Power chip resistor

Abstract

A power chip resistor includes a resistance layer, first and second inner electrodes, a passivation layer, first and second thermal conductive electrodes, and an insulating protection layer disposed on a first surface of a substrate, a third and fourth thermal conductive electrodes disposed on a second surface of the substrate, and first and second outer electrodes disposed on first and second end surfaces of the substrate. Each of the first to fourth thermal conductive electrodes is in a T-like shape. The first and third thermal conductive electrodes have the same pattern orientations as those of the second and fourth thermal conductive electrodes respectively after being rotated

Description

[Technical Field]

[0001] This disclosure relates to a manufacturing technique for an electronic component, and more particularly to a power chip resistor. [Previous Technology]

[0002] A typical power chip resistor includes two thermally conductive electrodes, which cover two opposing edge regions between two inner electrodes and a resistive layer. Two outer electrodes respectively cover these two thermally conductive electrodes. The outer electrodes contain a copper layer. The thermally conductive electrodes conduct the heat generated during resistor application to the outer electrodes, and the copper layer reduces the thermal resistance of the outer electrodes, thereby enabling the resistor to withstand higher power.

[0003] However, these two thermally conductive electrodes are symmetrically positioned above the two edge regions of the inner electrode and the resistive layer, and do not cover the main resistive heat-generating area in the middle of the chip. This symmetrical design causes heat conduction to be mainly concentrated at the outer electrodes at both ends of the power chip resistor. Since the outer electrodes are also symmetrically positioned, when the power chip resistor is in use, the middle part of the power chip resistor can only dissipate heat through thermal radiation. Therefore, such a structure cannot achieve a uniform heat distribution effect. [Summary of the Invention]

[0004] Therefore, one of the objectives of this disclosure is to provide a power chip resistor that can solve the problem that conventional power chip resistors cannot achieve uniform heat dissipation and can effectively improve heat dissipation.

[0005] In accordance with the above-mentioned objectives of this disclosure, a power chip resistor is provided, comprising a substrate, a resistive layer, a first internal electrode, a second internal electrode, a passivation layer, a first thermally conductive electrode, a second thermally conductive electrode, an insulating protective layer, a third thermally conductive electrode, a fourth thermally conductive electrode, a first external electrode, and a second external electrode. The substrate has a first surface and a second surface opposite to each other, and a first end face and a second end face opposite to each other between the first surface and the second surface. The resistive layer is disposed on the first surface. The resistive layer includes a resistance function portion, a first electrode portion, and a second electrode portion bonded together. The first electrode portion and the second electrode portion are respectively adjacent to the first end face and the second end face. The first internal electrode and the second internal electrode respectively cover the first electrode portion and the second electrode portion. The passivation layer covers a portion of the first surface, the resistance function portion, a portion of the first internal electrode, and a portion of the second internal electrode. The first thermally conductive electrode is disposed on the first internal electrode and a portion of the passivation layer, and includes a first protrusion. The second thermally conductive electrode is disposed on the second internal electrode and another portion of the passivation layer, and includes a second protrusion. The first and second protrusions are separated and staggered on the passivation layer. An insulating protective layer covers the passivation layer, a portion of the first thermally conductive electrode, and a portion of the second thermally conductive electrode. A third thermally conductive electrode is disposed on the second surface and adjacent to the first end face, and includes the third protrusion. A fourth thermally conductive electrode is disposed on the second surface and adjacent to the second end face, and includes the fourth protrusion. The third and fourth protrusions are separated and staggered. A first external electrode covers the first thermally conductive electrode, the first end face, and the third thermally conductive electrode. A second external electrode covers the second thermally conductive electrode, the second end face, and the fourth thermally conductive electrode, and is spaced apart from the first external electrode.

[0006] According to one embodiment of the present disclosure, the first thermally conductive electrode, the second thermally conductive electrode, the third thermally conductive electrode and the fourth thermally conductive electrode are all T-shaped structures.

[0007] According to one embodiment of this disclosure, the first thermally conductive electrode, after being rotated 180 degrees, has the same pattern orientation as the second thermally conductive electrode. The third thermally conductive electrode, after being rotated 180 degrees, has the same pattern orientation as the fourth thermally conductive electrode.

[0008] According to one embodiment of the present disclosure, after the third and fourth thermally conductive electrodes are flipped 180 degrees, they have the same pattern orientation as the first and second thermally conductive electrodes, respectively.

[0009] According to one embodiment of this disclosure, the power chip resistor further includes a plurality of first convex structures and a plurality of second convex structures. The first convex structures are arranged in a spaced-apart manner on a first L-shaped region of the second surface. A third thermally conductive electrode is located on the first L-shaped region and covers these first convex structures. The second convex structures are arranged in a spaced-apart manner on a second L-shaped region of the second surface. The second L-shaped region is separated from the first L-shaped region. A fourth thermally conductive electrode is located on the second L-shaped region and covers these second convex structures.

[0010] According to one embodiment of the present disclosure, the distance between the first L-shaped region and the second L-shaped region is 50 μm to 150 μm.

[0011] According to one embodiment of this disclosure, both the first convex structure and the second convex structure are circular and have a diameter of 50 μm to 100 μm. The distance between these first convex structures and second convex structures is 25 μm to 50 μm.

[0012] According to one embodiment of the present disclosure, the length of the first protrusion, the second protrusion, the third protrusion and the fourth protrusion is 1 / 3 of the length of the substrate, and the width is 1 / 4 to 1 / 3 of the width of the substrate.

[0013] According to one embodiment of this disclosure, the resistive layer further includes two thermally conductive portions and two connecting lines. The two thermally conductive portions are located between the first electrode portion and the second electrode portion, and are respectively located on opposite sides of the resistance functional portion. The two connecting lines respectively connect these two thermally conductive portions to the resistance functional portion. The power chip resistor further includes two thermally conductive blocks respectively covering the thermally conductive portions.

[0014] According to one embodiment of this disclosure, each heat-conducting part has a distance of 50 μm to 150 μm between itself and the resistance function part, the first electrode part, and the second electrode part. The width of each connecting line is 50 μm to 150 μm. The range of the distance of each connecting line from the closer of the first end face and the second end face is the width of each of the first electrode part and the second electrode part + the distance between each heat-conducting part and the resistance function part, the first electrode part, and the second electrode part + 50 μm to 100 μm.

[0015] According to the above embodiment, in the power chip resistor disclosed herein, one of the first and second thermally conductive electrodes is rotated 180 degrees to have the same pattern orientation as the other. This allows the heat generated by the resistive layer to be conducted more evenly to the first and second external electrodes at both ends of the power chip resistor. Furthermore, the third and fourth thermally conductive electrodes are rotated 180 degrees to have the same pattern orientation as the first and second thermally conductive electrodes, respectively. This allows the heat generated by the resistive layer to be conducted to the back of the power chip resistor via the substrate, and then again, the third and fourth thermally conductive electrodes can be used to evenly conduct the heat to the first and second external electrodes. Therefore, the power chip resistor has excellent heat dissipation and heat equalization effects.

[0016] Furthermore, the second surface of the substrate may be provided with a plurality of first convex structures and second convex structures, and the third thermally conductive electrode and the fourth thermally conductive electrode may respectively cover the first convex structures and the second convex structures. This increases the surface area of ​​the third thermally conductive electrode and the fourth thermally conductive electrode, thereby significantly improving the thermal radiation effect. In addition, the resistive layer may include two symmetrically arranged thermally conductive portions, and these two thermally conductive portions may be covered with thermally conductive blocks. Since the thermally conductive blocks and thermally conductive portions can assist in heat absorption when the resistive functional part generates heat, the heat dissipation performance of the power chip resistor can be further improved.

Implementation Method

[0017] The embodiments of this disclosure are discussed in detail below. However, it will be understood that the embodiments provide many applicable concepts that can be implemented in a wide variety of specific situations. The embodiments discussed and disclosed are for illustrative purposes only and are not intended to limit the scope of this disclosure. All embodiments of this disclosure disclose a variety of different features, but these features may be implemented individually or in combination as needed.

[0018] In addition, the terms "first", "second", etc. used in this document do not specifically refer to order or sequence, but are only used to distinguish elements or operations described with the same technical terms.

[0019] The spatial relationship between the two elements described in this disclosure applies not only to the orientation shown in the diagram, but also to orientations not shown in the diagram, such as inverted orientations. Furthermore, the terms "connection," "electrical connection," or similar expressions used in this disclosure to refer to two components are not limited to a direct or electrical connection, but may also include indirect or electrical connections as needed.

[0020] Please refer to Figures 1 to 4, which respectively illustrate a perspective view, a front view 10a, a view of the soldering surface 10b, and a cross-sectional view of the power chip resistor 10 obtained along the cross-sectional line AA of Figure 1, according to one embodiment of the present disclosure. The power chip resistor 10 can be used as a resistor for automotive applications such as vehicle charging piles, battery management systems (BMS), and engine control units (ECUs) for current sensing.

[0021] As shown in Figure 4, the power chip resistor 10 mainly includes a substrate 100, a resistive layer 200, a first inner electrode 300, a second inner electrode 310, a passivation layer 400, a first thermally conductive electrode 500, a second thermally conductive electrode 510, an insulating protective layer 600, a third thermally conductive electrode 700, a fourth thermally conductive electrode 710, a first external electrode 800, and a second external electrode 810.

[0022] The substrate 100 has a first surface 110 and a second surface 120 opposite to each other, and a first end face 130 and a second end face 140 opposite to each other. The first end face 130 and the second end face 140 are both located between the first surface 110 and the second surface 120. For example, the first surface 110 and the second surface 120 may be the lower surface and the upper surface of the substrate 100, respectively, and the first end face 130 and the second end face 140 are the two side faces of the substrate 100. The substrate 100 may be, for example, a cuboid or a cube. However, the substrate 100 may be a plate of other suitable shapes, which is not limited to this disclosure. For example, the material of the substrate 100 may be alumina (Al2O3), aluminum nitride (AlN), boron nitride (BN), zirconia-toughened alumina (ZTA), silicon dioxide (SiO2), or silicon carbide (SiC), etc.

[0023] Referring to Figures 4 and 9, a resistive layer 200 is disposed on the first surface 110 of the substrate 100. The resistive layer 200 includes a resistance function portion 210, a first electrode portion 220, and a second electrode portion 230 that are bonded to each other. The first electrode portion 220 and the second electrode portion 230 are located on opposite sides of the resistance function portion 210 and are respectively adjacent to the first end face 130 and the second end face 140. Both the first electrode portion 220 and the second electrode portion 230 are wider than the resistance function portion 210, and together with the resistance function portion 210, they form an H-shaped structure.

[0024] Optionally, as shown in FIG9, the resistive layer 200 may further include two heat-conducting portions 240 and 250, and two connecting lines 260 and 270. The heat-conducting portions 240 and 250 are located between the first electrode portion 220 and the second electrode portion 230, and are respectively located on opposite sides of the resistance function portion 210. The heat-conducting portions 240 and 250 may be symmetrical with respect to the resistance function portion 210. The connecting line 260 is located between the heat-conducting portion 240 and the resistance function portion 210, and connects the heat-conducting portion 240 and the resistance function portion 210. The connecting line 270 is located between the heat-conducting portion 250 and the resistance function portion 210, and connects the heat-conducting portion 250 and the resistance function portion 210. The connecting lines 260 and 270 may be asymmetrical with respect to the resistance function portion 210. In some embodiments, both the first electrode portion 220 and the second electrode portion 230 have a width CW, which is 3 / 5 to 4 / 5 of the width W of the substrate 100. Both the first electrode portion 220 and the second electrode portion 230 have a length C, which is between 1 / 5 and 1 / 3 of the length L of the substrate 100.

[0025] In some embodiments, each heat-conducting part 240 and 250 has a distance g between it and the resistance function part 210, the first electrode part 220, and the second electrode part 230. The distance g can be, for example, 50 μm to 150 μm. If the distance g is less than 50 μm, it may connect to the resistance function part 210, the first electrode part 220, and the second electrode part 230 during subsequent electroplating processes. If the distance g is greater than 150 μm, the heat storage design of the heat-conducting parts 240 and 250 is lost. The width e of each connecting line 260 and 270 is 50 μm to 150 μm. In addition, each connecting line 260 and 270 is closer to the one of the first end face 130 and the second end face 140, that is, the connecting line 260 is closer to the second end face 140 and the connecting line 270 is closer to the first end face 130, and both are separated by a distance eL. The range of distance eL can be from length C + distance g + 50 μm to 100 μm.

[0026] As shown in FIG12, in some embodiments, the resistive layer 200 includes one or more resistance-correcting grooves 280. For example, the resistance-correcting grooves 280 may be recessed into the resistance function portion 210. The resistive layer 200 may be a metal alloy such as copper-manganese alloy (MnCu), copper-nickel alloy (CuNi), copper-manganese-nickel alloy (CuMnNi), copper-manganese-tin alloy (CuMnSn), nickel-chromium alloy (NiCr), tantalum nitride (TaN), etc. However, the material of the resistive layer 200 may be other suitable resistive materials, and this disclosure is not limited thereto.

[0027] Referring to Figures 4 and 12, the first inner electrode 300 covers the first electrode portion 220, and the second inner electrode 310 covers the second electrode portion 230. In embodiments where the resistive layer 200 includes heat-conducting portions 240 and 250, the power chip resistor 10 further includes two heat-conducting blocks 320 and 330 respectively covering the heat-conducting portions 240 and 250. The materials of the first inner electrode 300, the second inner electrode 310, and the heat-conducting blocks 320 and 330 may be, for example, copper.

[0028] Referring to Figures 4 and 14, the passivation layer 400 covers a portion of the first surface 110 of the substrate 100, the resistance function portion 210, a portion of the first internal electrode 300, and a portion of the second internal electrode 310. In an embodiment where the power chip resistor 10 includes heat-conducting blocks 320 and 330, the passivation layer 400 completely covers the resistance function portion 210, the connecting lines 260 and 270, the heat-conducting blocks 320 and 330, and portions of the first internal electrode 300 and the second internal electrode 310 adjacent to the resistance function portion 210. The material of the passivation layer 400 may be silicon oxide, tantalum oxide, or silicon nitride.

[0029] Referring to Figures 4 and 18, a first thermally conductive electrode 500 is disposed on a first inner electrode 300 and a portion of the passivation layer 400. The first thermally conductive electrode 500 includes a first main body portion 502 and a first protrusion portion 504. The first main body portion 502 covers the entire first inner electrode 300, a portion of the passivation layer 400, and the portion of the first surface 110 exposed on both sides of the first inner electrode 300. The first protrusion portion 504 extends from the first main body portion 502 toward the second thermally conductive electrode 510 on the passivation layer 400. The second thermally conductive electrode 510 is disposed on a second inner electrode 310 and another portion of the passivation layer 400. The second thermally conductive electrode 510 includes a second main body portion 512 and a second protrusion portion 514. The second main body portion 512 covers the entire second inner electrode 310, another portion of the passivation layer 400, and the portion of the first surface 110 exposed on both sides of the second inner electrode 310. The second protrusion 514 extends from the second main body 512 toward the first thermally conductive electrode 500 on the passivation layer 400. The first protrusion 504 and the second protrusion 514 are separated and staggered on the passivation layer 400.

[0030] As shown in FIG. 18, both the first thermally conductive electrode 500 and the second thermally conductive electrode 510 have a T-shaped structure. In some embodiments, after the first thermally conductive electrode 500 is rotated 180 degrees, it has the same pattern orientation as the second thermally conductive electrode 510. Furthermore, the first thermally conductive electrode 500 and the second thermally conductive electrode 510 may have the same dimensions. For example, the width TWa of the first thermally conductive electrode 500 and the second thermally conductive electrode 510 may be 4 / 5 to 1 / 3 of the width W of the substrate 100. The length T3a of the first main body portion 502 and the second main body portion 512 may be 1 / 4 to 1 / 3 of the length L of the substrate 100. The width TWb of the first protrusion 504 and the second protrusion 514 may be 1 / 4 to 1 / 3 of the width W of the substrate 100. The length T3b of the first protrusion 504 and the second protrusion 514 may be 1 / 3 of the length L of the substrate 100. The distance h between the first protrusion 504 and the second protrusion 514 and the edge of the nearest substrate 100 can be 100 μm to 200 μm. The spacing Tg between the first thermally conductive electrode 500 and the second thermally conductive electrode 510 can be 50 μm to 150 μm.

[0031] In some embodiments, both the first thermally conductive electrode 500 and the second thermally conductive electrode 510 include sequentially stacked titanium-tungsten layers and copper layers. The titanium-tungsten layer serves as a bonding layer to improve the adhesion between the copper layer and the substrate 100 or the passivation layer 400. For example, the thickness of the titanium-tungsten layer can be from 0.01 μm to 0.1 μm, and the thickness of the copper layer can be from 0.5 μm to 5 μm. The thickness of the copper layer within this range allows the copper layer to have a certain thermally conductive thickness. If the thickness of the copper layer exceeds 5 μm, the sputtering time of the copper layer will be too long, causing the underlying mask to overheat and solidify, making it impossible to remove the mask.

[0032] Referring to Figures 4 and 19, the insulating protective layer 600 covers the passivation layer 400, a portion of the first thermally conductive electrode 500, and a portion of the second thermally conductive electrode 510. Specifically, the insulating protective layer 600 covers the passivation layer 400 exposed between the first thermally conductive electrode 500 and the second thermally conductive electrode 510, the entire first protrusion 504, the portion of the first main body 502 adjacent to the first protrusion 504, the entire second protrusion 514, and the portion of the second main body 512 adjacent to the second protrusion 514. The material of the insulating protective layer 600 may be, for example, epoxy resin, resin, or epoxy resin containing inorganic fillers. The inorganic fillers may be, for example, alumina, aluminum nitride, or silicon oxide.

[0033] Referring to Figures 4 and 8, the power chip resistor 10 may selectively include a plurality of first convex structures 900 and a plurality of second convex structures 910. The first convex structures 900 are spaced apart from each other and arranged on a first L-shaped region 122 of the second surface 120 of the substrate 100. The second convex structures 910 are spaced apart from each other and arranged on a second L-shaped region 124 of the second surface 120 of the substrate 100. The first L-shaped region 122 and the second L-shaped region 124 are spaced apart from each other. For example, the distance S between the first L-shaped region 122 and the second L-shaped region 124 may be 50 μm to 150 μm. After rotating 180 degrees, the first L-shaped region 122 and the second L-shaped region 124 have the same pattern orientation. In addition, the first L-shaped region 122 and the second L-shaped region 124 may have the same size. For example, the width BW of the first L-shaped region 122 and the second L-shaped region 124 is 3 / 5 to 4 / 5 of the width W of the substrate 100, and the length L1 of the first L-shaped region 122 and the second L-shaped region 124 is 2 / 3 of the length L of the substrate 100.

[0034] The first convex structure 900 and the second convex structure 910 can be any suitable shape, such as circular, elliptical, square, rectangular, or other polygonal shapes, which is not limited thereto. In some embodiments, both the first convex structure 900 and the second convex structure 910 are circular and have the same diameter d. The diameter d can be, for example, 50 μm to 100 μm. Furthermore, the first convex structure 900 and the second convex structure 910 can be regularly arranged, and both the first convex structure 900 and the second convex structure 910 have a spacing, which can be 25 μm to 50 μm. The first convex structure 900 and the second convex structure 910 can also be irregularly arranged, which is not limited thereto. The materials of the first convex structure 900 and the second convex structure 910 can be, for example, copper-manganese alloy, copper-nickel alloy, copper-manganese-nickel alloy, copper-manganese-tin alloy, nickel-chromium alloy, tantalum nitride, and other metal alloys. However, the materials of the first convex structure 900 and the second convex structure 910 can be other suitable metal alloy materials, and this disclosure is not limited thereto.

[0035] Referring to Figures 4 and 17, a third thermally conductive electrode 700 is disposed on the second surface 120 of the substrate 100 and adjacent to the first end face 130. The third thermally conductive electrode 700 is located on the first L-shaped region 122. The third thermally conductive electrode 700 includes a third main body portion 702 and a third protrusion 704. The third main body portion 702 may be opposite to the first main body portion 502. The third protrusion 704 extends from the third main body portion 702 toward the second convex structure 910. A fourth thermally conductive electrode 710 is disposed on the second surface 120 of the substrate 100 and opposite to the third thermally conductive electrode 700 and adjacent to the second end face 140. The fourth thermally conductive electrode 710 is located on the second L-shaped region 124. The fourth thermally conductive electrode 710 includes a fourth main body portion 712 and a fourth protrusion 714. The fourth main body portion 712 may be opposite to the second main body portion 512. The fourth protrusion 714 extends from the fourth main body 712 toward the first convex structure 900. The third protrusion 704 is separated from and staggered with the fourth protrusion 714. In the embodiment where the power chip resistor 10 includes the first convex structure 900 and the second convex structure 910, the third thermally conductive electrode 700 covers all of the first convex structures 900, and the fourth thermally conductive electrode 710 covers all of the second convex structures 910.

[0036] As shown in FIG. 17, both the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 have a T-shaped structure. In some embodiments, after the third thermally conductive electrode 700 is rotated 180 degrees, it has the same pattern orientation as the fourth thermally conductive electrode 710. Furthermore, after the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 are flipped 180 degrees, they have the same pattern orientation as the first thermally conductive electrode 500 and the second thermally conductive electrode 510, respectively. The third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 may have the same dimensions. For example, the width BWa of the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 may be 4 / 5 to 1 / 3 of the width W of the substrate 100. The length BLa of the third main body portion 702 and the fourth main body portion 712 may be 1 / 4 to 1 / 3 of the length L of the substrate 100. The width BWb of the third protrusion 704 and the fourth protrusion 714 may be 1 / 4 to 1 / 3 of the width W of the substrate 100. The length BLb of the third protrusion 704 and the fourth protrusion 714 can be 1 / 3 of the length L of the substrate 100. The distance k between the third protrusion 704 and the fourth protrusion 714 and the nearest edge of the substrate 100 can be 100μm to 200μm. The spacing Bg between the third thermal electrode 700 and the fourth thermal electrode 710 can be 50μm to 150μm.

[0037] In some embodiments, both the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 include a titanium-tungsten layer and a copper layer sequentially stacked on the second surface 120. The titanium-tungsten layer is a bonding layer, which can improve the bonding between the copper layer and the substrate 100. For example, the thickness of the titanium-tungsten layer can be 0.01 μm to 0.1 μm, and the thickness of the copper layer can be 0.5 μm to 5 μm, so that the copper layer has a certain thermally conductive thickness and avoids the underlying mask from overheating and solidifying due to excessive sputtering time of the copper layer.

[0038] As shown in Figures 1 and 4, the first external electrode 800 covers the first thermally conductive electrode 500, the first end face 130 of the substrate 100, and the third thermally conductive electrode 700. The first external electrode 800 extends from the third thermally conductive electrode 700 on the second surface 120 of the substrate 100 through the first end face 130 to the insulating protective layer 600 on the first surface 110. Therefore, the cross-sectional shape of the first external electrode 800 is C-shaped.

[0039] The second external electrode 810 covers the second thermally conductive electrode 510, the second end face 140 of the substrate 100, and the fourth thermally conductive electrode 710. The second external electrode 810 extends from the fourth thermally conductive electrode 710 on the second surface 120 of the substrate 100 through the second end face 140 to the insulating protective layer 600 on the first surface 110, so the cross-sectional shape of the second external electrode 810 is like an inverted C. The second external electrode 810 and the first external electrode 800 are spaced apart from each other.

[0040] In some embodiments, the first external electrode 800 includes a connection layer 802, a copper layer 804, a nickel layer 806, and a tin layer 808 stacked sequentially from the inside out, and the second external electrode 810 includes a connection layer 812, a copper layer 814, a nickel layer 816, and a tin layer 818 stacked sequentially from the inside out. The materials of the connection layers 802 and 812 may be, for example, a nickel-chromium alloy. In some exemplary embodiments, the distance G between the bottom surface of the copper layer 804 and the bottom surface of the copper layer 814 and the bottom surface of the insulating protective layer 600 is 5 μm to 20 μm. This prevents excessive solder paste from entering between the insulating protective layer 600 and the circuit board, thus affecting the bonding between the power chip resistor 10 and the external circuit board.

[0041] Please refer to Figure 5, which is a schematic diagram illustrating the heat flow of a power chip resistor 10 according to one embodiment of the present disclosure. The heat H generated by the resistive functional portion 210 of the resistive layer 200 can be conducted to the heat-conducting blocks 320 and 330 on both sides and the first internal electrode 300 and the second internal electrode 310 at both ends. The heat H can be further conducted from the first internal electrode 300 and the second internal electrode 310 to the first thermally conductive electrode 500 and the second thermally conductive electrode 510. The heat H can also be conducted through the substrate 100 to the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 on the second surface 120. Through this structural design, the power chip resistor 10 can achieve a uniform heat distribution effect and significantly improve the heat dissipation efficiency of the power chip resistor 10.

[0042] Please refer to Figures 4 and 6 through 19, where Figures 6 through 19 are schematic diagrams illustrating various manufacturing stages of a power chip resistor 10 according to one embodiment of this disclosure. Figures 6, 8, 15, and 17 are top views, and Figures 7, 9 through 14, 16, 18, and 19 are bottom views. When fabricating the power chip resistor 10 as shown in Figures 1 through 4, a substrate 100 is first provided. Then, using, for example, sputtering, a resistive material layer 290 and a thermally conductive electrode material layer 720 are formed on the first surface 110 and the second surface 120 of the substrate 100, respectively. Next, using, for example, printing, lamination, coating, or photolithography, a mask layer M1 is covered on the thermally conductive electrode material layer 720, and a mask layer M2 is covered on the resistive material layer 290, as shown in Figures 6 and 7. Mask layers M1 and M2 are patternable and removable etch-resistant protective layers. The areas uncovered by the thermally conductive electrode material layer 720 and the resistive material layer 290 are the areas to be etched. The materials of the masking layers M1 and M2 can be, for example, photoresist, removable adhesive film, or peelable ink.

[0043] Using an alloy metal etching solution such as ferric chloride, copper chloride, sulfuric acid, phosphoric acid, or nitric acid, the areas of the thermally conductive electrode material layer 720 not covered by the masking layer M1 and the areas of the resistive material layer 290 not covered by the masking layer M2 are etched until the second surface 120 and the first surface 110 of the substrate 100 are exposed. After etching the thermally conductive electrode material layer 720 and the resistive material layer 290, the masking layers M1 and M2 can be removed using, for example, a film-removing solvent or water washing. This allows several first convex structures 900 and second convex structures 910 to be formed on the second surface 120 of the substrate 100, as shown in FIG8. Additionally, a resistive layer 200 can be formed on the first surface 110 of the substrate 100, as shown in FIG9. The arrangement, shape, size, and material of the first convex structures 900, the second convex structures 910, and the resistive layer 200 have been described above and will not be repeated here.

[0044] Next, as shown in FIG10, a mask layer M3 can be applied to the resistive functional portion 210 and connecting lines 260 and 270 of the resistive layer 200, and to the exposed portion of the first surface 110, using methods such as printing, lamination, coating, or photolithography. The mask layer M3 is a patternable and removable electroplating protective layer. The first electrode portion 220, the second electrode portion 230, and the heat-conducting portions 240 and 250, which are not covered by the mask layer M3, are the areas to be electroplated. The second surface 120, the first convex structure 900, and the second convex structure 910 of the substrate 100 are fully covered by the mask layer M3 to avoid being affected by the electroplating solution. The material of the mask layer M3 can be, for example, photoresist, a removable adhesive film, or a peelable ink.

[0045] Next, as shown in FIG11, the first inner electrode 300 and the second inner electrode 310 can be plated on the first electrode portion 220 and the second electrode portion 230 respectively by means of, for example, electroplating, and the heat-conducting blocks 320 and 330 can be plated on the heat-conducting portions 240 and 250 respectively.

[0046] Subsequently, the masking layer M3 can be removed using, for example, a film-removing solvent or water washing, to expose the resistance function section 210, the connecting lines 260 and 270, and the first surface 110. After removing the masking layer M3, a resistance-adjusting operation can be selectively performed on the resistance function section 210 according to product requirements to adjust the resistance value of the resistive layer 200. As shown in FIG12, the resistance-adjusting operation removes at least a portion of the resistance function section 210, forming a resistance-adjusting groove 280 in the resistance function section 210. For example, the resistance-adjusting operation can be performed using laser or physical processing methods.

[0047] Next, as shown in FIG13, a patternable and removable mask layer M4 can be applied to a portion of the first inner electrode 300, a portion of the second inner electrode 310, and a portion of the first surface 110 using methods such as printing, lamination, coating, or photolithography. The areas not covered by the mask layer M4 are the areas to be coated. The material of the mask layer M4 can be, for example, photoresist, a removable adhesive film, or a peelable ink.

[0048] Next, a passivation layer 400 is formed covering the entire first surface 110 using, for example, sputtering or chemical vapor deposition. Then, the mask layer M4 and the passivation layer 400 thereon are removed using, for example, a film-removing solvent or water washing, exposing the first internal electrode 300 and the second internal electrode 310. The remaining passivation layer 400 completely covers the resistance function part 210, the heat conduction blocks 320 and 330, and the connecting lines 260 and 270.

[0049] Next, patternable and removable mask layers M5 and M6 can be formed on the second surface 120 and the first surface 110 of the substrate 100, respectively, using methods such as printing, lamination, coating, or photolithography, as shown in Figures 15 and 16. Mask layers M5 and M6 define the areas to be coated on the second surface 120 and the first surface 110, respectively. Mask layer M5 covers the portion of the second surface 120, and mask layer M6 covers the portion of the passivation layer 400. The materials of mask layers M5 and M6 can be, for example, photoresist, removable adhesive film, or peelable ink.

[0050] Next, a metal layer can be formed over the second surface 120 and the first surface 110 of the substrate 100 using, for example, sputtering. Subsequently, the masking layers M5 and M6 and portions of the metal layer thereon can be removed using a stripping solution. Thereby, a third thermally conductive electrode 700 and a fourth thermally conductive electrode 710 can be formed on the second surface 120, as shown in FIG17. Furthermore, a first thermally conductive electrode 500 and a second thermally conductive electrode 510 can be formed on the first surface 110, as shown in FIG18. In some embodiments, when forming the metal layer, a titanium-tungsten thin film and a copper film can be sputtered sequentially.

[0051] Subsequently, an insulating protective layer 600 may be applied to the exposed portions of the first thermally conductive electrode 500, the second thermally conductive electrode 510, and the passivation layer 400 using methods such as printing, lamination, coating, or photolithography. The insulating protective layer 600 exposes portions of the first main body 502 and the second main body 512, as shown in FIG19. The areas not covered by the insulating protective layer 600 are the areas to be coated with the external electrode.

[0052] Next, the first external electrode 800 and the second external electrode 810 are formed, thus substantially completing the power chip resistor 10 shown in Figures 1 to 4. When forming the first external electrode 800 and the second external electrode 810, the connecting layers 802 and 812 can be first covered on the first end face 130 and the second end face 140 respectively by, for example, sputtering. Then, the copper layer 804, the nickel layer 806, and the tin layer 808 are sequentially grown on the connecting layer 802, the first thermally conductive electrode 500, and the third thermally conductive electrode 700, and the copper layer 814, the nickel layer 816, and the tin layer 818 are sequentially grown on the connecting layer 812, the second thermally conductive electrode 510, and the fourth thermally conductive electrode 710.

[0053] After rotating one of the first thermally conductive electrodes 500 and 510 of the power chip resistor 10 by 180 degrees, it has the same pattern orientation as the other. This allows the heat H generated by the resistive layer 200 to be conducted more evenly to the first external electrode 800 and the second external electrode 810 at both ends of the power chip resistor 10. Furthermore, after rotating the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 by 180 degrees, they have the same pattern orientation as the first thermally conductive electrode 500 and the second thermally conductive electrode 510, respectively. This allows the heat H generated by the resistive layer 200 to be conducted to the back of the power chip resistor 10 via the substrate 100, and again, the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710, to be evenly conducted to the first external electrode 800 and the second external electrode 810. Therefore, the power chip resistor 10 has excellent heat dissipation and heat uniformity.

[0054] Furthermore, the second surface 120 of the substrate 100 may be provided with a plurality of first convex structures 900 and second convex structures 910, and the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710 may respectively cover the first convex structures 900 and the second convex structures 910. This increases the surface area of ​​the third thermally conductive electrode 700 and the fourth thermally conductive electrode 710, thereby significantly improving the thermal radiation effect. In addition, the resistive layer 200 may include two symmetrically arranged thermally conductive portions 240 and 250, and these two thermally conductive portions 240 and 250 may be respectively covered with thermally conductive blocks 320 and 330. Since the thermally conductive blocks 320 and 330 and the thermally conductive portions 240 and 250 can assist in heat absorption when the resistive functional portion 210 generates heat, the heat dissipation performance of the power chip resistor 10 can be further improved.

[0055] Although this disclosure has been disclosed above by way of embodiments, it is not intended to limit this disclosure. Anyone with ordinary knowledge in this art can make various modifications and refinements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0056] A better understanding of the nature of this disclosure can be obtained from the following detailed description taken in conjunction with the accompanying drawings. It should be noted that, according to industry standard practice, the features are not drawn to scale. In fact, the dimensions of the features can be arbitrarily increased or decreased for clarity of discussion. [Figure 1] is a perspective view of a power chip resistor according to one embodiment of this disclosure. [Figure 2] is a front view of a power chip resistor according to one embodiment of this disclosure. [Figure 3] is a schematic diagram of the solder surface of a power chip resistor according to one embodiment of this disclosure. [Figure 4] is a cross-sectional view of the power chip resistor obtained along section line AA of Figure 1. [Figure 5] is a heat flow diagram of a power chip resistor according to one embodiment of this disclosure. [Figures 6] to [Figure 19] are schematic diagrams illustrating various manufacturing stages of a power chip resistor according to one embodiment of this disclosure.

Claims

1. A power chip resistor, comprising: a substrate having a first surface and a second surface opposite to each other, and a first end face and a second end face opposite to each other between the first surface and the second surface; a resistive layer disposed on the first surface, wherein the resistive layer includes a resistance functional portion, a first electrode portion, and a second electrode portion bonded to each other, the first electrode portion and the second electrode portion being adjacent to the first end face and the second end face respectively; a first inner electrode and a second inner electrode respectively covering the first electrode portion and the second electrode portion; a passivation layer covering a portion of the first surface, the resistance functional portion, a portion of the first inner electrode, and a portion of the second inner electrode; a first thermally conductive electrode disposed on the first inner electrode and a portion of the passivation layer, and including a first protrusion; a second thermally conductive electrode disposed on the second inner electrode and another portion of the passivation layer, and including a second protrusion, wherein the first protrusion and the second protrusion are separated and staggered on the passivation layer; An insulating protective layer covers the passivation layer, a portion of the first thermally conductive electrode, and a portion of the second thermally conductive electrode; a third thermally conductive electrode is disposed on the second surface and adjacent to the first end face, and includes a third protrusion; a fourth thermally conductive electrode is disposed on the second surface and adjacent to the second end face, and includes a fourth protrusion, wherein the third protrusion and the fourth protrusion are spaced apart and staggered; a first external electrode covers the first thermally conductive electrode, the first end face, and the third thermally conductive electrode; and a second external electrode covers the second thermally conductive electrode, the second end face, and the fourth thermally conductive electrode, and is spaced apart from the first external electrode.

2. The power chip resistor as claimed in claim 1, wherein each of the first thermally conductive electrode, the second thermally conductive electrode, the third thermally conductive electrode, and the fourth thermally conductive electrode is a T-shaped structure.

3. The power chip resistor as claimed in claim 2, wherein the first thermally conductive electrode, after being rotated 180 degrees, has the same pattern orientation as the second thermally conductive electrode; and the third thermally conductive electrode, after being rotated 180 degrees, has the same pattern orientation as the fourth thermally conductive electrode.

4. The power chip resistor as claimed in claim 3, wherein the third thermal electrode and the fourth thermal electrode, after being flipped 180 degrees, have the same pattern orientation as the first thermal electrode and the second thermal electrode, respectively.

5. The power chip resistor as claimed in claim 3, further comprising: a plurality of first convex structures arranged spaced apart from each other on a first L-shaped region of one of the second surfaces, wherein the third thermally conductive electrode is located on the first L-shaped region and covers the first convex structures; and a plurality of second convex structures arranged spaced apart from each other on a second L-shaped region of one of the second surfaces, wherein the second L-shaped region is separated from the first L-shaped region, and the fourth thermally conductive electrode is located on the second L-shaped region and covers the second convex structures.

6. The power chip resistor as claimed in claim 5, wherein the spacing between the first L-shaped region and the second L-shaped region is 50 μm to 150 μm.

7. The power chip resistor as claimed in claim 5, wherein each of the first convex structures and the second convex structures is circular and has a diameter of 50 μm to 100 μm, and a spacing between the first convex structures and the second convex structures is 25 μm to 50 μm.

8. The power chip resistor as claimed in claim 1, wherein the length of each of the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion is 1 / 3 of the length of a substrate, and the width is 1 / 4 to 1 / 3 of the width of a substrate.

9. The power chip resistor as claimed in claim 1, wherein the resistive layer further comprises: two thermally conductive portions, located between the first electrode portion and the second electrode portion, and respectively on opposite sides of the resistance functional portion; and two connecting lines, respectively connecting the thermally conductive portions to the resistance functional portion; and the power chip resistor further comprises two thermally conductive blocks respectively covering the thermally conductive portions.

10. The power chip resistor as claimed in claim 9, wherein each of the thermally conductive portions has a distance of 50 μm to 150 μm between itself and the resistance function portion, the first electrode portion, and the second electrode portion; the width of each of the connecting lines is 50 μm to 150 μm; and the distance of each of the connecting lines from the closer of the first end face to the second end face is the width of each of the first electrode portion and the second electrode portion + the distance between each of the thermally conductive portions and the resistance function portion, the first electrode portion, and the second electrode portion + 50 μm to 100 μm.

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