TW202416302A - Method for manufacturing thick film resistor element - Google Patents

Abstract

A thick film resistor element comprises a substrate made of an insulating material, a plurality of positive electrodes formed on the front and back sides of the substrate, a plurality of back electrodes, a resistor layer formed on the front side of the substrate and made of copper and nickel, a protective layer unit coated on the resistor layer, two side conductors formed on the end faces of the substrate and used to connect the positive electrodes and the back electrodes, and a coating unit covering the side conductors, the positive electrodes and the back electrodes. The present invention can reduce the production cost of the thick film resistor element by using base metal as the constituent material of the resistor layer. In addition, the present invention also provides a method for manufacturing the thick film resistor element.

Description

Thick film resistor element and method for manufacturing the same

The present invention relates to a resistor element and a manufacturing method thereof, and in particular to a thick film resistor element and a manufacturing method thereof.

As one of the passive components, the resistor element is widely configured in various electronic products. The resistor element generally includes a substrate, a resistor arranged on the substrate, and a plurality of terminal electrodes located on both sides of the substrate and respectively connected to the resistor. And depending on the different structural forms of the resistor, different types of resistor elements such as thick film resistor elements, thin film resistor elements, or winding resistor elements can be formed. Among them, taking the thick film resistor element as an example, the resistor is arranged on the substrate in a printing manner, and is a film layer structure with a thickness ranging from several microns to tens of microns, which is conducive to withstanding higher voltage and power. In addition, since the thick film resistor element has a simple manufacturing process and is more flexible in the design of the resistor structure, it is suitable for mass production of small electronic components. However, the resistor of the thick film resistor element is usually selected from precious metal materials such as ruthenium, silver, or palladium, which makes the production cost of the thick film resistor element high.

Therefore, the object of the present invention is to provide a method for manufacturing a thick film resistor element.

Therefore, the manufacturing method of the thick film resistor element of the present invention includes a substrate forming step, an electrode forming step, a resistor forming step, an inert gas sintering step, a resistor repairing step, a protective layer forming step, a sintering step, a first segmentation step, a side conductor forming step, a second segmentation step, and an electroplating step.

The substrate forming step provides a foil made of an insulating material and having a front side and a back side facing each other, and forms a plurality of longitudinal grooves spaced apart from each other and arranged in an array on the foil, and a plurality of transverse grooves spaced apart from each other and located between any two adjacent longitudinal grooves, and forms a plurality of substrates defined by the longitudinal grooves and the transverse grooves and arranged in an array on the foil, wherein each longitudinal groove extends along a first direction, and each transverse groove extends along a second direction perpendicular to the first direction.

The electrode forming step is to form a plurality of back electrodes respectively located at two opposite sides of each substrate with conductive material on the back side, and to form a plurality of positive electrodes located within the projection range of the back electrodes on the front side, and the back electrodes are respectively adjacent to the longitudinal grooves adjacent to the substrate.

The resistor forming step is to form a resistor layer connected to the positive electrodes on the front surface of the substrates with a conductive material to obtain a first semi-finished product, wherein the component materials of the resistor layer include copper and nickel.

The inert gas sintering step is to place the first semi-finished product in a sintering furnace containing inert gas for sintering to obtain a second semi-finished product.

The resistance repairing step is to remove a part of the resistance layer of the second semi-finished product by laser.

The protective layer forming step is to form a protective layer unit covering the resistor layer after the resistance trimming step with an insulating material to obtain a third semi-finished product.

The first segmentation step is to cut along the longitudinal grooves to obtain a plurality of fourth semi-finished products, each of which has a plurality of substrates arranged along the first direction, and each substrate has an end surface connected to the front and back of the substrate and exposed to the outside.

The side conductor forming step is to form side conductors for connecting the positive electrodes and the back electrodes on the exposed end surfaces of the substrates of any fourth semi-finished product with conductive materials, so as to obtain a fifth semi-finished product.

The second segmentation step is to cut the fifth semi-finished product along the transverse grooves to obtain a plurality of independent resistor semi-finished products.

The electroplating step is to form a coating unit covering the side conductors, the positive electrodes, and the back electrodes on each resistor semi-finished product by electroplating to obtain a plurality of thick film resistor elements.

Furthermore, another object of the present invention is to provide a thick film resistor element.

Therefore, the thick film resistor element of the present invention includes a substrate, an electrode unit, a resistor layer, a protective layer unit, two side conductors, and a coating unit.

The substrate is made of insulating material and has a front surface, a back surface opposite to each other, and an end surface connecting the front surface and the back surface.

The electrode unit is made of conductive material, including a plurality of positive electrodes formed on the front surface of the substrate and located at two opposite sides, and a plurality of back electrodes formed on the back surface and corresponding to the projection ranges of the positive electrodes.

The resistor layer is formed on the front side of the substrate and connected to the positive electrodes. The components of the resistor layer include copper and nickel.

The protection layer unit is made of insulating material and covers the resistor layer.

The side conductors are made of conductive material, formed on the end surface of the substrate and adjacent to the two sides where the positive electrodes and the back electrodes are formed, and are used to connect the positive electrodes and the back electrodes respectively.

The coating unit is made of conductive material and is used to cover the side conductors and the electrode unit.

The effect of the present invention is that base metal materials (copper, nickel) are used as the constituent materials of the resistor layer, and a sintering furnace containing an inert gas is used for sintering to avoid the resistor layer from chemically reacting with the atmosphere in the sintering furnace during the sintering process, thereby replacing the conventional resistor layer composed of precious metal materials, thereby reducing the production cost of the thick film resistor element.

Before the present invention is described in detail, it should be noted that similar components are represented by the same number in the following description. In addition, it should be noted that the drawings of the present invention are only for representing the relative relationship of the structure and/or position between the components, and are not related to the actual size of each component.

Referring to FIG. 1 , the thick film resistor element of the present invention comprises a substrate 2, an electrode unit 3, a resistor layer 4, a protective layer unit 5, two side conductors 6, and a coating unit 7.

The substrate 2 is made of an insulating material and has a front surface 21, a back surface 22 facing each other, and an end surface 23 connecting the front surface 21 and the back surface 22. In this embodiment, the substrate 2 is made of a ceramic material selected from alumina.

The electrode unit 3 is made of conductive material, including a plurality of positive electrodes 31 formed on the front surface 21 of the substrate 2 and located at two opposite sides, and a plurality of back electrodes 32 formed on the back surface 22 and corresponding to the projection ranges of the positive electrodes 31. In this embodiment, the electrode unit 3 is illustrated by taking two positive electrodes 31 located at two opposite sides of the substrate 2 and two back electrodes 32 located opposite to the positive electrodes 31 as an example, and the positive electrodes 31 and the back electrodes 32 are selected from copper. However, in actual implementation, the material selection and quantity of the positive electrodes 31 and the back electrodes 32 are not limited to the above examples.

The resistor layer 4 is formed on the front surface 21 of the substrate 2, and partially covers the positive electrodes 31 located on the two sides and is connected to the positive electrodes 31. The resistor layer 4 is made of base metal material, and its constituent materials include copper and nickel. Preferably, the weight ratio of copper and nickel in the constituent materials of the resistor layer 4 is 1:1. In this embodiment, the thickness of the resistor layer 4 is between 7μm and 15μm, and has a strip-shaped trimming trench 41 extending downward from the surface of the resistor layer 4 and extending straight along the surface of the resistor layer 4, and the depth of the trimming trench 41 is approximately equal to the thickness of the resistor layer 4. The resistance value of the resistor layer 4 can be adjusted by forming the trimming trench 41.

It should be noted that the depth, shape, and number of the resistance trimming groove 41 can vary according to product design requirements. For example, a plurality of resistance trimming grooves 41 arranged at intervals can be formed on the surface of the resistor layer 4, or a resistance trimming groove 41 in an arc shape can be formed, etc. As long as the formation of the resistance trimming groove 41 can be utilized to adjust the resistance value of the resistor layer 4, it is not limited to the aforementioned examples.

The protective layer unit 5 covers the resistor layer 4 to provide protection to prevent the resistor layer 4 from being damaged in the subsequent packaging process, and includes a first protective layer 51, a second protective layer 52, and a plurality of marking patterns 53 sequentially covering the resistor layer 4. The first protective layer 51 and the second protective layer 52 are selected from insulating materials and can be the same or different. The marking patterns 53 can be formed on the surface of the insulating material (the second protective layer 52) by printing or laser. The marking patterns 53 may be characters, geometric patterns, or other patterns, and the structural aspects, materials, and quantities of the marking patterns 53 may vary according to actual needs and the manufacturing process used.

In this embodiment, the protective layer unit 5 has a double-layer insulation structure, and the first protective layer 51 and the second protective layer 52 are selected from epoxy resin, and the marking patterns 53 are formed by printing on the surface of the second protective layer 52. Most of the marking patterns 53 are composed of insulating materials (such as epoxy resin) and are arranged at intervals. However, in actual implementation, the protective layer unit 5 may also have only a single protective layer, and the marking pattern 53 may also be only one, and the number or form thereof is not limited to that shown in the figure. In addition, when the marking patterns 53 are formed by laser, they are composed of patterned grooves formed directly from the surface of the insulating material (the second protective layer 52) downward without using other materials.

It should be noted that in some embodiments, it is not necessary to form the marking patterns 53 as required.

The side conductors 6 are made of conductive material, formed on the end surface 23 of the substrate 2, and adjacent to the two sides where the positive electrodes 31 and the back electrodes 32 are formed, for respectively connecting the corresponding positive electrodes 31 and the back electrodes 32, so that the positive electrodes 31 and the back electrodes 32 located on the same side of the substrate 2 are electrically connected to each other, and the side conductors 6 can be selected from nickel, chromium or nickel-chromium alloy.

The plating unit 7 is made of a conductive material to cover the side conductors 6 and the electrode unit 3, and can be selected from nickel or tin. In this embodiment, the plating unit 7 is a multi-layer structure, and includes a first electroplating layer 71 and a second electroplating layer 72, and the constituent material of the first electroplating layer 71 is different from the constituent material of the second electroplating layer 72. In this embodiment, the first electroplating layer 71 is made of nickel and the second electroplating layer 72 is made of tin.

2 to 6 are used to illustrate the manufacturing method of the thick film resistor element of the present invention, so as to manufacture the thick film resistor element 200 as shown in FIG. 1. The manufacturing method includes a substrate forming step S1, an electrode forming step S2, a resistor forming step S3, an inert gas sintering step S4, a resistor repairing step S5, a protective layer forming step S6, a first segmentation step S7, a side conductor forming step S8, a second segmentation step S9, and an electroplating step S10.

Referring to FIG. 2 and FIG. 3 , the substrate forming step S1 provides a foil 20 made of an insulating material and having a front surface 21 and a back surface 22 opposite to each other, and forms a plurality of longitudinal grooves 201 spaced apart from each other and arranged in an array on the foil 20 by laser cutting, and a plurality of transverse grooves 202 located between any two adjacent longitudinal grooves 201, and forms a plurality of substrates 2 defined by the longitudinal grooves 201 and the transverse grooves 202 and arranged in an array on the foil 20. Each longitudinal groove 201 extends along a first direction X, and each transverse groove 202 extends along a second direction Y perpendicular to the first direction X. In this embodiment, the longitudinal grooves 201 and the transverse grooves 202 are marks extending downward from the front surface 21 of the foil 20 to serve as dividing lines for the first dividing step S7 and the second dividing step S9.

It should be noted that the longitudinal trenches 201 and the transverse trenches 202 have different depths according to the process method or the material selection of the foil 20. In some embodiments, the longitudinal trenches 201 and the transverse trenches 202 penetrate the foil 20, and the transverse trenches 202 are not connected to the adjacent longitudinal trenches 201.

2 and 4 , the electrode forming step S2 is to form two back electrodes 32 located at two opposite sides of the substrate 2 on the back side 22 of each substrate 2 by printing or coating a conductive material, and to form two positive electrodes 31 on the front side 21 corresponding to the projection range of the back electrodes 32, and the two side edges are adjacent to the longitudinal grooves 201 adjacent to the substrate 2.

The resistor forming step S3 is to form the resistor layer 4 connected to the positive electrodes 31 and having a thickness of 7 μm to 15 μm on the front surface 21 of each substrate 2 by printing or coating a conductive material, so as to obtain a first semi-finished product 300. The resistor layer 4 is made of base metal, and its constituent materials include copper and nickel. Preferably, the weight ratio of the copper to the nickel is 1:1.

The inert gas sintering step S4 is to place the first semi-finished product 300 in a sintering furnace (not shown) containing inert gas for sintering to obtain a second semi-finished product 400. In this embodiment, the first semi-finished product 300 is placed in a sintering furnace containing nitrogen ( _N2 ), and the oxygen content in the sintering furnace is controlled to be no more than 10ppm, and then sintered at a sintering temperature between 890°C and 910°C, so that the resistor layer 4 and the substrate 2 are fused to enhance the bonding force between the resistor layer 4 and the substrate 2, thereby solidifying the resistor layer 4. In addition, by placing the first semi-finished product 300 in a sintering furnace filled with an inert gas atmosphere for sintering, the resistor layer 4 composed of base metal (copper and/or nickel) can be prevented from chemically reacting with the atmosphere in the sintering furnace during the sintering process, resulting in the electrical properties of the resistor layer 4 not meeting expectations. Preferably, the sintering temperature in the inert gas sintering step S4 is 900°C.

The resistance trimming step S5 is to remove part of the structure of the resistor layer 4 of the second semi-finished product 400 by laser to form a resistance trimming groove 41 on the resistor layer 4 that extends vertically along the first direction X and penetrates the resistor layer 4. The resistance value of the resistor layer 4 can be trimmed by forming the resistance trimming groove 41 so that its resistance value meets expectations.

Referring to FIG. 2 and FIG. 5 , the protective layer forming step S6 is performed after the resistance repairing step S5 , and the first protective layer 51 made of epoxy resin and the second protective layer 52 made of epoxy resin are sequentially formed by printing with insulating material to cover the resistance layer 4 after the resistance value is repaired, and the first protective layer 51 partially fills the resistance repairing groove 41 to prevent the formation of a gap between the protective layer unit 5 and the resistance layer 4. Afterwards, epoxy resin is printed on the surface of the protective layer unit 5 to form the marking patterns 53 arranged at intervals. After the marking patterns 53 are formed, the protective layer unit 5 is cured by heat treatment (process temperature is about 200°C) to enhance the bonding strength between the resistor layer 4 and the protective layer unit 5, so as to obtain a third semi-finished product 500.

In other embodiments, the marking patterns 53 may be patterned grooves (not shown) formed by removing part of the surface structure of the protective layer unit 5 by laser, or, the marking patterns 53 may not be formed according to needs, and the protective layer unit 5 may be directly cured by heat treatment after being formed. In addition, the parameter conditions of the heat treatment method (such as process temperature, ambient atmosphere, and heating time, etc.) will vary depending on the material composition and thickness of the protective layer unit 5. The specific process steps and parameter details are known to those skilled in the art and will not be elaborated here.

The first segmentation step S7 is to cut along the longitudinal grooves 201 (see FIG. 3 ) of the third semi-finished product 500 to obtain a plurality of independent fourth semi-finished products 600 , and each fourth semi-finished product 600 has a plurality of substrates 2 arranged along the first direction X, and the end surface 23 of each substrate 2 along the first direction X is exposed to the outside.

2 and 6 , the side conductor forming step S8 is to form the side conductors 6 for connecting the positive electrodes 31 and the back electrodes 32 on the exposed end surfaces 23 of the substrates 2 of any fourth semi-finished product 600 (see FIG. 5 ) by sputtering with a conductive material, so as to obtain a fifth semi-finished product 700. In this embodiment, the side conductors 6 can be selected from nickel, chromium or nickel-chromium alloy.

The second segmentation step S9 is to cut the fifth semi-finished product 700 along the transverse grooves 202 (see FIG. 3 ) to obtain a plurality of resistor semi-finished products 800 that are independent of each other as shown in FIG. 6 .

The electroplating step S10 is to form a plating unit 7 covering the side conductors 6, the positive electrodes 31, and the back electrodes 32 on each resistor semi-finished product 800 by electroplating to obtain a plurality of thick film resistor elements 200 as shown in FIG1. The plating unit 7 includes the first electroplating layer 71 composed of nickel and the second electroplating layer 72 composed of tin, which are sequentially formed on the surface of the side conductors 6 and the electrode unit 3.

Finally, the thick film resistor element 200 obtained by the above-mentioned manufacturing method can be subjected to a packaging process. First, a resistance meter is used to measure the resistance value of the thick film resistor elements 200, and the appearance quality is screened, thereby screening out the thick film resistor elements 200 whose resistance value does not meet the expectation or whose appearance is poor (for example, the marking pattern 53 is damaged, or the coating unit 7 has incomplete coverage, etc.), and the thick film resistor elements 200 after screening can be subjected to subsequent packaging processes to ensure that the thick film resistor elements 200 of the present manufacturing method have a higher yield.

In summary, the thick film resistor element 200 of the present invention utilizes base metal materials (copper, nickel) as the constituent material of the resistor layer 4, and in the process of sintering to solidify the resistor layer 4 in the inert gas sintering step S4, nitrogen is utilized as the atmosphere of the sintering furnace, which can prevent the resistor layer 4 from chemically reacting during the sintering and solidifying process, thereby being able to replace the conventional resistor layer composed of precious metal materials, thereby reducing the production cost of the thick film resistor element 200, and thus being able to achieve the purpose of the present invention.

However, the above is only an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the present patent.

200: Thick film resistor element 2: Substrate 21: Front 22: Back 23: End face 20: Foil 201: Longitudinal trench 202: Transverse trench 3: Electrode unit 31: Positive electrode 32: Back electrode 4: Resistor layer 41: Repair trench 5: Protective layer unit 51: First protective layer 52: Second protective layer 53: Marking pattern 6: Side conductor 7: Plating unit 71: First plating layer 72: Second plating layer 300: First semi-finished product 400: Second semi-finished product 500: Third semi-finished product 600: Fourth semi-finished product 700: Fifth semi-finished product 800: Resistor semi-finished product S1: Substrate forming step S2: Electrode forming step S3: Resistor forming step S4: Inert gas sintering step S5: Resistor repairing step S6: Protective layer forming step S7: First segmentation step S8: Side conductor forming step S9: Second segmentation step S10: Electroplating step X: First direction Y: Second direction

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a cross-sectional schematic diagram illustrating an embodiment of the thick film resistor element of the present invention; FIG. 2 is a flow chart illustrating an embodiment of the method for manufacturing the thick film resistor element of the present invention; FIG. 3 is a schematic diagram illustrating a foil produced in the substrate forming step of the manufacturing method; and FIG. 4 to FIG. 6 are process schematic diagrams illustrating the manufacturing method of the thick film resistor element, and the process schematic diagrams correspond to the cross-sectional structure of the IV-IV cut line of FIG. 3 .

200: Thick film resistor element

2: Substrate

21: Front

22: Back

23: End face

3: Electrode unit

31: Positive electrode

32: Back electrode

4: Resistor layer

41: Repair the blocking groove

5: Protective layer unit

51: First protective layer

52: Second protective layer

53: Marking pattern

6: Side conductor

7: Plating unit

71: First coating layer

72: Second coating layer

Claims (10)

A method for manufacturing a thick film resistor element comprises: A substrate forming step, providing a foil made of an insulating material, having a front side and a back side facing each other, forming a plurality of longitudinal grooves spaced apart from each other and arranged in an array on the foil, and a plurality of transverse grooves spaced apart from each other and located between any two adjacent longitudinal grooves, and forming a plurality of substrates defined by the longitudinal grooves and the transverse grooves and arranged in an array on the foil, wherein each longitudinal groove extends along a first direction, and each transverse groove extends along a second direction perpendicular to the first direction; An electrode forming step, using a conductive material to form a plurality of back electrodes located at two opposite sides on the back side of each substrate, and forming a plurality of positive electrodes located within the projection range of the back electrodes on the front side, and the back electrodes are respectively adjacent to the longitudinal grooves adjacent to the substrate; A resistor forming step, using a conductive material to form a resistor layer connected to the positive electrodes on the front side of the substrates to obtain a first semi-finished product, wherein the component materials of the resistor layer include copper and nickel; An inert gas sintering step, placing the first semi-finished product in a sintering furnace containing an inert gas for sintering to obtain a second semi-finished product; A resistor repairing step, removing part of the structure of the resistor layer of the second semi-finished product by laser; A protective layer forming step, after the resistance repairing step, a protective layer unit covering the resistance layer after the resistance repairing step is formed with an insulating material to obtain a third semi-finished product; A first segmentation step, cutting along the longitudinal grooves to obtain a plurality of fourth semi-finished products, each of which has a plurality of substrates arranged along the first direction, and each substrate has an end surface connected to the front and the back of the substrate and exposed to the outside; A side conductor forming step, forming side conductors for connecting the positive electrodes and the back electrodes on the exposed end surfaces of the substrates of any fourth semi-finished product with a conductive material, respectively, to obtain a fifth semi-finished product; A second segmentation step, cutting the fifth semi-finished product along the transverse grooves to obtain a plurality of independent resistor semi-finished products; and An electroplating step is performed to form a coating unit covering the side conductors, the positive electrodes, and the back electrodes on each resistor semi-finished product by electroplating to obtain a plurality of thick film resistor elements. A method for manufacturing a thick film resistor element as described in claim 1, wherein the weight ratio of copper to nickel in the composition material of the resistor layer is 1:1. The method for manufacturing a thick film resistor element as described in claim 1, wherein, in the inert gas sintering step, the first semi-finished product is placed in a sintering furnace containing nitrogen and sintered at a sintering temperature between 890°C and 910°C. The manufacturing method of the thick film resistor element as described in claim 1, wherein the protective layer forming step is to first form a protective layer covering the resistor layer with an insulating material, and then form at least one marking pattern on the surface of the protective layer by printing or laser to obtain the protective layer unit. A method for manufacturing a thick film resistor element as described in claim 1, wherein the protective layer unit includes a first protective layer and a second protective layer sequentially covering the resistor layer, which can be selected from insulating materials, and the constituent materials of the first protective layer and the second protective layer can be the same or different from each other. A method for manufacturing a thick film resistor element as described in claim 1, wherein the plating unit includes a first plating layer and a second plating layer, which can be selected from nickel or tin, and the constituent material of the first plating layer is different from the constituent material of the second plating layer. A thick film resistor element comprises: A substrate, made of insulating material, having a front side and a back side opposite to each other, and an end face connecting the front side and the back side; An electrode unit, made of conductive material, including a plurality of positive electrodes formed on the front side of the substrate and located at two opposite sides, and a plurality of back electrodes formed on the back side and corresponding to the projection range of the positive electrodes; A resistor layer, formed on the front side of the substrate and connected to the positive electrodes, the constituent materials of the resistor layer including copper and nickel; A protective layer unit, made of insulating material and covering the resistor layer; Two side conductors, made of conductive material, formed on the end surface of the substrate and adjacent to the two sides where the positive electrodes and the back electrodes are formed, for connecting the positive electrodes and the back electrodes respectively; and A coating unit, made of conductive material, for covering the side conductors and the electrode unit. A thick film resistor element as described in claim 7, wherein the component material of the resistor layer includes copper and nickel, and the weight ratio of copper to nickel is 1:1. The thick film resistor element as described in claim 7, wherein the protective layer unit further includes at least one marking pattern formed on the surface of the protective layer unit. A thick film resistor element as described in claim 7, wherein at least one resistance repair trench is formed on the resistor layer.

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