Production method of thin-film resistor with high-precision resistance value

Abstract

The invention relates to the technical field of semiconductor device resistor production, in particular to a high-precision resistance value thin-film resistor production method which comprises the following steps: sintering a white substrate, and removing surface impurities through high-temperature sintering; electrode printing and drying; sintering the electrode; and magnetron sputtering: putting the white substrate after electrode sintering into a sputtering cavity, sputtering an alloy layer on the front surface of the white substrate to form a thin film, and in the magnetron sputtering process, measuring the change characteristics of the transmittance of the sputtering resistance layer thin film in the test sample after magnetron sputtering so as to measure the thickness of the thin film, the rationality of the sputtering temperature in the magnetron sputtering process is evaluated, and then the produced and packaged thin-film resistor is obtained through aging, shielding, exposure, developing, etching, laser processing, protective layer printing and drying, sintering, strip folding and stacking, terminal electrode sputtering, particle folding, barrel plating of electrode nickel tin, magnetic separation and package inspection. The production quality of the thin-film resistor can be improved.

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 a thin-film resistor with a high-precision resistance value. Background Art

[0002] In the production process of thin film resistors, it is necessary to perform vacuum physical sputtering on the area to be sputtered on the chip thin film resistor, so that atoms or molecules collide with the surface of the area to be sputtered on the chip thin film resistor and form a thin film resistor layer on its surface base. By measuring the film thickness of the thin film resistor layer and accurately judging the film uniformity of the thin film resistor layer, the sputtering temperature in the vacuum physical sputtering process can be adjusted according to the uniformity judgment result of the thin film resistor layer, so as to obtain the best resistance performance of the thin film resistor product finally produced.

[0003] Most existing technologies use optical properties to measure the film thickness on the sputtered resistor layer. This measurement method can analyze the uniformity of the film 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, thereby making it impossible to accurately and effectively feedback and adjust the sputtering parameters in 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 a thin-film resistor with high-precision resistance to solve the existing problems.

[0005] A method for producing a high-precision thin-film resistor of the present application adopts the following technical solution:

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

[0007] White substrate sintering: White substrate is an insulating sheet, 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: sinter 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 front of the white substrate to form a thin film; During the magnetron sputtering process, measure the transmittance of the sputtered resistance layer film in the test sample after magnetron sputtering; Analyze the deviation of the transmittance 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;

[0011] The transmittance of the target measurement point in each local band is modally decomposed, and the invalid fluctuation characteristic value of each target measurement point in each local band is constructed through the difference between the elements in the IMF component to screen the target band;

[0012] The film thickness is measured by the transmittance in the target band at each target measurement point, and the sputtering temperature in the magnetron sputtering process is adjusted according to 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, electrode nickel-tin rolling plating, magnetic separation and package inspection.

[0014] Preferably, 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.

[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 degree 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 of each measurement position are evenly divided into multiple local bands, and all transmittances of each measurement position in each local band are arranged in ascending order of wavelength to form transmittance subvectors 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 taken 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 taken as the transmittance difference vector of each measurement position in each local band.

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

[0022] In the formula, Pu i is the roughness significance coefficient of the ith measurement position, norm is the exponential normalization function, is the mean value of the elements in the rough interference vector at the ith measurement position, is the mean of the elements in the change difference vector of the ith 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 ​​higher than 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, and f u,j,k and f u,j,k-1 They are the kth and k-1th elements in the invalid component of the uth target measurement point in the jth local band, respectively; wherein, 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, the mean 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 taken 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 in the target band at the uth target measurement point, and α is the absorption coefficient of the sputtered resistor layer film.

[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 the measurement points that are less affected by the interference of the film surface roughness as the 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 in 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 in 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 in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. 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 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 2The present invention provides a flow chart of the film thickness measurement and analysis and sputtering temperature adjustment process during the magnetron sputtering process. DETAILED DESCRIPTION

[0036] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the method for producing a thin-film resistor with high precision resistance value proposed in the present application, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0037] Unless otherwise defined, terms such as "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so 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 also includes elements inherent to such articles or devices. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the article or device comprising the element. In addition, the term "and\or" 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 the present application belongs.

[0038] The specific scheme of a method for producing a thin-film resistor with high precision resistance 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 thin film resistor with high precision resistance. For details, please refer to Figure 1 , including the following steps:

[0040] S1, white substrate sintering: the white substrate is an insulating plate, and surface impurities are removed by high-temperature sintering: the white substrate is an insulating plate, and multiple horizontal lines and vertical lines are set on the front and back of the insulating plate, which cross to form each insulating module, and then high-temperature sintering is used to remove impurities on the surface of the white substrate. It should be noted that each insulating module corresponds to a resistor module to be produced, and a resistor module is formed through subsequent production and processing.

[0041] S2, electrode printing and drying: printing a front electrode on the front side of the white substrate and printing 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: put 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 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 the target measurement point by analyzing the transmittance characteristics of the sputtered resistor layer film in the test sample after magnetron sputtering, and selects the target band according to the disturbance of the transmittance of the target measurement point in different bands, so as to measure the film thickness and perform film uniformity analysis, and then feedback adjust the sputtering temperature during the magnetron sputtering process 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 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 measuring position in the sputtered resistor layer are obtained. All the measuring positions are evenly distributed on the sputtered resistor layer. In this embodiment, the number of measuring positions is 64, and the implementer can set the number of measuring positions according to actual conditions.

[0047] S402, analyzing the deviation of the transmittance of the film at each measurement position in each local band, constructing the roughness interference degree of each measurement position in each local band, combining the change of the roughness interference degree of each measurement position in all local bands, obtaining the roughness significance coefficient of each measurement position, so as to screen the target measurement point.

[0048] Generally speaking, the increase in film surface roughness will affect the optical properties at the 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] Generally, the surface roughness of the film will affect the transmittance at different wavelengths, rather than just the transmittance in a certain local band. Therefore, if the transmittance characteristics in all local bands at a certain measurement position are smaller than the overall transmittance characteristics in all local bands, the roughness characteristics at the measurement position can be better 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, which is recorded as the transmittance difference vector of each measurement position in each local band. Further, according to 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 degree 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, a vector composed of the roughness interference degrees of all local bands at each measurement position in the order of wavelength from small to large is recorded as the roughness interference vector of each measurement position, and the first-order difference vector of the roughness interference vector at each measurement position is calculated. 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, the change difference between the roughness interference degrees of different local bands is smaller at a position with higher surface roughness of the film, 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 significant coefficient of each measurement position is calculated. Preferably, in this embodiment, the calculation formula is:

[0056] In the formula, Pu i is the roughness significance coefficient of the ith measurement position, norm is the exponential normalization function, is the mean value of the elements in the rough interference vector at the ith measurement position, is the mean of the elements in the change difference vector of the ith measurement position, ∈ is a constant to avoid the denominator being 0, and its value range is 0 to 0.1. In this embodiment, its value 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 on 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, the roughness significance coefficient is used as the weight coefficient of the roughness interference characteristic, which 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 ​​of all measurement positions on the sputtered resistor layer are input into the maximum inter-class variance algorithm, and the segmentation threshold is obtained by the maximum inter-class variance algorithm, wherein the maximum inter-class variance algorithm is a well-known technology, and the specific process is not repeated. Further, in this embodiment, the measurement position corresponding to the roughness characteristic value higher than the segmentation threshold is used as the target measurement point, and the transmittance characteristic of the ultraviolet light-visible light at the target measurement point is less affected by the interference of the film roughness, or even not affected by the interference of the film roughness, and the film thickness can be measured more accurately.

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

[0060] In order to avoid the interference of ambient light on transmittance, it is necessary to analyze the interference effect of each local band at each target measurement point. The transmittance subvector of each local band at each target measurement point is input into the VMD variational mode decomposition, the preset mode number is 2, the penalty coefficient is 2000, the convergence tolerance is 3e-6, and the VMD variational mode decomposition outputs two IMF components of each local band at each target measurement point, where 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 is basically close to horizontal change. When affected by ambient light interference, the invalid component will more reflect the interference characteristics when affected by ambient light, making the fluctuation of the elements in the invalid component at a higher level.

[0062] Since the effective components of each local band reflect the changing characteristics of the transmittance, there is a high similarity between the effective components and the transmittance sub-vectors. By calculating the DTW distance between the transmittance sub-vectors 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 the ambient light on the band.

[0063] According to 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, and 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 bands that are 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 in the magnetron sputtering process by the measurement results of the film thickness at all target measurement points.

[0068] By measuring the transmittance of the sputtered resistor layer film in the standard sample after magnetron sputtering, the Beer-Lambert Law is used to determine the absorption coefficient of the sputtered resistor layer film. The film thickness at each target measurement point is calculated by 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 in the target band at the uth target measurement point, and α is the absorption coefficient of the sputtered resistor layer film. The calculation of the film thickness and the absorption coefficient are both well-known technologies, and the specific process will not be repeated.

[0070] Furthermore, the uniformity of the film thickness is measured by 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 value, 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 side 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 formed film has better uniformity. 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 value, 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 side 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 according to the uniformity of the film thickness, so as to feedback-adjust the sputtering temperature. Specifically, in this embodiment, the flow chart of the process of measuring and analyzing the film thickness during the magnetron sputtering process and adjusting the sputtering temperature 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, electrode nickel-tin rolling plating, magnetic separation and package inspection.

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

[0074] S501, aging: high temperature aging is performed to ensure that the film of 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 from acrylic polymer and photosensitive components, and completely covering the surface of the layer on the front side of the insulation board.

[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 of the unwanted pattern portion on the front side of the resistor after exposure, so as to form a desired resistor pattern, wherein the main component of the developing solution is sodium carbonate.

[0078] S505, etching: using etching solution to remove the part of the developed front resistor to be etched, and using potassium hydroxide solution to remove the 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 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 the protective layer, wherein the protective layer covers the insulating front film layer.

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

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

[0083] S510, end electrode sputtering: The strip insulating plates stacked in the jig are subjected to alloy sputtering on the end electrodes by magnetron sputtering.

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

[0085] S512, Roll-plated electrode nickel-tin: Through the roll-plating method, the Ni layer and Sn layer are evenly plated on the surface of each resistor.

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

[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 thin-film resistors are packaged.

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

[0089] It should be noted that the sequence of the above-mentioned embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above-mentioned specific embodiments of this specification are described. In addition, the process depicted in the accompanying drawings does 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 protection scope 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: White substrate is an insulating sheet, 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: sinter 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, measure the transmittance of the sputtered resistance layer film in the test sample after magnetron sputtering; Analyze the deviation of the transmittance 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; The transmittance of the target measurement point in each local band is modally decomposed, and the invalid fluctuation characteristic value of each target measurement point in each local band is constructed through the difference between the elements in the IMF component to screen the target band; The film thickness is measured by the transmittance in the target band at each target measurement point, and the sputtering temperature in the magnetron sputtering process is adjusted according to 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, electrode nickel-tin rolling plating, magnetic separation and package inspection.

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

3. A method for producing a thin film resistor with high precision resistance as claimed in claim 1, characterized in that: 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.

4. A method for producing a thin film resistor with high precision resistance as claimed in claim 1, characterized in that: The calculation method of the roughness interference degree of each measurement position in each local band is: Ds i,j =exp(-Xs i.j );where Ds i,j is the roughness interference degree 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; Among them, all wavelengths in the ultraviolet to visible light band of each measurement position are evenly divided into multiple local bands, and all transmittances of each measurement position in each local band are arranged in ascending order of wavelength to form transmittance subvectors 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 taken 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 taken 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 as claimed in claim 1, characterized in that: The method for obtaining the roughness significant 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 calculation method of the roughness significance coefficient of each measurement position is: In the formula, Pu i is the roughness significance coefficient of the ith measurement position, norm is the exponential normalization function, is the mean value of the elements in the rough interference vector at the ith measurement position, is the mean of the elements in the change difference vector of the ith measurement position, and ∈ is a constant to avoid the denominator being zero.

6. A method for producing a thin film resistor with high precision resistance as claimed in claim 1, characterized in that: 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 ​​higher than the segmentation threshold are used as target measurement points.

7. A method for producing a thin film resistor with high precision resistance as claimed in claim 4, characterized in that: The calculation method of the invalid fluctuation characteristic value of each target measurement point in each local band is: 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, and f u,j,k and f u,j,k-1 They are the kth and k-1th elements in the invalid component of the uth target measurement point in the jth local band, respectively; wherein, 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. A method for producing a thin film resistor with high precision resistance as claimed in claim 1, characterized in that: The method for screening the target band 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 taken as the target band.

9. A method for producing a thin film resistor with high precision resistance as claimed in claim 1, characterized in that: The calculation method of the film thickness is: Where, ds u is the film thickness at the uth target measurement point, T u is the average transmittance in the target band at the uth target measurement point, and α is the absorption coefficient of the sputtered resistor layer film.

10. A method for producing a thin film resistor with high precision resistance as claimed in claim 9, characterized in that: The step of adjusting the sputtering temperature during the magnetron sputtering process comprises: 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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