Thermistor and manufacturing method thereof
By using pure nickel, pure titanium or titanium tungsten alloy as thermistor materials, the problems of high production cost of platinum thermistors and poor change rate of temperature resistance are solved, and a lower cost and higher precision temperature sense is achieved Test.
Patent Information
- Application Number
- CN202310979840.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-04
- Publication Date
- 2025-02-14
AI Technical Summary
The existing platinum thermistors have high production costs and poor temperature resistance change rate, which affects the accuracy of temperature sensing.
Use pure nickel, pure titanium or titanium tungsten alloy as the thermistor material, and combine the process of thin film resistance for rapid and mass production.
Reduces production costs, increases resistance temperature coefficient (TCR), and provides a more sensitive and accurate temperature response.
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Figure CN119446689A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a thermistor and a method for manufacturing the thermistor, and more particularly to a positive temperature coefficient thermistor, wherein the thermistor is made of base metal. Background Art
[0002] In the field of thermistors, there are two main types: positive temperature coefficient thermistors and negative temperature coefficient thermistors. Traditional platinum thermistors use platinum metal as thermistor. However, platinum metal is rare and expensive, so the production cost is high.
[0003] In addition, the temperature coefficient of resistance (TCR) of platinum metal is about 3800 ppm / °C. Compared with other metals with a temperature coefficient of resistance greater than 4000 ppm / °C, platinum metal has a poor temperature resistance change rate, making the temperature sensing accuracy worse than other metals.
[0004] In view of the above, there is still a need to provide a thermistor and a method for manufacturing the thermistor that can solve the above problems. Summary of the invention
[0005] The thermistor in the thermistor of the present invention is composed of base metals such as pure nickel, pure titanium or titanium-tungsten alloy, so the production cost can be reduced. The thermistor of the present invention has a higher TCR and can provide a more sensitive and more accurate temperature response. In addition, the process of the thermistor of the present invention is similar to that of thin film resistors, so it can be quickly and mass-produced.
[0006] The thermistor provided by at least one embodiment of the present invention comprises a substrate, a first thermistor, a first surface electrode and a second surface electrode, a passivation protection layer and an external protection layer. The first thermistor is disposed on the first surface of the substrate, and the first thermistor does not include an oxide, wherein the first thermistor has a first trimming groove. The first surface electrode and the second surface electrode are respectively disposed on both sides of the first thermistor and contact the first thermistor. The passivation protection layer conformally covers the first thermistor, wherein the thickness of the passivation protection layer is 0.01 μm to 1 μm. The external protection layer covers the passivation protection layer.
[0007] In at least one embodiment of the present invention, a temperature coefficient of resistance of the first thermistor is greater than 4000 ppm / °C.
[0008] In at least one embodiment of the present invention, the thermistor further includes a second thermistor and a third surface electrode. The second thermistor is disposed on the first surface of the substrate, wherein the first thermistor is spaced apart from the second thermistor, the second surface electrode contacts the substrate and the second thermistor, wherein the second thermistor does not include an oxide, and the second thermistor has a second trimming groove. The third surface electrode is disposed on one side of the second thermistor and contacts the second thermistor, wherein the passivation protection layer also conformally covers the second thermistor, and the external protection layer covers the second surface electrode and the passivation protection layer.
[0009] In at least one embodiment of the present invention, the material of the first thermistor layer is pure nickel, pure titanium or titanium-tungsten alloy, and the material of the second thermistor is nickel-chromium alloy or titanium-tungsten alloy.
[0010] In at least one embodiment of the present invention, the thermistor further includes a pair of external electrodes, which are respectively disposed on the first surface electrode and the second surface electrode and respectively cover the sidewall of the first surface electrode, the sidewall of the second surface electrode and the opposite sidewall of the first thermistor.
[0011] In at least one embodiment of the present invention, the thermistor further comprises a pair of back electrodes disposed on a second surface opposite to the first surface of the substrate, wherein the pair of outer electrodes also cover opposite side walls of the substrate and the pair of back electrodes respectively.
[0012] The manufacturing method of the thermistor provided by at least one embodiment of the present invention comprises the following operations. A thermistor layer is formed on a first surface of a substrate. An electrode layer is formed on the thermistor layer, wherein the electrode layer covers at least a portion of the thermistor layer. A value adjustment operation is performed. A passivation protection layer is conformally formed on the thermistor layer, wherein the passivation protection layer completely covers the thermistor layer. An external protection layer is formed to cover the passivation protection layer and a portion of the electrode layer. A pair of external electrodes is formed by electroplating, wherein the pair of external electrodes covers the remaining portion of the electrode layer.
[0013] In at least one embodiment of the present invention, the method for manufacturing thermistor further comprises the following operations: forming a pair of back electrodes on a second surface opposite to the first surface of the substrate; forming a pair of side electrodes on opposite side walls of the substrate, wherein a pair of external electrodes covers the pair of back electrodes and the pair of side electrodes.
[0014] In at least one embodiment of the present invention, the operation of forming the thermistor layer includes forming a first thermistor and a second thermistor, wherein the first thermistor is spaced apart from the second thermistor. The operation of forming an electrode layer on the thermistor layer includes the following operations. A first surface electrode is formed on one side of the first thermistor and contacts the first thermistor. A second surface electrode is formed on one side of the second thermistor and contacts the second thermistor. A third surface electrode is formed to cover the other side of the first thermistor and the other side of the second thermistor, wherein the third surface electrode contacts the substrate.
[0015] In at least one embodiment of the present invention, the value adjustment operation further includes the following operations: Using an etching method, performing a first resistance adjustment process on the first thermistor to form a first value adjustment groove. Using a laser method, performing a second resistance adjustment process on the second thermistor to form a second value adjustment groove. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The various aspects of the present disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be understood that, in accordance with standard practice in the industry, the various features are not drawn to scale. In fact, the sizes of the various features may be arbitrarily increased or reduced for clarity.
[0017] Figure 1A , Figure 2A and Figure 3A 1 is a cross-sectional view of a thermistor at various stages of a process according to an embodiment of the present invention.
[0018] Figure 1B , Figure 2B and Figure 3B They are Figure 1A , Figure 2A and Figure 3A Top view of the .
[0019] Figure 4 FIG. 4 is a cross-sectional view of a thermistor according to another embodiment of the present invention.
[0020] Figure 5A , Figure 6 and Figure 7 1 is a cross-sectional view of a thermistor at various stages of a process according to an embodiment of the present invention.
[0021] Figure 5B for Figure 5A Top view of the .
[0022] Figure 8 FIG. 4 is a cross-sectional view of a thermistor according to another embodiment of the present invention. DETAILED DESCRIPTION
[0023] The following disclosure provides many different implementations or embodiments for implementing different features of the present disclosure. Specific implementations of components and arrangements are described below to simplify the present disclosure. These are of course only embodiments and are not intended to be limiting. For example, in the subsequent description, the formation of a first feature over or on a second feature may include an implementation in which the first feature and the second feature are formed in direct contact, and may also include an implementation in which another feature may be formed between the first feature and the second feature so that the first feature and the second feature may not be in direct contact.
[0024] In addition, spatially relative terms such as "below," "below," "below," "above," "above," and other similar terms are used herein for convenience in describing the relationship of one element or feature to another element or feature in the figures. Spatially relative terms encompass other orientations of the device when in use or operation in addition to the orientation depicted in the figures. The device may be oriented in other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.
[0025] It will be understood that, although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the embodiment, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items.
[0026] Figure 1A , Figure 2A and Figure 3A 1 is a cross-sectional view of a thermistor 100 at various stages of the process according to an embodiment of the present invention. Figure 1B , Figure 2B and Figure 3B They are Figure 1A , Figure 2A and Figure 3A Specifically, Figure 1A , Figure 2A and Figure 3A Along the Figure 1B , Figure 2B and Figure 3B The manufacturing method of the thermistor 100 will be described in detail below.
[0027] Please refer to Figure 1A , providing a substrate 110, a thermistor layer 120 is formed on a first surface 111 of the substrate 110, wherein the thermistor layer 120 includes a thermistor 122. Please refer to Figure 1B , thermistor 122 extends along the plane of direction X and direction Y. Figure 1A As shown, the electrode layer 130 is formed on both sides of the thermistor layer 120, wherein the electrode layer 130 includes a first surface electrode 130a and a second surface electrode 130b. Figure 1B , the first surface electrode 130a and the second surface electrode 130b both extend along the Y direction.
[0028] Since the thermistor layer 120 has been subjected to the value adjustment operation, the thermistor 122 has a plurality of value adjustment grooves 124. In some embodiments, the thermistor 122 is first formed on the substrate 110, and then the electrode layer 130 is formed on both sides of the thermistor 122, and then the value adjustment operation is performed to form a plurality of value adjustment grooves 124, wherein the value adjustment grooves 124 expose the first surface 111 of the substrate 110. In some embodiments, the value adjustment grooves 124 do not expose the first surface 111 of the substrate 110. It is understood that the depth, shape and number of the value adjustment grooves 124 can be adjusted according to the resistance requirement, and are not limited to Figure 1A and Figure 1B The trimming groove 124 is shown. In some embodiments, the trimming groove 124 is formed by etching. It is worth noting that the thermistor 122 is trimmed by a non-thermal processing method, so the film properties can be better and there will be no problem of thermal stress affecting the TCR of the film.
[0029] It should be noted that Figure 1A The thermistor 122 is shown as three separate thermistors, however, it is understood that the three separate thermistors are actually connected thermistors 122, such as Figure 1B shown.
[0030] In some embodiments, the substrate 110 may be a glass substrate or a ceramic substrate. In some embodiments, the material of the substrate 110 includes aluminum oxide (Al2O3) or aluminum nitride (AlN).
[0031] In some embodiments, the thermistor 122 is formed by printing, sputtering or electroplating. In some embodiments, the thickness of the thermistor 122 is 0.01 μm to 1 μm, for example 0.03, 0.05 or 0.08 μm. In some embodiments, the material of the thermistor 122 does not include oxides. In some embodiments, the material of the thermistor 122 is pure nickel, pure titanium or titanium-tungsten alloy. In some embodiments, the temperature coefficient of resistance of the thermistor 122 is greater than 4000 ppm / °C. In some embodiments, the material of the thermistor 122 does not include copper. In some embodiments, the material of the first surface electrode 130a and the second surface electrode 130b includes silver and / or copper.
[0032] Please refer to Figure 2A The passivation protection layer 140 is conformally formed on the thermistor layer 120. The passivation protection layer 140 is formed on the upper surface of the thermistor 122 and the sidewalls and bottom surface of the trimming groove 124. Figure 2B As shown, the passivation protection layer 140 completely covers the thermistor layer 120. Figure 2A and Figure 2B As shown, the passivation protection layer 140 also covers a portion of the first plane electrode 130a and a portion of the second plane electrode 130b. In some embodiments, the width w1 of the first plane electrode 130a and / or the second plane electrode 130b covered by the passivation protection layer 140 is less than or equal to 1 / 3 of the overall width w2 of the first plane electrode 130a and / or the second plane electrode 130b. In other words, the first plane electrode 130a and / or the second plane electrode 130b exposes at least 2 / 3 of the overall width w2.
[0033] In some embodiments, the passivation protective layer 140 is formed by sputtering, physical vapor deposition, or chemical vapor deposition. In some embodiments, the thickness of the passivation protective layer 140 is 0.01 μm to 1 μm, for example 0.03, 0.05, or 0.08 μm. The material of the passivation protective layer 140 is tantalum oxide (Ta2O5) or silicon nitride (Si3N4). The passivation protective layer 140 is a delicate and uniform protective layer that can prevent oxidation of the thermistor 122 below. When the thickness of the passivation protective layer 140 is less than 0.01 μm, the thermistor 122 below cannot be effectively protected. When the thickness of the passivation protective layer 140 is greater than 1 μm, the overall thickness of the thermistor cannot be reduced. In some embodiments, the passivation protective layer 140 does not contain glass material.
[0034] Please refer to Figure 3A The outer protection layer 150 covers the passivation protection layer 140 and a portion of the electrode layer 130, and a pair of outer electrodes 160 are formed by electroplating to form a flip chip thermistor 100, wherein the outer electrodes 160 cover the remaining portion of the electrode layer 130. Figure 3A As shown, the external electrode 160 also covers a portion of the external protection layer 150. The external electrode 160 also covers the sidewalls of the first surface electrode 130a, the sidewalls of the second surface electrode 130b, and the sidewalls of the thermistor 122.
[0035] In some embodiments, the outer protection layer 150 is formed by printing. In some embodiments, the material of the outer protection layer 150 includes insulating materials such as epoxy resin. In some embodiments, the material of the outer electrode 160 includes copper, tin, nickel or a combination thereof.
[0036] Please refer to Figure 4, which is a cross-sectional view of a thermistor 400 according to another embodiment of the present invention. Figure 4 The thermistor 400 with Figure 3B The thermistor 100 is different in that the thermistor 400 further includes an outer electrode 160 a , a back electrode 170 , and a side electrode 180 , wherein the outer electrode 160 a covers the back electrode 170 and the side electrode 180 .
[0037] like Figure 4 As shown, a pair of back electrodes 170 are first formed on the second surface 112 opposite to the first surface 111 of the substrate 110, and then a pair of side electrodes 180 are respectively formed on opposite side walls of the substrate 110. Next, the outer electrode 160a covers the pair of back electrodes 170 and the pair of side electrodes 180.
[0038] exist Figure 4 In some embodiments, the back electrode 170 is disposed relative to the first surface electrode 130a and the second surface electrode 130b. In other words, the back electrode 170 is disposed opposite to the first surface electrode 130a and the second surface electrode 130b. In some embodiments, the back electrode 170 is formed by printing. In some embodiments, the material of the back electrode 170 includes a silver paste having epoxy resin and silver.
[0039] In some embodiments, the side electrode 180 is formed on the sidewalls of the first side electrode 130a and the second side electrode 130b, the sidewalls of the thermistor 122, and the sidewalls of the back electrode 170 by sputtering to electrically connect the first side electrode 130a and the second side electrode 130b with the back electrode 170. Figure 4 In some embodiments, the material of the side electrode 180 is a nickel-chromium alloy.
[0040] In some embodiments, the outer electrode 160a may be formed by electroplating, and the material of the outer electrode 160a is similar or the same as the material of the outer electrode 160, which will not be described in detail. The thermistor 400 is a surface mount device (SMD).
[0041] Figure 5A , Figure 6 and Figure 7 1 is a cross-sectional view of a thermistor 500 at various stages of the process according to an embodiment of the present invention. Figure 5B for Figure 5A Specifically, Figure 5A For along Figure 5B The manufacturing method of the thermistor 500 will be described in detail below.
[0042] Please refer to Figure 5Aand Figure 5B The thermistor layer 520 is formed on the first surface 111 of the substrate 110. The thermistor layer 520 includes a first thermistor 522 and a second thermistor 526. The first thermistor 522 and the second thermistor 526 are spaced apart. The first thermistor 522 and the second thermistor 526 both extend along the plane of the direction X and the direction Y.
[0043] like Figure 5A As shown, the electrode layer 530 is formed on the thermistor layer 520, wherein the electrode layer 530 includes a first surface electrode 530a, a second surface electrode 530b and a third surface electrode 530c. Figure 5B , the first surface electrode 530a, the second surface electrode 530b, and the third surface electrode 530c all extend along the direction Y. The first surface electrode 530a is formed on one side of the first thermistor 522 and contacts the first thermistor 522. The second surface electrode 530b is formed on one side of the second thermistor 526 and contacts the second thermistor 526. The third surface electrode 530c covers the other side of the first thermistor 522 and the other side of the second thermistor 526, wherein the third surface electrode 530c also contacts the first surface 111 of the substrate 110.
[0044] Since the thermistor layer 520 has been subjected to the value adjustment operation, the first thermistor 522 has a value adjustment groove 524, and the second thermistor 526 has a value adjustment groove 528. In some embodiments, the first thermistor 522 and the second thermistor 526 are first formed on the substrate 110, and then the electrode layer 530 is formed, and then the value adjustment operation is performed to form a plurality of value adjustment grooves 524 and 528, wherein the value adjustment grooves 524 and 528 expose the first surface 111 of the substrate 110. In some embodiments, the value adjustment grooves 524 and / or the value adjustment grooves 528 do not expose the first surface 111 of the substrate 110. It is understood that the depth, shape, and number of the value adjustment grooves 524 and 528 can be adjusted according to the resistance requirements, and are not limited to Figure 5A and Figure 5B The trim tank 524 is shown.
[0045] In some embodiments, the formation method and material properties of the first thermistor 522 are similar or the same as the formation method and material properties of the thermistor 122, and will not be repeated here. The material of the first thermistor 522 is pure nickel, pure titanium or titanium-tungsten alloy. The trimming groove 524 is formed by etching, and the first thermistor 522 is the resistance area of the main thermistor. It is worth noting that the resistance trimming method of the first thermistor 522 is a non-thermal processing method, so the film properties can be better, and there will be no problem of thermal stress affecting the TCR of the film. In some embodiments, the formation method of the second thermistor 526 is similar or the same as the formation method of the thermistor 122. In some embodiments, the second thermistor 526 does not contain oxides. In some embodiments, the material of the second thermistor 526 is nickel-chromium alloy or titanium-tungsten alloy. The trimming groove 528 is formed by laser, and its purpose is to fine-tune the resistance value. The resistance trimming method of the second thermistor 526 can more accurately trim the resistance value. In some embodiments, the thickness of the first thermistor 522 is similar or the same as the thickness of the second thermistor 526. In some embodiments, the thickness of the first thermistor 522 and / or the thickness of the second thermistor 526 is 0.01 μm to 1 μm, such as 0.03, 0.05 or 0.08 μm.
[0046] Please refer to Figure 6 , the passivation protection layer 540 is conformally formed on the thermistor layer 520, wherein the passivation protection layer 540 completely covers the thermistor layer 520. Figure 6 In the embodiment of the present invention, the passivation protection layer 540 also covers the third surface electrode 530c. The passivation protection layer 540 is formed on the upper surface of the first thermistor 522 and the sidewalls and bottom surface of the trimming groove 524, and the upper surface of the second thermistor 526 and the sidewalls and bottom surface of the trimming groove 528.
[0047] like Figure 6 As shown, the passivation protection layer 540 also covers a portion of the first surface electrode 530a and a portion of the second surface electrode 530b. In some embodiments, the width w3 of the first surface electrode 530a and / or the second surface electrode 530b covered by the passivation protection layer 540 is less than or equal to 1 / 3 of the overall width w4 of the first surface electrode 530a and / or the second surface electrode 530b. In other words, the first surface electrode 530a and / or the second surface electrode 530b exposes at least 2 / 3 of the overall width w4.
[0048] In some embodiments, the formation method and material properties of the passivation protection layer 540 are similar or identical to the formation method and material properties of the passivation protection layer 140, and are not described in detail herein. In some embodiments, the thickness of the passivation protection layer 540 is 0.01 μm to 1 μm, such as 0.03, 0.05, or 0.08 μm. When the thickness of the passivation protection layer 140 is less than 0.01 μm, the thermistor 122 below cannot be effectively protected. When the thickness of the passivation protection layer 140 is greater than 1 μm, the overall thickness of the thermistor cannot be reduced.
[0049] Please refer to Figure 7 The outer protective layer 550 covers the passivation protective layer 540 and a portion of the first surface electrode 530a, a portion of the second surface electrode 530b, and the third surface electrode 530c, and is electroplated to form a pair of outer electrodes 560 to form a flip-chip thermistor 500. The outer electrodes 560 cover the remaining portion of the first surface electrode 530a and the remaining portion of the second surface electrode 530b. Figure 7 As shown, the external electrode 560 also covers a portion of the external protection layer 550. The external electrode 560 also covers the sidewalls of the first surface electrode 530a, the sidewalls of the second surface electrode 530b, the sidewalls of the first thermistor 522, and the sidewalls of the second thermistor 526.
[0050] In some embodiments, the formation method and material properties of the outer protective layer 550 are similar or the same as the formation method and material properties of the outer protective layer 150, which are not described in detail here. In some embodiments, the formation method and material properties of the outer electrode 560 are similar or the same as the formation method and material properties of the outer electrode 160, which are not described in detail here.
[0051] Please refer to Figure 8 , which is a cross-sectional view of a thermistor 800 according to another embodiment of the present invention. Figure 8 Thermistor 800 with Figure 7 Thermistor 500 differs in that thermistor 800 further includes an outer electrode 560a, a back electrode 570, and a side electrode 580. Figure 4 The structure, Figure 8 A pair of back electrodes 570 of the thermistor 800 is first formed on the second surface 112 of the substrate 110, and then a pair of side electrodes 580 are respectively formed on opposite side walls of the substrate 110. Next, the outer electrode 560a covers the pair of back electrodes 570 and the pair of side electrodes 580.
[0052] In summary, the thermistor in the thermistor of the present invention is composed of base metals such as pure nickel, pure titanium or titanium-tungsten alloy, and does not need to use noble metals such as platinum, so the production cost can be reduced. The thermistor of the present invention has a higher TCR and can provide a more sensitive and more accurate temperature response. In addition, the process of the thermistor of the present invention is similar to that of thin film resistors, so it can be quickly and mass-produced.
[0053] The features of multiple embodiments are summarized above so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art will appreciate that the present disclosure can be easily used as a basis for designing or modifying other processes and structures to perform the same purposes and / or achieve the same advantages of the embodiments described herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and modifications herein can be made without departing from the spirit and scope of the present disclosure.
[0054]
Explanation of symbols
[0055] 100,400,500,800: Thermistor
[0056] 110: Substrate
[0057] 111: First surface
[0058] 112: Second surface
[0059] 120,520: Thermistor layer
[0060] 522: First thermistor
[0061] 526: Second thermistor
[0062] 122: Thermistor
[0063] 124,524,528: Repair slot
[0064] 130,530: Electrode layer
[0065] 130a, 530a: first electrode
[0066] 130b, 530b: Second surface electrode
[0067] 530c: The third electrode
[0068] 140,540: Passivation protection layer
[0069] 150,550: External protective layer
[0070] 160,160a,560,560a: External electrode
[0071] 170,570: Back electrode
[0072] 180,580: Side electrode
[0073] A-A', B-B': hatch line
[0074] X, Y, Z: direction.
Claims
1. A thermistor, characterized in that: Include: substrate; A first thermistor is disposed on the first surface of the substrate, and the first thermistor does not contain oxide, wherein the first thermistor has a first trimming groove; A first surface electrode and a second surface electrode are respectively disposed on two sides of the first thermistor and contact the first thermistor; A passivation protection layer conformally covers the first thermistor, wherein the thickness of the passivation protection layer is 0.01 μm to 1 μm; and An outer protective layer covers the passivation protective layer. 2 . The thermistor according to claim 1 , wherein a temperature coefficient of resistance of the first thermistor is greater than 4000 ppm / ° C. .
3. The thermistor according to claim 1, wherein: Also includes: A second thermistor is disposed on the first surface of the substrate, wherein the first thermistor is spaced apart from the second thermistor, the second surface electrode contacts the substrate and the second thermistor, wherein the second thermistor does not include an oxide, and the second thermistor has a second trimming groove; and The third surface electrode is disposed on one side of the second thermistor and contacts the second thermistor, wherein the passivation protection layer also conformally covers the second thermistor, and the external protection layer covers the second surface electrode and the passivation protection layer.
4. The thermistor according to claim 3, wherein the material of the first thermistor layer is pure nickel, pure titanium or titanium-tungsten alloy, and the material of the second thermistor is nickel-chromium alloy or titanium-tungsten alloy.
5. The thermistor according to claim 1, wherein: Also includes: A pair of external electrodes are respectively disposed on the first surface electrode and the second surface electrode, and respectively cover the side wall of the first surface electrode, the side wall of the second surface electrode and the opposite side wall of the first thermistor.
6. The thermistor according to claim 5, wherein: Also includes: A pair of back electrodes is disposed on a second surface opposite to the first surface of the substrate, wherein the pair of external electrodes also covers opposite side walls of the substrate and the pair of back electrodes respectively.
7. A method for manufacturing a thermistor, characterized in that: Include: forming a thermistor layer on the first surface of the substrate; forming an electrode layer on the thermistor layer, wherein the electrode layer covers at least a portion of the thermistor layer; Perform value adjustment operation; Conformally forming a passivation protection layer on the thermistor layer, wherein the passivation protection layer completely covers the thermistor layer; forming an outer protective layer to cover the passivation protective layer and a portion of the electrode layer; and A pair of external electrodes is formed by electroplating, wherein the pair of external electrodes covers the remaining portion of the electrode layer.
8. The method for manufacturing a thermistor according to claim 7, wherein: Also includes: forming a pair of back electrodes on a second surface opposite to the first surface of the substrate; and A pair of side electrodes are formed on opposite side walls of the substrate, wherein the pair of external electrodes covers the pair of back electrodes and the pair of side electrodes.
9. The method for manufacturing a thermistor according to claim 7, wherein in the operation of forming the thermistor layer, the method comprises: forming a first thermistor and a second thermistor, wherein the first thermistor is spaced apart from the second thermistor; The operation of forming the electrode layer on the thermistor layer includes: forming a first surface electrode on one side of the first thermistor and contacting the first thermistor; forming a second surface electrode on one side of the second thermistor and contacting the second thermistor; and A third surface electrode is formed to cover the other side of the first thermistor and the other side of the second thermistor, wherein the third surface electrode contacts the substrate.
10. The method for manufacturing a thermistor according to claim 9, wherein the value adjustment operation further comprises: Using an etching method, performing a first resistance trimming process on the first thermistor to form a first trimming groove; and A second resistance trimming process is performed on the second thermistor by using a laser to form a second trimming groove.