Sintering method of semiconductor heat dissipation integrated substrate

Abstract

The present application relates to the field of semiconductor devices, in particular to a sintering method of a semiconductor heat dissipation integrated substrate, the method comprising the following steps: preparing a metal pin fin embryo, and processing a positioning groove for positioning a DBC or AMB copper-clad plate on the front surface of the metal pin fin embryo; placing the DBC or AMB copper-clad plate in the positioning groove of the metal pin fin embryo, and placing the preliminary positioned combination in a constraint environment; then sending the combination after fixing and constraining into a sintering furnace for one-time sintering; after sintering, removing the constraint environment, and taking out the sintered integrated substrate product. Through the innovative multi-dimensional constraint environment and positioning groove design, the warpage of the integrated substrate can be effectively controlled at a low level (such as below 3‰), which significantly improves the flatness and dimensional stability of the product, and at the same time, the one-time sintering process is used to improve the production efficiency and reduce the overall manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices, and more particularly to a sintering method for an integrated semiconductor heat dissipation substrate. Background Technology

[0002] As semiconductor devices continue to evolve towards higher power and higher density, heat dissipation has become an increasingly critical factor restricting performance improvement. Integrated heat dissipation substrates, due to their ability to integrate heat dissipation structures with the circuit board and effectively reduce thermal resistance, are gradually becoming the preferred solution for high-power module packaging. This structure is typically formed by high-temperature sintering of metal pins (such as copper or aluminum) with ceramic copper-clad laminates (such as DBC), aiming to replace traditional solder joints to improve thermal conductivity and operating junction temperature. However, integrated substrates face numerous technical challenges during the sintering process, especially the warping and deformation caused by differences in material thermal expansion coefficients and structural asymmetry, which has become a major concern in the industry.

[0003] In existing technologies, the manufacturing of integrated substrates typically employs step-by-step sintering or auxiliary connection materials. For example, some solutions use solder pads to connect the pins to the DBC substrate via vacuum reflow soldering. However, solder has low thermal conductivity, which not only reduces overall heat dissipation efficiency but also limits the module's application in high-temperature environments due to the low melting point of tin. Another approach is to use nano-silver or nano-copper sintering processes. These materials have high thermal conductivity and controllable sintering temperatures, but the raw material costs are expensive, and the process is complex, making it difficult to popularize in large-scale production. A more common alternative is to use copper-silver or copper-phosphorus-tin-nickel solders for one-step sintering. These are lower in cost and have moderate thermal conductivity. However, in practical applications, due to the significant thickness difference between the pins and the DBC substrate (pin thickness is often on the millimeter scale, while the DBC substrate is on the sub-millimeter scale), the uneven distribution of thermal stress between the metal pins and the ceramic substrate during high-temperature sintering can easily cause substrate warping. This warping not only affects the flatness of the module but may also lead to alignment deviations during subsequent chip mounting, reducing product reliability.

[0004] Existing technologies attempt to control warpage through mold constraints or hot pressing processes. For example, some methods use rigid molds to press the substrate during sintering to limit its deformation space. While these solutions can suppress warpage to some extent, they often ignore the physical changes of the material at high temperatures. Metal fins undergo dimensional expansion during sintering due to grain growth (typically increasing by 0.1%-0.3%), while ceramic substrates have higher dimensional stability. This difference can lead to a shift in the relative position of the fins and the substrate after sintering, making it difficult to meet the requirements of high-precision packaging. Furthermore, if the mold design does not consider expansion allowance, the fins may generate internal stress due to restricted expansion, even causing mold jamming or substrate cracking. Another approach is to apply pressure to the substrate in a protective atmosphere using hot pressing to balance stress on both sides. However, these methods are mostly designed for single-sided substrates and cannot effectively solve the problem of three-dimensional stress concentration in integrated structures. Especially when the substrate area is large or the structure is asymmetrical, local stress will exacerbate warpage, making it difficult to control the warpage rate below 0.5%.

[0005] Furthermore, existing processes typically rely on secondary sintering to stabilize the needle fin size. This involves first sintering the needle fins separately to allow for grain growth, and then bonding them to the substrate. While this approach alleviates positional accuracy issues, it increases production cycles and energy consumption. Additionally, repeated high-temperature treatments can introduce interface oxidation or contamination, reducing bonding strength. Moreover, it's worth noting that current technologies primarily focus on macroscopic warpage control, offering limited means to ensure micron-level positional accuracy. This, to some extent, restricts the application of integrated substrates in high-reliability scenarios (such as power modules for new energy vehicles).

[0006] Overall, existing technologies still have significant limitations in the field of integrated substrate sintering: First, warpage control is insufficient, making it difficult to simultaneously meet the requirements of low warpage rate (e.g., below 0.3%) and high flatness; second, there is a lack of positional accuracy assurance mechanisms, and the relative positioning of the pins and the substrate is easily affected by process fluctuations; third, process efficiency is low, and secondary sintering or complex post-processing increases costs. Therefore, the industry urgently needs an integrated substrate sintering technology that can achieve low warpage, high precision, and controllable cost in a single sintering process to adapt to the trend of semiconductor packaging towards efficient heat dissipation and miniaturization. Summary of the Invention

[0007] This application aims to overcome the shortcomings of existing technologies, such as severe warping and deformation, difficulty in ensuring positional accuracy, and high process costs during the sintering process of integrated semiconductor heat dissipation substrates. Therefore, it provides a sintering method for integrated semiconductor heat dissipation substrates to overcome the above-mentioned deficiencies.

[0008] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a sintering method for an integrated semiconductor heat dissipation substrate, comprising the following steps: S1. Prepare a metal needle-wing blank and machine a positioning groove for positioning the DBC or AMB copper-clad board on its front side, and screen print a layer of solder on the back side (B side) of the DBC or AMB copper-clad board. S2. Place the back of the DBC or AMB copper-clad laminate into the positioning groove of the metal needle-fin blank to initially position the two. S3. Place the assembled metal needle-fin blank and the DBC or AMB copper-clad laminate in a constrained environment; wherein... The constraint environment includes: A first constraint force is applied to the upper surface and surrounding area of ​​the DBC or AMB copper-clad laminate to restrict its in-plane movement and warping perpendicular to the plane during bonding with the metal needle-finned body. A second constraint force is applied to the periphery of the front and back surfaces of the metal needle-wing blank to limit its deformation due to thermal expansion during sintering. The wing needle portion on the back of the metal needle-wing blank is suspended in the air to avoid stress on the wing needle; S4. The assembly after being fixed and constrained in step S3 is sent into a sintering furnace for one-time sintering, so that the metal needle-fin blank is densified and bonded with the DBC or AMB copper-clad laminate by solder to form an integrated substrate. S5. After sintering is completed, the constraint environment is released, and the sintered integrated substrate product is taken out.

[0009] As shown in the background section, with the development of high-power semiconductor devices, more stringent requirements have been placed on the flatness, positional accuracy, and manufacturing cost of heat dissipation substrates. While existing technologies using copper-silver or copper-phosphorus-tin-nickel solders for single-stage sintering are cost-effective, the significant thickness difference and mismatch in thermal expansion coefficients between the metal pins and the ceramic copper-clad laminate (DBC or AMB) generate significant thermal stress during high-temperature sintering, leading to uncontrollable warping deformation of the substrate. More problematic is the increase in physical size of the metal pins due to grain growth during sintering, while the ceramic substrate remains dimensionally stable. This difference causes a shift in the pre-set relative positions, severely affecting the accuracy of subsequent chip packaging. To alleviate this issue, the industry often employs a two-stage sintering process, where the pins are sintered separately to stabilize their dimensions before being bonded to the substrate. However, this undoubtedly increases production cycle time, energy consumption, and cost, and multiple high-temperature treatments may introduce interface contamination. These factors collectively limit the reliable application of integrated substrates in high-end power modules.

[0010] Against this technical backdrop, the core innovation of this application lies in providing a systematic method that can simultaneously solve the problems of warpage control, positional accuracy assurance, and cost optimization in a single sintering process. This method is not a simple improvement on existing processes, but rather redefines the constraints and energy transfer paths of the sintering process through a series of synergistic technical features.

[0011] First, this application begins with the redesign of the needle-fin blank structure (step S1). By machining positioning grooves on the front side of the metal needle-fin blank for positioning the DBC or AMB copper-clad laminate, this seemingly simple structural modification can play an initial positioning role, thereby ensuring that the DBC or AMB copper-clad laminate maintains a precise relative position with the needle fin at the beginning of subsequent assembly and sintering, laying the foundation for the stability of the entire process. Compared with the existing technology that relies solely on external molds for alignment, this application internalizes the positioning function into the product structure itself, which can effectively improve the robustness of the system.

[0012] Secondly, initial positioning alone is insufficient to address the challenges posed by high-temperature sintering. In step S3 of this application, a "constraint environment" is specifically constructed to address these challenges. This "constraint environment" can apply differentiated constraint forces based on the deformation characteristics of different components and regions during sintering, thereby achieving "precise force application and effective suppression." Specifically, this constraint environment comprises three levels of function: (1) Apply a first constraint force to the upper surface and surrounding area of ​​the DBC or AMB copper-clad laminate. The purpose is to restrict in two ways: on the one hand, restrict the movement of the DBC or AMB copper-clad laminate in the plane during the bonding process, prevent it from slipping due to solder flow or uneven stress, and ensure positional accuracy; on the other hand, focus on restricting its warping deformation perpendicular to the plane, which is the key to ensuring the final flatness of the substrate. (2) Apply a second constraint force to the surrounding area of ​​the front and back sides of the metal needle-fin blank. This design is highly targeted, and its main purpose is to suppress the outward expansion and overall deformation of the needle-fin blank due to thermal expansion during sintering. In particular, considering the grain growth effect of the needle fin, the constraint of the surrounding area can effectively counteract the trend of its size increase, control its deformation within the elastic range, and avoid affecting the position of the DBC or AMB copper-clad laminate. (3) Make the back fin part of the metal needle-fin blank in a suspended state. In this application, because the fin part has a slender structure, if a constraint is applied, it is easy to cause stress concentration and deformation or damage. Therefore, suspending it in the air effectively avoids unnecessary stress, thus protecting the integrity of the fin structure, and also provides a release channel for gases or stresses that may be generated during the sintering process.

[0013] These three levels, when combined, form an organic whole, enabling coordinated control of the thermodynamic behavior of the entire assembly during the subsequent one-time high-temperature sintering process in step S4. Compared to the simple planar pressing or single-sided constraint in existing technologies, this multi-dimensional constraint environment can more effectively balance the three-dimensional internal stress caused by material differences and uneven temperature fields, thereby suppressing deformation in the initial stage of sintering.

[0014] The technical solution described in this application offers the following significant and synergistic technical benefits: First, the most direct effect is a substantial reduction in finished product warpage, which can be stably controlled at a low level, meeting the stringent requirements of high-power modules for substrate flatness. Simultaneously, due to the initial positioning effect of the positioning grooves and the constraint environment limiting the movement of the DBC or AMB, the positional accuracy of the DBC or AMB copper-clad laminate relative to the metal pins is reliably guaranteed, laying a solid foundation for subsequent high-precision chip mounting. More importantly, all these advantages are achieved through a single sintering process, completely eliminating the cumbersome secondary sintering steps, thereby significantly improving production efficiency and reducing energy consumption and manufacturing costs. This one-step molding method also avoids interface oxidation or performance degradation that may result from multiple high-temperature treatments, contributing to improved long-term reliability of the integrated substrate interface bonding.

[0015] Therefore, in summary, this application starts with the product structure (positioning groove) and uses a carefully designed multi-dimensional constraint environment to precisely control the sintering process, ultimately achieving the goals of low warpage, high precision, and low cost in a single sintering process.

[0016] Preferably, in step S1, the metal needle-wing blank is obtained by metal forging or powder metallurgy forming.

[0017] Preferably, the molding pressure of the metal needle-wing blank is 100-1200 MPa.

[0018] Preferably, in step S3, the constraint environment is provided by a mold, which includes an upper mold and a lower mold. The first constraint force is applied by the upper mold, and the second constraint force is applied jointly by the upper mold and / or the lower mold.

[0019] Preferably, in step S3, the mold size used to apply the second constraint force is configured to accommodate the dimensional expansion of the metal needle-fin blank due to grain growth during sintering.

[0020] Preferably, in step S3, an exhaust gap with a width of not less than 0.05 mm is formed between the front periphery of the metal needle-wing blank and the constraint environment.

[0021] Preferably, in step S4, the DBC or AMB copper-clad laminate is bonded to the metal needle-fin blank using copper-silver or copper-phosphorus-tin-nickel solder.

[0022] Preferably, in step S4, the sintering temperature is 500-1000℃ and the sintering time is 10-60 minutes.

[0023] Preferably, in step S4, the sintering is carried out under an inert gas protective atmosphere.

[0024] Preferably, the overall warpage of the integrated substrate obtained by the method is less than 3‰.

[0025] Preferably, the DBC or AMB copper-clad laminate is double-sided copper-clad DBC or AMB or single-sided copper-clad DBC or AMB.

[0026] Therefore, this application has the following beneficial effects: (1) This application, through innovative multi-dimensional constraint environment and positioning groove design, can effectively control the warpage of the integrated substrate to a low level (such as below 3‰), which significantly improves the flatness and dimensional stability of the product; (2) The positional accuracy of the DBC or AMB copper-clad laminate relative to the metal pin fins is greatly improved, and the error range is reduced to the micrometer level, ensuring the accuracy and reliability of subsequent chip packaging; (3) By using high thermal conductivity solder (such as copper-silver solder) and one-time sintering process, while achieving excellent thermal conductivity and high temperature resistance, the energy waste and interface risk of secondary sintering are avoided, thereby improving production efficiency and reducing overall manufacturing costs. (4) The synergistic integration of various technical elements, such as the setting of exhaust gaps and the treatment of suspended fins, further optimizes the process robustness, making the method have good engineering applicability while ensuring high performance. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0028] Example 1 This embodiment provides a sintering method for an integrated semiconductor heat dissipation substrate, the specific steps of which are as follows: S1. Preparation of Metal Needle-Fin Blank: Using T2 pure copper as raw material, a metal needle-fin blank with an array fin structure is forged under a pressure of 100 MPa using a forging press. Subsequently, a positioning groove with a depth of 0.08 mm is milled on the front side of the blank through precision machining. The shape of the groove matches the DBC copper-clad laminate used later. Then, a copper-phosphorus-tin-nickel solder paste (containing 3-6% phosphorus, 10-18% tin, 2-6% nickel, and the remainder copper) is printed onto the back side (B side) of the DBC copper-clad laminate using a screen printing process and dried at 100℃ for 10 minutes. The solder layer thickness is controlled to be approximately 0.03 mm.

[0029] S2. Assembly: Carefully place a 50 mm × 60 mm DBC copper-clad board (A side is the circuit layer, B side is the planar copper layer) with an Al2O3 ceramic layer and a copper layer thickness of 0.3 mm into the positioning groove of the metal needle-fin blank prepared in step S1, so that the copper layer of the B side of the DBC contacts the groove to achieve initial positioning.

[0030] S3. Fixing and Constraining: The assembly is transferred to a sintering mold made of mold steel. This mold consists of an upper mold and a lower mold. After mold closing, the upper mold applies a first constraint force to the A-side and surrounding area of ​​the DBC copper-clad laminate, while the lower mold applies a second constraint force to the surrounding area of ​​the metal needle-fin blank. The mold cavity dimensions are precisely calculated, with a 0.1 mm gap reserved to accommodate the thermal expansion of the needle-fin blank during sintering. Simultaneously, the mold design ensures that the back fin portion of the metal needle-fin blank is suspended and unaffected by pressure. A 0.08 mm wide venting gap is formed between the front periphery of the blank and the mold.

[0031] S4. One-time sintering: The mold containing the assembly is pushed into the atmosphere sintering furnace. High-purity nitrogen (purity ≥99.999%) is introduced into the furnace as a protective atmosphere. The furnace temperature is raised to 700℃ at a heating rate of 10℃ / min and held at this temperature for 30 minutes. During this process, the metal needle-fin blank is further densified, and the solder melts, allowing the blank and the DBC copper-clad laminate to form a strong bond through liquid-phase sintering, resulting in an integrated substrate.

[0032] Example 2 This embodiment provides a sintering method for an integrated semiconductor heat dissipation substrate, the specific steps of which are as follows: S1. Preparation of Metal Needle-Fin Blanks: Copper powder is used as raw material and pressed into shape under a pressure of 1200 MPa through powder metallurgy to obtain metal needle-fin blanks. Then, positioning grooves with a depth of 0.12 mm are machined, the shape of which matches the AMB copper-clad laminate used later. Copper-silver solder paste is then screen-printed onto the silicon nitride substrate on the back of the AMB copper-clad laminate and dried at 100℃ for 10 minutes. The thickness of the prepared solder layer is controlled to be approximately 0.03 mm.

[0033] S2. Assembly: Place the printed AMB (Active Metal Brazing) copper-clad laminate (with Si3N4 ceramic layer) into the positioning groove of the blank. This AMB copper-clad laminate is single-sided copper-clad, meaning only side A has a copper layer, and side B is a ceramic surface printed with solder. During placement, place side B (ceramic surface) into the groove, so that the solder surface of side B of the AMB contacts the inside of the groove to achieve initial positioning.

[0034] S3. Fixing and Constraining: The assembly is transferred to a sintering mold made of mold steel. This mold consists of an upper mold and a lower mold. After mold closing, the applied first and second constraint forces work together. The mold cavity takes into account material shrinkage at high temperatures, with a 0.05 mm interference fit. Simultaneously, the mold design ensures that the fin portion on the back of the metal needle-fin blank is suspended and unaffected by pressure. A 0.06 mm wide venting gap is formed between the front periphery of the blank and the mold.

[0035] S4. One-time sintering: The mold containing the assembly is pushed into the atmosphere sintering furnace. High-purity nitrogen (purity ≥99.999%) is introduced into the furnace as a protective atmosphere, and the temperature is increased to 900℃ at 10℃ / min, and held for 40 minutes to complete sintering. During this process, the metal needle-fin preform is further densified, and the solder melts, allowing the preform and the AMB copper-clad laminate to form a strong bond through liquid-phase sintering, resulting in an integrated substrate.

[0036] Example 3 This embodiment provides a sintering method for an integrated semiconductor heat dissipation substrate, the specific steps of which are as follows: S1. Preparation of metal needle-fin blanks: Oxygen-free copper (C1020) plates are forged and formed under a pressure of 650 MPa. Subsequently, after precision machining, positioning grooves with a depth of 0.1 mm are milled on the front side of the blank. Then, copper-phosphorus-tin-nickel solder paste (containing 3-6% phosphorus, 10-18% tin, 2-6% nickel, and the remainder copper) is printed on the back side (B side) of the AMB copper-clad laminate using a screen printing process and dried at 100℃ for 10 minutes.

[0037] S2. Assembly: Place the B side (ceramic side) of the printed double-sided copper-clad AMB board (the ceramic layer is AlN, and its A side is the circuit layer and the B side is the planar copper layer) into the groove, so that the solder side of the copper layer of the AMB B side contacts the groove to achieve initial positioning.

[0038] S3. Fixing and Constraint: A molybdenum alloy mold is used. The mold design ensures that the second constraint force mainly acts on the periphery of the front side of the blank, while the rear fin needles are suspended as before. The venting gap is 0.10 mm.

[0039] S4. One-time sintering: Under nitrogen protection, the temperature is raised to 700 ℃ and held for 35 minutes for sintering. During this process, the metal needle-fin blank is further densified, and the solder melts, so that the blank and the AMB copper-clad laminate form a firm bond through liquid phase sintering to obtain an integrated substrate.

[0040] Comparative Example 1 The traditional soldering reflow process is adopted. Tin-lead solder pads (Sn63Pb37) are used to connect the pins (pre-sintered to dimension stability) to the DBC copper-clad laminate in a vacuum reflow oven at a peak temperature of 230°C.

[0041] Comparative Example 2 This embodiment provides a sintering method for an integrated semiconductor heat dissipation substrate, the specific steps of which are as follows: S1. Preparation of metal needle-wing blanks: Using the same T2 pure copper raw material and 100 MPa forging process as in Example 1, metal needle-wing blanks with the same structure are prepared. However, the positioning grooves are not machined, and the upper surface of the blank is a complete plane.

[0042] S2. Assembly: Place the DBC copper-clad laminate directly on the flat surface of the metal needle-wing blank and roughly align it using the positioning pins on the mold.

[0043] S3. Fixing and Constraining: The same mold system as in Example 1 is used. The upper mold applies a first constraint force to the DBC, and the lower mold applies a second constraint force to the periphery of the needle-wing blank. Due to the lack of initial positioning with grooves, the DBC is prone to displacement during placement and mold closing.

[0044] S4. One-time sintering: The process parameters are exactly the same as in Example 1, with a temperature of 500℃ and a time of 60 minutes.

[0045] S5. Post-processing: Same as in Example 1.

[0046] Comparative Example 3 This comparative simulation is a scheme that only provides unidirectional planar pressure and lacks effective lateral constraints around the needle-wing embryo.

[0047] S1. Preparation of metal needle-wing blank: The process is the same as in Example 1, except that a positioning groove with a depth of 0.08 mm is machined and filled with solder.

[0048] S2. Assembly: Same as in Example 1.

[0049] S3. Fixing and Constraint: A simplified mold is used, consisting of only an upper pressure plate and a lower plate. The upper pressure plate applies a vertically downward pressure to the DBC copper-clad laminate (equivalent to the first constraint force). However, the mold cavity is much larger in the horizontal direction than the needle-fin blank, with a lateral clearance of 0.5 mm, making it impossible to apply an effective second constraint force (lateral constraint) to the periphery of the needle-fin blank. Furthermore, the needle portion is kept suspended during the fixing process.

[0050] S4. One-time sintering: The process parameters are exactly the same as in Example 1.

[0051] S5. Post-processing: Same as in Example 1.

[0052] Comparative Example 4 This comparative simulation demonstrates a step-by-step sintering process, namely the two-stage sintering method used in existing technologies to stabilize the size of the needle fins.

[0053] S1. Preparation of metal needle-wing embryo: Same as in Example 1.

[0054] S2. First sintering (pre-sintered needle fins): The metal needle fin blanks without grooves are placed separately in the sintering furnace and held at 500℃ for 60 minutes to allow them to complete grain growth and size stabilization.

[0055] S3. Machining and Assembly: Positioning grooves are machined on the pre-sintered needle-fin blank and filled with solder. Then, the DBC copper-clad laminate is assembled into place.

[0056] S4. Fixing and Constraining: Apply constraints using the same mold as in Example 1.

[0057] S5. Second sintering (connection sintering): The assembly is placed back into the sintering furnace and held at 500℃ for 60 minutes to bond the needles and DBC with solder.

[0058] S6. Post-processing: Same as in Example 1.

[0059] Key performance tests were conducted on the products obtained in Examples 1-3 and Comparative Examples 1-4, and the results are shown in Table 1 below: Table 1

[0060] As shown in Table 1 above, the integrated substrates prepared in Examples 1-3 of this invention all exhibit significantly lower warpage than 3‰, and the DBC and AMB demonstrate high positional accuracy, excellent thermal conductivity, and superior heat resistance. This is attributed to the one-time sintering molding process and precise constraint environment design of this invention. The integrated semiconductor heat dissipation substrate prepared in Example 1 of this invention showed no significant warpage after sintering. In contrast, the traditional soldering solution in Comparative Example 1 has significant shortcomings in thermal performance. In Comparative Example 2, due to the combined effect of the spreading force of the liquid solder and the mold constraint force during the initial solder melting stage of sintering, the DBC, which was not pre-limited, moved. The warpage was similar to that of Example 1, approximately 2.9‰, but the positional accuracy was severely degraded. In Comparative Example 3, the warpage of the product increased significantly after sintering. This was because the metal needle-fin blank expanded freely to the periphery at high temperatures, and the rigid compression of the DBC caused the composite structure to warp towards the needle-fin side. This indicates that the lack of effective restriction on the deformation of the needle-fin blank periphery makes it impossible to suppress warpage caused by uneven thermal expansion. The warpage and positional accuracy of the final product in Comparative Example 4 were comparable to those in Example 1. However, this process required two high-temperature sintering cycles, approximately doubling the total time and significantly increasing energy consumption. Furthermore, the multiple high-temperature treatments increased the risk of interface oxidation. This comparative example demonstrates the significant advantages of the present invention's one-time sintering process in terms of efficiency and cost while ensuring performance.

[0061] Therefore, in summary, this invention, through the organic combination of a series of technical features—"preliminary positioning with positioning grooves + deformation suppression by multi-dimensional constraint environment + one-time sintering with high thermal conductivity solder"—solves the problem of balancing warping, precision, efficiency, and performance in existing technologies.

Claims

1. A sintering method for an integrated semiconductor heat dissipation substrate, characterized in that, Includes the following steps: S1. Prepare a metal needle-wing blank and machine a positioning groove for positioning the DBC or AMB copper-clad laminate on its front side; and screen print a layer of solder on the back side of the DBC or AMB copper-clad laminate. S2. Place the back of the DBC or AMB copper-clad laminate into the positioning groove of the metal needle-fin blank to initially position the two. S3. Place the assembled metal needle-fin blank and the DBC or AMB copper-clad laminate in a constrained environment; wherein... The constraint environment includes: A first constraint force is applied to the upper surface and surrounding area of ​​the DBC or AMB copper-clad laminate to restrict its in-plane movement and warping perpendicular to the plane during bonding with the metal needle-finned body. A second constraint force is applied to the periphery of the front and back surfaces of the metal needle-wing blank to limit its deformation due to thermal expansion during sintering. The wing needle portion on the back of the metal needle-wing blank is suspended in the air to avoid stress on the wing needle; S4. The assembly after being fixed and constrained in step S3 is sent into a sintering furnace for one-time sintering, so that the metal needle-fin blank is densified and bonded with the DBC or AMB copper-clad laminate by solder to form an integrated substrate. S5. After sintering is completed, the constraint environment is released, and the sintered integrated substrate product is taken out.

2. The sintering method according to claim 1, characterized in that, In step S1, the metal needle-wing blank is obtained by metal forging or powder metallurgy forming.

3. The sintering method according to claim 2, characterized in that, The molding pressure of the metal needle-wing preform is 100-1200 MPa.

4. The sintering method according to claim 1, characterized in that, In step S3, the constraint environment is provided by a mold, which includes an upper mold and a lower mold. The first constraint force is applied by the upper mold, and the second constraint force is applied jointly by the upper mold and / or the lower mold. The mold size used to apply the second constraint force is configured to accommodate the dimensional expansion or contraction of the metal needle-wing preform during sintering.

5. The sintering method according to claim 1 or 4, characterized in that, In step S3, an exhaust vent with a width of not less than 0.05 mm is formed between the front side of the metal needle-wing blank and the constraint environment.

6. The sintering method according to claim 1, characterized in that, In step S4, the sintering temperature is 500-1000℃ and the sintering time is 10-60 minutes.

7. The sintering method according to claim 1 or 6, characterized in that, In step S4, the sintering is carried out under an inert gas protective atmosphere.

8. The sintering method according to claim 7, characterized in that, In step S4, the DBC or AMB copper-clad laminate is bonded to the metal needle-fin blank by copper-silver or copper-phosphorus-tin-nickel solder.

9. The sintering method according to claim 1, characterized in that, The DBC or AMB copper-clad laminate is either double-sided copper-clad DBC or AMB or single-sided copper-clad DBC or AMB.

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