Sputtering target material for thin film resistor as well as preparation method and application of sputtering target material

Abstract

According to the sputtering target material for the thin-film resistor as well as the preparation method and the application of the sputtering target material, proper additives are added into Si, Cr, Ni and Al to improve the grain size and strength, proper oxides are added to improve the resistivity and adjust the resistance temperature coefficient, the raw materials are prepared into intermediate powder in an alloy smelting gas atomization mode, and the sputtering target material is prepared into the thin-film resistor. The sputtering target material which is high in compactness, uniform in component distribution and fine in grain size is prepared by sintering and molding through a discharge plasma sintering method and a vacuum hot pressing sintering method, more additive choices are provided for preparation of the target material, and the method does not only depend on addition of rare earth elements; the initial resistance value of the film resistor prepared by sputtering the target material is greater than or equal to 2k omega, the resistance temperature coefficient is less than or equal to + / -10ppm / DEG C, and the film resistor has the advantages of high stability and high resistance value.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic materials and metallurgical technology, and in particular to a sputtering target material for a thin film resistor, a preparation method and application thereof. Background Art

[0002] With the rapid development of modern electronic technology, high-tech fields such as automotive electronics, aerospace, and communication systems have increasingly higher requirements for the performance of electronic components. As an important electronic component, thin film resistors are particularly suitable for high-precision electronic instruments such as aerospace and national defense, and their performance directly affects the accuracy and stability of electronic equipment.

[0003] The performance of thin film resistors mainly depends on the film material and film forming process. Magnetron sputtering technology has long been widely used in resistor film production, and has great advantages in resistance stability and output. However, the composition ratio and preparation method of the target material restrict the stability and reliability of thin film resistors.

[0004] Most of the high-resistance sputtering targets currently produced are produced by vacuum induction melting. However, segregation is prone to occur in the target material preparation process, and rare earth elements must be added to reduce element segregation. The tissue distribution is uneven, and the grains are generally coarse, resulting in a high temperature coefficient of resistance of the thin film resistor obtained by sputtering and limited stability. In order to reduce the temperature coefficient of resistance of the film resistor, the target material system used sacrifices some of the high-resistance characteristics, so that the initial resistance value of the sputtered thin film resistor is low, resulting in a decrease in film quality and anti-interference ability, and an increase in the risk of leakage current, which makes it difficult to meet the use requirements of high-precision resistor components. Summary of the invention

[0005] In view of the problems existing in the background technology, the present invention provides a sputtering target material, preparation method and application thereof for thin film resistors. By adding suitable additives to improve the grain size and strength, adding suitable oxides to improve the resistivity and adjust the temperature coefficient of resistance, a highly dense and uniform sputtering target material is prepared by using a discharge plasma sintering method and a vacuum hot pressing sintering method, which provides more additive options for the preparation of the target material and does not rely solely on the addition of rare earth elements. The thin film resistor prepared by the sputtering target material has an initial resistance of ≥2kΩ and a temperature coefficient of resistance of ≤±10ppm / ℃, and has the advantages of high stability and high resistance.

[0006] The specific content of the invention is as follows: According to a first aspect of the present invention, a method for preparing a sputtering target for a thin film resistor is provided, the preparation method specifically comprising the following steps: S1. Using Si, Cr, Ni, Al, additives and optional oxides as raw materials, the raw materials are prepared into intermediate powder by alloy melting gas atomization; S2, weighing a certain amount of the intermediate powder, loading it into a graphite mold, sintering it to obtain a target blank; S3, performing surface polishing treatment on the target blank, and processing the target target material according to the target size; In terms of mass fraction, the amount of Si added is 30-60wt%, the amount of Cr added is 20-40wt%, the amount of Ni added is 15-30wt%, the amount of Al added is 2-8wt%, the amount of additives added is 0.1-5wt%, and the amount of oxide added is 0-12.5wt%; The additive is selected from one or more of Mo, Ti and rare earth elements; The oxide is selected from one or more of CuO, MoO2, RuO2, SiO2 and V2O5.

[0007] Optionally, when the raw material contains oxides, preparing the raw material into an intermediate powder by alloy smelting gas atomization includes: Alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace to form an alloyed melt, and then using high-pressure Ar as an atomizing gas to prepare the melt into an alloy powder; Mixing the alloy powder and the oxide powder to obtain the intermediate powder; The temperature of the alloying treatment is 1200-1700°C; The pressure of the atomizing gas is 1.5-10 MPa.

[0008] Optionally, the alloy powder and the oxide powder are mixed by a three-dimensional mixing method or a vibration mixing method.

[0009] Optionally, when the raw material does not contain oxides, the process of preparing the raw material into an intermediate powder by alloy smelting and gas atomization includes: Alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace to form an alloyed melt, and then using high-pressure Ar as an atomizing gas to prepare the melt into the intermediate powder; The temperature of the alloying treatment is 1200-1700°C; The pressure of the atomizing gas is 1.5-10 MPa.

[0010] Optionally, the particle size of the intermediate powder is 10-60 μm.

[0011] Optionally, in step S2, the sintering molding adopts vacuum hot pressing sintering, and the vacuum hot pressing sintering is carried out under Ar protection conditions, with a vacuum degree lower than 500 Pa, a temperature of 1000~1250°C, and a pressure of 15~60MPa.

[0012] Optionally, in step S2, the sintering molding adopts spark plasma sintering, the vacuum degree of the spark plasma sintering is 20~100 Pa, the sintering temperature is 900~1100°C, and the pressure is 5~20MPa.

[0013] According to a second aspect of the present invention, a sputtering target prepared by the above preparation method is provided.

[0014] Optionally, the density of the sputtering target is ≥95%.

[0015] According to a third aspect of the present invention, there is provided an application of a sputtering target material for a thin film resistor, wherein the sputtering target is used as a sputtering target material for a thin film resistor.

[0016] Compared with the prior art, the present invention has the following advantages: The present invention provides a sputtering target material for thin film resistors, a preparation method and application thereof, the preparation method comprising the following steps: using Si, Cr, Ni, Al, additives and optional oxides as raw materials, preparing the raw materials into intermediate powders by alloy smelting gas atomization; weighing a certain amount of the intermediate powders into a graphite mold, sintering and forming, and obtaining a target blank; performing surface polishing on the target blank, and processing according to the target size to obtain a target target material. The sputtering target material is obtained by the above preparation method, and the sputtering target material is used as a sputtering target material for thin film resistors.

[0017] The method for preparing a sputtering target material for a thin film resistor provided by the present invention improves the grain size and strength by adding suitable additives, improves the resistivity and adjusts the resistance temperature coefficient by adding suitable oxides, prepares an intermediate powder with uniform particle size by alloy melting gas atomization, and then prepares a sputtering target material with high density, uniform component distribution and fine grain size by sintering molding, which provides more additive options for the preparation of the target material and does not rely solely on the addition of rare earth elements. The thin film resistor prepared by the sputtering target material has an initial resistance of ≥2kΩ and a resistance temperature coefficient of ≤±10ppm / ℃. Compared with the thin film resistor in the related art, the thin film resistor prepared by the present invention has a stability improved by more than 50%, and has the advantages of high stability and high resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1The flowchart of the method for preparing the sputtering target material for the thin film resistor provided by the present invention is shown. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the embodiments of the present invention, any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts falls within the scope of protection of the present invention. In addition, all other embodiments obtained by ordinary technicians in this field without carrying out creative work belong to the scope of protection of the present invention.

[0021] In the embodiment, no specific experimental steps or conditions are indicated, and the operation or conditions of the conventional experimental steps described in the prior art in this field can be carried out. The reagents used and other instruments that do not indicate the manufacturer are conventional reagent products that can be obtained commercially. In addition, the accompanying drawings are only schematic diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0022] Technologies, methods, and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the description of the present invention.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Thin film resistors are resistor elements made of thin film materials. They are usually made of a very thin metal or alloy film covered on an insulating substrate. They are used to control current, voltage, signal adjustment or prevent overcurrent. They have the characteristics of high power consumption per unit area, good stability, low noise, and wide frequency response range. They are widely used in precision electronic equipment, instruments, communication equipment, medical equipment and other occasions.

[0025] Sputtering targets are usually used in thin film deposition technology. The atoms or molecules on the surface of the target are sputtered out by bombardment of high-energy ions and deposited on the surface of the substrate to form a thin film. Among them, high-resistance targets have a higher resistivity and are usually used to manufacture thin film materials with specific resistance characteristics. They have important applications in the preparation of sensors, precision circuits, thin film resistors and other fields.

[0026] The performance of thin film resistors mainly depends on the film material and film forming process. Magnetron sputtering technology has long been widely used in resistor film production, and has great advantages in resistance stability and output. However, the composition ratio and preparation method of the target material restrict the stability and reliability of thin film resistors. Most of the high-resistance sputtering targets currently produced are produced by vacuum induction melting. For example, in CN1415779A, a corundum-graphite-magnesia composite vacuum induction furnace is used to prepare high-resistance targets. The surface of the target material is smooth and flat, with no cracks on the outside and no pores on the inside. The initial resistance of the thin film resistor obtained by sputtering is 100Ω~20kΩ, and the resistance temperature coefficient is less than 30ppm / ℃. The target products produced by this method are prone to segregation, uneven composition, and generally coarse grains, resulting in a high resistance temperature coefficient of the thin film resistor obtained by sputtering; in order to achieve high resistance, a high content of Si and Cr is added, which makes the target material difficult to cool and smelt, and the yield is low. In CN106244988, vacuum hot pressing sintering is used to prepare high-resistance target materials, overcoming the problem of high brittleness and easy cracking of the target materials caused by high Si content; by adding Al and Zr as grain refiners, a structure with an average grain size of 20~25µm is obtained; and by adding rare earth elements, the segregation of Zr elements in the alloy structure is reduced to improve the uniformity of the target material composition. The document "Preparation of Rare Earth Doped NiCrSi High-Resistance Target Materials and Study on Coating Performance" mentions that the resistance temperature coefficient of the thin film resistor sputtered by the target material is less than ±25ppm / ℃; however, the document does not reflect the initial resistance value of the corresponding thin film resistor, and rare earth elements must be added to reduce the segregation of Zr elements, thereby reducing the resistance temperature coefficient to within ±25ppm / ℃.

[0027] In view of this, in a first aspect, the present invention provides a method for preparing a sputtering target material for a thin film resistor. Figure 1 The flow chart of the method for preparing the sputtering target material for the thin film resistor provided by the present invention is shown as follows: Figure 1 As shown, the preparation method specifically comprises the following steps: S1. Using Si, Cr, Ni, Al, additives and optional oxides as raw materials, the raw materials are prepared into intermediate powder by alloy melting gas atomization; S2, weighing a certain amount of the intermediate powder, loading it into a graphite mold, sintering it to obtain a target blank; S3, performing surface polishing treatment on the target blank, and processing the target target material according to the target size; In terms of mass fraction, the amount of Si added is 30-60wt%, the amount of Cr added is 20-40wt%, the amount of Ni added is 15-30wt%, the amount of Al added is 2-8wt%, the amount of additives added is 0.1-5wt%, and the amount of oxide added is 0-12.5wt%; The additive is selected from one or more of Mo, Ti and rare earth elements; The oxide is selected from one or more of CuO, MoO2, RuO2, SiO2 and V2O5.

[0028] The method for preparing a sputtering target material for a thin film resistor provided by the present invention improves the grain size and strength by adding suitable additives to Si, Cr, Ni and Al, improves the resistivity and adjusts the resistance temperature coefficient by adding suitable oxides, prepares an intermediate powder with uniform particle size by alloy smelting gas atomization, and then prepares a sputtering target material with high density, uniform component distribution and fine grain size by sintering molding, which provides more additive options for the preparation of the target material and does not rely solely on the addition of rare earth elements. The thin film resistor prepared by the sputtering target material has an initial resistance of ≥2kΩ and a resistance temperature coefficient of ≤±10ppm / ℃. Compared with the thin film resistor in the related art, the thin film resistor prepared by the present invention has a stability improved by more than 50%, and has the advantages of high stability and high resistance.

[0029] In some embodiments, when the raw material contains oxides, the raw material is prepared into an intermediate powder by alloy melting gas atomization, including: alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace to form an alloyed melt, and then using high-pressure Ar as an atomizing gas to prepare the melt into an alloy powder; mixing the alloy powder with an oxide powder to obtain the intermediate powder; the temperature of the alloying treatment is 1200~1700℃; the pressure of the atomizing gas is 1.5~10 MPa.

[0030] When this embodiment is implemented, the raw materials contain oxides, that is, the raw materials are Si, Cr, Ni, Al, additives and oxides, and the amount of oxide added is 1~12.5wt%. First, Si, Cr, Ni, Al and additives are alloyed in a vacuum induction furnace with Ar as atomizing gas. The reason why Si, Cr, Ni, Al and additives are not melted together with oxides in a vacuum induction furnace is that: on the one hand, induction melting relies on electromagnetic induction heating, which requires the material to have good conductivity, and oxides are usually insulators and difficult to melt by induction heating; on the other hand, under vacuum, some oxides may decompose or reduce. Therefore, when it is implemented, Si, Cr, Ni, Al and additives are firstly subjected to alloy melting gas atomization treatment to obtain alloy powder, and then the alloy powder is mixed with oxide powder to obtain intermediate powder.

[0031] In this embodiment, a vacuum induction furnace is used to melt Si, Cr, Ni, Al and additive raw materials, and the raw materials are melted to form a melt. The electromagnetic force in the vacuum induction furnace smelting process produces a certain stirring effect on the melt, which can refine the grains in the alloy liquid. Electromagnetic stirring causes the alloy liquid to flow, breaks the growing grains, and makes them become more crystal nuclei, thereby obtaining a finer grain structure after solidification. Fine grain structure can usually improve the comprehensive mechanical properties of the alloy, such as strength, toughness, and plasticity, so that the alloy powder performs better in subsequent processing and use. The combined effect of electromagnetic stirring and vacuum environment helps to reduce element segregation and make the microstructure and composition of the alloy powder more uniform.

[0032] In this embodiment, the temperature of the alloying treatment is 1200~1700℃, and can be specifically set to 1200℃, 1250℃, 1300℃...1700℃. When the temperature of the alloying treatment is greater than 1700℃, the excessively high temperature makes the alloy liquid superheated, the nucleation rate is low and the growth rate is fast during cooling, and it is easy to form a coarse grain structure; when the temperature of the alloying treatment is less than 1200℃, the excessively low temperature makes the nucleation rate high but the atomic diffusion ability is weak, and small but uneven grains may be formed. The pressure of the atomizing gas is 1.5~10 MPa, and can be specifically set to 1.5 MPa, 2.0 MPa, 2.5 MPa...10 MPa. When the pressure of the atomizing gas is less than 1.5 MPa, too small a pressure will result in poor atomization effect, low powder production efficiency, too large powder particles, irregular shape, etc. When the pressure of the atomizing gas is greater than 10 MPa, too high a pressure will cause the powder particles to be too small, the powder shape to be abnormal, and the equipment wear to be aggravated. Therefore, the appropriate temperature can make the alloy structure uniform and obtain fine and uniform grains. The appropriate atomizing gas pressure can obtain alloy powder with suitable and uniform particle size and improve the powder production efficiency.

[0033] In some embodiments, the alloy powder and the oxide powder are mixed by a three-dimensional mixing method or a vibration mixing method.

[0034] In the specific implementation, the alloy powder and oxide powder obtained after alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace are added to the barrel of the three-dimensional mixer in accordance with the proportion. After the loading is completed, the barrel is sealed to ensure that the material will not leak during the mixing process. The three-dimensional mixer is started, and the barrel begins to perform complex three-dimensional movements, including rotation, revolution and swing. During the movement, the material continuously rolls, translates and rotates in the barrel, thereby achieving full mixing.

[0035] In the specific implementation, the alloy powder and oxide powder obtained after alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace are added to the hopper of the vibration mixer in accordance with the proportion, and the hopper is fixed on the workbench of the vibration mixer to ensure that the hopper does not move during the vibration process. Start the vibration mixer, and the hopper begins to vibrate at a high frequency under the action of the vibration source. During the vibration process, the materials continue to roll and collide in the hopper to achieve mixing. These two mixing methods can make the alloy powder and oxide powder reach a highly uniform distribution state in the entire mixing system.

[0036] In specific implementation, high-energy ball milling can also be used for mixing. High-energy ball milling is also called mechanochemistry. First, Si, Cr, Ni, Al and additives are alloyed in a vacuum induction furnace to obtain an alloy powder and a single element powder corresponding to the oxide. For example, the oxide to be used in this embodiment is CuO. The alloy powder and Cu powder can be loaded into the ball mill of a high-energy ball mill according to the ratio, and an appropriate amount of grinding balls are introduced. The ball-to-material ratio can be 5:1~20:1. The atmosphere is introduced into the ball mill. The atmosphere is a mixed atmosphere of inert gas (such as argon) and oxygen. During the ball milling process, the grinding balls and the single element powders are constantly collided, squeezed and rubbed. On the one hand, this mechanical force makes the single element powders continuously refined, increases their specific surface area, and improves the reaction activity; on the other hand, it also provides energy for the contact and reaction between the element and oxygen. As the ball milling proceeds, the surface of the single element powder gradually reacts chemically with oxygen, and begins to form oxides, thereby realizing the addition of oxides in the raw material components.

[0037] In some embodiments, when the raw material does not contain oxides, the raw material is prepared into an intermediate powder by alloy melting gas atomization, including: alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace to form an alloyed melt, and then using high-pressure Ar as an atomizing gas to prepare the melt into the intermediate powder; the temperature of the alloying treatment is 1200~1700℃; the pressure of the atomizing gas is 1.5~10MPa.

[0038] In the specific implementation of this embodiment, the raw materials do not contain oxides, that is, the raw materials are only Si, Cr, Ni, Al, and additives, and the amount of oxide added is 0. Si, Cr, Ni, Al and additives are alloyed in a vacuum induction furnace, and Ar is introduced as an atomizing gas to directly obtain an intermediate powder.

[0039] In this embodiment, different types of metal raw materials are mixed and smelted in a vacuum induction furnace to ensure the consistency and stability of the alloy performance. The electromagnetic stirring effect during the smelting process in the vacuum induction furnace can refine the grains in the alloy liquid. The combined effect of electromagnetic stirring and vacuum environment helps to reduce element segregation and make the microstructure and composition of the alloy powder more uniform. The appropriate temperature can homogenize the organizational structure of the alloy and obtain fine and uniform grains. The appropriate atomizing gas pressure can obtain alloy powder with suitable and uniform particle size, thereby improving the powder production efficiency.

[0040] In some embodiments, the particle size of the intermediate powder is 10-60 μm.

[0041] In this embodiment, the powder particle size obtained by the above preparation method is 10~60µm, which can be 10µm, 15µm, 20µm...60µm. When the powder particle size is less than 10µm, the powder particle size is too fine. During the molding process, the friction between the particles is large and the fluidity becomes poor. In order to obtain a green body of a certain density, it is necessary to apply greater pressure. Powders of appropriate particle size have good fluidity and stacking properties, can be filled more evenly in the graphite mold, and the required molding pressure is relatively low, which reduces the pressure requirements and energy consumption of the equipment. In addition, when the powder particle size is between 10~60µm, the powder can be stacked in a relatively dense manner, reducing the porosity in the green body, which is conducive to obtaining a high-density target material during the sintering process.

[0042] In some embodiments, in step S2, the sintering molding adopts vacuum hot pressing sintering, and the vacuum hot pressing sintering is carried out under Ar protection conditions, with a vacuum degree lower than 500 Pa, a temperature of 1000~1250°C, and a pressure of 15~60MPa.

[0043] In the specific implementation, a certain amount of intermediate powder is weighed and evenly loaded into a graphite mold, and the mold containing the powder is placed in the furnace of a vacuum hot pressing sintering furnace, the vacuum system is started, the air in the furnace is extracted, and Ar is introduced to make the furnace reach a predetermined vacuum degree, that is, less than 500Pa, so as to reduce the influence of impurities and gases on the sintering process and prevent the oxidation of the powder. According to the preset temperature rise curve, for example, the sintering temperature is set to 1100°C, and the heating system is started to gradually increase the temperature in the furnace. When the temperature reaches a certain value, the pressure system is started to apply pressure to the mold, for example, set to 20MPa. When the temperature and pressure reach the set value, keep the heat and pressure for a period of time to realize the gradual densification of the target material. After the heat preservation and pressure maintenance are completed, stop heating and let the temperature in the furnace gradually decrease. The cooling method can be natural cooling or forced cooling. When the temperature drops to a certain level, slowly remove the pressure to avoid cracks in the target material due to too fast pressure changes. In this embodiment, vacuum hot pressing sintering is adopted, and the temperature is set at 1000-1250° C., which is conducive to the diffusion of elements in the target material and makes the composition more uniform. The pressure is set in the range of 15-60 MPa, which can promote the densification of the target material and refine the grains.

[0044] In some embodiments, in step S2, the sintering is performed by spark plasma sintering, the vacuum degree of the spark plasma sintering is 20-100 Pa, the sintering temperature is 900-1100° C., and the pressure is 5-20 MPa.

[0045] During the specific implementation, the intermediate powder is evenly loaded into the graphite mold, and the mold containing the powder is placed in the sintering chamber of the spark plasma sintering equipment to ensure that the mold is placed stably and in good contact with the electrodes and other components. Connect components such as pressure sensors and heating electrodes to ensure that the equipment can accurately apply pressure and transmit current. Start the vacuum system, extract the air in the sintering chamber to make the vacuum degree lower than 100Pa, turn on the power, and apply a pulse current to the mold. When the pulse current passes through the mold and the powder, Joule heat is generated, causing the powder to heat up rapidly. When the set sintering temperature is reached, for example 900°C, keep it warm for a period of time to fully sinter and densify the powder.

[0046] In this embodiment, spark plasma sintering is adopted, and the temperature is set at 900-1100° C., which is conducive to the diffusion of elements in the target material and makes the composition more uniform. The pressure is set in the range of 5-20 MPa, which can promote the densification of the target material and refine the grains.

[0047] In a second aspect, the present invention provides a sputtering target material for a thin film resistor, wherein the sputtering target material is obtained according to the above-mentioned preparation method; the density of the sputtering target material obtained by the above-mentioned method is ≥95%.

[0048] The sputtering target material provided by the invention has high density, uniform component distribution and fine target grain size.

[0049] In a third aspect, the present invention provides an application of a sputtering target material for a thin film resistor, wherein the sputtering target is used as a sputtering target material for a thin film resistor.

[0050] In a specific implementation, the above-mentioned target material is used to deposit a resistive film on a 0805 type alumina substrate, with a sputtering power of 120 W, Ar:N=50:0 sccm, and a gas pressure of 0.5 Pa.

[0051] The thin film resistor provided by the present invention improves the grain size and strength by adding suitable additives to Si, Cr, Ni and Al, improves the resistivity and adjusts the resistance temperature coefficient by adding suitable oxides, prepares an intermediate powder with uniform particle size by alloy melting gas atomization, and then prepares a sputtering target material with high density, uniform component distribution and fine grain size by sintering and molding by a discharge plasma sintering method and a vacuum hot pressing sintering method, which provides more additive options for the preparation of the target material and does not rely solely on the addition of rare earth elements. The initial resistance of the thin film resistor prepared by the sputtering target material is ≥2kΩ and the resistance temperature coefficient is ≤±10ppm / ℃. Compared with the thin film resistor in the related art, the stability of the thin film resistor prepared by the present invention is improved by more than 50%, and it has the advantages of high stability and high resistance.

[0052] In order to enable those skilled in the art to understand the present application more clearly, the sputtering target material, preparation method and application of a thin film resistor described in the present application are now described in detail through the following embodiments.

[0053] Example 1 Si, Cr, Ni, Al and additives are used as raw materials, and the additives are Ti and Y. The raw materials are prepared according to the following proportions. According to the mass fraction, the addition amount of Si is 47.5wt%, the addition amount of Cr is 28.9wt%, the addition amount of Ni is 18.1wt%, the addition amount of Al is 3.5wt%, the addition amount of Ti is 1.8wt%, and the addition amount of Y is 0.2wt%.

[0054] The above raw materials are loaded into the crucible of the vacuum induction furnace for alloying treatment. The vacuum system is started first. When the vacuum degree in the furnace reaches the requirement, the induction heating system is started. The temperature of the alloying treatment is 1450℃, and the raw materials are melted to form a melt; when the raw materials are completely melted, Ar is used as the atomizing gas with a pressure of 3MPa, and the alloy melt is atomized into fine droplets through the nozzle; the droplets are rapidly cooled and solidified into powder in the high-pressure gas; the atomized powder is collected by a collection device, and then sieved to obtain an intermediate powder with an average particle size of 35µm.

[0055] An appropriate amount of intermediate powder was weighed and loaded into a graphite mold. The discharge plasma sintering method was used with a vacuum degree of about 50 Pa. The sintering temperature was set to 900°C and the pressure was set to 8 MPa for sintering to obtain a target blank.

[0056] The target blank is dry-ground to produce a target material of a target size.

[0057] The density of the target material obtained by the above preparation method is 96.5%, and the volume resistivity is 1865.4µΩ·cm. The target material is used to deposit a resistive film on a 0805 type alumina substrate, with a sputtering power of 120W, Ar:N=50:0sccm, and a gas pressure of 0.5Pa to obtain a thin film resistor with an initial resistance of 2.2kΩ and a resistance temperature coefficient of -8.72ppm / ℃.

[0058] In this embodiment 1, suitable additives are added to Si, Cr, Ni, and Al to improve the grain size and strength, and a sputtering target with high density, uniform component distribution, and fine grain size is prepared by a spark plasma sintering method. The initial resistance of the thin film resistor obtained by the sputtering target is ≥2kΩ, and the resistance temperature coefficient is ≤±10ppm / ℃. Compared with the thin film resistors in the related art, the stability of the thin film resistor prepared in this embodiment is improved by more than 50%, and it has the advantages of high stability and high resistance.

[0059] Example 2 Si, Cr, Ni, Al, additives and oxides are used as raw materials, the additive is Ti, the oxide is SiO2. The raw materials are prepared according to the following proportions. According to the mass fraction, the addition amount of Si is 37.0wt%, the addition amount of Cr is 24.6wt%, the addition amount of Ni is 21.9wt%, the addition amount of Al is 4.2wt%, the addition amount of Ti is 2.3wt%, and the addition amount of SiO2 is 10wt%.

[0060] Si, Cr, Ni, Al and Ti raw materials are loaded into the crucible of the vacuum induction furnace for alloying treatment. Start the vacuum system first. When the vacuum degree in the furnace reaches the requirement, start the induction heating system. The temperature of the alloying treatment is 1450℃, and the raw materials are melted to form a melt; when the raw materials are completely melted, Ar is used as the atomizing gas with a pressure of 5MPa, and the alloy melt is atomized into fine droplets through the nozzle; the droplets are rapidly cooled and solidified into powder in the high-pressure gas; the atomized powder is collected by a collection device, and then sieved to obtain an alloy powder with an average particle size of 25µm. SiO2 powder and alloy powder are added to the three-dimensional mixer according to the above ratio to obtain an intermediate powder.

[0061] An appropriate amount of intermediate powder was weighed and loaded into a graphite mold. The target blank was obtained by sintering using a discharge plasma sintering method with a vacuum degree of about 30 Pa, a sintering temperature of 1000°C and a pressure of 15 MPa.

[0062] The target blank is dry-ground to produce a target material of a target size.

[0063] The density of the target material obtained by the above preparation method is 97.6%, and the volume resistivity is 2879.1µΩ·cm. The thin film resistor is obtained by the same method of preparing a thin film resistor as in Example 1. The initial resistance of the thin film resistor is 6.8kΩ, and the resistance temperature coefficient is -7.6ppm / ℃.

[0064] In this embodiment, suitable additives are added to Si, Cr, Ni, and Al to improve the grain size and strength, and suitable oxides are added to improve the resistivity and adjust the resistance temperature coefficient. A spark plasma sintering method is used to prepare a sputtering target material with high density, uniform composition distribution, and fine grain size. More additive options are provided for the preparation of the target material, and it does not rely solely on the addition of rare earth elements. The initial resistance of the thin film resistor prepared by the sputtering target material is ≥2kΩ and the resistance temperature coefficient is ≤±10ppm / ℃. Compared with the thin film resistor in the related art, the stability of the thin film resistor prepared by the present invention is improved by more than 50%, and it has the advantages of high stability and high resistance.

[0065] Example 3 Si, Cr, Ni, Al, additives and oxides are used as raw materials, the additive is Mo, and the oxides are CuO and SiO2. The raw materials are prepared according to the following proportions: by mass fraction, the addition amount of Si is 39.9wt%, the addition amount of Cr is 24.6wt%, the addition amount of Ni is 21.9wt%, the addition amount of Al is 5.1wt%, the addition amount of Mo is 1.3wt%, the addition amount of CuO is 0.8 wt%, and the addition amount of SiO2 is 6.4wt%.

[0066] Si, Cr, Ni, Al and Mo raw materials are loaded into the crucible of the vacuum induction furnace for alloying treatment. Start the vacuum system first. When the vacuum degree in the furnace reaches the requirement, start the induction heating system. The temperature of the alloying treatment is 1600℃, and the raw materials are melted to form a melt; when the raw materials are completely melted, Ar is used as the atomizing gas with a pressure of 5MPa, and the alloy melt is atomized into fine droplets through a nozzle; the droplets are rapidly cooled and solidified into powder in the high-pressure gas; the atomized powder is collected by a collection device, and then sieved to obtain an alloy powder with an average particle size of 25µm. Add CuO powder and SiO2 powder together with alloy powder into a three-dimensional mixer according to the above ratio to obtain an intermediate powder.

[0067] An appropriate amount of intermediate powder was weighed and loaded into a graphite mold. The discharge plasma sintering method was used with a vacuum degree of about 30 Pa. The sintering temperature was set to 950°C and the pressure was set to 9 MPa for sintering to obtain a target blank.

[0068] The target blank is dry-ground to produce a target material of a target size.

[0069] The density of the target material obtained by the above preparation method is 98.5%, and the volume resistivity is 3263.9µΩ·cm. The thin film resistor is obtained by the same method of preparing a thin film resistor as in Example 1. The initial resistance of the thin film resistor is 5.4kΩ, and the resistance temperature coefficient is -6.5ppm / ℃.

[0070] Example 4 Si, Cr, Ni, Al and additives are used as raw materials, and the additives are Ti and Y. The raw material ratio and implementation steps for preparing the intermediate powder are the same as those in Example 1, except that an appropriate amount of the intermediate powder is weighed and loaded into a graphite mold, and a vacuum hot pressing sintering method is adopted, the vacuum degree is about 400Pa, the sintering temperature is set to 1100°C, and the pressure is 45MPa for sintering molding to obtain a target blank.

[0071] The target material prepared by the above method has a size of 559x127x13mm, a density of 97.1%, and a volume resistivity of 1763.2µΩ·cm. The same method for preparing a thin film resistor as in Example 1 is used to obtain a thin film resistor, the initial resistance of which is 2.4kΩ, and the temperature coefficient of resistance is -8.51ppm / ℃.

[0072] Example 5 Si, Cr, Ni, Al, additives and oxides are used as raw materials, the additive is Mo, and the oxides are MoO2 and SiO2. The raw materials are prepared according to the following proportions: by mass fraction, the addition amount of Si is 37.6wt%, the addition amount of Cr is 25.1wt%, the addition amount of Ni is 24.0wt%, the addition amount of Al is 4.9wt%, the addition amount of Mo is 1.3wt%, the addition amount of MoO2 is 0.9wt%, and the addition amount of SiO2 is 6.2wt%.

[0073] The mixed Si, Cr, Ni, Al and Mo raw materials are placed in a crucible of a vacuum induction furnace for alloying treatment. The alloying treatment temperature is 1580°C, the atomization pressure is 5MPa, and the remaining steps are the same as in Example 3 to obtain an alloy powder with an average particle size of 25µm. MoO2 powder and SiO2 powder are added to a vibration mixer together with the alloy powder according to the above ratio to obtain an intermediate powder.

[0074] An appropriate amount of intermediate powder was weighed and loaded into a graphite mold. The discharge plasma sintering method was used with a vacuum degree of about 100 Pa, a sintering temperature of 900°C, and a pressure of 11 MPa to obtain a target blank.

[0075] The target blank is dry-ground to produce a target material of a target size.

[0076] The density of the target material obtained by the above preparation method is 95.7%, and the volume resistivity is 3024.7µΩ·cm. The thin film resistor is obtained by the same method of preparing a thin film resistor as in Example 1. The initial resistance of the thin film resistor is 4.3kΩ, and the resistance temperature coefficient is -6.2ppm / ℃.

[0077] Example 6 Si, Cr, Ni, Al, additives and oxides are used as raw materials, the additive is Ti, and the oxides are RuO2 and V2O5. The raw materials are prepared according to the following proportions: by mass fraction, the addition amount of Si is 42.3wt%, the addition amount of Cr is 21.6wt%, the addition amount of Ni is 18.9wt%, the addition amount of Al is 4.2wt%, the addition amount of Ti is 2.3wt%, the addition amount of RuO2 is 6.5wt%, and the addition amount of V2O5 is 4.2wt%.

[0078] Si, Cr, Ni, Al and Ti raw materials are placed in a crucible of a vacuum induction furnace for alloying treatment. The alloying temperature is 1580°C, the pressure of the atomizing gas is 5 MPa, and the remaining steps are the same as in Example 3 to obtain an alloy powder with an average particle size of 25 µm. RuO2 powder and V2O5 powder are added to a three-dimensional mixer together with the alloy powder according to the above ratio to obtain an intermediate powder.

[0079] An appropriate amount of intermediate powder was weighed and loaded into a graphite mold. The discharge plasma sintering method was used with a vacuum degree of about 100 Pa, a sintering temperature of 900°C, and a pressure of 10 MPa to obtain a target blank.

[0080] The target blank is dry-ground to produce a target material of a target size.

[0081] The density of the target material obtained by the above preparation method is 95.5%, and the volume resistivity is 3963.9µΩ·cm. The thin film resistor is obtained by the same method of preparing a thin film resistor as in Example 1. The initial resistance of the thin film resistor is 6.6kΩ, and the resistance temperature coefficient is -8.9ppm / ℃.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0083] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily required by the present invention.

[0084] The sputtering target material, preparation method and application of a thin film resistor provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for preparing a sputtering target for a thin film resistor, characterized in that: The preparation method specifically comprises the following steps: S1. Using Si, Cr, Ni, Al, additives and optional oxides as raw materials, the raw materials are prepared into intermediate powder by alloy melting gas atomization; S2, weighing a certain amount of the intermediate powder, loading it into a graphite mold, sintering it to obtain a target blank; S3, performing surface polishing treatment on the target blank, and processing the target target material according to the target size; In terms of mass fraction, the amount of Si added is 30-60wt%, the amount of Cr added is 20-40wt%, the amount of Ni added is 15-30wt%, the amount of Al added is 2-8wt%, the amount of additives added is 0.1-5wt%, and the amount of oxide added is 0-12.5wt%; The additive is selected from one or more of Mo, Ti and rare earth elements; The oxide is selected from one or more of CuO, MoO2, RuO2, SiO2 and V2O5.

2. The preparation method according to claim 1, characterized in that: When the raw material contains oxides, the process of preparing the raw material into an intermediate powder by alloy smelting and gas atomization includes: Alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace to form an alloyed melt, and then using high-pressure Ar as an atomizing gas to prepare the melt into an alloy powder; Mixing the alloy powder and the oxide powder to obtain the intermediate powder; The temperature of the alloying treatment is 1200-1700°C; The pressure of the atomizing gas is 1.5-10 MPa.

3. The preparation method according to claim 2, characterized in that: The alloy powder and the oxide powder are mixed by a three-dimensional mixing method or a vibration mixing method.

4. The preparation method according to claim 1, characterized in that: When the raw material does not contain oxides, the method of preparing the raw material into an intermediate powder by alloy smelting gas atomization includes: Alloying Si, Cr, Ni, Al and additives in a vacuum induction furnace to form an alloyed melt, and then using high-pressure Ar as an atomizing gas to prepare the melt into the intermediate powder; The temperature of the alloying treatment is 1200-1700°C; The pressure of the atomizing gas is 1.5-10 MPa.

5. The preparation method according to claim 1, characterized in that: The particle size of the intermediate powder is 10-60 μm.

6. The preparation method according to claim 1, characterized in that: In step S2, the sintering molding adopts vacuum hot pressing sintering, and the vacuum hot pressing sintering is carried out under Ar protection conditions, with a vacuum degree lower than 500 Pa, a temperature of 1000-1250° C., and a pressure of 15-60 MPa.

7. The preparation method according to claim 1, characterized in that: In step S2, the sintering molding adopts spark plasma sintering, the vacuum degree of the spark plasma sintering is 20~100Pa, the sintering temperature is 900~1100℃, and the pressure is 5~20MPa.

8. A sputtering target material for a thin film resistor, characterized in that: The sputtering target is obtained by the preparation method according to any one of claims 1 to 7; The density of the sputtering target is ≥95%.

9. An application of the sputtering target material for the thin film resistor according to claim 8, characterized in that: The sputtering target is used as a sputtering target material for a thin film resistor.

Images