High-temperature chip thin-film resistor and manufacturing method thereof

Abstract

The invention discloses a high-temperature chip thin-film resistor and a manufacturing method thereof, and relates to the technical field of resistor manufacturing, the resistor comprises a ceramic substrate, a resistive film layer is arranged on the front side of the ceramic substrate, positive electrodes are symmetrically arranged on the two sides of the resistive film layer, and back electrodes are arranged on the edges of the two sides of the back side of the ceramic substrate; side electrodes are symmetrically arranged at the ends of the two sides of the ceramic substrate, nickel layers and outer gold layers are arranged outside the side electrodes from inside to outside, and a passivation layer and an encapsulation layer are arranged on the front face of the resistive film layer from bottom to top. The manufacturing method comprises the following steps of scribing, sputter coating, resistor photoetching, passivation, silicon photoetching, high-temperature heat treatment, laser resistor trimming, encapsulation layer printing, strip splitting, side electrode forming, particle crushing and electroplating. The gold layer is used as the outer plating layer, so that the use temperature range of the resistor is widened, and the resistor can keep excellent performance in a harsh high-temperature environment.

Description

Technical Field

[0001] The present invention relates to the technical field of resistor manufacturing, and in particular to a high-temperature chip-type thin-film resistor and a manufacturing method thereof. Background Art

[0002] At present, many manufacturers use a thick-thin film combination process to produce chip thin-film resistors, that is, screen-printing silver or silver-palladium alloy materials to make the electrode bottom layer, and then electroplating nickel and tin layers on the electrode bottom layer. Since silver or silver-palladium alloy materials are used to make electrodes, the product precision level is not high and the stability is general. At the same time, long-term use in a sulfur-containing environment will cause a sulfide reaction at the joint between the electrode and the film layer, which will eventually lead to an open circuit between the electrode and the film layer, and the resistance value becomes infinite. In addition, due to the outer coating of the electrode, tin is used as the outermost welding layer. The melting point of tin determines that the product's operating temperature range is up to 150°C. Therefore, a high-temperature chip thin-film resistor is needed to achieve a higher operating temperature. Summary of the invention

[0003] The object of the present invention is to provide a high temperature chip type thin film resistor and a manufacturing method thereof, so as to solve the problem that the use temperature of the conventional chip type thin film resistor is limited and the electrode is easy to be vulcanized.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A high-temperature chip-type thin-film resistor comprises a ceramic substrate, a resistor film layer is arranged on the front side of the ceramic substrate, positive electrodes are symmetrically arranged on both sides of the resistor film layer, back electrodes are arranged on both sides of the back side of the ceramic substrate, side electrodes are symmetrically arranged on the ends of both sides of the ceramic substrate, a nickel layer and an outer gold layer are arranged on the outside of the side electrodes from the inside to the outside, and a passivation layer and an encapsulation layer are arranged on the front side of the resistor film layer from bottom to top.

[0006] As a further solution of the present invention: the positive electrode and the back electrode are arranged in one-to-one correspondence.

[0007] As a further solution of the present invention: the nickel layer and the outer gold layer are both U-shaped, covering the positive electrode, the back electrode and the side electrode on the same side.

[0008] As a further solution of the present invention: the edges on both sides of the passivation layer and the encapsulation layer are larger than the resistance film layer.

[0009] As a further solution of the present invention: the positive electrode is provided with a positive tungsten-titanium layer and a positive gold layer in sequence from the side close to the ceramic substrate to the outside, the back electrode is provided with a back tungsten-titanium layer and a back gold layer in sequence from the side close to the ceramic substrate to the outside, and the side electrode is provided with a side tungsten-titanium layer and a side gold layer in sequence from the side close to the ceramic substrate to the outside.

[0010] As a further solution of the present invention: the resistance film layer is a nickel-chromium alloy film layer, which is arranged on the front side of the ceramic substrate by sputtering coating.

[0011] As a further solution of the present invention: the positive electrode, the back electrode and the side electrodes are all arranged on the ceramic substrate by sputtering coating.

[0012] As a further solution of the present invention: a method for manufacturing a high temperature chip type thin film resistor, characterized in that it is used to manufacture the above-mentioned high temperature chip type thin film resistor, comprising the following steps:

[0013] Step 1: Marking: Laser marking the upper surface of the ceramic substrate according to the size of the resistors of different models, with a laser power of 30 to 50 W;

[0014] Step 2: Sputtering coating: The upper surface of the ceramic substrate is coated with a resistor film layer, a positive tungsten titanium layer and a positive gold layer by sputtering coating, and the lower surface of the ceramic substrate is coated with a back tungsten titanium layer and a back gold layer by sputtering coating. The sputtering power is 500W~1200W, and the vacuum degree is 2×10 -4 Pa~7×10 -4 Pa, time 30 minutes to 90 minutes;

[0015] Step 3: Photolithography resistors: Design masks of corresponding specifications according to different types of resistors, and form resistor and electrode patterns by photolithography;

[0016] Step 4: Passivation: Through electron beam evaporation process, a silicon dioxide passivation protective layer, i.e., a passivation layer, is plated on the surface of the resistor film layer and the positive electrode. The vacuum degree of the electron beam evaporation process is 2×10 -4 Pa~7×10 -4 Pa, hot drying temperature 200℃-300℃, time 30 minutes-60 minutes, evaporation rate / s, oxygen content 10sccm-20sccm, thickness 0.5μm-1μm;

[0017] Step 5: Photolithography of silicon: remove the passivation layer on the surface of the positive electrode by photolithography;

[0018] Step 6: High temperature heat treatment: The resistor film layer is treated by high temperature aging to make it reach a stable state, with a temperature of 290°C-400°C and a time of 2-4 hours;

[0019] Step 7: Laser resistance trimming: Cut the resistor film layer by laser cutting to form grooves to meet the corresponding resistance requirements; heat treatment after initial adjustment at a temperature of 150℃-200℃ for 48 hours-96 hours; finally, high-precision trimming is performed;

[0020] Step 8: Encapsulation layer printing: Printing the encapsulation layer on the surface of the passivation layer by screen printing;

[0021] Step 9: Split strips, side electrodes, and fragments: Split the whole resistor into strips by stacking the strips and put them into a jig. Sputter the side of the resistor in order from the inside to the outside with a tungsten-titanium layer and a gold layer, cover the positive electrode and the back electrode, connect the positive electrode and the back electrode, and finally split the strip resistor into resistor units by fragments, that is, forming a single resistor shape.

[0022] Step 10, electroplating: The positive electrode, the back electrode and the side electrode are plated with a nickel layer and an outer gold layer by electroplating to form the final finished resistor. The electroplating current is 20A-40A and the time is 60 minutes-80 minutes.

[0023] Beneficial effects of the present invention:

[0024] The resistor of the present invention uses gold as the electrode bottom layer, so that the electrode does not contain silver, which can completely prevent sulfidation and reduce the impact on the service life of the resistor; and further, by using a gold layer as an outer plating layer, the operating temperature range of the resistor is broadened, so that it can maintain excellent performance in a more severe high-temperature environment, and can be used and installed by bonding or bonding. This product structure can meet special usage needs in certain situations while improving product accuracy and stability and ensuring product quality requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Figure 1 The resistor structure of the present invention is shown in FIG. Figure 1 ;

[0027] Figure 2 The resistor structure of the present invention is shown in FIG. Figure 2 ;

[0028] Figure 3 yes Figure 2 The enlarged structural diagram at A in the middle;

[0029] Figure 4 It is a schematic diagram of the manufacturing process of the resistor of the present invention.

[0030] In the figure: 1. Ceramic substrate; 2. Resistor film layer; 3. Positive electrode; 31. Positive tungsten titanium layer; 32. Positive gold layer; 4. Back electrode; 41. Back tungsten titanium layer; 42. Back gold layer; 5. Side electrode; 51. Side tungsten titanium layer; 52. Side gold layer; 6. Nickel layer; 7. Outer gold layer; 8. Passivation layer; 9. Encapsulation layer. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention Figure 1-Figure 3 As shown, a high-temperature chip-type thin-film resistor is provided, which includes a ceramic substrate 1, a resistor film layer 2 is arranged on the front side of the ceramic substrate 1, positive electrodes 3 are symmetrically arranged on both sides of the resistor film layer 2 and located on the front side of the ceramic substrate 1, and back electrodes 4 are arranged at the positions of the positive electrodes 3 at the edges of both sides of the back side of the ceramic substrate 1, wherein two groups of positive electrodes 3 and back electrodes 4 are arranged, and they correspond to each other, side electrodes 5 are symmetrically arranged on the ends of both sides of the ceramic substrate 1, and the two ends of the side electrodes 5 respectively cover the positive electrode 3 and the back electrode 4 on the same side, and a nickel layer 6 and an outer gold layer 7 are arranged outside the two side electrodes 5 from the inside to the outside, and the nickel layer 6 and the outer gold layer 7 are both U-shaped, covering the positive electrode 3, the back electrode 4 and the side electrodes 5 on the same side, and a passivation layer 8 and an encapsulation layer 9 are arranged from bottom to top on the front side of the resistor film layer 2, and the edges of the passivation layer 8 and the encapsulation layer 9 on both sides are larger than the resistor film layer 2.

[0033] The resistance film layer 2 is a nickel-chromium alloy film layer, which is disposed on the front surface of the ceramic substrate 1 by sputtering coating.

[0034] Furthermore, specifically Figure 3 As shown, the above-mentioned positive electrode 3 is provided with a positive tungsten-titanium layer 31 and a positive gold layer 32 in sequence from the side close to the ceramic substrate 1 to the outside, the back electrode 4 is provided with a back tungsten-titanium layer 41 and a back gold layer 42 in sequence from the side close to the ceramic substrate 1 to the outside, and the side electrode 5 is provided with a side tungsten-titanium layer 51 and a side gold layer 52 in sequence from the side close to the ceramic substrate 1 to the outside.

[0035] Furthermore, the positive electrode 3 , the back electrode 4 and the side electrode 5 are all disposed on the ceramic substrate 1 by sputtering coating.

[0036] The resistor uses gold as the electrode bottom layer, so that the electrode does not contain silver, which can completely prevent sulfidation and reduce the impact on the service life of the resistor; and further, by using a gold layer as an outer plating layer, the operating temperature range of the resistor is broadened, so that it can maintain excellent performance in more stringent high-temperature environments; for example, compared with traditional chip-type thin-film resistors, since traditional chip-type thin-film resistors use side tin plating, in which the melting point of gold is much higher than the melting point of tin, the use temperature can be increased by using a gold layer instead of a traditional tin layer as an outer plating layer. The resistor of the present invention can operate stably in a high-temperature environment, which is impossible for traditional chip-type thin-film resistors.

[0037] The resistor has a sputtered gold electrode layer with an electroplated nickel layer 6 and an outer gold layer 7, so that the welding point can withstand a higher operating temperature and remain stable.

[0038] The resistor can be installed by bonding or bonding when in use. This product structure can meet special usage requirements in certain situations while improving product accuracy and stability and ensuring product quality requirements.

[0039] Furthermore, the present invention also provides a method for manufacturing a high temperature chip thin film resistor, such as Figure 4 As shown, the method for manufacturing the above-mentioned high temperature chip thin film resistor specifically includes the following steps:

[0040] Step 1: Marking: Laser marking is performed on the upper surface of the ceramic substrate 1 according to the sizes corresponding to different types of resistors, and the laser power is 30 to 50 W;

[0041] Step 2, sputtering coating: The resistor film layer 2, the positive tungsten titanium layer 31 and the positive gold layer 32 are sequentially coated on the upper surface of the ceramic substrate 1 by sputtering coating, and the back tungsten titanium layer 41 and the back gold layer 42 are sequentially coated on the lower surface of the ceramic substrate 1 by sputtering coating, wherein the resistor film layer 2 is a nickel-chromium alloy film layer, the positive tungsten titanium layer 31 and the back tungsten titanium layer 41 are barrier layers, and the positive gold layer 32 and the back gold layer 42 are electrode layers. The sputtering power is 500W-1200W, and the vacuum degree is 2×10 -4 Pa~7×10 -4 Pa, time 30 minutes to 90 minutes (adjusted according to different square resistance values).

[0042] Step 3, photolithography resistors: design masks of corresponding specifications according to different types of resistors, and form resistor and electrode patterns through photolithography; the photolithography process steps are: coating - pre-baking - exposure - development - hardening - etching - stripping, which is the existing photolithography process and will not be repeated here.

[0043] Step 4: Passivation: A silicon dioxide passivation protective layer, i.e., a passivation layer 8, is plated on the surface of the resistor film layer 2 and the positive electrode 3 by electron beam evaporation process; the vacuum degree of the electron beam evaporation process is 2×10 -4 Pa~7×10 -4 Pa, hot drying temperature 200℃-300℃, time 30 minutes-60 minutes, evaporation rate Oxygen content 10sccm-20sccm, thickness 0.5μm-1μm;

[0044] Step 5, photolithography of silicon: remove the passivation layer 8 on the surface of the positive electrode 3 by photolithography (the process steps of photolithography of silicon are consistent with the process steps of photolithography of resistors). After the photolithography of silicon is completed, the edge of the passivation layer 8 is larger than the resistor film layer 2, and can completely cover and protect the resistor film layer 2;

[0045] Step 6, high temperature heat treatment: treat the resistor film layer 2 by high temperature aging to make it reach a stable state, the temperature is 290℃-400℃, and the time is 2-4 hours;

[0046] Step 7: Laser resistance trimming: Cut the resistor film layer 2 by laser cutting to form grooves so that it meets the corresponding resistance value requirements; after the initial adjustment, the cut film layer needs to be cured by heat treatment at a temperature of 150°C-200°C for 48 hours-96 hours; finally, it is trimmed with high precision;

[0047] Step 8: Printing the encapsulation layer 9: Printing the encapsulation layer 9 on the surface of the passivation layer 8 by screen printing. The encapsulation layer 9 includes a protective layer and a marking layer, which protects the resistor film layer 2 and marks the resistor. The edge of the printed encapsulation layer 9 is larger than the protective resistor film layer 2, and can completely cover and protect the protective resistor film layer 2.

[0048] Step nine: splitting strips, side electrodes, and fragments: splitting the whole resistor into strip resistors by stacking the split strips and placing them into a jig, and coating the side tungsten-titanium layer 51 and the side gold layer 52 of the resistor in order from the inside to the outside by sputtering, covering the positive electrode 3 and the back electrode 4, so that the positive electrode 3 and the back electrode 4 are connected. The process steps are consistent with the process steps of sputtering the lower surface of the ceramic substrate 1 in step two, and finally the strip resistor is split into resistor units by fragments, that is, a single resistor shape is formed;

[0049] Step 10, electroplating: The positive electrode 3, the back electrode 4 and the side electrode 5 are plated with a nickel layer 6 and an outer gold layer 7 by electroplating to form a final finished resistor. The electroplating current is 20A-40A and the time is 60 minutes-80 minutes.

[0050] Furthermore, the high temperature chip thin film resistors of the present invention are screened through a temperature shock test (low temperature -65°C, high temperature 200°C, 10 cycles in total, each time for 30 minutes), and then the screened resistors are subjected to appearance inspection and resistance test, and finally qualified high temperature chip thin film resistors are obtained.

[0051] Furthermore, the qualified high temperature chip thin film resistors were subjected to a load test at high temperature: the qualified high temperature chip thin film resistors were mounted on the test substrate using conductive epoxy glue and the resistance value was tested at room temperature. The test temperature was 200℃±5℃, and the load was applied in a manner of 1.5h power-on and 0.5h power-off. After the test, the appearance was checked and the resistance change was measured. The test results are shown in Table 1:

[0052] Where R1 is the resistance value measured before the test, R is the nominal value, (R1-R) / R is the resistance accuracy value before the test; R2 is the resistance value measured after the test, R is the nominal value, (R2-R) / R is the resistance accuracy value after the test; △R is the resistance change value before and after the test:

[0053] Table 1: Load test data under high temperature:

[0054]

[0055]

[0056] It can be seen from Table 1 above that the high temperature chip thin film resistor of the present invention can stably operate at a high temperature of 200°C ±5°C, and the resistance change is less than ±(0.5%R+0.01Ω).

[0057] Furthermore, the qualified high temperature chip thin film resistors were subjected to a high temperature storage test: the qualified high temperature chip thin film resistors were mounted on a test substrate using conductive epoxy adhesive and the resistance value was tested at room temperature, and stored at a test temperature of 200°C ± 5°C for 100 hours. After the test, the appearance was checked and the resistance change was measured. The test results are shown in Table 2:

[0058] Wherein, R1 is the resistance value measured before the test, R is the nominal value, (R1-R) / R is the resistance accuracy value before the test; R2 is the resistance value measured after the test, R is the nominal value, (R2-R) / R is the resistance accuracy value after the test; △R is the resistance change value before and after the test.

[0059]

[0060]

[0061] It can be seen from Table 2 above that the high temperature chip thin film resistor of the present invention can be stored for a long time at a high temperature of 200°C ±5°C, and the resistance change is less than ±(0.1%R+0.01Ω).

[0062] Furthermore, the qualified high-temperature chip thin film resistors were subjected to a temperature characteristic test: the qualified high-temperature chip thin film resistors were mounted on the test substrate using conductive epoxy glue and the accuracy was tested at room temperature, and the resistance was tested at a test temperature of 200°C±5°C for 30min±10min. After the test, the appearance was checked and the resistance change was measured. The test results are shown in Table 3:

[0063] Wherein, R1 is the resistance value measured before the test, R is the nominal value, (R1-R) / R is the resistance accuracy value before the test; R2 is the resistance value measured after the test, R is the nominal value, (R2-R) / R is the resistance accuracy value after the test; RTC is the temperature characteristic value.

[0064]

[0065]

[0066] It can be seen from Table 3 above that the high temperature chip thin film resistor of the present invention can work normally at a high temperature of 200°C±5°C, and the resistance change is less than ±25ppm / K.

[0067] In summary, the present invention broadens the operating temperature range of the resistor by using a gold layer as the outer plating layer, so that it can maintain excellent performance (low temperature drift, high storage, etc.) in more stringent high temperature environments, such as meeting normal performance requirements at a high temperature of 200°C.

[0068] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A high temperature chip type thin film resistor, characterized in that: The invention comprises a ceramic substrate (1), wherein a resistor film layer (2) is arranged on the front side of the ceramic substrate (1), positive electrodes (3) are symmetrically arranged on both sides of the resistor film layer (2), back electrodes (4) are arranged on both sides of the back side of the ceramic substrate (1), side electrodes (5) are symmetrically arranged on both ends of the ceramic substrate (1), a nickel layer (6) and an outer gold layer (7) are arranged on the outside of the side electrodes (5) from the inside to the outside, and a passivation layer (8) and an encapsulation layer (9) are arranged on the front side of the resistor film layer (2) from the bottom to the top.

2. A high temperature chip type thin film resistor according to claim 1, characterized in that: The positive electrode (3) and the back electrode (4) are arranged in one-to-one correspondence.

3. The high temperature chip type thin film resistor according to claim 1, characterized in that: The nickel layer (6) and the outer gold layer (7) are both U-shaped and cover the positive electrode (3), the back electrode (4) and the side electrode (5) on the same side.

4. The high temperature chip type thin film resistor according to claim 1, characterized in that: The edges on both sides of the passivation layer (8) and the encapsulation layer (9) are larger than those of the resistance film layer (2).

5. A high temperature chip type thin film resistor according to claim 1 or 2, characterized in that: The positive electrode (3) is provided with a positive tungsten-titanium layer (31) and a positive gold layer (32) in sequence from the side close to the ceramic substrate (1) to the outside, the back electrode (4) is provided with a back tungsten-titanium layer (41) and a back gold layer (42) in sequence from the side close to the ceramic substrate (1) to the outside, and the side electrode (5) is provided with a side tungsten-titanium layer (51) and a side gold layer (52) in sequence from the side close to the ceramic substrate (1) to the outside.

6. The high temperature chip type thin film resistor according to claim 1, characterized in that: The resistor film layer (2) is a nickel-chromium alloy film layer, which is arranged on the front surface of the ceramic substrate (1) by means of sputtering coating.

7. The high temperature chip type thin film resistor according to claim 1, characterized in that: The positive electrode (3), the back electrode (4) and the side electrode (5) are all arranged on the ceramic substrate (1) by means of sputtering coating.

8. A method for manufacturing a high temperature chip thin film resistor, characterized in that: The method for manufacturing the high temperature chip thin film resistor according to any one of claims 1 to 7 comprises the following steps: Step 1: scribing: laser scribing is performed on the upper surface of the ceramic substrate (1) according to the sizes corresponding to the resistors of different types, with the laser power being 30 to 50 W; Step 2, sputtering coating: coating the resistor film layer (2), the positive tungsten titanium layer (31) and the positive gold layer (32) in sequence on the upper surface of the ceramic substrate (1) by sputtering coating, and coating the back tungsten titanium layer (41) and the back gold layer (42) in sequence on the lower surface of the ceramic substrate (1) by sputtering coating, the sputtering power is 500W to 1200W, the vacuum degree is 2×10-4Pa to 7×10-4Pa, and the time is 30 minutes to 90 minutes; Step 3: Photolithography resistors: Design masks of corresponding specifications according to different types of resistors, and form resistor and electrode patterns by photolithography; Step 4: Passivation: A silicon dioxide passivation protective layer, i.e., a passivation layer (8), is plated on the surface of the resistor film layer (2) and the positive electrode (3) by electron beam evaporation process; the vacuum degree of the electron beam evaporation process is 2×10-4Pa to 7×10-4Pa, the heat drying temperature is 200°C to 300°C, the time is 30 minutes to 60 minutes, and the evaporation rate is Oxygen content 10sccm-20sccm, thickness 0.5μm-1μm; Step 5: Photolithography of silicon: removing the passivation layer (8) on the surface of the positive electrode (3) by photolithography; Step 6, high temperature heat treatment: treating the resistor film layer (2) by high temperature aging to make it reach a stable state, the temperature is 290° C.-400° C., and the time is 2-4 hours; Step 7: Laser resistance adjustment: cutting the resistor film layer (2) by laser cutting to form grooves so as to achieve the corresponding resistance value requirements; performing heat treatment after initial adjustment at a temperature of 150° C. to 200° C. for a period of 48 hours to 96 hours; and finally performing high-precision adjustment; Step 8: Printing the encapsulation layer (9): Printing the encapsulation layer (9) on the surface of the passivation layer (8) by screen printing; Step 9: splitting, side electrode, and crushing: splitting the whole resistor into strip resistors by stacking the strips and placing them into a jig, and coating the side tungsten titanium layer (51) and the side gold layer (52) on the side of the resistor in order from the inside to the outside by sputtering, covering the positive electrode (3) and the back electrode (4), so that the positive electrode (3) and the back electrode (4) are connected, and finally the strip resistor is split into resistor units by crushing, that is, a single resistor shape is formed; Step 10, electroplating: The positive electrode (3), the back electrode (4) and the side electrode (5) are plated with a nickel layer (6) and an outer gold layer (7) by electroplating to form a final finished resistor. The electroplating current is 20A-40A and the time is 60 minutes-80 minutes.

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