Mixed-voltage circuit board and preparation method thereof
By setting daughter boards with different dielectric constants in the mixed circuit board and filling the plug material with consistent plugs, the problem of high-speed signal impedance jump is solved and the signal quality is improved.
Patent Information
- Application Number
- CN202510329684.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-07-01
AI Technical Summary
In circuit boards with asymmetric laminated structures, the impedance of high-speed signals will jump, affecting signal integrity and signal quality.
By setting the first and second daughter boards with different dielectric constants in the mixed circuit board, and opening the reverse pad holes on the second daughter board to fill the plug-in material consistent with the dielectric constant of the first daughter board, a high-speed signal hole passing through the daughter board is formed to avoid impedance jump.
It effectively maintains the impedance consistency of high-speed signal holes and improves the signal quality of high-speed signal transmission in network equipment.
Smart Images
Figure CN120239168A_ABST
Abstract
Description
Technical Field
[0001] This specification relates to the field of electronic technology, and in particular, to a hybrid pressure circuit board and a preparation method thereof. Background Art
[0002] With the development of network technology, the demand for network transmission speed has gradually increased. The lines formed on the circuit board of network devices are divided into high-speed signal lines for fast data interaction, low-speed signal lines for management and control, and power supply lines for power supply, etc. In order to improve the current-carrying capacity and signal integrity on the circuit board, an asymmetric stacked structure has emerged, which is formed by laminating a high-speed sub-board and a low-speed sub-board made of different base materials.
[0003] However, in order to achieve the reliability of fast data interaction in the circuit board, it is necessary to maintain the impedance consistency of high-speed signals. In an asymmetric stacked structure, since high-speed signals need to pass through the high-speed sub-board and the low-speed sub-board, under other unchanged conditions, the impedance of high-speed signals will jump, affecting the signal integrity of high-speed signal transmission and reducing the signal quality of high-speed signals on network devices. Summary of the Invention
[0004] To overcome the problems existing in the related art, this specification provides a hybrid pressure circuit board and a preparation method thereof.
[0005] According to the first aspect of the embodiments of this specification, a hybrid pressure circuit board is provided, including:
[0006] A first sub-board;
[0007] A second sub-board, where the dielectric constant of the base material of the first sub-board is less than the dielectric constant of the base material of the second sub-board;
[0008] An adhesive layer, clamped between the first sub-board and the second sub-board, and adhesively bonded to the first sub-board and the second sub-board respectively;
[0009] Wherein, a high-speed signal hole passing through the first sub-board and the second sub-board is formed on the hybrid pressure circuit board, an anti-pad hole corresponding to the high-speed signal hole is drilled on the periphery of the high-speed signal hole, and a plugging material is filled in the anti-pad hole, and the dielectric constant of the plugging material is consistent with the dielectric constant of the base material of the first sub-board.
[0010] Optionally, the dielectric constant of the adhesive material of the adhesive layer is consistent with the dielectric constant of the base material of the first sub-board.
[0011] According to the second aspect of the embodiments of this specification, a preparation method of a hybrid pressure circuit board is provided, including:
[0012] Prepare circuit patterns on a number of first core boards, press them to form a first pressed board, and drill first high-speed signal holes in the first pressed board to form a first sub-board;
[0013] Prepare circuit patterns on a number of second core boards, press them to form a second pressed board, drill anti-pad holes in the second pressed board, and fill the anti-pad holes with plugging materials to form a second sub-board, wherein the dielectric constant of the substrate of the first core board is less than the dielectric constant of the substrate of the second core board, and the dielectric constant of the plugging material is consistent with the dielectric constant of the first core board;
[0014] Clamp a prepreg between the first sub-board and the second sub-board and press them to form a third pressed board, wherein the prepreg forms an adhesive layer;
[0015] On the third pressed board, drill second high-speed signal holes passing through the first sub-board and the second sub-board corresponding to the anti-pad holes of the second sub-board to form a mixed-pressed circuit board.
[0016] Optionally, the dielectric constant of the adhesive material of the adhesive layer is consistent with the dielectric constant of the first sub-board.
[0017] Optionally, the step of preparing circuit patterns on a number of first core boards, pressing them to form a first pressed board, and drilling first high-speed signal holes in the first pressed board to form a first sub-board includes:
[0018] Prepare circuit patterns on a number of first core boards and press them to form a first pressed board;
[0019] Drill first through-holes in the first pressed board, metallize the first through-holes to form first metallized through-holes;
[0020] Back-drill and plug the first metallized through-holes to form first high-speed signal holes, and prepare a first sub-board.
[0021] Optionally, the step of drilling second high-speed signal holes passing through the first sub-board and the second sub-board corresponding to the anti-pad holes of the second sub-board on the third pressed board to form a mixed-pressed circuit board includes:
[0022] On the third pressed board, drill second through-holes passing through the first sub-board and the second sub-board corresponding to the anti-pad holes of the second sub-board, and metallize the second through-holes to form second metallized through-holes;
[0023] Back-drill and plug the second metallized through-holes to form second high-speed signal holes, and prepare a mixed-pressed circuit board.
[0024] Optionally, the diameter of the back-drilled hole is smaller than the diameter of the anti-pad hole.
[0025] Optionally, before forming the hybrid laminate circuit board, it further includes:
[0026] Attach copper layers to the top and bottom surfaces of the third laminate, and etch via pads.
[0027] Optionally, before forming the hybrid laminate circuit board, it further includes:
[0028] Drill low-speed signal holes, power supply holes, and ground holes in the third laminate.
[0029] Optionally, before forming the second sub-board, it further includes:
[0030] Drill low-speed signal holes, power supply holes, and ground holes in the second laminate.
[0031] The technical solutions provided in the embodiments of this specification may include the following beneficial effects:
[0032] In the embodiments of this specification, a first sub-board and a second sub-board with different dielectric constants of the base material are provided in the hybrid laminate circuit board, and they are bonded through an adhesive layer. At the positions where high-speed signal holes need to be set to pass through the first sub-board and the second sub-board, anti-pad holes are opened in the second sub-board with a higher dielectric constant, and the anti-pad holes are filled with plugging materials having the same dielectric constant as the base material of the first sub-board, so that the high-speed signal holes passing through the first sub-board and the second sub-board can avoid the problem of impedance jump and improve the signal quality of high-speed signal transmission in the network device.
[0033] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this specification. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The drawings here are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with this specification, and are used together with the specification to explain the principles of this specification.
[0035] Figure 1 is a schematic structural diagram of a hybrid laminate circuit board involved in the present application;
[0036] Figure 2 is a schematic structural diagram of the second sub-board in the preparation process of a hybrid laminate circuit board involved in the present application;
[0037] Figure 3 is a flowchart of a method for manufacturing a hybrid laminate circuit board involved in the present application;
[0038] Figure 4 is a schematic structural diagram of the preparation of the first sub-board in a method for manufacturing a hybrid laminate circuit board involved in the present application, where Figure 4 (A) is a schematic diagram of drilling through holes after forming the first laminate,Figure 4 (B) is a schematic diagram after metallizing the via holes, Figure 4 (C) is a schematic diagram after back drilling the metallized via holes;
[0039] Figure 5 It is a schematic structural diagram of the preparation of the second sub - board in a method for preparing a hybrid - pressed circuit board involved in the present application. Among them, Figure 5 (A) is a schematic diagram of drilling via holes after forming the second press - bonded board, Figure 5 (B) is a schematic diagram after metallizing the via holes;
[0040] Figure 6 It is a schematic structural diagram of preparing a hybrid - pressed circuit board after pressing the first sub - board and the second sub - board in a method for preparing a hybrid - pressed circuit board involved in the present application. Among them, Figure 6 (A) is a schematic diagram of drilling via holes after forming the third press - bonded board, Figure 6 (B) is a schematic diagram after metallizing the via holes. Detailed implementation manners
[0041] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with this specification. On the contrary, they are merely examples of devices and methods consistent with some aspects of this specification as detailed in the appended claims.
[0042] The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this specification. The singular forms "a", "the" and "said" used in this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.
[0043] It should be understood that although the terms first, second, third, etc. may be used in this specification to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this specification, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".
[0044] The present application provides a hybrid - pressed circuit board 100, as Figure 1 shown, including:
[0045] The first sub-board 1;
[0046] The second sub-board 2, the dielectric constant of the base material of the first sub-board 1 is less than the dielectric constant of the base material of the second sub-board 2;
[0047] The adhesive layer 3 is clamped between the first sub-board 1 and the second sub-board 2 and is respectively bonded to the first sub-board 1 and the second sub-board 2. The adhesive layer 3 can be formed after the semi-cured sheet applied during the pressing of the first sub-board 1 and the second sub-board 2 melts and is shaped;
[0048] Among them, a high-speed signal hole 40 passing through the first sub-board 1 and the second sub-board 2 is formed on the hybrid multilayer circuit board 100. An anti-pad hole 41 corresponding to the high-speed signal hole 40 is drilled on the periphery of the high-speed signal hole 40, and a plugging material is filled in the anti-pad hole 41. The dielectric constant of the plugging material is consistent with the dielectric constant of the base material of the first sub-board 1. The so-called consistent dielectric constant here can mean that the dielectric constants of the materials are similar or the same. Taking avoiding impedance jump when the high-speed signal hole 40 passes through as the standard, it is best to use materials with the same dielectric constant.
[0049] The hybrid multilayer circuit board 100 refers to a circuit board formed by pressing sub-boards formed based on different base materials. The base material can refer to the insulating material during the preparation of the circuit board, and the circuit pattern is prepared on this base material.
[0050] A high-speed signal hole 40 can be formed on the hybrid multilayer circuit board 100. The high-speed signal hole 40 can be divided into a high-speed signal blind hole 40A, a high-speed signal via hole 40B, etc. Among them, the high-speed signal blind hole 40A can be formed on the first sub-board 1, and the high-speed signal via hole 40B can pass through the first sub-board 1 and the second sub-board 2.
[0051] On the hybrid multilayer circuit board 100, low-speed signal holes 42, current-carrying holes 43, ground holes 44, etc. can also be formed, which can be set according to actual requirements without limitation. On the hybrid multilayer circuit board 100, a plurality of current-carrying layers, ground layers, and signal layers are formed. The signal layer can be connected to the low-speed signal hole 42 and / or the high-speed signal hole 40 according to requirements to achieve the transmission of high-speed signals and / or low-speed signals. The current-carrying layer is connected to the current-carrying hole 43 to transmit power supply to the required position, and the ground layer is connected to the ground hole to achieve shielding between signal layers and shielding between the high-speed signal hole 40 and the low-speed signal hole 42. At the positions where the low-speed signal hole 42 and the high-speed signal hole 40 cross the ground layer and the current-carrying layer in the hybrid multilayer circuit board 100, anti-pads need to be formed. Anti-pads also need to be set when the current-carrying hole 43 passes through the ground layer and the ground hole 44 passes through the current-carrying layer. The anti-pad refers to an isolation area formed on the layer being penetrated with a diameter larger than the diameter of the via passing through the layer. According to the different vias, the anti-pad can be formed into a circular shape, a strip shape, or other required shapes.
[0052] In the structure of the hybrid multilayer circuit board 100, the dielectric constant of the base material of the first sub-board 1 is relatively low, and the dielectric constant of the base material of the second sub-board 2 is relatively high. When a signal hole passes through the first sub-board 1 and the second sub-board 2, impedance jump of the signal hole will occur. Due to the impedance sensitivity of the high-speed signal hole 40, therefore, when the high-speed signal hole 40 passes through the first sub-board 1 and the second sub-board 2 with different dielectric constants, it is necessary to maintain the impedance of the high-speed signal hole 40 consistent. To solve the impedance consistency of the high-speed signal hole 40, when preparing the second sub-board 2, as Figure 2 shown, it is necessary to drill an anti-pad hole 41 at the position where the high-speed signal hole 40 passes through, and use a plugging material with the same dielectric constant as the base material of the first sub-board 1 to plug the anti-pad hole 41, so as to achieve impedance consistency at the part corresponding to the high-speed signal hole 40 passing through the second sub-board 2 on the second sub-board 2. After laminating the first sub-board 1 and the second sub-board 2, when drilling the high-speed signal hole 40, drill a hole from the first sub-board 1 to the second sub-board 2 at the position of the anti-pad hole 41, and form the high-speed signal hole 40 (i.e., the high-speed signal via 40B) through processes such as metallization, so as to ensure the impedance consistency of the high-speed signal hole 40 on the hybrid multilayer circuit board 100 and improve the signal quality of high-speed signal transmission on the network device applying this hybrid multilayer circuit board.
[0053] Optionally, the dielectric constant of the bonding material of the bonding layer 3 is the same as the dielectric constant of the base material of the first sub-board 1.
[0054] After the first sub-board 1 and the second sub-board 2 are prepared, it is necessary to laminate them by clamping a prepreg between the first sub-board 1 and the second sub-board 2. After lamination, the prepreg will form the bonding layer 3.
[0055] When the high-speed signal holes 40 pass through the first sub-board 1 and the second sub-board 2, they also need to pass through the adhesive layer 3. Therefore, impedance jumps may also occur when the high-speed signal holes 40 pass through the adhesive layer 3. To avoid the above problems, the dielectric constant of the adhesive material selected for the adhesive layer 3 can also be consistent with the dielectric constant of the base material of the first sub-board 1, so as to avoid impedance jumps when the high-speed signal holes 40 pass through the adhesive layer 3 over a short distance, and further improve the signal quality of high-speed signal transmission in the network device.
[0056] Correspondingly, the present application also provides a method for manufacturing a hybrid-pressure circuit board, as Figure 3 shown, including:
[0057] S300. Prepare circuit patterns on a number of first core boards, press them to form a first pressed board, and drill first high-speed signal holes in the first pressed board to form a first sub-board.
[0058] A circuit board is generally formed by pressing core boards, and the core board may refer to a board including a base material and copper-clad layers attached to both sides of the base material. Before pressing, board manufacturing processes such as coating photoresist, exposure, development, and etching need to be performed on the core board to form circuit patterns on the core board.
[0059] Specifically, the step S300. Prepare circuit patterns on a number of first core boards, press them to form a first pressed board, and drill first high-speed signal holes in the first pressed board to form a first sub-board, includes:
[0060] S300A. Prepare circuit patterns on a number of first core boards and press them to form a first pressed board.
[0061] S300B. Drill first through-holes in the first pressed board, metallize the first through-holes to form first metallized through-holes.
[0062] S300C. Back-drill and plug the holes of the first metallized through-holes to form first high-speed signal holes, and prepare the first sub-board.
[0063] As Figure 4 shown, for the preparation of the first sub-board 1, first core boards can be used for preparation, and after the preparation of the circuit patterns is completed, they are pressed to form a first pressed board 101, as Figure 4 (A) shown. After the first pressed board 101 is formed, first through-holes 40C are drilled in the first pressed board 101, and first metallized through-holes 40D are formed through processes such as metallization, as Figure 4(As shown in (B), these vias are for the first sub-board 1. In subsequent processes, after laminating to form the hybrid laminate circuit board 100, the vias can be formed into blind vias according to requirements. Of course, in some cases, the low-speed signal holes 42, current-carrying holes 43, and grounding holes 44 can also be formed into blind vias in the form of vias and can be set according to actual requirements without limitation.)
[0064] After the vias undergo processes such as metallization to form the first high-speed signal holes, the first high-speed signal holes can be understood as the high-speed signal blind holes 40A formed on the subsequent hybrid laminate circuit board 100, and the first sub-board 1 is formed.)
[0065] And, after forming the first metallized hole 40D, processes such as back drilling can be performed to reduce crosstalk, as Figure 4 (As shown in (C), further improving the transmission quality of the high-speed signals of the network device.)
[0066] S301. Prepare circuit patterns on a number of second core boards, laminate to form a second laminate board, drill anti-pad holes on the second laminate board, and fill the anti-pad holes with plugging materials to form a second sub-board.)
[0067] As Figure 5 shown, prepare circuit patterns on a number of second core boards through the above board manufacturing processes and laminate to form the second laminate board 102. Drill two types of vias on the second laminate board 102 to form the structure as shown in Figure 5 (A). One type forms low-speed signal holes 42, current-carrying holes 43, and / or grounding holes 44 through metallization. Only the low-speed signal holes 42 are implemented in Figure 5 . After the subsequent hybrid laminate circuit board 100 is formed, the low-speed signal holes 42, current-carrying holes 43, and grounding holes 44 can be respectively formed into low-speed signal blind holes, current-carrying blind holes, and grounding blind holes, etc. Another type of via is drilled at the position corresponding to the formation of the high-speed signal via 40B without metallization. The size of this type of via is larger than the vias for forming the low-speed signal holes 42, current-carrying holes 43, and / or grounding holes 44. Another type of via is not metallized and can be referred to as an anti-pad hole 41, and the anti-pad hole 41 is plugged with plugging materials to form the second sub-board 2 as shown in Figure 5 (B).
[0068] Among them, the dielectric constant of the base material of the first core board is less than the dielectric constant of the base material of the second core board, and the dielectric constant of the plugging material is consistent with the dielectric constant of the first core board. Through the above settings, impedance jumps during the subsequent formation of the high-speed signal via 40B can be avoided.)
[0069] Before forming the second sub-board in step S301, it further includes:
[0070] S301A. Drill low-speed signal holes, power supply holes, and grounding holes on the second laminate board.)
[0071] As described above, it will not be repeated herein.
[0072] S302. Clamp a prepreg between the first sub-board and the second sub-board, and press and laminate to form a third laminated board.
[0073] In order to realize the lamination of the first sub-board 1 and the second sub-board 2, it is necessary to clamp a prepreg between them and perform pressing and lamination. This prepreg forms an adhesive layer 3, which bonds the first sub-board 1 and the second sub-board 2 to form a third laminated board 103.
[0074] Among them, the prepreg forms an adhesive layer 3 after the pressing process. Optionally, the dielectric constant of the adhesive material of the adhesive layer 3 is consistent with the dielectric constant of the first sub-board 1.
[0075] S303. On the third laminated board, drill second high-speed signal holes passing through the first sub-board and the second sub-board corresponding to the anti-pad holes of the second sub-board to form a mixed-laminated circuit board.
[0076] Specifically, in step S303, on the third laminated board, drilling second high-speed signal holes passing through the first sub-board and the second sub-board corresponding to the anti-pad holes of the second sub-board to form a mixed-laminated circuit board includes:
[0077] S303A. On the third laminated board, drill second through-holes passing through the first sub-board and the second sub-board corresponding to the anti-pad holes of the second sub-board, and metallize the second through-holes to form second metallized through-holes.
[0078] As Figure 6 shown, after the third laminated board 103 is formed, it is necessary to prepare a hole structure passing through the first sub-board 1 and the second sub-board 2, which includes high-speed signal vias 40B that need to pass through the first sub-board 1 and the second sub-board 2.
[0079] First, as Figure 6 (A) shown, it is necessary to first drill a second through-hole 40E corresponding to the position of the anti-pad hole 41, and this second through-hole 40E is located in the anti-pad hole 41.
[0080] Secondly, as Figure 6 (B) shown, metallize the second through-hole 40E to form a second metallized through-hole 40F.
[0081] S303B. Back-drill and plug the second metallized through-hole to form second high-speed signal holes, and prepare a mixed-laminated circuit board.
[0082] To reduce the crosstalk of high-speed signal vias, after forming the second metallized via 40F, the second metallized via 40F can also be back-drilled and plugged to form a high-speed signal via 40B.
[0083] Before step S303, forming the hybrid multilayer circuit board, it further includes:
[0084] S303C: Drilling low-speed signal vias, power supply vias, and ground vias on the third pressing board.
[0085] During the preparation of the hybrid multilayer circuit board 100, in addition to the above-mentioned high-speed signal via 40B, low-speed signal vias, power supply vias, and ground vias passing through the first sub-board 1 and the second sub-board 2 can also be formed on the third pressing board 103 through processes such as drilling and metallization, and finally form the hybrid multilayer circuit board 100 as shown in Figure 1 shown.
[0086] Before step S303, forming the hybrid multilayer circuit board, it further includes:
[0087] S303D: Attaching copper layers to the top and bottom surfaces of the third pressing board and etching out pad holes.
[0088] In some cases, there are also metal structures on the surface of the hybrid multilayer circuit board 100. These metal structures can be formed by attaching copper layers to the third pressing board 103 and performing several of the above-mentioned board manufacturing processes, and can be set according to requirements without limitation.
[0089] Optionally, the diameter of the back-drilling is smaller than the diameter of the anti-pad hole 41.
[0090] To avoid the impact of back-drilling on the impedance of the high-speed signal via 40B, the diameter of the back-drilling needs to be set smaller than the diameter of the anti-pad hole 41 during back-drilling.
[0091] Since the structures on the hybrid multilayer circuit board 100 can be set according to actual requirements, therefore, the first sub-board 1, the second sub-board 2, and the formed hybrid multilayer circuit board 100 can also include other hole structures or surface line patterns, etc.
[0092] The technical solutions provided by the embodiments of this specification may include the following beneficial effects:
[0093] In the embodiments of the present specification, a first sub-board and a second sub-board with different dielectric constants of the base material are provided in the mixed-pressure circuit board and bonded through an adhesive layer. At the position where a high-speed signal hole needs to pass through the first sub-board and the second sub-board, an anti-pad hole is opened in the second sub-board with a higher dielectric constant, and the anti-pad hole is filled with a plugging material consistent with the dielectric constant of the base material of the first sub-board, so that the high-speed signal hole passing through the first sub-board and the second sub-board can avoid the problem of impedance jump and improve the signal quality of high-speed signal transmission in the network device.
[0094] After considering the specification and practicing the invention claimed herein, those skilled in the art will readily conceive of other embodiments of the present specification. The present specification is intended to cover any variations, uses, or adaptations of the present specification, which follow the general principles of the present specification and include known common knowledge or conventional technical means in the technical field not claimed in the present specification. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present specification are pointed out by the following claims.
[0095] It should be understood that the present specification is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present specification is only limited by the appended claims.
[0096] The above are only the preferred embodiments of the present specification and are not intended to limit the present specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present specification shall be included within the scope of protection of the present specification.
Claims
1. A hybrid circuit board, characterized in that: include: The first sub-board; a second sub-board, wherein the dielectric constant of the substrate of the first sub-board is smaller than the dielectric constant of the substrate of the second sub-board; an adhesive layer, sandwiched between the first sub-board and the second sub-board, and respectively bonded to the first sub-board and the second sub-board; A high-speed signal hole passing through the first sub-board and the second sub-board is formed on the hybrid circuit board, an anti-pad hole corresponding to the high-speed signal hole is drilled on the circumference of the high-speed signal hole, and a plugging material is filled in the anti-pad hole, and the dielectric constant of the plugging material is consistent with the dielectric constant of the substrate of the first sub-board.
2. The hybrid circuit board according to claim 1, characterized in that: The dielectric constant of the adhesive material of the adhesive layer is consistent with the dielectric constant of the substrate of the first sub-board.
3. A method for preparing a mixed pressure circuit board, characterized in that: include: Preparing circuit patterns on a plurality of first core boards, laminating them to form a first pressed board, and drilling first high-speed signal holes on the first pressed board to form a first sub-board; Preparing circuit patterns on a plurality of second core boards, laminating them to form second pressed boards, drilling anti-pad holes on the second pressed boards, and filling the anti-pad holes with plugging materials to form second sub-boards, wherein the dielectric constant of the substrate of the first core board is smaller than the dielectric constant of the substrate of the second core board, and the dielectric constant of the plugging material is consistent with the dielectric constant of the first core board; sandwiching a prepreg between the first sub-board and the second sub-board, and pressing them together to form a third pressed board, wherein the prepreg forms an adhesive layer; On the third pressing board, a second high-speed signal hole corresponding to the anti-pad hole of the second sub-board is drilled through the first sub-board and the second sub-board to form a mixed pressure circuit board.
4. The method according to claim 3, characterized in that The dielectric constant of the adhesive material of the adhesive layer is consistent with the dielectric constant of the first sub-board.
5. The method according to claim 3, characterized in that: The method comprises preparing circuit patterns on a plurality of first core boards, laminating them to form a first pressed board, and drilling a first high-speed signal hole on the first pressed board to form a first sub-board, including: Preparing circuit patterns on a plurality of first core boards and laminating them to form a first pressed board; Drilling a first through hole on the first pressing plate, and metalizing the first through hole to form a first metallized through hole; The first metallized through hole is back-drilled and plugged to form a first high-speed signal hole, thereby preparing a first daughter board.
6. The method according to claim 3, characterized in that On the third pressing board, a second high-speed signal hole corresponding to the anti-pad hole of the second sub-board is drilled through the first sub-board and the second sub-board to form a mixed pressure circuit board, including: On the third pressing board, a second through hole is drilled through the first sub-board and the second sub-board corresponding to the anti-pad hole of the second sub-board, and the second through hole is metallized to form a second metallized through hole; The second metallized through hole is back-drilled and plugged to form a second high-speed signal hole, and a hybrid circuit board is prepared.
7. The method according to claim 6, characterized in that The back-drilled hole has a smaller diameter than the anti-pad hole.
8. The method according to claim 3, characterized in that Before forming the mixed pressure circuit board, it also includes: Copper layers are attached to the top and bottom surfaces of the third pressing plate, and a hole plate is etched out.
9. The method according to claim 3, characterized in that: Before forming the mixed pressure circuit board, it also includes: A low-speed signal hole, a power supply hole and a grounding hole are drilled on the third pressing plate.
10. The method according to claim 3, characterized in that: Before forming the second daughter board, the method further includes: A low-speed signal hole, a power supply hole and a grounding hole are drilled on the second pressing plate.