Four-layer thermally separated copper substrate and its manufacturing process

Abstract

This application discloses a fabrication process for a four-layer thermally separated copper substrate, comprising the following steps: S1, creating windows in the copper foil layer and the insulating layer; S2, sequentially stacking the copper foil layer, the insulating layer, and another copper foil layer to form a first press plate; S3, hot-pressing the first press plate; S4, etching circuits on the copper foil layers on both sides of the first substrate; S5, sequentially stacking the copper foil layer, the insulating layer, and the first substrate, and repeating S3 to form a second substrate; S6, etching circuits on the copper foil layer of the second substrate away from the first substrate; S7, sequentially stacking the copper foil layer, the insulating layer, and the second substrate, and repeating S3 to form a panel; S8, etching circuits on the copper foil layer of the panel away from the second substrate; S9, drilling holes in the panel and performing electroless copper plating; S10, sequentially stacking the panel, the insulating layer, and the copper base plate, and hot-pressing to form a composite board. This application avoids contact between the copper foil layer and the thermally conductive copper platform by forming a lateral protrusion that wraps around the sidewalls of the copper foil layer windows.

Description

Technical Field

[0001] This application relates to the field of copper-based circuit board manufacturing technology, and in particular to a four-layer thermally separated copper substrate and its manufacturing process. Background Technology

[0002] With the rapid development of the electronics industry, especially the new energy and AI industries, the power of electronic components is increasing, and the integration of electronic components is also required.

[0003] The copper substrate achieves thermal-electric separation by creating a thermally conductive copper platform on a copper base plate, placing a copper foil layer and an insulating layer on the copper base plate to separate the copper base plate and the copper foil layer, setting the circuit structure on the copper foil and dissipating heat through the copper plate.

[0004] With the rapid development of the electronics industry, the circuit structures of electronic components are becoming increasingly complex. Existing single-layer copper substrates cannot accommodate complex circuit structures, or if complex circuit structures are implemented, they cannot meet the demands for high integration of electronic components. Multilayer thermoelectrically separated copper substrates are gradually replacing single-layer copper substrates.

[0005] When forming windows that penetrate each layer using mechanical or laser methods after multilayer thermoelectric separation copper substrates are completed, it is difficult to control the depth of the windows. Furthermore, the copper foil layer on the sidewall of the window will be exposed, which can easily lead to contact between the copper foil layer and the thermally conductive copper platform in subsequent processes, resulting in short circuits in the copper substrate and causing safety risks.

[0006] Therefore, it is necessary to propose a four-layer circuit thermoelectric separation copper substrate and its manufacturing process to improve the safety performance of the copper substrate, which has become an important technical problem that needs to be solved urgently. Summary of the Invention

[0007] This application provides a four-layer thermoelectric separation copper substrate and its manufacturing process, aiming to solve the problem that in the prior art, multi-layer thermoelectric separation copper substrates are prone to contact between the copper foil layer and the thermally conductive copper platform, which leads to short circuits in the copper substrate and induces safety risks.

[0008] To achieve the above objectives, this application proposes a fabrication process for a four-layer thermally separated copper substrate. The fabrication process includes the following steps: S1, opening windows in the copper foil layer and the insulating layer to accommodate the heat-conducting copper platform on the copper substrate; S2, sequentially stacking the copper foil layer, the insulating layer, and the copper foil layer to form a first press plate; S3, hot-pressing the first press plate to connect the insulating layer with the copper foil layers on both sides to form the first substrate, and deforming the portion of the insulating layer near the window to form a lateral protrusion that wraps around the sidewall of the copper foil layer window; S4, copper foil layers on both sides of the first substrate... S5. Etch circuits on the layer; S6. Sequentially stack copper foil layer, insulating layer, and first substrate, and repeat S3 to form second substrate; S7. Etch circuits on the copper foil layer of the second substrate away from the first substrate; S8. Sequentially stack copper foil layer, insulating layer, and second substrate, and repeat S3 to form panel; S9. Etch circuits on the copper foil layer of the panel away from the second substrate; S10. Drill holes in the panel and perform electroless copper plating; S11. Sequentially stack panel, insulating layer, and copper base plate, and hot press to form composite board.

[0009] In some embodiments, S1 specifically includes the following steps: S11, opening a first window adapted to a heat-conducting copper platform on a copper foil layer; S12, opening a second window adapted to a heat-conducting copper platform on an insulating layer, wherein the area of ​​the second window is smaller than that of the first window.

[0010] In some embodiments, the manufacturing steps of the copper base plate in S10 are as follows: S101, obtaining a copper plate blank; S102, attaching a photosensitive dry film to the surface of the copper plate blank, and exposing and developing the photosensitive dry film to cover the area corresponding to the heat-conducting copper platform; S103, etching the upper surface of the copper plate blank to form a heat-conducting copper platform; S104, removing the photosensitive dry film and performing a browning treatment on the copper plate blank.

[0011] In some embodiments, the stacking operations in S2, S5 and S7 above are performed on a stacking device, which specifically includes: a base plate, the base plate having a boss in a corresponding area that is the same as the heat-conducting copper stage; a top plate, the top plate having a clearance window in a corresponding area to avoid the boss, the top plate being disposed on the upper side of the base plate; and pins, the base plate, the top plate, the copper foil layer and the insulating layer all having positioning holes adapted to the pins.

[0012] In some embodiments, the lamination device further includes: a negative pressure chamber, the negative pressure chamber having a positioning hole adapted to the pin, the negative pressure chamber being disposed on the lower side of the base plate; an enlarged diameter portion, the pin including a constant diameter portion and an enlarged diameter portion, the enlarged diameter portion and the constant diameter portion forming an abutment surface of the positioning base plate; and a plurality of through holes, the base plate being provided with a plurality of through holes communicating with the negative pressure chamber at intervals.

[0013] In some embodiments, the stacking device further includes: an abutting nut, wherein the expanded diameter portion is provided with a thread adapted to the abutting nut, the abutting nut is screwed onto the expanded diameter portion and abuts against the negative pressure chamber; a plurality of protrusions, wherein a plurality of protrusions are provided on the base plate; and a plurality of grooves, wherein grooves adapted to the protrusions are provided at intervals on the negative pressure chamber.

[0014] In some embodiments, the stacking device further includes: an airbag disposed in a groove; an air inlet provided on the airbag; a valve body connected to the air inlet and disposed on a negative pressure chamber; a valve core movably disposed within the valve body; an elastic element disposed between the valve core and the valve body; a sealing surface provided within the valve body to adapt to the valve core; and an air inlet pipe connected to the valve body.

[0015] In some embodiments, the stacking device further includes: a mounting hole, wherein the boss is provided with a mounting hole; and a heating rod, wherein the heating rod is mounted in the mounting hole.

[0016] In some embodiments, the pin further includes a guide portion, one end of which is connected to the guide portion and the other end of which is connected to the guide portion.

[0017] Based on another objective of this application, this application also provides a four-layer circuit thermoelectric separation copper substrate, which is manufactured using the manufacturing process described above. The copper substrate includes: a copper base plate; a thermally conductive copper platform disposed on the copper base plate; multiple copper foil layers, which are vertically spaced on the copper base plate, with adjacent copper foil layers electrically connected, and the copper foil layers are etched with circuit structures; an insulating layer, which is disposed between the copper base plate and the copper foil layers adjacent to the copper base plate, and between adjacent copper foil layers; windows adapted to the thermally conductive copper platform are provided on the insulating layer and the copper foil layers; characterized in that an integrally formed side protrusion is wrapped on the side wall of the window of the copper foil layer, the side protrusion being made of the material of the insulating layer, and insulating and isolating the copper foil layer and the thermally conductive copper platform from each other.

[0018] This application proposes a four-layer thermally separated copper substrate fabrication process, which includes the following steps: S1, opening windows in the copper foil layer and the insulating layer to accommodate the heat-conducting copper platform on the copper substrate; S2, sequentially stacking the copper foil layer, the insulating layer, and the copper foil layer to form a first press plate; S3, hot-pressing the first press plate to connect the insulating layer with the copper foil layers on both sides to form the first substrate, and deforming the portion of the insulating layer near the window to form a lateral protrusion that wraps around the sidewall of the copper foil layer window; S4, the copper foil layers on both sides of the first substrate... The process involves: S5, sequentially stacking a copper foil layer, an insulating layer, and a first substrate, and repeating S3 to form a second substrate; S6, etching circuitry on the copper foil layer of the second substrate away from the first substrate; S7, sequentially stacking a copper foil layer, an insulating layer, and a second substrate, and repeating S3 to form a panel; S8, etching circuitry on the copper foil layer of the panel away from the second substrate; S9, drilling holes in the panel and performing electroless copper plating; S10, sequentially stacking the panel, an insulating layer, and a copper base plate, and hot-pressing to form a composite board. This application utilizes a technique of first creating windows in the copper foil layer and the insulating layer, and then performing hot-pressing to deform the insulating layer near the window, forming a lateral bulge that surrounds the sidewall of the copper foil layer window. This avoids contact between the copper foil layer and the thermally conductive copper platform, preventing short circuits, increased system error rates, communication failures, and control malfunctions. It effectively enhances the safety and stability of the copper substrate. By using semi-cured thermally conductive silicone to create an insulating layer, the heat generated on the copper foil layer and some components that are not suitable for thermally conductive copper platforms can be transferred between the insulating layer and the copper foil layer, and finally transferred to the copper base plate. The copper base plate dissipates the heat, ensuring the thermal stability of the four-layer thermally separated copper substrate. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 This is a technical roadmap of the fabrication process of a four-layer circuit thermoelectric separation copper substrate in one embodiment of this application;

[0021] Figure 2 This is a three-dimensional structural diagram of the stacked device in one embodiment of this application;

[0022] Figure 3 This is a cross-sectional view of a stacked device according to an embodiment of this application;

[0023] Figure 4 for Figure 3 Enlarged view of part A in the middle;

[0024] Figure 5 This is a three-dimensional structural diagram of the base plate in one embodiment of this application;

[0025] Figure 6 This is a cross-sectional view of the base plate in one embodiment of this application;

[0026] Figure 7 for Figure 6 Enlarged view of part B in the middle;

[0027] Figure 8 This is a front view of the finished plate in one embodiment of this application;

[0028] Figure 9 This is a cross-sectional view of the composite plate in one embodiment of this application;

[0029] Figure 10 for Figure 9 A magnified view of part C in the middle.

[0030] In the diagram: Plate area 11, Ring edge area 12, Copper base plate 111, Insulation layer 112, Side protrusion 113, Copper foil layer 114, Heat-conducting copper platform 115, Top plate 2, Second ring edge 21, Top plate area 22, Clearance window 23, Equal diameter section 31, Guide section 32, Expanded diameter section 33, Base plate 4, First ring edge 41, Boss 42, Mounting hole 421, Thermal contact 43, Second connecting part 431, Base plate area 44, Through hole 45, Protrusion 46, Heating rod 47, First connecting part 471, Negative pressure chamber 5, Air extraction pipe 51, Negative pressure chamber 52, Third ring plate 53, Air inlet pipe 54, Groove 55, Airbag 56, Air inlet 57, Valve body 58, Elastic element 59, Valve core 510, Sealing surface 511, Abutment nut 6, Positioning hole 7. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0034] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0035] Example 1

[0036] See Figure 1 As shown, the fabrication process of the four-layer thermally separated copper substrate of this application includes the following steps:

[0037] S1. Windows are made in the copper foil layer 114 and the insulating layer 112 to fit the heat-conducting copper platform 115 on the copper base plate 111. The windows in the copper foil layer 114 and the insulating layer 112 are made by laser cutting machine. Corresponding board areas 11 and edge areas 12 are provided on the copper foil layer 114 and the insulating layer 112. The positioning holes 7 on the copper foil layer 114 and the insulating layer 112 are all opened in the edge areas 12 to facilitate the positioning and clamping of the copper foil layer 114 and the insulating layer 112.

[0038] In this embodiment, the insulating layer 112 is preferably made of semi-cured thermally conductive silicone. Semi-cured thermally conductive silicone has excellent electrical insulation properties, and through its good thermal conductivity, it can quickly transfer heat to the copper base plate 111. During the operation of the copper substrate, the copper foil layer 114 in the non-thermal conductive copper platform 115 area will also generate a certain amount of heat. In addition, some components are not suitable for thermal conductive copper platforms 115, and the heat generated by these components cannot be transferred through the thermal conductive copper platforms 115. The insulating layer 112 made of semi-cured thermally conductive silicone can effectively conduct the heat generated on the copper foil layer 114 and some components that are not suitable for thermal conductive copper platforms 115, ensuring the thermal stability of the four-layer thermally separated copper substrate and extending the service life of the four-layer thermally separated copper substrate.

[0039] S2. Copper foil layer 114, insulating layer 112, and copper foil layer 114 are sequentially stacked to form a first pressing plate; S3. The first pressing plate is hot-pressed to connect the insulating layer 112 with the copper foil layers 114 on both sides to form a first substrate, and to deform the portion of the insulating layer 112 near the window to form a side protrusion 113 that wraps around the sidewall of the window of the copper foil layer 114; During the stacking process, the stacking equipment must ensure that the insulating layer 112 and the copper foil layers 114 on both sides are perfectly overlapped, and then the pressing equipment directly acts on the stacking equipment to make the copper foil layer 114, insulating layer 112, and copper foil layer 114 composite into the first substrate. Furthermore, due to the setting of the stacking equipment, the deformation direction of the insulating layer 112 can be restricted, and by… Windows are pre-cut into both the copper foil layer 114 and the insulating layer 112, allowing the portion of the insulating layer 112 near the window to deform under high temperature and pressure, forming a side protrusion 113 that wraps around the sidewall of the window in the copper foil layer 114. This prevents the copper foil layer 114 from contacting the heat-conducting copper platform 115. The copper foil layer 114 carries the circuit current, while the heat-conducting copper platform 115 is typically grounded or connected to a heat sink. Contact between the two would create a low-resistance path between different nodes in the circuit, potentially leading to a short circuit and safety risks. Even without a short circuit, it would introduce an additional grounding path or capacitive coupling to the copper substrate, resulting in severe distortion, crosstalk, reflection, and signal attenuation of high-speed digital or high-frequency analog signals. This could lead to increased system error rates, communication failures, and control malfunctions. The side protrusion 113 effectively enhances the safety and stability of the copper substrate.

[0040] S4. Etch the circuit on the copper foil layer 114 on both sides of the first substrate. During the etching process, the circuit design pattern on the copper foil layer 114 needs to be transferred to the photosensitive material first. Then, the photo-pattern is exposed on the copper foil layer 114 by ultraviolet light. The unexposed areas are removed by the developer to form the circuit pattern. The unwanted copper foil is dissolved by chemical solution (such as ferric chloride, copper sulfate, etc.). Finally, the chemical residues from the etching are removed to avoid affecting the subsequent processes. The required circuit structure can then be etched on the copper foil layer 114 on both sides of the first substrate.

[0041] S5. Copper foil layer 114, insulating layer 112, and first substrate are stacked sequentially, and S3 is repeated to form second substrate; S6. Circuits are etched on copper foil layer 114 of second substrate away from first substrate; S7. Copper foil layer 114, insulating layer 112, and second substrate are stacked sequentially, and S3 is repeated to form panel; S8. Circuits are etched on copper foil layer 114 of panel away from second substrate; The above stacking, hot pressing, and etching steps are the same as those mentioned in S2, S3, and S4, and will not be repeated here.

[0042] S9. Drill holes in the panel and perform copper plating. Using a rotating drill head, create blind or through holes of varying depths at different locations on the panel. These holes are used to connect different copper foil layers 114 or to mount electronic components. A high-precision CNC drilling machine can quickly and accurately drill the required holes on the circuit board. After drilling, copper is deposited into the hole walls using a copper plating process to form electrical connections within the holes. This ensures that current can be transmitted between the different layers of the panel through the copper foil layers 114.

[0043] S10. The panel, insulating layer 112, and copper base plate 111 are stacked sequentially and hot-pressed to form a composite board. The composite board then undergoes solder resist, text, shaping, surface treatment, inspection, and packaging processes to form the final finished copper substrate. Solder resist is a crucial process where a solder resist layer is applied to the circuit board to protect the copper foil layer 114 from oxidation and prevent short circuits during soldering. The solder resist layer is typically green. Text is the printing of characters onto the solder resist layer, used to identify components, pin numbers, and other important information on the copper substrate. This is essential for later assembly and maintenance. Surface treatments for the copper substrate typically include tin plating, gold plating, and immersion silver plating to improve solderability and prevent oxidation. Different surface treatments are suitable for different operating environments and cost requirements.

[0044] Specifically, this application employs a technique of first creating windows in the copper foil layer 114 and the insulating layer 112, and then performing lamination and hot pressing. This causes the portion of the insulating layer 112 near the window to deform, forming a side protrusion 113 that wraps around the sidewall of the window in the copper foil layer 114. This prevents the copper foil layer 114 from contacting the thermally conductive copper platform 115, thus avoiding short circuits, increased system error rates, communication failures, and control malfunctions. This effectively enhances the safety and stability of the copper substrate. By using semi-cured thermally conductive silicone to fabricate the insulating layer 112, the heat generated on the copper foil layer 114 and some components where the thermally conductive copper platform 115 is not suitable can be transferred between the insulating layer 112 and the copper foil layer 114, ultimately reaching the copper base plate 111. The copper base plate 111 then dissipates the heat, ensuring the thermal stability of the four-layer thermally separated copper substrate.

[0045] Among them, the use of layered lamination can effectively improve the quality of the final copper substrate.

[0046] In some embodiments, S1 specifically includes the following steps: S11, opening a first window adapted to the heat-conducting copper platform 115 on the copper foil layer 114; multiple first windows are provided, and the multiple first windows are spaced apart in the board area 11 of the copper foil layer 114. Preferably, when opening the first window, positioning holes 7 are simultaneously opened in the circumferential edge area 12 of the copper foil layer 114 to facilitate positioning during subsequent copper foil layer 114 stacking and pressing processes.

[0047] S12. A second window adapted to the heat-conducting copper platform 115 is opened on the insulating layer 112. The area of ​​the second window is smaller than that of the first window. Multiple second windows are provided, spaced apart in the sheet material area 11 of the insulating layer 112. Preferably, when opening the second window, positioning holes 7 are simultaneously opened in the circumferential edge area 12 of the insulating layer 112 to facilitate positioning during subsequent stacking and pressing of the insulating layer 112. Because the area of ​​the second window is smaller than that of the first window, during the hot pressing process, excess material of the insulating layer 112 can be effectively deformed to form a side protrusion 113, ensuring the stability of the side protrusion 113 formation.

[0048] In this embodiment, the second window is obtained by proportionally reducing the first window by 0.95-0.98 times. More preferably, the second window is obtained by proportionally reducing the first window by 0.95 times. This reduction ratio can better promote the formation of the lateral protrusion 113.

[0049] In some embodiments, the manufacturing steps of the copper base plate 111 in S10 are as follows: S101, obtaining a copper plate blank; S102, attaching a photosensitive dry film to the surface of the copper plate blank, and exposing and developing the photosensitive dry film to cover the area corresponding to the thermally conductive copper platform 115; S103, etching the upper surface of the copper plate blank to form the thermally conductive copper platform 115; S104, removing the photosensitive dry film and performing a browning treatment on the copper plate blank. In this embodiment, the thermally conductive copper platform 115 can also be formed on the copper plate blank by milling grooves, and the specific forming method of the thermally conductive copper platform 115 is not specifically limited here.

[0050] See Figure 2 , Figure 3 and Figure 5As shown, in some embodiments, the stacking operations in S2, S5, and S7 are performed on a stacking device, which specifically includes: a base plate 4, which has a boss 42 in a corresponding area that is the same as the heat-conducting copper platform 115; the base plate 4 is placed on a hot press, and the pressing block of the hot press has a clearance hole for avoiding the boss 42; a top plate 2, which has a clearance window 23 in a corresponding area for avoiding the boss 42; the top plate 2 is located on the upper side of the base plate 4; both the base plate 4 and the top plate 2 are metal plates, preferably high-temperature resistant stainless steel plates; the base plate 4 and the top plate 2 are formed on a milling machine; each type of copper substrate corresponds to one base plate 4 and one top plate 2; and pins, which have positioning holes 7 for matching pins in the base plate 4, the top plate 2, the copper foil layer 114, and the insulating layer 112; the hot press has fixing holes for fixing pins; and the pressing block of the hot press has clearance holes for avoiding pins. In step S2, the bottom copper foil layer 114 is first placed on the bottom plate 4, followed by the insulating layer 112, and finally another copper foil layer 114. The top plate 2 is then placed over the top copper foil layer 114. At this point, the insulating layer 112 is connected to the copper foil layers 114 on both sides using a pressing block in a hot press. The lamination steps in steps S5 and S7 are similar to those in step S2 and will not be repeated here. The design of the pins and positioning holes effectively ensures the overlap between the copper foil layer 114 and the insulating layer 112. By mimicking the protrusion 42 structure of the heat-conducting copper platform 115, the deformation direction of the insulating layer 112 is effectively limited, allowing it to deform along the thickness direction of the window sidewall of the copper foil layer 114. The top plate 2 prevents the insulating layer 112 from overflowing the window of the copper foil layer 114. The side protrusion 113 effectively covers the sidewall of the copper foil layer 114 window, effectively isolating the copper foil layer 114 and the thermally conductive copper platform 115, thus preventing short circuits, increased system error rates, communication failures, control malfunctions, and other issues. This effectively enhances the safety and stability of the copper substrate.

[0051] In this embodiment, the base plate 4 includes a base plate material area 44 and a first ring edge 41, and the top plate 2 includes a top plate material area 22 and a second ring edge 21. Positioning holes 7 are all disposed on the first ring edge 41 and the second ring edge 21. Bosses 42 are spaced apart in the base plate material area 44, and clearance windows 23 are spaced apart in the top plate material area 22.

[0052] The base plate 4 has anti-slip textures in the area facing the top plate 2 and near the protrusion 42, and the top plate 2 has anti-slip textures in the area facing the base plate 4 and near the clearance window 23. This anti-slip texture design firstly enhances the contact force between the top plate 2 and the base plate 4 and the copper foil layer 114, preventing the copper foil layer 114 from slipping under pressure, causing wrinkles, affecting the quality of the final copper substrate, and even leading to defective boards. Secondly, the anti-slip texture design can create grooves 55 on the upper or lower surface of the side protrusions 113, further enhancing the contact force between adjacent side protrusions 113, thereby improving the stability of the final copper substrate.

[0053] See Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, in some embodiments, the lamination device further includes: a negative pressure chamber 5, which has positioning holes adapted to the pins, and is located on the lower side of the base plate 4. The negative pressure chamber 5 includes a negative pressure compartment 52 and a third ring plate 53, which are welded together. The positioning holes are located on the third ring plate 53. An enlarged diameter portion 33 is also included, where the pin includes a constant diameter portion 31 and an enlarged diameter portion 33. The enlarged diameter portion 33 and the constant diameter portion 31 form an abutment surface for positioning the base plate 4. The abutment surface restricts the installation position of the base plate 4 and the negative pressure chamber 5. A plurality of through holes 45 are provided at intervals on the base plate 4, communicating with the negative pressure chamber 5. By creating negative pressure within the negative pressure compartment 52, the copper foil is adsorbed, preventing the bottom copper foil layer 114 from sliding under high temperature and pressure, causing interlayer misalignment, affecting the alignment accuracy of the copper substrate, and potentially even resulting in scrap.

[0054] In this embodiment, the negative pressure chamber 52 is equipped with an extraction pipe 51, which is connected to a cooling tank. The cooling tank is connected to a vacuum pump, which maintains the negative pressure inside the negative pressure chamber 52. The cooling tank prevents high-temperature gas from directly entering the vacuum pump, thus extending the service life of the vacuum pump.

[0055] The diameter of the through-hole 45 is related to the thickness of the copper foil layer 114. When the thickness of the copper foil layer 114 is greater than 12 μm, the diameter of the through-hole 45 is 100 μm, and the gap between two adjacent through-holes 45 is about 400 μm. When the thickness of the copper foil layer 114 is greater than 6 μm and less than or equal to 12 μm, the diameter of the through-hole 45 is 60 μm, and the gap between two adjacent through-holes 45 is about 300 μm. When the thickness of the copper foil layer 114 is less than 6 μm, the diameter of the through-hole 45 is 20 μm, and the gap between two adjacent through-holes 45 is about 200 μm.

[0056] The diameter of the through-hole 45 in the bottom plate material area 44 is smaller than the diameter of the through-hole 45 in the first ring edge area 12. This is to compensate for edge airflow loss during the pressing process and improve the overall adsorption uniformity.

[0057] See Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, the stacking device further includes: an abutment nut 6, an expanded diameter portion 33 having threads adapted to the abutment nut 6, the abutment nut 6 being screwed onto the expanded diameter portion 33 and abutting against the negative pressure cavity 5; during the pressing process, the base plate 4 is subjected to downward pressure, the abutment nut 6 and the expanded diameter portion 33 are used to support the negative pressure cavity 5 and the base plate 4, ensuring tight contact between the negative pressure cavity 5 and the base plate 4 while reducing the contact force at the abutment surface. A plurality of protrusions 46 are provided on the base plate 4; the protrusions 46 are rectangular annular protrusions 46, the size of the plurality of protrusions 46 is proportionally enlarged, and the plurality of protrusions 46 are all located at the bottom of the first ring edge 41; a plurality of grooves 55 are provided at intervals on the negative pressure cavity 5 to adapt to the protrusions 46. The grooves 55 are rectangular annular grooves 55 to adapt to the protrusions 46, and the plurality of grooves 55 are all located at the top of the third ring edge. Through the cooperation of the protrusions 46 and the grooves 55, the sealing between the negative pressure cavity 5 and the base plate 4 is ensured.

[0058] See Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, the lamination device further includes an airbag 56, which is disposed within a groove 55. The airbag 56 is made of aramid fiber 1313 to enable it to withstand high temperature and high pressure environments. During the hot pressing process, the temperature is below 180°C and the pressure is between 350 and 420°C. The gas has a pressure of psi and the aramid 1313 has excellent elasticity; an air inlet 57 is provided on the air bladder 56 to inject gas into the air bladder 56; a valve body 58 is connected to the air inlet 57 and is located on the negative pressure chamber 5; a valve core 510 is movably disposed within the valve body 58; an elastic element 59 is disposed between the valve core 510 and the valve body 58; a sealing surface 511 is provided inside the valve body 58 to adapt to the valve core 510; during the gas injection process, the gas pressure drives the valve core 510 to move towards the air inlet 57, thereby driving the valve core 510 to disengage from the sealing surface, at which time gas can be injected; when the gas injection stops, the valve core 510 moves towards the sealing surface under the action of the internal pressure of the air bladder 56, and the cooperation between the valve core 510 and the sealing surface prevents gas leakage. An air inlet pipe 54 is connected to the valve body 58. The air intake pipe 54 is used to inject gas. The airbag 56 further enhances the seal between the negative pressure chamber 5 and the base plate 4, ensuring stable and effective adsorption of the copper foil layer 114.

[0059] In this embodiment, the valve body 58 includes a first sub-valve body 58 and a second sub-valve body 58. The valve core 510 is partially movably disposed within the second sub-valve body 58, and a sealing surface 511 is provided within the first sub-valve body 58. The first sub-valve body 58 and the second sub-valve body 58 are welded together.

[0060] The gas filled in the airbag 56 is preferably helium, which has good stability and thermal expansion properties. During the operation of the airbag 56, the high temperature and high pressure environment provided by the pressure block facilitates the deformation of the airbag 56 under pressure, effectively filling the gap between the pressure chamber and the base plate 4, enhancing the sealing between the negative pressure chamber 5 and the base plate 4, and ensuring stable and effective adsorption of the copper foil layer 114. Under the high temperature environment, both the negative pressure chamber 5 and the base plate 4 will undergo different degrees of thermal deformation. Under the action of this thermal deformation, new gaps will be generated between the negative pressure chamber 5 and the base plate 4, or the previous gaps will increase. At this time, the helium in the airbag 56 expands under the action of high temperature, further filling the gaps generated by thermal deformation, enhancing the sealing between the negative pressure chamber 5 and the base plate 4, and ensuring stable and effective adsorption of the copper foil layer 114.

[0061] See Figure 2 , Figure 3 , Figure 6 and Figure 7 As shown, in some embodiments, the lamination device further includes: a mounting hole 421, with the boss 42 having the mounting hole 421; the mounting hole 421 is drilled by a drilling device. A heating rod 47 is mounted in the mounting hole 421. The heating rod 47 includes a first connecting portion 471, a heating section, and a tail. The tail is used to connect to a power source, and the first connecting portion 471 is used to form a connection with the mounting hole 421. The connection method between the first connecting portion 471 and the mounting hole 421 can be one or a combination of adhesive bonding and screwing. Due to the setting of the negative pressure chamber 5, it becomes more difficult for the heat generated by the hot pressing device to be transferred to the copper foil layer 114 and the insulating layer 112. The heating rod 47 can effectively heat the copper foil layer 114 and the insulating layer 112, allowing the copper foil layer 114 and the insulating layer 112 to reach the working temperature.

[0062] In this embodiment, a thermal contact 43 is provided within a portion of the mounting hole 421. The thermal contact 43 includes a second connecting portion 431, which connects to the mounting hole 421. The connection between the second connecting portion 431 and the mounting hole 421 can be achieved through bonding, screwing, or a combination of both. The thermal contact 43 is used to detect the temperature of the copper foil layer 114 and the insulating layer 112, preventing overheating.

[0063] See Figure 2 and Figure 3As shown, in some embodiments, the pin further includes a guide portion 32, one end of the equal diameter portion 31 is connected to the guide portion 32, and the other end of the equal diameter portion 31 is connected to the guide portion 32. The guide portion 32 facilitates the insertion of the pin into the positioning holes on the base plate 4, the copper foil layer 114, the insulating layer 112, and the top plate 2.

[0064] Example 2

[0065] In this embodiment, the parts that are the same as in Embodiment 1 are given the same reference numerals, and the same text descriptions are omitted.

[0066] See Figure 8 , Figure 9 and Figure 10 As shown, this embodiment discloses a four-layer thermally separated copper substrate. The copper substrate is manufactured using the process described in Embodiment 1. The copper substrate includes: a copper base plate 111; a thermally conductive copper platform 115 disposed on the copper base plate 111; multiple copper foil layers 114, which are vertically spaced along the copper base plate 111 and electrically connected to adjacent copper foil layers 114, with circuit structures etched on the copper foil layers 114; an insulating layer 112; and the copper base plate 111. An insulating layer 112 is provided between the copper foil layer 114 adjacent to the copper base plate 111 and the insulating layer 112 is provided between two adjacent copper foil layers 114. Windows adapted to the heat-conducting copper platform 115 are provided on the insulating layer 112 and the copper foil layer 114. The feature is that an integrally formed side protrusion 113 is wrapped on the side wall of the window of the copper foil layer 114. The side protrusion 113 is made of the same material as the insulating layer 112 and insulates the copper foil layer 114 from the heat-conducting copper platform 115. The multi-layered copper foil layer 114 can be configured with complex and intricate circuit structures to meet the complex wiring requirements of electronic components. Some electronic components contact the copper base plate 111 through the heat-conducting copper platform 115. The heat generated by the electronic components during operation is absorbed by the copper base plate 111 and dissipated through heat exchange between the copper base plate 111 and the external environment, meeting the rapid heat dissipation requirements of the electronic components. A side protrusion 113 is provided between the copper foil layer 114 and the thermally conductive copper platform 115 to prevent the copper foil layer 114 from contacting the thermally conductive copper platform 115. The copper foil layer 114 carries the circuit current, while the thermally conductive copper platform 115 is usually grounded or connected to a heat sink. Contact between the two is equivalent to establishing a low-resistance path between different nodes of the circuit, which can lead to a short circuit and induce safety risks. Even if a short circuit does not occur, it will introduce an additional grounding path or capacitive coupling to the copper substrate, resulting in severe distortion, crosstalk, reflection, and signal attenuation of high-speed digital signals or high-frequency analog signals. This may lead to an increase in the system's bit error rate, communication failure, and control malfunction. The side protrusion 113 can effectively enhance the safety and stability of the copper substrate.

[0067] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A fabrication process for a four-layer thermally separated copper substrate, characterized in that, The manufacturing process includes the following steps: S1. Open windows in the copper foil layer (114) and the insulating layer (112) to fit the thermally conductive copper platform (115) on the copper base plate (111). S2. Copper foil layer (114), insulating layer (112), and copper foil layer (114) are stacked in sequence to form the first plate to be pressed. S3. Press the first platen to be pressed to connect the insulating layer (112) with the copper foil layers (114) on both sides to form the first substrate, and deform the part of the insulating layer (112) near the window to form a side protrusion (113) that wraps the side wall of the window of the copper foil layer (114). S4. Etch lines on the copper foil layers (114) on both sides of the first substrate; S5. Copper foil layer (114), insulating layer (112) and first substrate are stacked in sequence, and S3 is repeated to form second substrate; S6. Etch a circuit on the copper foil layer (114) of the second substrate away from the first substrate; S7. Copper foil layer (114), insulating layer (112) and second substrate are stacked in sequence, and S3 is repeated to form a panel; S8. Etch a circuit on the copper foil layer (114) of the panel away from the second substrate; S9. Drill holes in the panel and perform copper plating. S10. The panel, the insulating layer (112), and the copper base plate (111) are stacked in sequence and hot-pressed to form a composite board. The stacking operations in S2, S5, and S7 described above are performed on a stacking device, which specifically includes: The base plate (4) has a boss (42) in the corresponding area that is the same as the heat-conducting copper platform (115). Top plate (2), the top plate (2) is provided with a clearance window (23) in the corresponding area to avoid the boss (42), the top plate (2) is located on the upper side of the bottom plate (4); The base plate (4), the top plate (2), the copper foil layer (114) and the insulating layer (112) are all provided with positioning holes (7) adapted to the pin. The stacking device further includes: The negative pressure chamber (5) is provided with a positioning hole (7) adapted to the pin, and the negative pressure chamber (5) is located on the lower side of the base plate (4); The pin includes an enlarged diameter portion (33) and an equal diameter portion (31) and the enlarged diameter portion (33), and the enlarged diameter portion (33) and the equal diameter portion (31) form an abutment surface for positioning the base plate (4); A plurality of through holes (45) are provided on the bottom plate (4) at intervals to connect the negative pressure chamber (5). The stacking device further includes: The abutting nut (6) is provided with a thread adapted to the abutting nut (6) and the abutting nut (6) is screwed into the expanded diameter part (33) and abuts against the negative pressure chamber (5). A plurality of protrusions (46) are provided on the base plate (4). Several grooves (55) are provided on the negative pressure chamber (5) at intervals to adapt to the protrusion (46). The stacking device further includes: An airbag (56) is disposed within the groove (55); Air inlet (57), the airbag (56) is provided with the air inlet (57); Valve body (58), the air inlet (57) is connected to the valve body (58), and the valve body (58) is disposed on the negative pressure chamber (5); Valve core (510), which is movably disposed within the valve body (58); The elastic element (59) is disposed between the valve core (510) and the valve body (58). The valve body (58) is provided with a sealing surface (511) adapted to the valve core (510). An air intake pipe (54) is connected to the valve body (58).

2. The fabrication process of the four-layer circuit thermoelectric separation copper substrate according to claim 1, characterized in that, The above S1 specifically includes the following steps: S11. A first window adapted to the heat-conducting copper platform (115) is opened on the copper foil layer (114); S12. A second window adapted to the heat-conducting copper platform (115) is opened on the insulating layer (112), and the area of ​​the second window is smaller than that of the first window.

3. The fabrication process of the four-layer circuit thermoelectric separation copper substrate according to claim 1, characterized in that, The specific steps for manufacturing the copper base plate (111) in S10 above are as follows: S101. Obtain the copper plate blank; S102, attach a photosensitive dry film to the surface of the copper plate blank, and expose and develop the photosensitive dry film to cover the area corresponding to the thermally conductive copper platform (115); S103. The upper surface of the copper plate blank is etched to form the thermally conductive copper platform (115). S104. Remove the photosensitive dry film and perform browning treatment on the copper plate blank.

4. The fabrication process of the four-layer circuit thermoelectric separation copper substrate according to claim 1, characterized in that, The stacking device further includes: Mounting hole (421), the boss (42) is provided with mounting hole (421). A heating rod (47) is installed in the mounting hole (421).

5. The fabrication process of the four-layer circuit thermoelectric separation copper substrate according to claim 1, characterized in that, The pin also includes: Guide portion (32), one end of the equal diameter portion (31) is connected to the guide portion (32), and the other end of the equal diameter portion (31) is connected to the guide portion (32).

6. A four-layer thermally separated copper substrate, wherein the copper substrate is manufactured using any one of the manufacturing processes described in claims 1 to 5, and the copper substrate comprises: Copper base plate (111); A heat-conducting copper platform (115) is disposed on the copper base plate (111); Multiple copper foil layers (114) are arranged vertically on the copper base plate (111), and two adjacent copper foil layers (114) are electrically connected. The copper foil layers (114) are etched with circuit structures. An insulating layer (112) is provided between the copper base plate (111) and the copper foil layer (114) adjacent to the copper base plate (111), and an insulating layer (112) is provided between two adjacent copper foil layers (114). The insulating layer (112) and the copper foil layer (114) are provided with windows adapted to the heat-conducting copper platform (115); characterized in that an integrally formed side protrusion (113) is wrapped on the side wall of the window of the copper foil layer (114), the side protrusion (113) is made of the material of the insulating layer (112), and the copper foil layer (114) and the heat-conducting copper platform (115) are mutually insulated and isolated.

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