machining to obtain a sputtering target having a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 300 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 2 Nb powder having an average particle size of 3 μm and sufficiently dried silicon oxide powder having an average particle size of 1 μm were mixed in a molar ratio of Nb/SiO _x = 55/45.
The mixture was mixed in a ball mill in a vacuum for 18 hours. Then, this mixed powder was subjected to a pressure of 100 kg/ ^cm² in a vacuum hot press at 1400°C for 1 hour, and reactive sintering was carried out to obtain the desired sintered body. The components contained in this sintered body were analyzed by an X-ray microanalyzer and X-ray diffraction.
Identification by X-ray diffraction confirmed the presence of niobium oxide, niobium silicide, and silicon oxide.
The surface of the sintered body was ground by about 1 mm by machining to obtain a sputtering target having a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 300 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 3 Nb powder having an average particle size of 3 μm and sufficiently dried silicon oxide powder having an average particle size of 1 μm were mixed in a molar ratio of Nb/SiO _x = 45/55.
The mixture was mixed in a ball mill in a vacuum for 18 hours. Then, this mixed powder was subjected to a pressure of 100 kg/ ^cm² in a vacuum hot press at 1400°C for 1 hour, and reactive sintering was carried out to obtain the desired sintered body. The components contained in this sintered body were analyzed by an X-ray microanalyzer and X-ray diffraction.
Identification by X-ray diffraction confirmed the presence of niobium oxide, niobium silicide, and silicon oxide.
The surface of the sintered body was ground by about 1 mm by machining to obtain a sputtering target having a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 300 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 4 Nb alloy powder (Nb) containing 15 mol% of Ta and having an average particle size of 3 μm
The powder mixture was mixed in ^a ball mill under vacuum for 18 hours. Then, the mixture was heated at 100 ^kg / _cm² in a vacuum hot press ^.
Pressure was applied and reaction sintering was carried out at 1400°C for 1 hour.
The desired sintered body was obtained. The components contained in this sintered body were
Identification by X-ray microanalysis and X-ray diffraction confirmed the presence of niobium oxide, tantalum oxide, niobium silicide, tantalum silicide, and silicon oxide.
After grinding by 1 mm, a sputtering target having a diameter of 5 inches and a thickness of 5 mm was obtained.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 300 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 5 Nb alloy powder (Nb) containing 35 mol% of Ta and having an average particle size of 3 μm
The powder mixture was mixed in ^a ball mill under vacuum for 18 hours. Then, the mixture was heated at 100 ^kg / _cm² in a vacuum hot press ^.
Pressure was applied and reaction sintering was carried out at 1400°C for 1 hour.
The desired sintered body was obtained. The components contained in this sintered body were
Identification by X-ray microanalysis and X-ray diffraction confirmed the presence of niobium oxide, tantalum oxide, niobium silicide, tantalum silicide, and silicon oxide.
After grinding by 1 mm, a sputtering target having a diameter of 5 inches and a thickness of 5 mm was obtained.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 6 Nb alloy powder containing 15 mol% Fe and having an average particle size of 3 μm (N
The powder mixture was mixed in ^a ball mill under vacuum for 18 hours. Then, the mixture was heated at 100 ^kg / _cm² in a vacuum hot press ^.
Pressure was applied and reaction sintering was carried out at 1400°C for 1 hour.
The desired sintered body was obtained. The components contained in this sintered body were
Identification by ray microanalysis and X-ray diffraction confirmed the presence of niobium oxide, iron oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then ground by machine to a depth of about 1 mm, yielding a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 7 Nb alloy powder containing 35 mol% Fe and having an average particle size of 3 μm (N
The powder mixture was mixed in ^a ball mill under vacuum for 18 hours. Then, the mixture was heated at 100 ^kg / _cm² in a vacuum hot press ^.
Pressure was applied and reaction sintering was carried out at 1400°C for 1 hour.
The desired sintered body was obtained. The components contained in this sintered body were
Identification by ray microanalysis and X-ray diffraction confirmed the presence of niobium oxide, iron oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then ground by machine to a depth of about 1 mm, yielding a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 8 A mixed powder of _Nb5Si3 and _Nb2O5 with a weight ratio _of 2:1 and an average particle size of ₇ μm was mixed with silicon dioxide powder with an average particle size of 3 μm so that the weight ratio of Nb in the sputtering target was 78%, and mixed in a ball mill in an argon atmosphere for 18 hours. Then, this mixed powder was mixed in a vacuum hot press.
The target sintered body was obtained by applying a pressure of 100 kg/ ^cm² and sintering at 1500°C for 3.5 hours. The components of the sintered body were identified by X-ray microanalysis and X-ray diffraction, confirming the presence of niobium oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then machined to remove approximately 1 mm, yielding a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 9 A mixed powder of _Nb5Si3 and _Nb2O5 with a weight ratio _of 2:1 and an average particle size of ₇ μm was mixed with silicon dioxide powder with an average particle size of 3 μm so that the weight ratio of Nb in the sputtering target was 78%, and mixed in a ball mill in an argon atmosphere for 18 hours. Then, this mixed powder was mixed in a vacuum hot press.
The target sintered body was obtained by applying a pressure of 100 kg/ ^cm² and sintering at 1600°C for 3.5 hours. The components of the sintered body were identified by X-ray microanalysis and X-ray diffraction, confirming the presence of niobium oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then machined to remove approximately 1 mm, yielding a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 10: A 10: ₃ weight ratio mixed powder of _{Nb5Si3 and Nb2O5} with an average particle size of 7 μm was mixed with silicon oxide powder with an average particle size of 3 μm to achieve a Nb weight ratio of 65.4% in the sputtering target. The powder mixture was then mixed in a ball mill in an argon atmosphere for 18 hours. The mixed powder was then sintered in a vacuum hot press at 100 kg/ ^cm2 pressure at 1500°C for 3.5 hours to obtain the desired sintered body. X-ray microanalysis and X-ray diffraction analysis identified the components of the sintered body, confirming the presence of niobium oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then machined to remove approximately 1 mm to obtain a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 11: A 10: ₃ weight ratio mixed powder of _{Nb5Si3 and Nb2O5} with an average particle size of 7 μm was mixed with silicon dioxide powder with an average particle size of 3 μm to achieve a 65.4% Nb weight ratio in the sputtering target. The powder mixture was then mixed in a ball mill in an argon atmosphere for 18 hours. The mixed powder was then sintered in a vacuum hot press at 100 kg/ ^cm2 pressure at 1600°C for 3.5 hours to obtain the desired sintered body. X-ray microanalysis and X-ray diffraction analysis identified the components of the sintered body, confirming the presence of niobium oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then machined to remove approximately 1 mm to obtain a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 12 A mixed powder of _Nb5Si3 and _Nb2O5 with a weight ratio of 10:9 and an average particle size of _{7 μm} was mixed with silicon dioxide powder with an average particle size of 3 μm so that the weight ratio of Nb in the sputtering target was 56%, and the mixture was mixed in a ball mill in an argon atmosphere for 18 hours. Then, the mixed powder was mixed in a vacuum hot press.
The target sintered body was obtained by applying a pressure of 100 kg/ ^cm² and sintering at 1500°C for 3.5 hours. The components of the sintered body were identified by X-ray microanalysis and X-ray diffraction, confirming the presence of niobium oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then machined to remove approximately 1 mm, yielding a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Example 13 _: A mixed powder of _Nb5Si3 and _Nb2O5 with a weight ratio of 10:9 and an average particle size of ₇ μm was mixed with silicon dioxide powder with an average particle size of 3 μm so that the weight ratio of Nb in the sputtering target was 56%, and the mixture was mixed in a ball mill in an argon atmosphere for 18 hours. Then, the mixed powder was mixed in a vacuum hot press.
The target sintered body was obtained by applying a pressure of 100 kg/ ^cm² and sintering at 1600°C for 3.5 hours. The components of the sintered body were identified by X-ray microanalysis and X-ray diffraction, confirming the presence of niobium oxide, niobium silicide, and silicon oxide. The surface of the sintered body was then machined to remove approximately 1 mm, yielding a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Comparative Example 1 Ta powder having an average particle size of 3 μm and sufficiently dried silicon oxide powder having an average particle size of 1 μm were mixed in a molar ratio of Ta/SiO _x = 70/30.
The powder mixture was mixed in a ball mill under vacuum for 18 hours. This mixed powder was then sintered in a vacuum hot press at 100 kg/ ^cm² and 1400°C for 1 hour to obtain the desired sintered body. The surface of the sintered body was then ground by approximately 1 mm to obtain a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

Comparative Example 2 Ta powder having an average particle size of 3 μm and sufficiently dried silicon oxide powder having an average particle size of 1 μm were mixed in a molar ratio of Ta/SiO _x = 45/55.
The powder mixture was mixed in a ball mill under vacuum for 18 hours. This mixed powder was then sintered in a vacuum hot press at 100 kg/ ^cm² and 1500°C for 1 hour to obtain the desired sintered body. The surface of the sintered body was then ground by approximately 1 mm to obtain a sputtering target with a diameter of 5 inches and a thickness of 5 mm.

Next, using the above sputtering target, high-frequency magnetron sputtering was performed at an output of 200 W and an Ar flow rate of 17 scc.
A film having a thickness of 100 nm was formed on a 3-inch glazed alumina substrate under conditions of 5.3 mTorr to 5.5 mTorr and a gas pressure of 5.3 mTorr to 5.5 mTorr.

The variations in resistivity and sheet resistance of the thin films obtained in the above-described manner in each of the examples and comparative examples were measured.
The results are shown in Table 1. The variation in sheet resistance was determined by the above-mentioned formula and method.

As is clear from Table 1, when conventional targets are used, the sheet resistance varies greatly, making it difficult to control the resistance of the film. By using the reaction-sintered sputtering target of the present invention, the structure of the sputtering target is densified, resulting in the production of a stable film with extremely small sheet resistance variations. It was also found that even when a sputtering target made by sintering a mixed powder of silicon oxide, niobium oxide, and niobium silicide is used, a film with less sheet resistance variation than conventional targets is produced. Furthermore, Table 1 shows that the greater the metal content, the smaller the sheet resistance variation, and that stability is maintained even in alloys containing Ta, Fe, etc.

Next, from the measurement results of the resistivity of the thin films in the above-mentioned Examples and Comparative Examples, the relationship between the amount of _SiO2 in the Nb and Ta targets and the resistivity was investigated and shown in Figure 1. As shown in Figure 1, the resistivity of both metals increases significantly with an increase in the amount of _SiO2 , but the rate of increase was more remarkable for Nb.

Table 2 below shows the relationship between the composition of the targets manufactured in each Example and Comparative Example and the composition of the films produced by sputtering them. These results show that by forming a film using each sputtering target according to the Example, a film having almost the same composition as the target can be formed with good reproducibility. In addition, Ta and Fe
It was also shown that the performance of alloys containing these elements remains almost unchanged.

Furthermore, a sputtering target of 121 mm x 378 mm x 7.5 ^mm was prepared with the same composition as in Example 3, and a glazed glass substrate (A4 size) was reciprocated perpendicular to the longitudinal direction of the target to form a film with a thickness of 100 nm, and the film resistance was measured.
A target with ^dimensions of 7.5 mm × 7.5 mm was fabricated and similar measurements were carried out.
The results are shown in Figure 2. It is clear from this figure that the sputtering target of the present invention has significantly improved dispersion within the substrate compared to conventional targets.

Next, an embodiment of the thermal printer head of the present invention will be described. The structure of the thermal printer head used in this embodiment will be explained with reference to Fig. 3. In this figure, reference numeral 1 denotes an insulating substrate such as a ceramic substrate or a metal substrate having an insulating layer on its surface. A heating resistor layer 2 is formed on this insulating substrate 1. This heating resistor layer 2 is patterned to form a group of heating resistors. On each of these heating resistors 2, a heating portion 3 is formed.
A common electrode 4 and individual electrodes 5 made of Al or the like are provided so as to form openings that serve as the heat generating portions 3, and a protective layer 6 having a thickness of about 100 nm to 10 μm is formed so as to cover at least the heat generating portions 3. The preferred thickness of this protective layer is 1
μm to 5 μm, more preferably 3 μm to 4 μm
is.

First, a glazed alumina substrate on which film resistors were formed according to Example 3 was used as the insulating substrate 1 of the thermal printer head described above, and the film resistors were used as the heating resistor layer 2. After patterning the film resistors, Al electrodes 4 and 5 were formed on each heating resistor 2, and a protective film was then formed to fabricate a thermal printer head. Figure 4 shows the rate of change in resistance when a heat pulse with a pulse width of 0.3 seconds and a cycle of 5 msec was applied to the resulting thermal printer head. Test results for a thermal printer head using a conventional TaN resistive film are also shown as a comparative example.

As is clear from these results, the thermal printer head of the present invention exhibits less resistance fluctuation due to heat pulses and is superior in heat resistance compared to a thermal printer head using a Ta resistive film.

In the present invention, the same effect can be obtained even if a trace amount of Fe is contained in an alloy made of Nb and Ta, or even if a trace amount of Ta is contained in an alloy made of Nb and Fe.

As is clear from the above examples, the sputtering target of the present invention makes it possible to reproducibly form a high-resistance film with stable resistance and film composition. Furthermore, when Nb is used as the target material, the sputtering rate is generally more uniform than when Ta is used, so films formed using this target also have excellent uniformity. Furthermore, the target of the present invention does not use a reactive sputtering method, so there is no need for delicate adjustment of gases, and it has the advantage of being a simple manufacturing method. Also,
The thermal printer head of the present invention is a thin-film thermal printer head that uses the above-described film resistor of the present invention as a heating element, which has high resistivity, high thermal stability, and excellent heat resistance. This makes it possible to easily achieve higher speeds and higher heat resistance in thermal printer heads, and by making the resistance within the head uniform, it is possible to obtain thermal printer heads with excellent printing characteristics, and therefore has great industrial value.

As described above, a film resistor formed using the sputtering target of the present invention has stable film composition and resistance value and can achieve high specific resistance, making it useful as a heating element in a thermal printer head, etc. Furthermore, the thermal printer head of the present invention can easily accommodate higher speeds and higher heat resistance, and further satisfies high printing performance, making it useful as a recording device that requires small size and high performance.

Claims (21)

[Claims] 1. A sputtering target comprising an oxide of niobium or a composite oxide of niobium and tantalum and/or iron, and a silicide of niobium or a composite silicide of niobium and tantalum and/or iron, with the remainder consisting essentially of silicon oxide. 2. The sputtering target according to claim 1, wherein the sputtering target is produced by reactive sintering niobium powder or a mixed powder of niobium and tantalum and/or iron, containing silicon oxide in a molar ratio of 15 mol % to 70 mol %. [Claim 3] A sputtering target according to claim 1, characterized in that it is obtained by sintering a mixed powder containing niobium oxide powder or composite oxide powder of niobium and tantalum and/or iron, and niobium silicide powder or composite silicide powder of niobium and tantalum and/or iron, with the remainder being essentially silicon oxide powder. [Claim 4] A film resistor formed by sputtering using a sintered sputtering target containing niobium oxide and niobium silicide, with the remainder consisting essentially of silicon oxide, characterized in that the film resistor is essentially composed of niobium, oxygen, and silicon. 5. The film resistor according to claim 4, wherein the sputtering target contains silicon oxide in a molar ratio of
A film resistor characterized in that the target is made by reactive sintering niobium powder containing niobium in the range of 15 mol % to 70 mol %. [Claim 6] A film resistor according to claim 4, characterized in that the sputtering target is a target obtained by sintering a mixed powder containing niobium oxide powder and niobium silicide powder, with the remainder being essentially silicon oxide powder. [Claim 7] A film resistor formed by sputtering using a sintered sputtering target containing a composite oxide of niobium and tantalum and/or iron, and a composite silicide of niobium and tantalum and/or iron, with the remainder consisting essentially of silicon oxide, characterized in that the film resistor is essentially composed of niobium, at least one selected from tantalum and iron, oxygen, and silicon. 8. The film resistor according to claim 7, wherein the sputtering target contains silicon oxide in a molar ratio of
A film resistor characterized in that the target is made by reactive sintering an alloy powder of niobium and tantalum and/or iron contained in a range of 15 mol % to 70 mol %. [Claim 9] A film resistor according to claim 7, characterized in that the sputtering target is a target obtained by sintering a mixed powder containing a composite oxide powder of niobium and tantalum and/or iron, and a composite silicide powder of niobium and tantalum and/or iron, with the remainder being essentially silicon oxide powder. 10. The film resistor according to claim 4 or 7, wherein the specific resistance is 10 ² μΩcm to ^{10 6} μΩcm. 11. The film resistor according to claim 4 or 7, wherein the variation in sheet resistance is 20% or less. 12. The film resistor according to claim 4 or claim 7, wherein the film resistor is a thin film having a thickness of 5 nm to 3000 nm. 13. A thermal printer head comprising an insulating substrate, a number of heating resistors provided on the insulating substrate, and electrodes connected to the heating resistors, wherein the heating resistors are formed by sputtering using a sintered sputtering target containing niobium oxide and niobium silicide, with the remainder being substantially silicon oxide;
A thermal printer head comprising a film resistor substantially composed of niobium, oxygen and silicon. 14. A thermal printer head according to claim 13, wherein the heating resistor contains silicon oxide in a molar ratio of 15 mol % to 70 mol %.
% niobium powder by reactive sintering. [Claim 15] A thermal printer head according to claim 13, wherein the heating resistor is a film resistor formed by sputtering using a sintered sputtering target obtained by sintering a mixed powder containing niobium oxide powder and niobium silicide powder, with the remainder being essentially silicon oxide powder. [Claim 16] A thermal printer head comprising an insulating substrate, a number of heating resistors provided on the insulating substrate, and electrodes connected to these heating resistors, wherein the heating resistors are formed by sputtering using a sintered sputtering target containing a composite oxide of niobium and tantalum and/or iron, and a composite silicide of niobium and tantalum and/or iron, with the remainder consisting essentially of silicon oxide, and the thermal printer head is made of a film resistor consisting essentially of niobium, at least one selected from tantalum and iron, oxygen, and silicon. 17. A thermal printer head according to claim 16, wherein the heating resistor contains silicon oxide in a molar ratio of 15 mol % to 70 mol %.
% of an alloy powder of niobium and tantalum and/or iron, which is subjected to reactive sintering to form a film resistor by sputtering using a sintered sputtering target. [Claim 18] A thermal printer head according to claim 16, wherein the heating resistor is a film resistor formed by sputtering using a sintered sputtering target obtained by sintering a mixed powder containing a composite oxide powder of niobium and tantalum and/or iron, and a composite silicide powder of niobium and tantalum and/or iron, with the remainder being essentially silicon oxide powder. 19. A thermal printer head according to claim 13 or 16, wherein the heat generating resistor has a specific resistance value of 10 ² μΩcm to ^{10 6} μΩcm. 20. A thermal printer head according to claim 13 or 16, wherein the variation in sheet resistance of said heating resistor is 20% or less. 21. A thermal printer head according to claim 13 or 16, wherein the heating resistor has a protective film having a thickness of 100 nm to 10 μm.