Method for optimizing NiCr alloy resistance temperature coefficient

Abstract

The invention provides a method for optimizing a NiCr alloy resistance temperature coefficient, which comprises the following steps of: producing by adopting a thin film process, selecting an insulating substrate with a certain thickness, firstly entering a metallization process, preparing a series of NiCr alloy thin film samples by adding a certain amount of doping gas and changing the content of argon in the NiCr metallization process, and then carrying out photoetching on the NiCr alloy thin film samples in a photoetching process to obtain the NiCr alloy resistance temperature coefficient. The method comprises the following steps: photoetching an electrode pattern by using a photoetching plate, carrying out secondary photoetching after an etching process to obtain a resistor pattern, carrying out thermal annealing on an insulating substrate engraved with the pattern under a vacuum condition at a certain temperature for a period of time, and after thermal annealing treatment, placing a test article in a hot plate to carry out resistance test at different temperatures. And finally, the metal film resistors prepared under different argon contents are used at different temperatures, TCR is calculated and compared to obtain the optimized NiCr alloy film resistor, the NiCr film is deposited on the insulating substrate by adjusting the argon content, and the resistance temperature coefficient of the NiCr film can be further optimized on the existing performance.

Description

Technical Field

[0001] This application relates to the technical field of optimizing the temperature coefficient of alloy resistance, and particularly relates to a method for optimizing the temperature coefficient of NiCr alloy resistance. Background Art

[0002] NiCr alloy thin films are commonly used as precision resistors in hybrid integrated circuits. With the development of technology, the requirements for the electrical properties of resistors are getting higher and higher, and TCR is a key indicator for evaluating whether the electrical properties of a resistor are excellent.

[0003] For NiCr alloy resistor thin films, a resistance temperature coefficient (TCR) tending to 0 is one of the guarantees for obtaining high-performance resistors. The existing TCR of NiCr alloy resistor thin films is commonly ±25 - ±50 ppm / °C, and there is still some room for improvement in its TCR performance. Currently, optimizing the resistance temperature coefficient of NiCr resistor thin films can be achieved by changing the thermal annealing temperature or time, but it usually has a greater impact on the TCR value. By adjusting the gas content of metal deposition, the performance of NiCr thin films can be improved to a certain extent, thereby improving its TCR. On this basis, the present invention aims to provide a method that can optimize the existing TCR performance of NiCr thin films. Summary of the Invention

[0004] To solve the above problems, this application proposes a method for optimizing the temperature coefficient of NiCr alloy resistance. It is produced by thin film technology. A certain thickness of insulating substrate less than 1 mm is selected. First, it enters the metallization process. In the NiCr metallization process, a certain amount of doping gas is added, and the content of argon is changed to prepare a series of NiCr alloy thin film samples; in the photolithography process, a special photomask is used to lithograph the electrode pattern. After the etching process, secondary lithography is performed to obtain the resistor pattern. After thermal annealing treatment, the test samples are placed on a hot plate to measure the resistance values at different temperatures and calculate the TCR. By comparing the TCR, the optimized NiCr alloy thin film resistor is obtained. The present invention deposits NiCr thin films on the insulating substrate by adjusting the argon content, and its resistance temperature coefficient can be further optimized on the existing performance.

[0005] This application is achieved through the following technical solutions:

[0006] This application proposes a method for optimizing the temperature coefficient of NiCr alloy resistance, including the following steps:

[0007] S1. First, deposit a multi-layer metal thin film on the insulating substrate. During the deposition process, a doping gas is introduced, and argon is introduced simultaneously. Different metal thin film samples are prepared by introducing different contents of argon.

[0008] S2. Lithographically pattern the metal thin film sample obtained in step S1 to form a pattern that meets the test requirements and then etch it;

[0009] S3. Place the insulating substrate with the patterned film in a vacuum at a certain temperature and perform thermal annealing for a period of time;

[0010] S4. Place the thermally annealed insulating substrate in a high and low temperature oven at different temperatures and measure its resistance value;

[0011] S5. Use the metal thin film resistors prepared under different argon contents at different temperatures, calculate the TCR value, compare the TCR values obtained from the calculation, and obtain an optimized alloy thin film resistor.

[0012] Further, in step S1, a multi-layer metal thin film is deposited on the insulating substrate by physical vapor deposition technology, and the physical vapor deposition technology includes evaporation, sputtering, and ion plating.

[0013] Further, the multi-layer metal thin film includes a resistance layer, a transition layer, and an electrode layer. The resistance layer is a NiCr alloy layer, the transition layer is a TiW alloy layer, and the electrode layer is a gold layer.

[0014] Further, in step S1, the doping gases include oxygen and nitrogen.

[0015] Further, in step S1, the different argon contents are the base value, 90% of the base value, and 110% of the base value, respectively.

[0016] Further, in step S2, the etching method for the metal thin film sample is as follows: First, use a mask and photoresist to cover the resistor pattern to be formed, and then use an etching solution to remove the uncovered area to form the resistor pattern.

[0017] Further, in step S3, the temperature at which the patterned insulating substrate is placed is 350 °C, and the thermal annealing time under vacuum conditions is 2 h.

[0018] Further, in step S4, the different temperatures at which the thermally annealed insulating substrate is placed are: -55 °C, room temperature, 75 °C, and 125 °C.

[0019] Further, in step S4, a digital multimeter of model keysight3458 is used to measure the resistance value of the alloy thin film resistor at different temperatures.

[0020] Further, in step S5, the TCR is calculated by the following formula:

[0021]

[0022] Where, R tR represents the resistance value after thermal annealing, R0 represents the resistance value before thermal annealing, T represents the thermal annealing temperature, and T0 represents the room temperature.

[0023] Advantages of the present application: The main purpose of the present invention is to provide a method capable of optimizing the temperature coefficient of resistance. It is produced by a thin-film process. A certain thickness of insulating substrate less than 1 mm is selected. First, it enters the metallization process. In the NiCr metallization process, a certain amount of doping gas is added, and the content of argon is changed to prepare a series of NiCr alloy thin-film samples. In the photolithography process, a special photomask is used to photolithograph the electrode pattern. After the etching process, secondary photolithography is performed to obtain the resistance pattern. After thermal annealing treatment, the test samples are placed on a hot plate to measure the resistance values at different temperatures and calculate the TCR. By comparing the TCR, an optimized NiCr alloy thin-film resistor is obtained. The present invention deposits NiCr thin films on the insulating substrate by adjusting the argon content, and its temperature coefficient of resistance can be further optimized on the existing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the overall process of the present invention;

[0025] Figure 2 is a schematic diagram of the change in the test temperature - TCR of the NiCr resistor of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Among them, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0028] In addition, the descriptions involving "first", "second", etc. in this application are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the said features. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this invention.

[0029] Please refer to Figure 1 , this application proposes a method for optimizing the temperature coefficient of resistance of NiCr alloy, including the following steps:

[0030] S1. First, deposit multiple layers of metal films on an insulating substrate. During the deposition process, introduce a doping gas and simultaneously introduce argon gas, and prepare different metal film samples by introducing different contents of argon gas.

[0031] Specifically, the insulating substrate can be a silicon substrate or a ceramic substrate of aluminum oxide. The embodiments of the present invention do not make specific limitations on this. After preparing the insulating substrate, use a thin film cleaning process to clean the insulating substrate. For example, first remove the obvious dry fixed particles on the surface of the insulating substrate, and then use chemical reagents such as alcohol, acetone, and cleaning agents to remove the dirt on the surface of the silicon substrate. It can be cleaned in large batches simultaneously, saving time costs. After cleaning, use physical vapor deposition technology to deposit multiple layers of metal films on the insulating substrate. Physical vapor deposition is a technology for depositing thin films by physical methods in a vacuum environment. It mainly heats solid materials to the sublimation temperature to vaporize them, and then condenses these gaseous atoms or molecules into solid thin films on the substrate. Physical vapor deposition technology includes evaporation, sputtering, and ion plating methods. Among them, evaporation is to heat the material to evaporate it to form a gas and condense it into a solid thin film on the substrate; sputtering is to place the material in a vacuum environment and bombard the surface of the material with high-energy particles to ionize it and deposit it on the substrate; ion plating is to utilize the movement characteristics and energy of ions in an electric field, and by controlling the energy and angle of the ion beam, deposit it directionally on the substrate. In this embodiment, sputtering deposition is used to deposit multiple layers of metal films on the insulating substrate. The multiple layers of metal films are a resistance layer, a transition layer, and an electrode layer respectively. The resistance layer is a NiCr alloy layer, the transition layer is a TiW alloy layer, and the electrode layer is a gold layer. And during the deposition process, introduce a doping gas, and the doping gas is oxygen and nitrogen. In this embodiment, the argon content in the NiCr deposition process is set to the base value, 90% of the base value, and 110% of the base value respectively. By adjusting the argon content, deposit NiCr films on the insulating substrate, and its temperature coefficient of resistance can be further optimized on the existing performance.

[0032] S2. Lithographically pattern the metal thin film sample obtained in step S1 to meet the test requirements and etch it.

[0033] Specifically, after depositing multiple layers of metal thin film on the insulating substrate, etch the resistor pattern on the metal thin film sample. First, use a mask and photoresist to cover the pattern of the resistor to be formed, protecting the designed resistor pattern area, and then use an etching solution to remove the unprotected area to form the resistor pattern.

[0034] S3. Place the insulating substrate with the pattern etched thereon in a vacuum at a certain temperature and perform thermal annealing for a period of time.

[0035] Specifically, after the etching of the resistor pattern is completed, place the insulating substrate with the pattern etched thereon in a vacuum at a certain temperature and perform thermal annealing for a period of time. In this embodiment, the temperature is 350 °C and the thermal annealing time is 2 h.

[0036] S4. Place the insulating substrate after thermal annealing in a high and low temperature oven at different temperatures and measure its resistance value.

[0037] Specifically, after thermal annealing is completed, place the insulating substrate in a high and low temperature oven at different temperatures. In this embodiment, the temperatures at which the insulating substrate is placed are -55 °C, room temperature, 75 °C, and 125 °C respectively. Under different temperature conditions, use a digital multimeter of model keysight3458 to measure the resistance values of the alloy thin film resistors at different temperatures.

[0038] S5. Use the metal thin film resistors prepared under different argon contents at different temperatures, calculate the TCR value, and compare the calculated TCR values to obtain an optimized alloy thin film resistor.

[0039] Specifically, use the alloy thin film resistors prepared under different argon contents at different temperatures and calculate their TCR values at different temperatures. The TCR value of the alloy thin film resistor is calculated by the following formula:

[0040]

[0041] where R t represents the resistance value after thermal annealing, R0 represents the resistance value before thermal annealing, T represents the thermal annealing temperature, and T0 represents the room temperature. Compare the calculated TCR values to obtain an optimized alloy thin film resistor.

[0042] As Figure 2 shown, Figure 2It is a schematic diagram of the temperature-TCR change of the NiCr resistor. In this embodiment, the TCR change calculated when the NiCr resistor is used at different temperatures is measured under the conditions that the argon content is the base value, 90% of the base value, and 110% of the base value. According to the values and trends in the figure, an optimized NiCr alloy thin film resistor can be obtained.

[0043] The main purpose of the present invention is to provide a method capable of optimizing the temperature coefficient of resistance. It is produced by a thin film process. A certain thickness of insulating substrate less than 1 mm is selected. First, it enters the metal chemical process. In the NiCr metallization process, a certain amount of doping gas is added, and a series of NiCr alloy thin film samples are prepared by changing the argon content; in the lithography process, a special lithography mask is used to lithograph the electrode pattern. After the etching process, secondary lithography is performed to obtain the resistor pattern. After thermal annealing treatment, the test sample is placed on a hot plate to measure the resistance value at different temperatures and calculate the TCR. By comparing the TCR, an optimized NiCr alloy thin film resistor is obtained. The present invention deposits the NiCr thin film on the insulating substrate by adjusting the argon content, and its temperature coefficient of resistance can be further optimized on the existing performance.

[0044] Of course, the present application can also have many other implementation manners. Based on this implementation manner, other implementation manners obtained by those of ordinary skill in the art without any creative work belong to the scope protected by the present application.

Claims

1. A method for optimizing the temperature coefficient of resistance of NiCr alloy, characterized in that, It includes the following steps: S1. First, deposit multiple layers of metal thin films on an insulating substrate. During the deposition process, introduce a doping gas and simultaneously introduce argon gas, and prepare different metal thin film samples by introducing different contents of argon gas; S2. Lithograph a pattern that meets the test requirements on the metal thin film sample obtained in step S1 and perform etching; S3. Place the insulating substrate with the patterned film under vacuum conditions at a certain temperature and anneal it for a period of time; S4. Place the thermally annealed insulating substrate in a high and low temperature oven at different temperatures and measure its resistance value; S5. Use the metal thin film resistors prepared with different argon contents at different temperatures, calculate the TCR value, compare the TCR values obtained by calculation, and obtain an optimized alloy thin film resistor.

2. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 1, wherein In step S1, a physical vapor deposition technique is used to deposit multiple layers of metal thin films on the insulating substrate, and the physical vapor deposition technique includes evaporation, sputtering, and ion plating.

3. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 2, characterized in that The multiple layers of metal thin films include a resistance layer, a transition layer, and an electrode layer. The resistance layer is a NiCr alloy layer, the transition layer is a TiW alloy layer, and the electrode layer is a gold layer.

4. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 1, wherein, In step S1, the doping gas includes oxygen and nitrogen.

5. The method for optimizing the temperature coefficient of resistance of the NiCr alloy according to claim 1, characterized in that, In step S1, the different contents of argon gas are the base value, 90% of the base value, and 110% of the base value, respectively.

6. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 1, characterized in that In step S2, the etching method for the metal thin film sample is as follows: First, use a mask and photoresist to cover the resistance pattern to be formed, and then use an etching solution to remove the uncovered area to form the resistance pattern.

7. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 1, characterized in that, In step S3, the temperature at which the insulating substrate with the patterned film is placed is 350 °C, and the thermal annealing time under vacuum conditions is 2 h.

8. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 1, characterized in that In step S4, the different temperatures at which the thermally annealed insulating substrate is placed are: -55 °C, room temperature, 75 °C, and 125 °C.

9. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 8, characterized in that, In step S4, a digital multimeter of model keysight3458 is used to measure the resistance value of the alloy thin film resistor at different temperatures.

10. The method for optimizing the temperature coefficient of resistance of NiCr alloy according to claim 1, wherein, In step S5, calculate TCR through the following formula: Among them, R t represents the resistance value after thermal annealing, R0 represents the resistance value before thermal annealing, T represents the thermal annealing temperature, and T0 represents the room temperature.

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