Preparation method of high-power miniaturized thick-film resistor

Abstract

The invention discloses a preparation method of a high-power miniaturized thick-film resistor, which comprises the steps of printing, sintering, curing and grain folding of each functional layer material, and is characterized in that when printing is carried out on a single substrate, longitudinally arranged effective columns and auxiliary columns are alternately distributed, and the auxiliary columns are arranged on the head side and the tail side close to the edge of the substrate; the effective column is an effective resistance particle single column including a resistance layer, and the auxiliary column is a single column including an auxiliary conductor layer; the transverse length range of the resistance layer extends outwards from the position close to the inner side of a single folding grain line to exceed the length of a single resistance unit to form an ultra-long resistance layer, and when the resistance layer is corrected through laser, a measuring probe takes the auxiliary conductor layer in the adjacent auxiliary column as a detection base point to correct the resistance layer in the effective column. By changing the internal structure and the material layout, a new material and a new process do not need to be introduced while the small size is kept, and the expected effects of product miniaturization, high power, high electrical performance and high weather resistance are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a thick film resistor preparation method, in particular to a high-power miniaturized thick film resistor preparation method, which realizes the effects of miniaturization, high power, high electrical performance and high weather resistance. BACKGROUND

[0002] Miniature thick film resistors are resistors made by screen printing and high-temperature sintering process, and the thickness of the resistance layer is usually between 5 to 100 microns, which are widely used in power supply equipment, automotive electronics, industrial frequency converters and other fields.

[0003] Thick film resistors usually include a substrate, a resistance layer, internal electrodes, a conductive layer, and an outer protective layer, wherein the geometric parameters of the resistance layer have a decisive influence on the electrical performance of the device. Under the condition that the resistivity and cross-sectional area of the resistance material remain unchanged, the resistance value is in a positive relationship with the length of the resistance layer. This feature provides a controllable dimension for resistance value design, and the optimal electrical performance of the target resistance value can be achieved by accurately adjusting the length of the resistance layer. However, the length design of the resistance layer in the existing process is restricted by the preparation process and equipment, such as laser trimming system. The resistance value trimming process needs to rely on laser cutting technology, which requires real-time measurement of resistance value during the folding process (response time ≤5ms), and the measurement probe must form stable electrical contact with both ends of the resistance. This requires sufficient space for the probe to step on (the internal electrode layer below the resistance layer is the detection base point for the probe), so in the existing process, the resistance layer needs to be smaller than the length of the single folding, and a certain space (probe landing point) is left between the folding line, otherwise it will cause unstable resistance value trimming and affect the electrical performance of the resistance. Therefore, the length of the resistance layer is limited and cannot maximize the performance of the single resistance.

[0004] In the field of preparation of high-power miniaturized thick film resistors, traditional processes face multiple technical bottlenecks, and innovative solutions are urgently needed to meet the stringent requirements of modern electronic devices for high reliability, high power density and miniaturization, and to provide technical support for the manufacture of the next generation of high-performance electronic components. SUMMARY

[0005] The present application aims to provide a high-power miniaturized thick film resistor preparation method, which increases the effective resistance layer proportion of single resistance by process improvement, thereby meeting the product miniaturization while improving the power and electrical performance to meet market needs.

[0006] To achieve the above object, the technical scheme adopted by the present application is: a preparation method of a high-power small-sized thick-film resistor, comprising printing, sintering, solidifying and folding of each functional layer material, when printing on a single substrate, effective columns and auxiliary columns arranged longitudinally are alternately distributed, and the first and last sides close to the edge of the substrate are set as auxiliary columns, the effective column is an effective resistor particle single column containing a resistor layer, and the auxiliary column is a single column containing an auxiliary conductor layer; The transverse length of the resistor layer ranges from close to the inside of the single resistor unit length to extending beyond the single resistor unit length, forming an ultra-long resistor layer, and the part of the resistor layer extending beyond the single resistor unit length is printed on the auxiliary conductor layer of the adjacent auxiliary column, and when the resistor layer is corrected by laser, the measuring probe takes the auxiliary conductor layer in the adjacent auxiliary column as the detection base point to correct the resistor layer in the effective column.

[0007] In the above technical scheme, the single resistor unit length is a standard resistor parameter value, when the transverse length of the resistor layer approaches the standard resistor parameter value, the auxiliary conductor layer is printed in the auxiliary column, and the auxiliary conductor layer extends to the adjacent effective column on both sides, the extension segment of the single resistor unit line forms an inner electrode layer in the effective column, and the resistor layer is printed on the inner electrode layer; when the transverse length of the resistor layer exceeds the standard resistor parameter value, the resistor layer exceeding part is lapped on the conductor layer in the auxiliary column, and after laser correction of the resistor layer, the effective resistor layer length in the effective column reaches the maximum length, which is: single particle resistor length = single length - 2 times the lapping length of the inner electrode and the resistor.

[0008] In the above technical scheme, the auxiliary conductor layer is an integral design covering the entire length of the auxiliary column or a split design with a blank area in the middle.

[0009] In the above technical scheme, the auxiliary conductor layer of the integral design is covered and printed with a glass protection layer, which provides protection for the auxiliary conductor layer and is used as a zero-ohm resistor subsequently.

[0010] In the above technical scheme, an auxiliary outer electrode is printed at the separation between the effective column and the auxiliary column and is connected between the two columns.

[0011] In the above technical scheme, the specific process steps include: S1: providing a substrate, printing inner electrodes on the front and back surfaces of the substrate by silk screen printing process, and sintering; S2: printing a resistor layer on the front inner electrode of the effective column according to the design drawing, and sintering; S3: printing a glass protection layer on the resistor layer of the effective column, and sintering; S4: correcting the resistor layer in step S3 by a laser trimming system; S5: printing an insulating resin protective layer outside the glass protective layer; S6: printing an auxiliary outer electrode layer at the intersection of the effective column and the auxiliary column, the width of which is less than or equal to the minimum unit width of the single resistance, and the length is adapted to the size of the front terminal; S7: printing MK on the insulating resin protective layer, and then curing; S8: striping, separating the auxiliary column from the effective column, and arranging the effective column in a strip shape to prepare for subsequent automatic particle folding; S9: vacuum plating layer; S10: particle folding, mechanically breaking the strip-shaped arranged resistance into the minimum resistance unit; S11: terminal preparation, forming metal electrodes at both ends of the resistance particle obtained after step S9, for connection with the PCB pad; S12: testing and packaging, completing the preparation of the resistance chip.

[0012] In the above technical solution, after the resistance layer is printed and dried, the pattern of the single resistance unit is outlined by means of laser scribing operation, which provides assistance for trimming operation.

[0013] In the above technical solution, after the auxiliary outer electrode layer is printed and dried, the pattern of the single resistance unit is outlined by means of laser scribing operation, which provides assistance for precise control of the pattern.

[0014] Due to the use of the above technical solution, the present application has the following advantages compared with the prior art: 1. In the present application, the resistance is arranged in an interval type, that is, the effective column (containing the resistance layer) and the auxiliary column (without the resistance layer) are alternately distributed, and the auxiliary conductor layer in the auxiliary column provides sufficient probe stepping space for laser cutting and trimming of the resistance layer, without occupying the limited space in the effective column. The effects brought by this are: 1. sufficient measurement position, improving the accuracy and stability of probe measurement; 2. the resistance layer can be extended to the folding line of the single resistance unit, or even extended to the adjacent auxiliary column, thereby increasing the length of the effective resistance. The maximum effective resistance length can reach the length of the single resistance minus 2 times the safe lap length of the inner electrode layer and the resistance layer, which enables small size components to achieve the performance of large size components, for example, a 0201 size resistance can reach an effective resistance length close to a 0603 size, providing a guarantee for power and electrical performance improvement; 2. In conventional design, due to the measurement requirement of laser particle folding process, the inner electrode must have sufficient length ratio (generally 50% to 65% of the length is the inner electrode). In the present application, the space of the auxiliary conductor layer of the auxiliary column is used to maximize the effective resistance layer, and the resistance width is greater than the inner electrode width, and the conductor silver is covered under the resistance, which can better improve the environmental corrosion resistance of anti-sulfurization and salt spray; 3. The application adopts two design ways of auxiliary conductor layer. The full-coverage overall design of auxiliary column can be used for zero-ohm particle piece in subsequent use according to the demand of different resistance layer length. The split design of auxiliary column is blank design (blank is substrate without printing material layer), which is recycled after subsequent particle folding, thereby reducing cost investment to the maximum extent. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a process flow diagram in an embodiment of the application; Figure 2 is a distribution diagram of effective column and auxiliary column in an embodiment of the application; Figure 3 is a structure cross-sectional view diagram (overall design of auxiliary conductor layer) in an embodiment of the application; Figure 4 is a structure cross-sectional view diagram (split design of auxiliary conductor layer) in an embodiment of the application; Figure 5 is a distribution diagram of overall auxiliary conductor layer and resistance layer in an embodiment of the application; Figure 6 is a distribution diagram of split auxiliary conductor layer and resistance layer in an embodiment of the application; Figure 7 is a distribution diagram of glass protective layer (overall design of auxiliary conductor layer) in an embodiment of the application; Figure 8 is a distribution diagram of glass protective layer (split design of auxiliary conductor layer) in an embodiment of the application; Figure 9 is a distribution diagram of auxiliary outer electrode (overall design of auxiliary conductor layer) in an embodiment of the application; Figure 10 is a distribution diagram of auxiliary outer electrode (split design of auxiliary conductor layer) in an embodiment of the application; Figure 11 is a 0201-ESD test comparison diagram in an embodiment of the application; Figure 12 is a 0201-short-time overload test comparison diagram in an embodiment of the application.

[0016] Wherein: 1, effective column; 2, auxiliary column; 3, resistance layer; 4, auxiliary conductor layer; 5, single particle folding line; 6, super-long resistance layer; 7, inner electrode layer; 8, particle folding line; 9, blank area. DETAILED DESCRIPTION

[0017] The following description is only preferred embodiments of the present application and is not intended to limit the scope of the present application. In addition, the terms "vertical", "horizontal", "top", "bottom", "front", "back", "upper", "lower", "inner", "outer" and the like mentioned in the embodiments of the present application indicate the orientation or positional relationship based on the drawings shown or the orientation or positional relationship commonly placed when the product is used, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. Figure 3 、 4 The orientation or positional relationship shown in the drawings or the orientation or positional relationship commonly placed when the product is used is only for the convenience of describing the present application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. Figures 1-12 The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. Embodiments

[0018] A high-power miniaturized thick film resistor manufacturing method, comprising printing, sintering, curing and folding of each functional layer material, when printing on a single substrate, longitudinally arranged effective column 1 and auxiliary column 2 are alternately distributed, and the first and last sides close to the edge of the substrate are set as auxiliary columns, the effective column is an effective resistor particle single column containing a resistor layer 3, and the auxiliary column 2 is a single column containing an auxiliary conductor layer 4; see Figure 2 .

[0019] The transverse length of the resistor layer 3 ranges from close to the inside of the single particle folding line 5 to extending outward beyond the single particle resistor unit length, forming an ultra-long resistor layer 6, see Figures 3-6 . The part of the resistor layer that extends beyond the single particle resistor unit length is printed on the auxiliary conductor layer 4 of the adjacent auxiliary column 2. When laser correcting the resistor layer, the measurement probe takes the auxiliary conductor layer 4 in the adjacent auxiliary column 2 as the detection base point to correct the resistor layer 3 in the effective column 1.

[0020] In one embodiment, the single particle resistor unit length is a standard resistor parameter value. When the transverse length of the resistor layer 3 approaches the standard resistor parameter value, the auxiliary conductor layer 4 is printed in the auxiliary column 2, and the auxiliary conductor layer 4 extends into the adjacent effective column on both sides, the extended segment of the single particle folding line forms an inner electrode layer 7 in the effective column, and the resistor layer 3 is printed on the inner electrode layer 7. When the transverse length of the resistor layer 3 exceeds the standard resistor parameter value, the excess part of the resistor layer is lapped on the auxiliary conductor layer 4 in the auxiliary column 2. After laser correcting the resistor layer 3, the effective resistor layer length in the effective column 1 reaches the maximum length, which is: single particle resistor length = single particle length - 2 times the lapped length of the inner electrode and the resistor, see Figure 3 、 4 . Due to the extension of the resistor layer 3 to both sides, the inner electrode layer 7 can be shortened (stabilize the lapped length, such as Figure 4As shown, after subtracting the overlapping portions on both sides that coincide with the inner electrode layer 7 from the length of the resistive layer 3, the effective resistive layer in the middle is obtained, maximizing the effective resistive length and improving the resistor performance.

[0021] In one embodiment, the auxiliary conductor layer 4 is an integral design that covers the entire length of the auxiliary column 2, such as... Figure 5 As shown. In this configuration, the inner electrode located in auxiliary column 2 is called auxiliary conductor layer 4, and the portion extending into effective column 1 constitutes the inner electrode layer 7 of a single resistor. Based on the folding line of the single resistor, the inner electrode retained in the effective column extends to the edge of the folded portion. In this configuration, resistor layer 3 can extend to both sides to the folding line 8, or even further beyond the folding line 8, resulting in resistor layer 3 of maximum length. Auxiliary column 2, after folding, can be used as a zero-ohm resistor in subsequent processes.

[0022] In another embodiment, the auxiliary conductor layer 4 is a split design with a blank area 9 in the middle, such as... Figure 6 As shown. In this method, the auxiliary conductor layer 4 is only set at the splicing of the effective columns on both sides, which is to say, it is divided into two pieces with a blank space in the middle. In the subsequent pelletizing process, the auxiliary column 2 will be discarded and recycled as edge material, and the part in the effective column will be retained as the inner electrode layer 7.

[0023] In one embodiment, a printed glass protective layer G1 is placed over the auxiliary conductor layer 4 of the overall design to protect the auxiliary conductor layer 4, which is then used as a zero-ohm resistor. Figure 7 As shown.

[0024] In another embodiment, an auxiliary external electrode C3 is printed at the separation point between the effective column 1 and the auxiliary column 2, bridging the two columns. For example... Figure 8 As shown.

[0025] The specific process steps of this invention include: Figure 1 As shown, S1: Provide a substrate, and use screen printing technology to print the internal electrode C1 on both the front and back sides of the substrate, and then sinter it; S2: According to the design diagram, print the resistive layer R on the front inner electrode C1 of the effective column and sinter it; S3: Print a glass protective layer G1 on the resistor R layer of the effective column and sinter it; S4: Trim the resistive layer R in step S3 using a laser trimming system; S5: Print an insulating resin protective layer G2 on the outside of the glass protective layer G1; S6: At the junction of the active column and the auxiliary column, an auxiliary external electrode layer is printed. Its width is less than or equal to the width of the smallest single resistor unit, and its length is adapted to the front terminal size. S7: Print MK onto the insulating resin protective layer, and then cure; S8: Strip arrangement, separates the auxiliary column from the effective column, and arranges the effective column in strips to prepare for subsequent automatic folding; S9: Vacuum coating layer; S10: Folding, mechanically breaking apart, breaking the strip-shaped resistors into the smallest resistance units; S11: Terminal preparation, metal electrodes are formed at both ends of the resistor particles obtained after step S9 for connection with PCB pads; S12: Test and package to complete the fabrication of the resistor chip.

[0026] In one embodiment, after the resistive layer 3 is printed and dried, the pattern of a single resistive unit can be outlined by laser scribing, which assists in the trimming operation.

[0027] In another embodiment, after the auxiliary outer electrode layer C3 is printed and dried, the pattern of a single resistor unit can be outlined by means of a laser scribing operation, which provides assistance for precise control of the pattern.

[0028] By using the process improvements of this invention, product miniaturization is achieved while simultaneously improving power and electrical performance, and enhancing weather resistance. Using a 0201-sized resistor as the test object, the data obtained after the improvement of this invention will be compared with the data obtained from existing resistor measurements. Figure 11 , 12 As shown, the analysis considers both ESD testing (anti-static testing) and short-time overload testing. The trend graph of the resistance change rate under different voltages for ESD testing is shown below. Figure 11 In the diagram, the left side shows the new design improved using the technical solution of this invention, and the right side shows the test node line segment diagram of the current design 0201-F1K2. From the two diagrams, we can clearly see that the measured data in the left diagram fluctuates very little and is relatively stable when the voltage changes, while the measured data in the right diagram drops sharply after the voltage increases, and the greater the voltage, the greater the drop.

[0029] Similarly, in Figure 12 As can be seen, the left side shows the product test results using the technology of this invention, while the right side shows the test results using the existing technology. Under different power conditions, the short-time overload test results on the left side are almost on the same straight line (before 0.225W), and fluctuate within 3% after reaching 0.250W; while the product test results on the right side show divergent changes after 0.100W, and the data is extremely unstable.

[0030] The current standard is: 0201 size resistors have a power rating of 0.05W and an ESD@500V (test method: human body anti-static mode) resistance change rate (ΔR / R) specification of ±3%, while 0603 size resistors have a power rating of 0.2W and an ESD@500V (test method: human body anti-static mode) resistance change rate (ΔR / R) specification of ±3%. Using the design and fabrication method of this invention, the power rating of 0201 size resistors can reach greater than 0.25W (meeting the ±3% specification), and the ESD@1000V resistance change rate (ΔR / R) specification can meet ±1%, and even smaller tolerances can be achieved. Therefore, the performance of large size (0603) resistors can be achieved in a small size (0201) configuration, overcoming the bottleneck of reduced power and electrical performance caused by miniaturization of existing thick-film resistors.

[0031] Of course, the design and preparation methods of this invention can also effectively improve the power and performance of large-scale products, which will not be listed here.

[0032] After the implementation of this invention: 1. Internal electrode length optimization: Within a single resistor unit, the internal electrode retains a sufficient length ratio (usually 50% to 65%), which can effectively increase the effective resistance length.

[0033] 2. By using auxiliary conductor layers, the problem of insufficient space for the laser cutting probe to step on due to excessive resistance is solved by setting adjacent auxiliary conductor layers, making the resistance adjustment more stable.

[0034] 3. Significantly increased effective resistance length: The maximum effective resistance length can be the length of a single resistor minus twice the safe overlap length between the inner electrode C1 and the resistance layer R, which enables small-sized components to achieve the performance of large-sized components.

[0035] 4. Performance improvement and size optimization: For example, a 0201 size resistor can achieve an effective resistance length close to that of a 0603 size resistor, which provides a guarantee for improved power and electrical performance.

[0036] 5. Enhanced resistance to environmental corrosion: The resistor width is greater than the inner electrode width, and the conductor silver (inner electrode) covers the bottom of the resistor, which can better resist sulfidation and salt spray.

[0037] This design significantly improves the performance and reliability of resistors while maintaining a small size by optimizing the internal structure and material layout.

[0038] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for fabricating a high-power miniaturized thick-film resistor, comprising printing, sintering, curing, and granulation of various functional layer materials, characterized in that: When printing on a single substrate, the effective columns and auxiliary columns are arranged alternately in a vertical direction, and the first and last sides near the edge of the substrate are set as auxiliary columns. The effective column is a single column of effective resistive particles including a resistive layer, and the auxiliary column is a single column containing an auxiliary conductor layer. The lateral length of the resistive layer extends from close to the inner side of a single fold line to beyond the length of a single resistive unit, forming an ultra-long resistive layer. The portion of the resistive layer that exceeds the length of a single resistive unit is printed on the auxiliary conductor layer of the adjacent auxiliary column. When the resistive layer is corrected by laser, the measurement probe uses the auxiliary conductor layer in the adjacent auxiliary column as the detection base point to perform correction operation on the resistive layer in the effective column.

2. The method for fabricating a high-power miniaturized thick-film resistor according to claim 1, characterized in that: The length of the single resistor unit is the standard resistance parameter value. When the lateral length of the resistor layer is close to the standard resistance parameter value, an auxiliary conductor layer is printed in the auxiliary column, and the auxiliary conductor layer extends into the adjacent effective columns on both sides. The extension segment beyond the single fold line constitutes the inner electrode layer in the effective column, and the resistor layer is printed on the inner electrode layer. When the lateral length of the resistive layer exceeds the standard resistance parameter value, the excess resistive layer overlaps with the conductor layer in the auxiliary column. After the resistive layer is corrected by laser, the length of the effective resistive layer in the effective column reaches the maximum length, which is: single particle resistance length = single particle length - 2 times the overlap length between the inner electrode and the resistor.

3. The method for fabricating a high-power miniaturized thick-film resistor according to claim 1 or 2, characterized in that: The auxiliary conductor layer is either an integral design that covers the entire length of the auxiliary column or a separate design with a blank area in the middle.

4. The method for fabricating a high-power miniaturized thick-film resistor according to claim 3, characterized in that: The auxiliary conductor layer of the overall design is covered with a printed glass protective layer to protect the auxiliary conductor layer, which will then be used as a zero-ohm resistor.

5. The method for fabricating a high-power miniaturized thick-film resistor according to claim 1, characterized in that: An auxiliary external electrode is printed at the separation point between the effective column and the auxiliary column, bridging the two columns.

6. The method for fabricating a high-power miniaturized thick-film resistor according to claim 1, characterized in that: The specific process steps include: S1: Provide a substrate, and use screen printing technology to print internal electrodes on both the front and back sides of the substrate, and then sinter them; S2: According to the design drawing, print a resistive layer on the front inner electrode of the effective column and sinter it; S3: Print a glass protective layer on the resistor layer of the effective column and sinter it; S4: The resistive layer in step S3 is repaired using a laser repair system; S5: Print an insulating resin protective layer outside the glass protective layer; S6: At the junction of the active column and the auxiliary column, an auxiliary external electrode layer is printed. Its width is less than or equal to the width of the smallest single resistor unit, and its length is adapted to the front terminal size. S7: Print MK onto the insulating resin protective layer, and then cure; S8: Strip arrangement, separates the auxiliary column from the effective column, and arranges the effective column in strips to prepare for subsequent automatic folding; S9: Vacuum coating layer; S10: Folding, mechanically breaking apart, breaking the strip-shaped resistors into the smallest resistance units; S11: Terminal preparation, metal electrodes are formed at both ends of the resistor particles obtained after step S9 for connection with PCB pads; S12: Test and package to complete the fabrication of the resistor chip.

7. The method for fabricating a high-power miniaturized thick-film resistor according to claim 6, characterized in that: After the resistive layer is printed and dried, the pattern of each individual resistive unit is outlined using a laser scribing operation, which assists in the trimming operation.

8. The method for fabricating a high-power miniaturized thick-film resistor according to claim 6, characterized in that: After the auxiliary external electrode layer is printed and dried, the pattern of each individual resistor unit is outlined using a laser scribing operation, which provides assistance for precise control of the pattern.

Images