Thin-film resistor with low resistance temperature coefficient and preparation method thereof

Abstract

The invention discloses a thin-film resistor with a low resistance temperature coefficient and a preparation method of the thin-film resistor. The resistor comprises a substrate and a resistor structure, and further comprises a deposition layer located between the substrate and the resistor structure, and the deposition layer is of a rough insulation structure and is used for reducing the temperature coefficient of the resistor. The method specifically comprises the following steps of: degreasing a substrate by using a mixed detergent; preparing a nanoparticle suspension by using deionized water, and adjusting the concentration and the pH value of the suspension; using an automatic impregnator to adsorb the nanoparticles onto the substrate, thereby depositing a layer of nanoparticle film; the roughness of the surface of the substrate is controlled in a mode of increasing the number of layers by depositing nano-particles for multiple times, and then sputtering of the thin-film resistor is carried out. The resistance temperature coefficient is reduced in a mode of pre-depositing a layer of insulating material, and the surface roughness after deposition can be accurately controlled through a manufacturing process, so that the resistance value and the TCR of the resistive film are controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuits, in particular to a thin film resistor with a low temperature coefficient of resistance and a preparation method thereof. Background Art

[0002] Thin film resistors are made by evaporating a certain resistivity material onto the surface of an insulating material using a similar evaporation method, such as Figure 1 As shown, it includes a substrate 101 and a resistor structure 102. Thin film resistors are widely used in the manufacture of various chips. The temperature coefficient of resistance (TCR) indicates the relative change in resistance when the temperature changes by 1 degree Celsius, with the unit being ppm / °C.

[0003]

[0004] T is the temperature at the time of measurement, R and R0 are the sheet resistances at the measurement temperature T and room temperature T0, and ppm (Parts per million) means one part per million.

[0005] Controlling the TCR (Temperature Cross-Resistance Ratio) of thin-film resistors is a significant technical challenge in industry, as it directly impacts the stability of the resistor's performance across various temperatures. By selecting materials with low TCRs, such as certain special alloys or oxides, thin-film resistors with lower temperature coefficients can be manufactured. TCR can be effectively controlled by designing specific thin-film structures, such as multilayer films or films with specialized shapes. Annealing or heat treatment can reduce stress and defects in the film, or introduce new phases, altering the film's internal structure and thereby improving its temperature coefficient.

[0006] However, the selected materials may be expensive and difficult to process, and may require high-precision deposition technology. Designing specific structures or annealing will increase additional processing time and cost, and the precision requirements are also very high, making it difficult to obtain the ideal temperature coefficient. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a thin film resistor with a low temperature coefficient of resistance and a preparation method thereof.

[0008] In a first aspect, the present invention provides a thin film resistor comprising a substrate and a resistor structure, and further comprising a deposition layer located between the substrate and the resistor structure, wherein the deposition layer is a rough insulating structure for reducing the temperature coefficient of resistance.

[0009] In a second aspect, the present invention provides a method for preparing the thin film resistor.

[0010] Degrease the substrate with a mixed detergent;

[0011] preparing a nanoparticle suspension using deionized water, and adjusting the concentration and pH value of the suspension;

[0012] Adsorbing the nanoparticles onto the substrate using an automated impregnation machine, thereby depositing a thin film of nanoparticles;

[0013] The roughness of the substrate surface is controlled by depositing nanoparticles multiple times to increase the number of layers, followed by sputtering of thin film resistors.

[0014] Beneficial effects of the present invention: The present invention can reduce the temperature coefficient of resistance by pre-depositing a layer of insulating material. The surface roughness after deposition can be precisely controlled through the manufacturing process, thereby controlling the resistance value and TCR of the resistor film, and obtaining a thin film resistor with a low temperature coefficient in a simple manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a thin film resistor in the prior art;

[0016] Figure 2 A thin film resistor according to an embodiment of the present application;

[0017] Figure 3 The relationship between roughness and resistance in the embodiment of this application;

[0018] Figure 4 This is the relationship between roughness and temperature coefficient TCR in the embodiment of this application. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings and examples.

[0020] like Figure 2 As shown, the embodiment of the present application provides a thin film resistor, including a substrate 201 and a resistor structure 203, and also includes a deposition layer 202 located between the substrate and the resistor structure, wherein the deposition layer is a rough insulating structure for reducing the temperature coefficient of resistance. Since the thin film resistor is very thin, even a very small surface roughness can cause a large change in the performance of the thin film resistor. In the present application, a rough insulating structure is first made under the thin film resistor, which will cause the surface of the thin film resistor to be sputtered later to be uneven, which will cause the thin film resistance to increase and the TCR to decrease, see Figure 3 and Figure 4 ,It can be seen from the figure that as the substrate roughness increases, the resistance of the thin film resistor on the substrate will increase, and the absolute value of the temperature coefficient will approach 0.

[0021] In some embodiments, the roughness of the insulating structure is controlled by depositing nanoparticles multiple times to increase the number of layers.

[0022] Furthermore, the nanoparticles are SiO2 nanoparticles, which are adsorbed onto the substrate by an automatic impregnation machine. Nanoparticles generally refer to ultrafine particles with a size between 1 and 100 nm. The components making up the nanoparticles can be metals, oxides, or other various compounds. Nanoparticles should possess novel physical and chemical properties. High-purity nanopowders can be used as fine ceramic materials, catalysts, and pharmaceuticals.

[0023] Furthermore, the resistor structure is obtained by magnetron sputtering. Magnetron sputtering is a type of physical vapor deposition (PVD). The general sputtering method can be used to prepare a variety of materials such as metals, semiconductors, and insulators, and has the advantages of simple equipment, easy control, large coating area, and strong adhesion.

[0024] The present application also provides a method for preparing the thin film resistor, which is as follows:

[0025] Before sputtering thin film resistors, nanoparticles are used to adjust the roughness of the substrate. Specifically, the substrate is degreased with a mixed detergent of hydrochloric acid, hydrogen peroxide and ultrapure water; then the residue is cleaned with an aqueous nitric acid solution, and then cleaned with a NaOH solution under ultrasound for a certain period of time. Deionized water is used to make a nanoparticle suspension. The concentration of the nanoparticle suspension is adjusted to 0.03wt% and the pH value of the solution is adjusted to 3.0 (using HCl solution). An automatic impregnation machine is used to adsorb SiO2 nanoparticles onto the substrate. The immersion time in each nanoparticle solution is 10 minutes, followed by three rinses in deionized water. This can deposit a layer of nanoparticle film. The roughness of the substrate surface can be controlled by depositing nanoparticles multiple times to increase the number of layers.

[0026] Then the thin film resistor is sputtered and finally annealed at 550℃ for 3h.

[0027] This embodiment uses a method of pre-depositing a layer of insulating material to reduce the temperature coefficient of resistance. The surface roughness after deposition can be precisely controlled through the manufacturing process, thereby controlling the resistance value and TCR of the resistor film, thereby obtaining a lower ideal TCR.

[0028] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A thin film resistor, comprising a substrate and a resistor structure, characterized in that: The invention also comprises a deposition layer located between the substrate and the resistance structure, wherein the deposition layer is a rough insulation structure and is used for reducing the resistance temperature coefficient.

2. A thin film resistor according to claim 1, characterized in that: The roughness of the insulating structure is controlled by depositing nanoparticles multiple times to increase the number of layers.

3. A thin film resistor according to claim 2, characterized in that: The nanoparticles are SiO2 nanoparticles, which are adsorbed onto the substrate by an automatic impregnation machine.

4. A thin film resistor according to any one of claims 1 to 3, characterized in that: The resistor structure is obtained by magnetron sputtering.

5. A method for preparing the thin film resistor according to any one of claims 1 to 4, characterized in that: Degrease the substrate with a mixed detergent; Using deionized water to prepare a nanoparticle suspension, and adjusting the concentration and pH value of the suspension; Adsorbing the nanoparticles onto the substrate using an automated impregnation machine, thereby depositing a nanoparticle film; The roughness of the substrate surface is controlled by depositing nanoparticles multiple times to increase the number of layers, followed by sputtering of thin film resistors.

6. The method according to claim 5, characterized in that: The mixed detergent consists of hydrochloric acid, hydrogen peroxide and ultrapure water.

7. The method according to claim 5, characterized in that: After degreasing, the residues were cleaned with aqueous nitric acid solution and then with sodium hydroxide solution under ultrasound.

8. The method according to claim 5, characterized in that: The concentration of the suspension is 0.03wt% and the pH value is 3.

0.

9. The method according to claim 5, characterized in that: The nanoparticles are SiO2 nanoparticles.

10. The method according to claim 5, characterized in that: After sputtering, the film was annealed at 550°C for 3 h.

Images