A method for producing thin film resistors with high precision resistance

Abstract

The present application relates to the technical field of semiconductor device resistor production, and specifically to a method for producing thin-film resistors with high-precision resistance, comprising: sintering a white substrate, removing surface impurities through high-temperature sintering; printing and drying electrodes; sintering electrodes; and magnetron sputtering: placing the white substrate after electrode sintering into a sputtering chamber, sputtering an alloy layer on the entire front of the white substrate to form a thin film. During the magnetron sputtering process, measuring the transmittance variation characteristics of the sputtered resistor layer film in the test sample after magnetron sputtering to measure the film thickness and evaluate the rationality of the sputtering temperature during the magnetron sputtering process. Subsequently, through aging, masking, exposure, development, etching, laser, protective layer printing and drying, sintering, strip folding and stacking, end electrode sputtering, granular folding, nickel-tin roller plating of electrodes, magnetic separation, and package inspection, a thin-film resistor that has been produced and packaged is obtained. The present application can improve the production quality of thin-film resistors.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor device resistor production, and in particular to a method for producing high-precision thin-film resistors. Background Art

[0002] During the thin-film resistor production process, vacuum sputtering is performed on the chip's thin-film resistor surface area. This allows atoms or molecules to collide with the surface of the chip's thin-film resistor and form a thin-film resistor layer. By measuring the thickness of the thin-film resistor layer and accurately assessing its uniformity, the sputtering temperature can be adjusted based on this uniformity to achieve optimal resistance performance in the final thin-film resistor product.

[0003] Most existing technologies use optical properties to measure the thickness of the film on the sputtered resistor layer. This measurement method can analyze the film uniformity between different measurement positions in the sputtered resistor layer. However, due to the interference of ambient light and the surface roughness of the film, the authenticity of the optical properties of the film at different positions is poor, resulting in the inability to accurately test and analyze the film uniformity of the sputtered resistor layer, and thus making it impossible to accurately and effectively feedback adjust the sputtering parameters during the magnetron sputtering process. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a method for producing thin-film resistors with high-precision resistance to solve the existing problems.

[0005] The present invention discloses a method for producing a high-precision thin-film resistor using the following technical solutions:

[0006] One embodiment of the present application provides a method for producing a thin film resistor with high precision resistance, comprising the following steps:

[0007] White substrate sintering: The white substrate is an insulating plate, which is sintered at high temperature to remove surface impurities;

[0008] Electrode printing and drying: Print the front electrode on the front of the white substrate and the back electrode on the back, and then dry them;

[0009] Electrode sintering: sintering the front and back electrodes of the white substrate after printing and drying;

[0010] Magnetron sputtering: Place the white substrate after electrode sintering into the sputtering chamber, and sputter the alloy layer on the entire front of the white substrate to form a thin film. During the magnetron sputtering process, measure the transmittance of the sputtered resistor layer thin film in the test sample after magnetron sputtering. Analyze the deviation of the transmittance of the thin film in each local band at each measurement position, and construct the roughness interference of each measurement position in each local band. Combined with the change of the roughness interference of each measurement position in all local bands, the roughness significance coefficient of each measurement position is obtained to screen the target measurement point.

[0011] Perform modal decomposition on the transmittance of the target measurement point in each local band, and construct the invalid fluctuation characteristic value of each target measurement point in each local band through the difference between the elements in the IMF component to screen the target band;

[0012] The film thickness is measured by the transmittance within the target band at each target measurement point, and the sputtering temperature during the magnetron sputtering process is adjusted based on the measurement results of the film thickness at all target measurement points;

[0013] After that, the thin film resistor is produced and packaged through aging, masking, exposure, development, etching, laser, protective layer printing and drying, sintering, strip folding and stacking, end electrode sputtering, particle folding, roller electrode nickel-tin plating, magnetic separation and package inspection.

[0014] Preferably, a plurality of horizontal lines and vertical lines are provided on the front and back of the insulating plate, which cross to form each insulating module, and each insulating module serves as a resistor module to be produced.

[0015] Preferably, in the electrode printing and drying step, the front electrode partially covers the front side of the white substrate, and the back electrode partially covers the back side of the white substrate.

[0016] Preferably, the calculation method of the roughness interference degree of each measurement position in each local band is:

[0017] Ds i,j =exp(-Xs i.j );where Ds i,j is the roughness interference of the i-th measurement position in the j-th local band, exp() is an exponential function with a natural constant as the base, Xs i.j is the mean value of the elements in the transmittance difference vector of the i-th measurement position in the j-th local band;

[0018] Among them, all wavelengths in the ultraviolet to visible light band at each measurement position are evenly divided into multiple local bands, and all transmittances in each local band at each measurement position are arranged in ascending order of wavelength to form a transmittance sub-vector of each measurement position in each local band;

[0019] The mean vector of the transmittance sub-vectors of all measurement positions in each local band is used as the overall transmittance sub-vector of each local band, and the difference vector between the transmittance sub-vector of each measurement position in each local band and the overall transmittance sub-vector is used as the transmittance difference vector of each measurement position in each local band.

[0020] Preferably, the method for obtaining the roughness significance coefficient of each measurement position is:

[0021] The roughness interference degrees of all local bands at each measurement position are arranged in ascending order of wavelength to form the roughness interference vector of each measurement position. The vector obtained by taking the absolute value of each element in the first-order difference vector of the roughness interference vector is used as the change difference vector of each measurement position. The roughness significance coefficient of each measurement position is calculated as follows:

[0022] Where Pu i is the roughness significance coefficient of the i-th measurement position, norm is the exponential normalization function, is the mean value of the elements in the rough interference vector at the i-th measurement position, is the mean of the elements in the change difference vector of the i-th measurement position, and ∈ is a constant to avoid the denominator being zero.

[0023] Preferably, the method for screening the target measurement points is:

[0024] The sum of the roughness interference degrees of each measurement position in all local bands is calculated, and the product of the roughness significance coefficient of each measurement position and the sum corresponding to each measurement position is used as the roughness eigenvalue of each measurement position. The roughness eigenvalues of all measurement positions are threshold segmented, and the measurement positions corresponding to the roughness eigenvalues above the segmentation threshold are used as target measurement points.

[0025] Preferably, the calculation method of the invalid fluctuation characteristic value of each target measurement point in each local band is:

[0026] In the formula, Ge u,j is the invalid fluctuation characteristic value of the u-th target measurement point in the j-th local band, K is the number of elements in the invalid component of the u-th target measurement point in the j-th local band, f u,j,k and f u,j,k-1 are the kth and k-1th elements in the invalid component of the uth target measurement point in the jth local band, respectively. The DTW distance between the transmittance subvector of the target measurement point in each local band and its IMF components is calculated, and the IMF component with the largest DTW distance is recorded as the invalid component of the target measurement point in each local band.

[0027] Preferably, the method for screening the target band is: for each local band, calculate the average of the invalid fluctuation characteristic values of all target measurement points in the local band, record it as the invalid fluctuation level value of the local band, and take the local band corresponding to the minimum invalid fluctuation level value as the target band.

[0028] Preferably, the film thickness is calculated as follows: Where ds u is the film thickness at the uth target measurement point, T u is the average transmittance within the target band at the u-th target measurement point, and α is the absorption coefficient of the sputtered resistor layer.

[0029] Preferably, the adjusting the sputtering temperature during the magnetron sputtering process includes:

[0030] The coefficient of variation of the film thickness at all target measurement points is counted. If the coefficient of variation is higher than a preset threshold, the sputtering temperature is increased; otherwise, the sputtering temperature is kept unchanged.

[0031] This application has at least the following beneficial effects:

[0032] The present application is based on measuring the transmittance of the sputtered resistor layer film in the test sample after magnetron sputtering, analyzing the transmittance characteristics of the film at different positions, and screening out measurement points that are less affected by the interference of the film surface roughness as target measurement points; further, analyzing the interference influence of the transmittance in different local bands in all target measurement points, and screening out the band that is less affected by the interference of ambient light as the target band; accurately measuring the film thickness through the transmittance within the target band at the target measurement point, and testing and analyzing the film uniformity of the sputtered resistor layer through the measurement results of the film thickness at all target measurement points, thereby improving the accuracy of the test and analysis of the film uniformity of the sputtered resistor layer, and then accurately and effectively feedback-adjusting the sputtering temperature during the magnetron sputtering process to improve the production quality of the thin film resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A flowchart of the steps of a method for producing a high-precision thin-film resistor provided in this application;

[0035] Figure 2This is a flow chart of the film thickness measurement and analysis and sputtering temperature adjustment process during the magnetron sputtering process provided in this application. DETAILED DESCRIPTION

[0036] To further illustrate the technical means and effectiveness of this application to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effectiveness of a method for producing a high-precision thin-film resistor proposed in this application. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0037] Unless otherwise defined, terms such as "comprises," "comprising," or any other variants thereof are intended to encompass non-exclusive inclusion, such that a circuit structure, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such article or device. In the absence of further restrictions, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the article or device comprising the element. In addition, the term "and\or" as used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains.

[0038] The specific scheme of the method for producing a high-precision thin-film resistor provided by the present application is described in detail below with reference to the accompanying drawings.

[0039] An embodiment of the present application provides a method for producing a high-precision thin-film resistor. For details, please refer to Figure 1 , including the following steps:

[0040] S1, White Substrate Sintering: The white substrate is an insulating sheet material that undergoes high-temperature sintering to remove surface impurities. Multiple horizontal and vertical lines are laid on the front and back of the white substrate, intersecting to form each insulating module. High-temperature sintering is then used to remove surface impurities. It should be noted that each insulating module corresponds to a resistor module to be produced, and subsequent production and processing steps result in a single resistor module.

[0041] S2, electrode printing and drying: printing a front electrode on the front side of the white substrate and a back electrode on the back side, and performing drying treatment, wherein the front electrode partially covers the front side of the white substrate and the back electrode partially covers the back side of the white substrate.

[0042] S3, electrode sintering: sintering the front electrode and the back electrode of the printed and dried white substrate.

[0043] S4, magnetron sputtering: Place the white substrate after electrode sintering into the sputtering chamber, and use the magnetron sputtering coating machine to sputter the alloy layer on the front surface of the white substrate insulator to form a thin film to generate the initial resistance value.

[0044] During the magnetron sputtering process, this embodiment selects target measurement points by analyzing the transmittance characteristics of the sputtered resistor layer in the test sample after magnetron sputtering. The target band is selected based on the interference of the transmittance of the target measurement point in different bands to measure the film thickness and perform film uniformity analysis. The sputtering temperature during the magnetron sputtering process is then feedback-regulated to ensure the production quality of the thin film resistor. The specific steps are as follows:

[0045] S401 , during the magnetron sputtering process, measuring the transmittance of the sputtered resistance layer thin film in the test sample after magnetron sputtering.

[0046] By using an ultraviolet-visible spectrophotometer to measure the transmittance of the sputtered resistor layer film in the sample after magnetron sputtering, all transmittance data within the ultraviolet to visible light band at each measurement position in the sputtered resistor layer are obtained. All the measurement positions are evenly distributed on the sputtered resistor layer. In this embodiment, the number of measurement positions is 64. The implementer can set the number of measurement positions according to actual conditions.

[0047] S402: Analyze the transmittance deviation of the film at each measurement position in each local band, construct the roughness interference of each measurement position in each local band, and combine the change of the roughness interference of each measurement position in all local bands to obtain the roughness significance coefficient of each measurement position to screen the target measurement point.

[0048] Generally speaking, the increase in film surface roughness will affect the optical properties at its measurement position, increase the surface scattering of ultraviolet-visible light, and thus reduce the transmittance of ultraviolet-visible light. In order to reduce the interference of film surface roughness on film thickness measurement, it is necessary to analyze the optical transmittance characteristics at different measurement positions.

[0049] In order to analyze the roughness characteristics of the surface film at different measurement positions, in this embodiment, all wavelengths in the ultraviolet to visible light band at each measurement position are evenly divided into 20 local bands, and all transmittance data in each local band are composed of vectors in the order of wavelength from small to large, which are recorded as transmittance sub-vectors of each measurement position in each local band. The transmittance sub-vectors reflect the transmittance characteristics of each measurement position in each local band. At the same time, the mean vector of the transmittance sub-vectors of all measurement positions in the same local band is calculated to obtain the overall transmittance sub-vector of each local band. The overall transmittance sub-vector reflects the overall transmittance characteristics of the sputtered resistor layer in each local band.

[0050] Typically, film surface roughness affects transmittance at different wavelengths, not just a certain local band. Therefore, if the transmittance characteristics of all local bands at a certain measurement location are smaller than the overall transmittance characteristics of all local bands, the roughness characteristics at that measurement location are more clearly reflected.

[0051] Through the above analysis, the difference vector between the transmittance subvector of each measurement position in each local band and the overall transmittance subvector of each local band is calculated, and recorded as the transmittance difference vector of each measurement position in each local band. Furthermore, based on the transmittance difference vector of each local band at each measurement position, the roughness interference degree of each measurement position in each local band is calculated. In this embodiment, the calculation formula is specifically:

[0052] Ds i,j =exp(-Xs i.j );where Ds i,j is the roughness interference of the i-th measurement position in the j-th local band, exp() is an exponential function with a natural constant as the base, Xs i.j is the mean of the elements in the transmittance difference vector of the i-th measurement position in the j-th local band.

[0053] Due to the interference of the roughness of the film surface, the transmittance of ultraviolet-visible light will be reduced. If the transmittance characteristics in the local band at the measurement position are significantly smaller than the overall transmittance characteristics in the corresponding local band, then the transmittance of the corresponding band at the measurement position is more likely to be affected by the interference of the roughness of the film surface, causing the transmittance characteristics in the local band to be at a lower level.

[0054] Furthermore, the roughness interference degrees of all local bands at each measurement position are composed of a vector in order of wavelength from small to large, which is recorded as the roughness interference vector of each measurement position. The first-order difference vector of the roughness interference vector at each measurement position is calculated, and the vector obtained by taking the absolute value of each element in the first-order difference vector of the roughness interference vector is recorded as the change difference vector of each measurement position. The change difference vector reflects the change difference between the roughness interference degrees of different local bands. Since the roughness of the film surface will affect the transmittance of multiple bands, at a position with higher film surface roughness, the change difference between the roughness interference degrees of different local bands is smaller, and the roughness interference degrees of different local bands are all at a higher level, then the significance feature of the roughness at the measurement position is stronger.

[0055] Through the above analysis, the roughness significance coefficient of each measurement position is calculated. Preferably, in this embodiment, the calculation formula is:

[0056] Where Pu i is the roughness significance coefficient of the i-th measurement position, norm is the exponential normalization function, is the mean value of the elements in the rough interference vector at the i-th measurement position, is the mean of the elements in the change difference vector of the i-th measurement position, ∈ is a constant to avoid the denominator being 0, and its value range is 0 to 0.1. In this embodiment, it is 0.01.

[0057] In order to more accurately measure the roughness of the film at different measurement positions, the sum of the roughness interference degrees of all local bands at each measurement position is calculated. The sum of the roughness interference degrees reflects the comprehensive level of the roughness interference characteristics of all local bands. The product of the roughness significance coefficient at each measurement position and the sum of the roughness interference degrees of all local bands at each measurement position is recorded as the roughness characteristic value at each measurement position. Among them, using the roughness significance coefficient as the weight coefficient of the roughness interference characteristic can more clearly measure the roughness characteristics of the film surface, thereby accurately and effectively screening out the measurement points on the sputtered resistor layer that are less affected by the interference of the film surface roughness.

[0058] Furthermore, the roughness characteristic values at all measurement locations on the sputtered resistor layer are input into a maximum inter-class variance algorithm, which is used to determine a segmentation threshold. The maximum inter-class variance algorithm is a well-known technique, and the specific process is not described in detail here. Furthermore, in this embodiment, the measurement locations corresponding to roughness characteristic values exceeding the segmentation threshold are used as target measurement points. The transmittance characteristics of violet-visible light at these target measurement points are less affected by, or even unaffected by, film roughness, enabling more accurate measurement of film thickness.

[0059] S403 , performing modal decomposition on the transmittance of the target measurement point in each local band, and constructing the invalid fluctuation characteristic value of each local band at each target measurement point based on the difference between the elements in the IMF component, so as to screen the target band.

[0060] To avoid the interference of ambient light on transmittance, it is necessary to analyze the interference effects of each local band at each target measurement point. The transmittance subvectors of each local band at each target measurement point are input into VMD variational mode decomposition. The preset number of modes is 2, the penalty coefficient is 2000, and the convergence tolerance is 3e-6. VMD variational mode decomposition outputs two IMF components for each local band at each target measurement point. VMD variational mode decomposition is a well-known technology, and the specific process is not repeated here.

[0061] Normally, the two IMF components of each local band represent the effective component and the invalid component, respectively. When not affected by ambient light interference, the fluctuation level of the elements in the invalid component basically tends to horizontal changes. However, when affected by ambient light interference, the invalid component will more reflect the interference characteristics when affected by ambient light, causing the fluctuation of the elements in the invalid component to be at a higher level.

[0062] Since the effective component of each local band reflects the variation characteristics of the transmittance, there is a high similarity between the effective component and the transmittance subvector. By calculating the DTW distance between the transmittance subvector of each local band and its K IMF components, the IMF component with the largest DTW distance is recorded as the invalid component of each local band. The higher the fluctuation level of the elements in the invalid component, the greater the interference effect of ambient light on the band.

[0063] Based on the above analysis, the invalid fluctuation characteristic value of each target measurement point in each local band is calculated. In this embodiment, the specific calculation formula is:

[0064] In the formula, Ge u,j is the invalid fluctuation characteristic value of the u-th target measurement point in the j-th local band, K is the number of elements in the invalid component of the u-th target measurement point in the j-th local band, f u,j,k and f u,j,k-1 They are respectively the kth and k-1th elements in the invalid component of the jth local band of the uth target measurement point.

[0065] Due to the interference of ambient light, the fluctuation level of the elements in the invalid component will be at a high level, and the interference of ambient light on a certain local band is often reflected at different measurement points.

[0066] In order to screen out the local band that is less affected by ambient light interference, the mean of the invalid fluctuation characteristic values of all target measurement points in the jth local band is calculated and recorded as the invalid fluctuation level value of the jth local band. The local band corresponding to the minimum invalid fluctuation level value is recorded as the target band. The target band is the local band that is least affected by ambient light interference. Measuring the transmittance on the target band can measure the film thickness more accurately.

[0067] S404 , measuring the film thickness by the transmittance in the target band at each target measurement point, and adjusting the sputtering temperature during the magnetron sputtering process by the measurement results of the film thickness at all target measurement points.

[0068] The transmittance of the sputtered resistor layer film in the standard sample after magnetron sputtering is measured, and the absorption coefficient of the sputtered resistor layer film is determined using the Beer-Lambert Law. The film thickness at each target measurement point is calculated based on the absorption coefficient of the sputtered resistor layer film. In this embodiment, the specific calculation formula is:

[0069] Where ds u is the film thickness at the uth target measurement point, T u is the average transmittance within the target band at the uth target measurement point, and α is the absorption coefficient of the sputtered resistor layer. The calculation of film thickness and absorption coefficient are both well-known techniques, and the specific process will not be repeated here.

[0070] Furthermore, the uniformity of the film thickness is measured using the coefficient of variation CV, and the coefficient of variation CV of the film thickness at all target measurement points is calculated. If the coefficient of variation CV is higher than the preset threshold, it means that the uniformity of the film thickness on the sputtered resistor layer in the sample to be tested is poor. When the alloy layer is sputtered on the front surface of the substrate insulator to form a thin film next time by the magnetron sputtering coating machine, the sputtering temperature can be increased to enhance the diffusion ability of the sputtered particles, so that the uniformity of the formed film is better. In this embodiment, the preset threshold is 0.45, and when the coefficient of variation CV exceeds 0.45, in this embodiment, the next sputtering temperature is increased by 5°C. In actual application scenarios, the implementer can set it according to actual conditions, and no special restrictions are made here. If the coefficient of variation CV is lower than the preset threshold, it means that the uniformity of the film thickness on the sputtered resistor layer in the sample to be tested is good. When the alloy layer is sputtered on the front surface of the substrate insulator to form a thin film next time by the magnetron sputtering coating machine, the sputtering temperature is kept unchanged.

[0071] Thus, the film thickness during the sputtering process can be measured and analyzed through the above process of this embodiment, and the rationality of the sputtering temperature during the magnetron sputtering process can be evaluated based on the uniformity of the film thickness, so as to perform feedback adjustment on the sputtering temperature. Specifically, in this embodiment, the flow chart of the process of measuring and analyzing the film thickness and adjusting the sputtering temperature during the magnetron sputtering process is as follows: Figure 2 shown.

[0072] S5, after which the thin film resistor is produced and packaged through aging, masking, exposure, development, etching, laser, protective layer printing and drying, sintering, strip folding and stacking, end electrode sputtering, particle folding, roller electrode nickel-tin plating, magnetic separation and package inspection.

[0073] In this embodiment, after magnetron sputtering is completed, post-processing to obtain thin film resistors specifically includes the following process:

[0074] S501, aging: high temperature aging is performed to ensure that the sputtered alloy layer is deposited more uniformly and densely on the surface of the white substrate.

[0075] S502, masking: forming a photosensitive dry film made of acrylic polymer and photosensitive components, and completely covering the surface of the front side of the insulation board with the photosensitive dry film.

[0076] S503, exposure: exposing the required pattern on the front side of each resistor by exposure.

[0077] S504, development: using a developing solution to remove the dry film on the unwanted pattern portion of the resistor front after exposure to form a desired resistor pattern, wherein the main component of the developing solution is sodium carbonate.

[0078] S505, etching: using an etching solution to remove the portion of the developed front resistor to be etched, and using potassium hydroxide solution to remove excess dry film on the front side, wherein the etching solution mainly contains hydrochloric acid and sulfuric acid.

[0079] S506, Laser: Use laser to cut thin film resistors to form the target resistance value.

[0080] S507, printing and drying of protective layer: printing a protective layer on the film layer of each resistor module and drying it, wherein the protective layer covers the insulating front film layer.

[0081] S508, sintering: hardening the protective layer through high temperature.

[0082] S509, folding and stacking: Fold the insulating sheet with the positive and back electrodes, film layer, and protective layer into strips and stack them in the jig.

[0083] S510, end electrode sputtering: The strip insulating plates stacked in the jig are sputtered on the end electrodes using magnetron sputtering.

[0084] S511, folding: Fold the sputtered strip insulating sheet into small pieces, each piece is a resistor.

[0085] S512, barrel plating of nickel-tin electrodes: Through barrel plating, the surface of each resistor is evenly plated with Ni and Sn layers.

[0086] S513, magnetic separation: Using the magnetic properties of Ni, a magnetic separator is used to remove materials with thin Ni layers.

[0087] S514, package inspection: perform appearance inspection on the resistors. In this embodiment, an appearance CCD machine is used to perform appearance inspection, resistors with poor appearance are removed, and the thin film resistors are packaged.

[0088] It is understood that references to "one embodiment" or "some embodiments" in the present specification mean that one or more embodiments of the present application include a particular feature, structure, or characteristic described in conjunction with that embodiment. Thus, if "in one embodiment," "in some embodiments," "in other embodiments," or "in other embodiments" appear in different places in this specification, they do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0089] It should be noted that the above-mentioned sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above description is of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-tasking and parallel processing are also possible or may be advantageous. At the same time, the size of the sequence number of each step in the embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments in this specification.

[0090] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for producing a thin film resistor with high precision resistance, characterized in that: The following steps are involved: White substrate sintering: The white substrate is an insulating plate, which is sintered at high temperature to remove surface impurities; Electrode printing and drying: Print the front electrode on the front of the white substrate and the back electrode on the back, and then dry them; Electrode sintering: sintering the front and back electrodes of the white substrate after printing and drying; Magnetron sputtering: Place the white substrate after electrode sintering into the sputtering chamber, and sputter the alloy layer on the front of the white substrate to form a thin film; During the magnetron sputtering process, the transmittance of the sputtered resistor layer film in the test sample after magnetron sputtering is measured; all wavelengths in the ultraviolet to visible light band at each measurement position are evenly divided into multiple local bands, the deviation of the transmittance of the film at each measurement position in each local band is analyzed, and the roughness interference degree of each measurement position in each local band is constructed. Combined with the change of the roughness interference degree of each measurement position in all local bands, the roughness significance coefficient of each measurement position is obtained to screen the target measurement point; Perform modal decomposition on the transmittance of the target measurement point in each local band. According to the difference between the elements in the IMF component, construct the invalid fluctuation eigenvalue of each target measurement point in each local band. Based on the minimum mean value of the invalid fluctuation eigenvalues of all target measurement points in each local band, select the target band. The film thickness is measured by the transmittance within the target band at each target measurement point, and the sputtering temperature during the magnetron sputtering process is adjusted based on the measurement results of the film thickness at all target measurement points; After that, the thin film resistor is produced and packaged through aging, masking, exposure, development, etching, laser, protective layer printing and drying, sintering, strip folding and stacking, end electrode sputtering, particle folding, roller electrode nickel-tin plating, magnetic separation and package inspection.

2. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: A plurality of horizontal lines and vertical lines are arranged on the front and back of the insulating plate, which cross to form each insulating module, and each insulating module serves as a resistor module to be produced.

3. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: In the electrode printing and drying step, the front electrode partially covers the front surface of the white substrate, and the back electrode partially covers the back surface of the white substrate.

4. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: The calculation method of the roughness interference degree of each measurement position in each local band is: Where, is the rough interference degree of the i-th measurement position in the j-th local band, is an exponential function with a natural constant as base, is the mean value of the elements in the transmittance difference vector of the i-th measurement position in the j-th local band; Arrange all transmittances of each measurement position in each local band in ascending order of wavelength to form a transmittance subvector of each measurement position in each local band; The mean vector of the transmittance sub-vectors of all measurement positions in each local band is used as the overall transmittance sub-vector of each local band, and the difference vector between the transmittance sub-vector of each measurement position in each local band and the overall transmittance sub-vector is used as the transmittance difference vector of each measurement position in each local band.

5. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: The method for obtaining the roughness significance coefficient of each measurement position is: The roughness interference degrees of all local bands at each measurement position are arranged in ascending order of wavelength to form the roughness interference vector of each measurement position. The vector obtained by taking the absolute value of each element in the first-order difference vector of the roughness interference vector is used as the change difference vector of each measurement position. The roughness significance coefficient of each measurement position is calculated as follows: Where, is the roughness significance coefficient of the i-th measurement position, is the exponential normalization function, is the mean value of the elements in the rough interference vector at the i-th measurement position, is the mean of the elements in the change difference vector of the i-th measurement position, To avoid constants with denominators equal to 0.

6. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: The method for screening the target measurement points is: The sum of the roughness interference degrees of each measurement position in all local bands is calculated, and the product of the roughness significance coefficient of each measurement position and the sum corresponding to each measurement position is used as the roughness eigenvalue of each measurement position. The roughness eigenvalues of all measurement positions are threshold segmented, and the measurement positions corresponding to the roughness eigenvalues above the segmentation threshold are used as target measurement points.

7. The method for producing a thin film resistor with high precision resistance according to claim 4, wherein: The calculation method of the invalid fluctuation characteristic value of each target measurement point in each local band is: Where, is the invalid fluctuation characteristic value of the u-th target measurement point in the j-th local band, is the number of elements in the invalid component of the jth local band at the uth target measurement point, and are the kth and k-1th elements in the invalid component of the uth target measurement point in the jth local band, respectively. The DTW distance between the transmittance subvector of the target measurement point in each local band and its IMF components is calculated, and the IMF component with the largest DTW distance is recorded as the invalid component of the target measurement point in each local band.

8. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: The target band screening method is as follows: for each local band, the average of the invalid fluctuation characteristic values of all target measurement points in the local band is calculated, recorded as the invalid fluctuation level value of the local band, and the local band corresponding to the minimum invalid fluctuation level value is used as the target band.

9. The method for producing a thin film resistor with high precision resistance according to claim 1, wherein: The calculation method of the film thickness is: Where, is the film thickness at the u-th target measurement point, is the mean transmittance within the target band at the u-th target measurement point, is the absorption coefficient of the sputtered resistor layer.

10. The method for producing a thin film resistor with high precision resistance according to claim 9, characterized in that: The step of adjusting the sputtering temperature during the magnetron sputtering process includes: The coefficient of variation of the film thickness at all target measurement points is counted. If the coefficient of variation is higher than a preset threshold, the sputtering temperature is increased; otherwise, the sputtering temperature is kept unchanged.

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