TWI447746B - Method for manufacturing current sensing element - Google Patents

Description

Method of manufacturing current sensing element

The present invention relates to a method of fabricating a sensing element, and more particularly to a method of fabricating a current sensing element.

With the development of technology, the miniaturization of electronic devices has become a trend, and the application of current sensing components, especially wafer-type current sensing components, has become more and more popular. Due to the trend of thinner and lighter electronic devices, current sensing components are becoming more and more demanding in terms of precision and manufacturing process. How to produce high-performance and low-cost current sensing by rapid manufacturing. Components are a major issue.

The conventional current sensing element is manufactured by attaching a metal plate having a low temperature resistivity to the substrate, and then forming a line pattern of the current sensing element by screen printing on the metal plate, and then performing current sensing on the current sensing element. The resistor is trimmed to obtain a precise resistance value, and finally the electrode is formed to connect the current sensing element to an external circuit. However, since screen printing cannot control the paint overflow, the accuracy is not good. Further, since the thermal expansion coefficients of the substrate and the metal plate are different, the substrate and the metal plate are bent at the time of exposure. This not only affects the accuracy of the current sensing component, but is more likely to cause breakage of the substrate or metal plate.

In order to solve the above problems, an invention (for example, TWI220164) proposes to use a metal plate to be bonded to both sides of a substrate to overcome the bending caused by the difference in thermal expansion coefficient between the substrate and the metal. However, this method of double-sided bonding wastes human resources and material costs, thereby greatly increasing the cost of production.

Therefore, there is a need in the market for a method of manufacturing a current sensing element that can resolve the bending caused by the difference in thermal expansion coefficients of the metal plate and the substrate without the use of an additional metal plate. In this way, not only can the current sensing component with precise resistance be produced, but also the manufacturing cost can be reduced.

In order to achieve the above objects and effects, the present invention adopts a new technical means and method.

According to an embodiment of the invention, a method of fabricating a current sensing component includes: bonding a low temperature coefficient metal plate to a first surface of a substrate; etching the metal plate to the metal Forming a line pattern of one or more current sensing elements on the board; and forming electrodes at both ends of the one or more current sensing elements.

In order to make the foregoing and other objects, features and advantages of the present invention more comprehensible, the preferred embodiments of the accompanying drawings.

Fig. 1 shows an embodiment of a method of manufacturing a current sensing element of the present invention. First, step S11 applies a colloid to the surface of the substrate 1 (in an embodiment, this surface may be referred to as a "first surface"). In step S12, the metal plate 3 having a low temperature resistivity is attached to the surface of the substrate 1 coated with the colloid. Step S13 is followed by the step of etching the metal plate to form a line pattern of one or more current sensing elements on the metal plate. Finally, step S16 is performed to form electrodes 7 at both ends of the current sensing element so that they can be connected to an external circuit.

In another embodiment, in step S12, after bonding the metal plate 3, The colloid is then briefly baked to give a viscous bond that is not fully bonded, so that the metal plate 3 can be temporarily fixed to the surface of the substrate 1, but the metal plate 3 is not completely bonded to the substrate 1.

In the process of forming the circuit pattern in step S13, the reticle is first attached to the metal plate 3, the reticle has a circuit pattern of the current sensing element to be formed, and then the reticle is exposed to The circuit pattern of the current sensing element forms a mask, and then the glue is completely baked until the gel is completely cured, the metal plate 3 is completely fixed to the substrate 1, and finally, the unnecessary portion is etched away after development to form The line pattern of the current sensing element. Since the first exposure and then the metal plate and the substrate are completely fixed, the bending phenomenon can be eliminated after the etching step is completed. Therefore, the bending phenomenon caused by the difference in thermal expansion coefficients of the metal plate and the substrate can be solved.

In another embodiment, the electrode 7 is formed by first forming a terminal electrode seed layer at both ends of the one or more current sensing elements by sputtering, and then in a bar plating manner at the current sensing element. The electrodes 7 are formed at both ends.

In another embodiment, the sheet material on which the line pattern of the current sensing element has been formed may be divided into individual current sensing elements by stamping, cutting or folding, as shown in step S15.

In another embodiment, the method can control the width of the line of the current sensing element in the exposure step of step S13 to obtain the resistance value of the desired current sensing element without requiring an additional trimming step.

In another embodiment, the method can also trim the current sensing element after the etching step, and a more accurate resistance value has been obtained. According to an embodiment of the present invention, the step of repairing may use grinding (for example, a grinding wheel, a diamond knife) The way the current sensing element is trimmed. Compared to the laser trimming, the repair by grinding can avoid the thermal energy generated by the laser and affect the accuracy of the current sensing component.

In another embodiment, the method may apply a photoresist coating on the line pattern of the etched current sensing element to form the protective layer 5 in step S15. Since the shape and size of the protective layer can be effectively controlled by the photoresist type protective layer, the resistance value of the current sensing element can be prevented from being changed due to the inability to control the flow rate of the printing liquid during printing.

According to another embodiment of the present invention, the present invention can form the electrode 9 on the other side of the substrate 1 (the surface not bonded to the metal plate. In an embodiment, the surface can be referred to as a "second surface"), The surface area of the electrodes of the current sensing element is increased to facilitate bonding with other circuits. As shown in FIG. 2, in step S21, the electrode 9 is printed on the other side of the substrate 1, and then the electrode 9 on the other side of the substrate 1 is bonded to the both end electrodes of the current sensing element, as shown in step S24. The steps performed on the surface of the substrate 1 and the metal plate 3 are the same as those in FIG. 1 and will not be described again.

In another embodiment, the method may mark a trademark, a resistance value or a related pattern on the other side of the substrate in step S22.

In another embodiment, the metal plate may be made of manganese copper (Mn-Cu) alloy or nickel copper (Ni-Cu) alloy.

In another embodiment, the substrate is a ceramic substrate or a semiconductor substrate.

In another embodiment, the material of the plurality of electrodes may be gold (Au), silver (Ag), copper (Cu), aluminum (Al) or alloys thereof.

Although the technical content and features of the present invention are as described above, the present invention Many variations and modifications can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is not limited to the disclosed embodiments, and other changes and modifications may be made without departing from the scope of the invention.

1‧‧‧Substrate

3‧‧‧Metal plates

5‧‧‧Protective layer

7‧‧‧Electrode

9‧‧‧Electrode

1 shows a method of fabricating a current sensing element in an embodiment of the present invention.

2 shows a method of fabricating a current sensing element in another embodiment of the present invention.

1‧‧‧Substrate

3‧‧‧Metal plates

5‧‧‧Protective layer

7‧‧‧Electrode

Claims (13)

A method of manufacturing a current sensing component, comprising: bonding a low temperature coefficient metal plate to only one of the first surfaces of a substrate; etching the metal plate to form one or more of the metal plates a line pattern of the current sensing element; and forming an electrode at both ends of the one or more current sensing elements. The method of claim 1, further comprising dividing the one or more current sensing elements into a single current sensing element by stamping, folding or cutting. The method of claim 1, further comprising trimming the current sensing element to obtain a more accurate resistance value, wherein the repairing is performed by grinding the current sensing element. The method of claim 1, wherein the etching the metal plate comprises the step of exposing the colloid after the metal plate is temporarily cured to the first surface of the substrate. The method of claim 4, further comprising the step of completely curing and developing the colloid after the exposing step. The method of claim 5, wherein the width of the line of the one or more current sensing elements is controlled, and the resistance value of the current sensing element is adjusted. The method of any of claims 1-6, further comprising the step of forming a protective layer on the metal sheet. The method of any one of claims 1-6, further comprising: And forming a plurality of electrodes on a second surface of the substrate; and connecting the two end electrodes of the one or more current sensing elements to the plurality of electrodes of the second surface. The method of claim 7, wherein the protective layer is formed of a photoresist type coating. The method of claim 8, further comprising forming a terminal electrode seed layer at both ends of the one or more current sensing elements before forming the electrodes at the two ends of the one or more current sensing elements, wherein the electrode system It is formed by barrel plating, and the terminal electrode seed layer is formed by sputtering. The method of any one of claims 1 to 6, wherein the metal plate is made of manganese copper (Mn-Cu) or nickel-copper (Ni-Cu) alloy. The method of any one of claims 1 to 6, wherein the substrate is a ceramic substrate or a semiconductor substrate. The method of any one of claims 1 to 6, wherein the plurality of electrodes are made of gold (Au), silver (Ag), copper (Cu), aluminum (Al) or an alloy thereof.