Improved heat dissipation surface structure and method for manufacturing a resistor

Abstract

The application provides an improved heat dissipation surface structure resistor and a resistor preparation method, and belongs to the technical field of electronic components and electronic heat management, and comprises an insulating substrate, a resistor functional layer arranged on the insulating substrate, and a first protective layer arranged above the resistor functional layer. The resistor functional layer comprises electrode layers arranged on both sides of the insulating substrate and a functional metal layer electrically connected between the electrode layers on both sides. The first protective layer covers at least the upper surface of the functional metal layer, and the first protective layer has a corrugated structure that undulates up and down along the thickness direction. By arranging the first protective layer as a corrugated structure that undulates up and down along the thickness direction, the heat dissipation area of the outer surface of the resistor is improved, the surface air convection path is optimized, the convection heat dissipation and thermal radiation heat dissipation efficiency of the resistor are strengthened, and the resistance drift, precision decline and power attenuation caused by heat accumulation are avoided.

Description

Technical Field

[0001] This invention belongs to the field of electronic components and electronic thermal management technology, specifically relating to resistors with improved heat dissipation surface structures and resistor preparation methods. Background Technology

[0002] As one of the most fundamental and widely used passive electronic components in modern electronic circuits, surface mount resistors are widely used in various electronic products such as consumer electronics, automotive electronics, industrial control, and communication equipment. Their performance stability and reliability directly determine the operational safety of the entire system. With the rapid development of the global electronics industry towards miniaturization, high-density integration, and high power density, the package size of electronic products continues to shrink, and the component mounting density and power load per unit area are constantly increasing. This places increasingly stringent requirements on the heat dissipation performance, size adaptability, and long-term reliability of surface mount resistors.

[0003] Conventional surface mount resistors mainly consist of an insulating substrate, a resistive functional layer on the insulating substrate, and a protective layer covering the surface of the resistive functional layer. A smooth-surfaced protective layer design is commonly used in the industry. In this type of surface mount resistor, the heat generated during operation is mainly dissipated through conduction from the insulating substrate to the printed circuit board and natural convection between the outer surface of the protective layer and the air. Heat radiation dissipation accounts for a relatively small proportion, which limits the heat dissipation efficiency to some extent. Especially in miniaturized package applications, such as 0402 and smaller micro-surface mount resistors, compared to larger packages like 0603, the effective heat dissipation area decreases proportionally with the package volume, while the power density continues to increase. This leads to a significant increase in temperature rise during operation, making it prone to resistance drift, decreased accuracy, and shortened lifespan.

[0004] To address the issue of insufficient heat dissipation performance in surface mount resistors, various improvement solutions have emerged in existing technologies, but all have varying degrees of technical limitations. One approach involves adding an auxiliary heat sink to the outside of the resistor. While this method can improve heat dissipation to some extent, it increases the overall size of the component, completely contradicting the core development requirement of miniaturization in electronic products. Furthermore, it lacks sufficient mounting space in high-density mounting circuit boards, and increases assembly processes and material costs, making it unsuitable for the large-scale application of miniature surface mount resistors. A second approach involves improving the material system of the resistor's layers, using insulating substrates, protective layers, or resistive functional layer materials with high thermal conductivity. However, this approach is limited by the high cost of electronic-grade high thermal conductivity materials, significantly increasing manufacturing costs. Moreover, some high thermal conductivity materials have poor adhesion and thermal expansion matching with the resistive functional layer, easily leading to delamination, cracking, and other problems, which ultimately reduce the resistor's long-term stability and environmental tolerance. The third approach involves increasing the heat dissipation area by roughening the surface of the protective layer. This method uses an irregular, rough surface design, which makes it impossible to control the increase in heat dissipation area. The batch-to-batch stability of the heat dissipation effect is poor. At the same time, the irregular, rough surface is prone to accumulating impurities, affecting the compatibility of subsequent conformal coating and mounting processes. It also reduces the moisture-proof, corrosion-proof, and electrical insulation performance of the protective layer, and cannot meet the reliability requirements of industrial applications.

[0005] In summary, existing surface mount resistor heat dissipation improvement solutions have consistently failed to simultaneously address the multiple demands of improved heat dissipation performance, miniaturized packaging adaptation, process compatibility, and low-cost mass production, thus becoming an industry bottleneck restricting the development of miniature high-power surface mount resistors. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an improved heat dissipation surface structure, which solves the technical problems of insufficient heat dissipation, large resistor volume due to the addition of heat dissipation structures, and increased manufacturing costs due to poor process compatibility in the prior art.

[0007] To achieve the above objectives, the present invention is accomplished by the following specific technical means:

[0008] A resistor with an improved heat dissipation surface structure includes an insulating substrate, a resistive functional layer disposed on the insulating substrate, and a first protective layer disposed above the resistive functional layer. The resistive functional layer includes electrode layers disposed on both sides of the insulating substrate and a functional metal layer electrically connected between the two electrode layers. The first protective layer covers at least the upper surface of the functional metal layer and has a corrugated structure that undulates up and down along its thickness direction.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] 1. Significantly Improved Heat Dissipation Performance: By setting the first protective layer as a corrugated structure that undulates up and down along its thickness direction, this invention increases the heat dissipation area of ​​the resistor's outer surface without changing the overall package size or increasing the volume of components. At the same time, it optimizes the surface air convection path and enhances the resistor's convective and radiative heat dissipation efficiency, reducing the steady-state temperature rise during resistor operation. This avoids resistance drift, accuracy degradation, and power attenuation caused by heat accumulation, thereby improving the resistor's power tolerance and long-term electrical performance stability.

[0011] 2. While improving heat dissipation efficiency, it meets the needs of miniaturization and high-density integration of electronic products: Based on the leap in heat dissipation performance brought about by the corrugated structure, this invention can achieve miniaturized design of resistor package specifications without reducing the rated power and electrical performance indicators of the resistor, and adapt to the high-density and miniaturized mounting needs of electronic products.

[0012] 3. It has the ability to protect the components and ensure their long-term reliability: The corrugated structure of the present invention is the surface morphology forming structure of the first protective layer itself. The forming process only changes the surface undulation of the protective layer, without reducing the minimum protective thickness of the protective layer or forming any penetrating structure. It can completely retain the core protective functions of the first protective layer for the internal functional metal layer, such as electrical insulation, moisture protection, corrosion protection and mechanical damage resistance. While improving the heat dissipation effect, it ensures the long-term working stability of the resistor under high temperature, high humidity and complex working conditions.

[0013] 4. Strong process compatibility, suitable for low-cost mass production: The corrugated structure of this invention is a regular continuous undulating structure, which can be formed by existing mature hot pressing and laser etching processes. It does not require major modifications to the main production process of existing chip resistors, nor does it require the use of expensive high thermal conductivity special materials. While achieving a leap in performance, it controls the product manufacturing cost. At the same time, the regular corrugated surface has excellent process adaptability and can be perfectly compatible with subsequent conventional processes such as conformal coating and SMT assembly. It does not have the defects of irregular rough surfaces that are prone to accumulating impurities and affecting subsequent assembly processes.

[0014] 5. Optimize thermal stress matching performance and improve the environmental tolerance of components: The continuous corrugated structure of the first protective layer can effectively buffer the internal stress caused by the difference in thermal expansion coefficients of each layer of materials during the operation of the resistor in hot and cold cycles, reduce the risk of delamination and cracking between the protective layer and the functional metal layer, further improve the temperature cycle tolerance and adaptability of the resistor to complex environments, and extend the service life of the product.

[0015] Furthermore, the surface of the first protective layer is provided with several grooves to improve the adhesion of the protective layer and provide a good adhesion substrate for subsequent conformal coating on the protective layer.

[0016] Furthermore, the grooves are all formed in the recessed area of ​​the corrugated structure of the first protective layer. Setting the grooves in this area can better ensure that the protective material can fill and smooth the grooves when further conformal coating is applied, thus ensuring the smoothness of the product surface.

[0017] Furthermore, the two ends of the first protective layer extend above the corresponding electrode layer and cover part of the upper surface of the electrode layer, ensuring that the first protective layer can completely cover the functional metal layer.

[0018] Furthermore, it also includes a second protective layer, which is attached to the upper surface of the first protective layer and has a corrugated structure that matches the corrugated structure of the first protective layer, thus effectively protecting the protective layer and ensuring the stability of the product.

[0019] Furthermore, the corrugated structure of the first protective layer is a sinusoidal corrugated structure. The sinusoidal corrugated structure has a smooth wall surface, which makes the airflow smooth, the boundary layer development stable, the overall heat exchange efficiency higher, the temperature distribution more uniform, and the long-term reliability better.

[0020] As a preferred option, the wavelength of the sinusoidal corrugated structure is 50-500μm and the amplitude is 5-50μm, in order to fit the volume of existing conventional chip resistors.

[0021] Furthermore, when the surface of the first protective layer has grooves, the second protective layer has protrusions that correspond one-to-one with the grooves and are embedded in the grooves, so that the second protective layer and the first protective layer are more tightly bonded.

[0022] The present invention also provides a method for preparing a resistor with an improved heat dissipation surface structure, which includes the following steps:

[0023] S1 Substrate Pretreatment: Obtain an insulating substrate, and perform cleaning and activation treatment on the surface of the insulating substrate;

[0024] S2 Fabrication of a resistive functional layer: A resistive functional layer is fabricated on the upper surface of a pretreated insulating substrate. The resistive functional layer includes electrode layers disposed on both sides and a functional metal layer electrically connected between the two electrode layers.

[0025] S3. Prepare the first protective layer: Cover the upper surface of the resistive functional layer with a first protective layer, such that the first protective layer at least covers the upper surface of the functional metal layer;

[0026] S4 Protective layer surface forming: The first protective layer is formed into a corrugated structure that undulates up and down along its thickness direction by etching or hot pressing process.

[0027] Furthermore, step S5 involves preparing the attachment structure of the first protective layer: by etching, several grooves are formed in the recessed area of ​​the corrugated structure of the first protective layer.

[0028] To effectively protect the first protective layer, step S6, the preparation of the second protective layer, is also included:

[0029] For cases where the first protective layer does not have grooves: a second protective layer is prepared by bonding it to the upper surface of the first protective layer, so that the second protective layer forms a corrugated structure that matches the corrugated structure of the first protective layer.

[0030] In the case where the first protective layer has a groove: a second protective layer is prepared by attaching it to the upper surface of the first protective layer, so that the second protective layer forms a corrugated structure that matches the corrugated structure of the first protective layer, and the second protective layer forms a protrusion that is embedded in the groove. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the assembled resistor structure provided in Example 1;

[0032] Figure 2 An exploded view of the resistor provided in Example 1;

[0033] Figure 3 A front view of the resistor provided in Example 1;

[0034] Figure 4 Top view of the resistor provided in Example 1;

[0035] Figure 5 A schematic diagram of the second protective layer protrusion structure of the resistor provided in Embodiment 1;

[0036] Figure 6 For this Figure 2 Enlarged view of area a in the image;

[0037] Figure 7 This is a flowchart of the first method for preparing a resistor provided in Example 2;

[0038] Figure 8 This is a flowchart of the second method for preparing a resistor provided in Example 3;

[0039] In the diagram, the correspondence between component names and drawing numbers is as follows:

[0040] 11. Insulating substrate; 12. First protective layer; 13. Electrode layer; 14. Functional metal layer; 15. Groove; 16. Second protective layer; 17. Protrusion. Detailed Implementation

[0041] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0042] Example 1 provides a resistor with an improved heat dissipation surface structure.

[0043] See Figures 1 to 3 This application provides a resistor with an improved heat dissipation surface structure. The resistor mainly includes an insulating substrate 11 and a resistive functional layer disposed on the insulating substrate 11, and a first protective layer 12 disposed above the resistive functional layer. The resistive functional layer includes electrode layers 13 disposed on both sides of the insulating substrate 11, and a functional metal layer 14 electrically connected between the two electrode layers 13. The first protective layer 12 covers at least the upper surface of the functional metal layer 14 and has a corrugated structure that undulates up and down along its thickness direction.

[0044] By configuring the first protective layer 12 as a corrugated structure undulating along its thickness direction, the thermal conductivity area of ​​the functional metal layer can be increased without changing the overall package dimensions of the resistor or increasing the volume of the components. Specifically, this corrugated structure increases the thermal conductivity area of ​​the functional metal layer. When the resistor is operating, more heat can be dissipated through the larger heat dissipation area, allowing it to be transferred more smoothly from the inside of the resistor to the external environment. At the same time, this corrugated structure also optimizes the surface air convection path. When air flows across the resistor surface, the corrugated structure guides the air to form a flow path, promoting more thorough contact and heat exchange between the air and the resistor surface, thereby enhancing the convective heat dissipation efficiency of the resistor.

[0045] Furthermore, the increased heat dissipation area and optimized convection path further enhance heat radiation heat dissipation efficiency. Through these series of heat dissipation performance improvement measures, the steady-state temperature rise during resistor operation is reduced, avoiding problems such as resistance drift, accuracy degradation, and power attenuation caused by heat accumulation. This, in turn, improves the resistor's power tolerance and long-term electrical performance stability. By utilizing the leap in heat dissipation performance brought about by the corrugated structure, the embodiments of this application can improve the adaptability of resistors in the miniaturization and high-density integration of electronic products, solving the problem that existing resistors cannot meet the growing miniaturization and high-density mounting requirements of electronic products. Based on this improved heat dissipation performance, without reducing the resistor's rated power and electrical performance indicators, miniaturized resistor package specifications can be achieved, enabling the resistor to better adapt to the high-density, miniaturized mounting requirements of electronic products, providing strong support for further miniaturization and functional integration of electronic products.

[0046] By setting the corrugated structure as the surface of the first protective layer 12 to form a protective structure, only the surface undulation of the protective layer is changed during the molding process. The minimum protective thickness of the protective layer is not reduced, and no penetrating structure is formed. This allows the first protective layer 12 to fully retain the core protective functions of electrical insulation, moisture protection, corrosion protection, and mechanical damage resistance of the internal functional metal layer 14 while improving heat dissipation. This ensures the long-term working stability of the resistor under high temperature, high humidity, and complex working conditions, and solves the problem of balancing heat dissipation requirements and component protection requirements.

[0047] By employing existing mature hot pressing and laser etching processes to form the first protective layer 12 with a regular continuous undulating corrugated structure, it is possible to control product manufacturing costs while achieving a leap in performance, thus solving the problem of excessively high costs in the resistor manufacturing process.

[0048] This setup requires no modification to the existing main production process of surface mount resistors, nor does it require the use of expensive high thermal conductivity special materials, thus reducing production costs. At the same time, the regular corrugated surface has excellent process adaptability, perfectly compatible with subsequent conventional processes such as conformal coating and SMT assembly, and does not have the defects of irregular rough surfaces that easily accumulate impurities and affect subsequent assembly processes, ensuring the feasibility of large-scale production.

[0049] By setting the continuous corrugated structure of the first protective layer 12, it can also buffer the internal stress caused by the difference in thermal expansion coefficients of the materials in each layer during the thermal cycling process of the resistor. This reduces the risk of delamination and cracking between the protective layer and the functional metal layer 14, further improving the resistor's temperature cycling tolerance and adaptability to complex environments, extending the product's service life, and solving the problem of reduced reliability caused by thermal stress in complex environments. Several grooves 15 are formed on the surface of the first protective layer 12. This design improves the adhesion of the protective layer, providing a good adhesion substrate for subsequent conformal coating, solving the problem of poor material adhesion during conformal coating. Furthermore, the grooves 15 are all located within the recessed area of ​​the corrugated structure of the first protective layer 12. Placing the grooves 15 in this area ensures that the protective material can fill and smooth the grooves 15 during further conformal coating, ensuring the smoothness of the product surface and preventing surface unevenness caused by the grooves 15 from affecting product performance and appearance. The first protective layer 12 extends to the top of the corresponding electrode layer 13 at both ends and covers part of the upper surface of the electrode layer 13. This arrangement ensures that the first protective layer 12 can completely cover the functional metal layer 14, providing more comprehensive protection for the functional metal layer 14.

[0050] See Figures 2 to 6The resistor also includes a second protective layer 16, which is attached to the upper surface of the first protective layer 12. The second protective layer 16 has a corrugated structure that is compatible with the corrugated structure of the first protective layer 12. This arrangement protects the protective layer, ensures the stability of the product, and further improves the protection performance of the resistor.

[0051] The corrugated structure of the first protective layer 12 is a sinusoidal corrugated structure. The sinusoidal corrugated structure has advantages, such as smooth wall surface, which makes the airflow smooth, the boundary layer development stable, the overall heat exchange efficiency higher, the temperature distribution more uniform, and the long-term reliability better. Furthermore, for the case where the surface of the first protective layer 12 has grooves 15, the second protective layer 16 has protrusions 17 that correspond one-to-one with the grooves 15 and are embedded in the grooves 15. Through this structural setting, the second protective layer 16 and the first protective layer 12 are more tightly bonded, which enhances the connection stability between the two protective layers, thereby improving the stability and reliability of the entire resistive structure.

[0052] The above describes the setting when the electrode layer is located on the narrow side of the functional metal layer. In addition, the electrode layer can also be set on the long side of the functional metal layer. The setting method is the same and the effect achieved is to increase the heat conduction area of ​​the functional metal layer.

[0053] Example 2 provides a method for preparing a resistor with an improved heat dissipation surface structure, the specific implementation of which is as follows:

[0054] See Figure 7 First, when manufacturing a resistor with an improved heat dissipation surface structure, a suitable insulating substrate 11 is selected. The insulating substrate 11 must have good electrical insulation properties, certain mechanical strength and thermal stability.

[0055] After acquisition, ultrasonic cleaning technology is used to immerse it in a specific organic solvent. The cavitation effect generated by the high-frequency vibration of ultrasound is used to remove impurities such as oil, dust, and oxides adhering to the surface. Then, it is rinsed multiple times with high-purity deionized water. After that, it is activated by means of chemical etching or plasma treatment to improve the surface chemical activity and the bonding force with the subsequent resistive functional layer.

[0056] Then, a resistive functional layer is fabricated on the upper surface of the pretreated and ideally surfaced insulating substrate 11 using physical vapor deposition or chemical vapor deposition. The resistive functional layer consists of an electrode layer 13 disposed on both sides of the insulating substrate 11 and a functional metal layer 14 electrically connecting them. By adjusting relevant parameters, the thickness and performance of the electrode layer 13 and the functional metal layer 14 are ensured to meet the electrical functional requirements of the resistor.

[0057] Next, a coating process such as spin coating, spray coating or vacuum coating is used to uniformly cover the first protective layer 12 on the upper surface of the resistive functional layer, ensuring that it at least completely covers the upper surface of the functional metal layer 14, providing all-round protection for the functional metal layer 14, while strictly controlling the coating parameters to ensure its quality.

[0058] Subsequently, through etching or hot pressing processes, the first protective layer 12 is formed into a corrugated structure that undulates up and down along its thickness direction.

[0059] In order to effectively protect the first protective layer 12, a second protective layer 16 is prepared on the first protective layer 12 to form a corrugated structure that is compatible with the corrugated structure of the first protective layer 12.

[0060] Example 3 provides another method for preparing a resistor with an improved heat dissipation surface structure, the specific implementation of which is as follows:

[0061] See Figure 8 The difference from the preparation method provided in Example 2 is that, after the corrugated structure of the first protective layer is formed, several grooves are formed in the recessed area of ​​the corrugated structure of the first protective layer 12 by etching process to prepare the attachment structure of the first protective layer 12. Then, a second protective layer 16 is prepared on the first protective layer 12 to form a corrugated structure that is compatible with the corrugated structure of the first protective layer 12, and the second protective layer fills the grooves during the natural leveling process to form a corresponding filling protrusion structure.

[0062] The remaining preparation process is the same as that provided in Example 2, and will not be described again here.

[0063] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A resistor with an improved heat dissipation surface structure, comprising an insulating substrate (11), a resistive functional layer disposed on the insulating substrate (11), and a first protective layer (12) disposed above the resistive functional layer, characterized in that: The resistive functional layer includes an electrode layer (13) disposed on both sides of the insulating substrate (11) and a functional metal layer (14) electrically connected between the two electrode layers (13); the first protective layer (12) covers at least the upper surface of the functional metal layer (14), and the upper surface of the first protective layer (12) has a corrugated structure that undulates up and down along its thickness direction.

2. The resistor with an improved heat dissipation surface structure as described in claim 1, characterized in that, The surface of the first protective layer (12) has several grooves (15).

3. The resistor with an improved heat dissipation surface structure as described in claim 2, characterized in that, The grooves (15) are all formed in the recessed area of ​​the corrugated structure of the first protective layer (12).

4. The resistor with an improved heat dissipation surface structure as described in claim 1, characterized in that, The first protective layer (12) extends to the electrode layer (13) on the corresponding side at both ends and covers part of the upper surface of the electrode layer (13).

5. The resistor with an improved heat dissipation surface structure as described in any one of claims 1 to 4, characterized in that, The corrugated structure of the first protective layer (12) is a sinusoidal corrugated structure.

6. The resistor with an improved heat dissipation surface structure as described in claim 5, characterized in that, It also includes a second protective layer (16), which is attached to the upper surface of the first protective layer (12).

7. The resistor with an improved heat dissipation surface structure as described in claim 6, characterized in that, When the surface of the first protective layer (12) is provided with a groove, the second protective layer (16) is provided with a protrusion (17) that corresponds one-to-one with the groove (15) and is embedded in the groove (15).

8. A method for preparing a resistor with an improved heat dissipation surface structure, used to prepare the resistor with the improved heat dissipation surface structure as described in claim 1, characterized in that, Includes the following steps: S1 Substrate Pretreatment: Obtain an insulating substrate, and perform cleaning and activation treatment on the surface of the insulating substrate; S2 Fabrication of a resistive functional layer: A resistive functional layer is fabricated on the upper surface of a pretreated insulating substrate. The resistive functional layer includes electrode layers disposed on both sides and a functional metal layer electrically connected between the two electrode layers. S3. Prepare the first protective layer: Cover the upper surface of the resistive functional layer with a first protective layer, such that the first protective layer at least covers the upper surface of the functional metal layer; S4 Protective layer surface forming: The first protective layer is formed into a corrugated structure that undulates up and down along its thickness direction by etching or hot pressing process.

9. The preparation method according to claim 8, characterized in that, It also includes step S5, which involves preparing the attachment structure of the first protective layer: by etching, several grooves are formed in the recessed area of ​​the corrugated structure of the first protective layer.

10. The preparation method according to claim 8 or 9, characterized in that, It also includes step S6, preparation of the second protective layer: For cases where the first protective layer does not have grooves: a second protective layer is prepared by bonding it to the upper surface of the first protective layer, so that the second protective layer forms a corrugated structure that matches the corrugated structure of the first protective layer; In the case where the first protective layer has a groove: a second protective layer is prepared by attaching it to the upper surface of the first protective layer, so that the second protective layer forms a corrugated structure that matches the corrugated structure of the first protective layer, and the second protective layer forms a protrusion that is embedded in the groove.

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