A method for manufacturing a hole-coated copper and a method for manufacturing an asymmetric structure HDI board

Abstract

The present invention provides a method for manufacturing a hole-coated copper and a method for manufacturing an asymmetric structure HDI board, belonging to the technical field of PCB board production. The method for manufacturing a hole-coated copper comprises: reserving a hole position for connecting the substrate with other layers on the surface of the substrate of the HDI board; making a groove at the hole of the reserved hole position, wherein the groove is recessed inward from the surface of the substrate; wherein the diameter of the groove is larger than the diameter of the corresponding hole position; drilling a connecting hole for connecting the substrate with other layers of the HDI board from the produced groove, and electroplating the drilled connecting hole; and forming a clad copper layer at the groove. The method can ensure that clad copper with reliable quality is formed at the blind hole, thereby ensuring the reliability of the connection between the hole copper and the surface copper, and ensuring the quality of the HDI product.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB processing, and in particular to a method for manufacturing a hole-coated copper and a method for manufacturing an asymmetric structure HDI board. Background Art

[0002] HDI boards are often used in electronic devices that require high-density interconnects, such as smartphones, tablets, and other portable devices. These devices require smaller, more compact circuit boards to support high-performance processors, memory, and other components. Asymmetric HDI (High Density Interconnect) boards are a special type of electronic board that features an asymmetric conductive layer layout. This structure allows the circuit board to have more conductive layers on one side and fewer on the other side, thereby meeting different needs in specific applications. Asymmetric HDI boards have higher wiring density and better signal transmission by optimizing the layout of the conductive layer, and can also reduce material and manufacturing costs by reducing unnecessary conductive layers. However, the design and production of asymmetric HDI boards also face some challenges. In particular, in the process of making blind holes and copper-cladding the hole mouths, since multiple blind hole electroplating and multiple copper layer thinning on the copper surface are required during the production of multiple blind holes, there is a certain difference in copper layer thickness between each electroplating and copper layer thinning. After multiple blind hole electroplating and copper layer thinning, the copper layer on the surface of some blind holes is too thin, and copper coating cannot be achieved on the surface of the blind holes, which eventually causes the copper in the blind holes and the copper layer on the surface of the substrate to crack and form stratification, affecting the stability and reliability of the product, and may even cause circuit performance degradation or failure.

[0003] Therefore, it is necessary to improve the existing production process of asymmetric HDI to avoid the problem of missing copper coating on the hole. Summary of the invention

[0004] In order to overcome the problems existing in the related art, one of the purposes of the present invention is to provide a method for manufacturing hole-mouth copper cladding, which can ensure that reliable quality copper cladding is formed at the blind hole, thereby ensuring the reliability of the connection between the hole copper and the surface copper, and ensuring the quality of HDI products.

[0005] A method for manufacturing a hole-coated copper, comprising:

[0006] On the surface of the substrate of the HDI board, holes are reserved for connecting the substrate with the remaining layers;

[0007] Making a groove at the opening of the reserved hole, wherein the groove is sunken inward from the surface of the substrate; wherein the diameter of the groove is larger than the diameter of the corresponding hole;

[0008] Drilling connecting holes connecting the substrate and other layers of the HDI board from the produced grooves, and electroplating the drilled connecting holes;

[0009] A cladding copper layer is formed at the groove.

[0010] In a preferred technical solution of the present invention, the step of forming a copper coating layer at the groove includes:

[0011] After copper plating is performed on the drilled connecting holes, surface copper is plated on the HDI board, and a copper coating layer is formed at the grooves;

[0012] The copper cladding layer extends outward from the opening of the communicating hole, the thickness of the copper cladding is greater than 5 μm, and the minimum distance from the edge of the copper cladding to the edge of the opening of the communicating hole is greater than 25 μm.

[0013] In a preferred technical solution of the present invention, the step of making a groove at the opening of the reserved hole comprises:

[0014] A dry film is applied to the surface of the substrate of the motherboard, and according to the design requirements, a window is opened on the surface of the substrate for connecting the substrate with the other layers of the HDI board, so that the hole positions of the connecting holes are exposed;

[0015] Reducing copper on the substrate after window opening;

[0016] The substrate after copper reduction is subjected to film stripping treatment, so that grooves are formed at the exposed holes.

[0017] In a preferred technical solution of the present invention, a connecting hole connecting the substrate and the remaining layers of the HDI board is drilled from the manufactured groove, and the drilled connecting hole is electroplated, including:

[0018] According to the design requirements, connecting holes connecting the substrate surface with the remaining layers are drilled layer by layer from the groove;

[0019] The drilled connecting hole is subjected to copper electroplating, and the surface copper is electroplated to form a cladding copper layer connected to the hole copper of the connecting hole at the groove;

[0020] The formed groove is plugged.

[0021] In a preferred technical solution of the present invention, the step of making a groove at the opening of the reserved hole comprises:

[0022] On the substrate, a dry film is applied at the positions of the connecting holes connecting the substrate with the other layers of the HDI board;

[0023] Electroplating copper on the substrate after film application;

[0024] The copper-plated substrate is stripped to form grooves at the positions of the connecting holes on the substrate.

[0025] In a preferred technical solution of the present invention, the method of drilling a connecting hole connecting the substrate and the remaining layers of the HDI board from the produced groove includes:

[0026] plugging the formed groove;

[0027] According to the design requirements, connecting holes connecting the substrate with the remaining layers are drilled layer by layer from the groove behind the plug hole;

[0028] The drilled connecting holes are subjected to copper electroplating and surface copper electroplating.

[0029] In a preferred technical solution of the present invention, plugging the formed groove further comprises:

[0030] Before the next connecting hole production process, according to the design requirements, the resin in the groove is removed layer by layer using a laser, and the residual resin is cleaned with a plasma machine to expose the groove;

[0031] A connecting hole is drilled from the exposed groove to connect the substrate with the remaining layers of the HDI board;

[0032] The drilled connecting holes are subjected to copper plating and surface copper plating to form a cladding copper connected to the hole copper of the connecting holes at the grooves.

[0033] A second object of the present invention is to provide a method for manufacturing an asymmetric HDI board, the HDI board comprising a motherboard and a daughterboard, the motherboard comprising a multi-layer core board and a substrate;

[0034] In the process of manufacturing the communicating hole, the manufacturing method of the hole opening cladding copper as described above is adopted to form cladding copper at the hole opening of the communicating hole.

[0035] In a preferred technical solution of the present invention, the process of making a motherboard includes:

[0036] Drilling through holes on the substrate of the motherboard, and electroplating and plugging the drilled through holes with resin;

[0037] Obtain the core boards of each layer of the motherboard, perform copper reduction treatment on the obtained core boards of each layer, and drill, electroplate, plug holes and make circuit patterns on the core boards of each layer;

[0038] Laminating the core board with completed circuit pattern on the substrate layer by layer;

[0039] Wherein, during the pressing process, the above-mentioned method for manufacturing the orifice-coated copper is adopted to make a connecting hole on the substrate that is connected to the pressed core plate;

[0040] After the motherboard is manufactured, the daughterboard is laminated on the motherboard layer by layer, and the laminated daughterboard is drilled, copper plated and circuit patterned to obtain an asymmetric HDI board.

[0041] In a preferred technical solution of the present invention, during the electroplating process of the core board of the motherboard, N rows of cyclic holes are drilled on the edge of a single core board, where N is a natural number greater than or equal to 1;

[0042] Wherein, the diameter of the circulation hole is greater than 0.2 mm;

[0043] After the daughter board is pressed onto the mother board, it also includes:

[0044] Drilling an improvement hole at the edge of the pressed HDI board, wherein the improvement hole penetrates the motherboard and the daughterboard;

[0045] And along the direction from the center to the edge of the HDI board, the improved holes are arranged in M ​​rows, where M is a natural number greater than 1;

[0046] Among them, the positions of the improved holes in two adjacent rows are staggered;

[0047] The diameter of the improvement hole is 0.3mm-0.5mm, and in the same row of improvement holes, the diameter of the improvement hole is greater than the minimum distance between two adjacent improvement holes; and the diameter of the improvement hole is related to the material and thickness of the core plate;

[0048] In a preferred technical solution of the present invention, before the motherboard is manufactured, it also includes engineering graphic design;

[0049] The engineering graphic design includes:

[0050] During the graphic design process of the core board of the motherboard, multiple PCB board graphics of the core board are spliced ​​on a substrate;

[0051] During the splicing process, the pattern of a single PCB board is rotated by a preset angle so that the pattern of the single PCB board and the longitude and latitude of the prepreg are staggered;

[0052] Among them, the preset angle is 10°-45°.

[0053] The beneficial effects of the present invention are:

[0054] The present invention provides a method for manufacturing orifice-clad copper, which comprises: reserving a hole position for connecting the substrate with the remaining layers on the surface of the substrate of the HDI board; making a groove at the hole position of the reserved hole position, wherein the groove is recessed inward from the surface of the substrate; wherein the diameter of the groove is larger than the diameter of the corresponding hole position; drilling a connecting hole for connecting the substrate with the remaining layers of the HDI board from the made groove, and electroplating the drilled connecting hole; and forming a clad copper layer at the groove. The method for manufacturing orifice-clad copper, by making a groove at the hole position of the hole position reserved on the surface of the substrate, and drilling a connecting hole for connecting the substrate with the remaining layers of the HDI board, can form a clad copper layer at the groove during the electroplating process. Since the diameter of the groove is larger than the diameter of the corresponding hole position, the clad copper layer extends from the hole position of the connecting hole to the groove, which can enhance the bonding force between the hole copper of the connecting hole and the substrate, and prevent the hole copper and the copper layer on the surface of the substrate from being pulled apart to form stratification, thereby helping to improve the quality of the product.

[0055] The present application also provides a method for manufacturing an asymmetric HDI board including the above-mentioned method for manufacturing hole-coated copper. The HDI board product manufactured by the method has reliable quality and outstanding performance, and is not prone to poor circuit connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a flow chart of a method for manufacturing a hole-clad copper provided in an embodiment of the present invention;

[0057] Figure 2 is a schematic diagram of forming a groove on a substrate provided in Example 1 of the present invention;

[0058] Figure 3 is a schematic diagram of forming a groove on a substrate provided in Example 2 of the present invention;

[0059] Figure 4 is a schematic diagram of setting the improved holes on a single PCB board provided in an embodiment of the present invention;

[0060] Figure 5 It is a schematic diagram of the arrangement of the circulation holes provided in an embodiment of the present invention on a single PCB board.

[0061] Reference numerals:

[0062] 1. Improved hole; 2. Circulation hole; 100. Copper coating; 200. Groove; 300. Dry film; 400. Connecting hole. DETAILED DESCRIPTION

[0063] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0064] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. 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 associated listed items.

[0065] It should be understood that although the terms "first", "second", "third", etc. may be used to describe various information in the present invention, 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 the present invention, 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. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0066] The design and production of asymmetric HDI boards face some challenges. In particular, in the process of making blind holes and coating the hole mouth with copper, since multiple blind hole electroplating and multiple copper layer thinning on the copper surface are required in the process of making multiple blind holes, there is a certain difference in copper layer thickness between each electroplating and copper layer thinning. After multiple blind hole electroplating and copper layer thinning, the copper layer on the surface of some blind holes is too thin, and copper coating cannot be achieved on the surface of the blind holes, which eventually causes the copper in the blind holes and the copper layer on the surface of the substrate to tear and form stratification, affecting the stability and reliability of the product, and may even cause circuit performance degradation or failure. Based on this, the present application provides a method for manufacturing hole mouth coated copper to overcome the defects of the prior art.

[0067] Example 1

[0068] like Figure 1 As shown, the present invention provides a method for manufacturing a hole-coated copper;

[0069] S100, on the surface of the substrate of the HDI board, holes are reserved for connecting the substrate with other layers;

[0070] The HDI board has multiple layers, for example, it may have 12 layers in total, namely, L1, L2, ..., L12, wherein the substrate is the L1 layer. During the production process, a plurality of holes communicating with the remaining layers have been reserved on the surface of the L1 layer according to design requirements.

[0071] S200, making a groove at the opening of the reserved hole, wherein the groove is sunken inward from the surface of the substrate; wherein the diameter of the groove is larger than the diameter of the corresponding hole;

[0072] There are many ways to make the groove, which can be processed by mechanical drilling or laser cutting technology, or by etching copper reduction technology to form the groove on the substrate, i.e., the L1 layer. In a more specific embodiment, the diameter of the groove is designed to be 0.2 mm larger than the corresponding hole diameter to ensure that the subsequent copper coating layer 100 has enough attachment space.

[0073] S300, drilling a connecting hole 400 connecting the substrate and the other layers of the HDI board from the produced groove, and electroplating the drilled connecting hole; drilling a connecting hole 400 from the center of each groove to ensure that the hole penetrates the substrate and connects with the other layers of the HDI board. Subsequently, the entire HDI board is electroplated, and the copper ions in the electroplating solution are deposited on the surface of the connecting hole and the groove to form a uniform copper layer.

[0074] S400, forming a clad copper layer 100 at the groove 200. After the electroplating is completed, more copper deposits will accumulate at the groove due to its larger diameter, thereby forming a thicker clad copper layer in the groove. This copper layer not only covers the opening of the connecting hole, but also extends to the inside of the groove, significantly enhancing the bonding force between the hole copper and the substrate.

[0075] The above-mentioned method for manufacturing a hole-mouth copper coating can form a coating copper layer at the groove by making a groove at the hole mouth of the hole position reserved on the surface of the substrate, and drilling a connecting hole connecting the substrate with the other layers of the HDI board during the electroplating process. Since the diameter of the groove is larger than the diameter of the corresponding hole position, the coating copper layer extends from the hole mouth of the connecting hole to the groove, which can enhance the bonding force between the hole copper of the connecting hole and the substrate, prevent the hole copper and the copper layer on the surface of the substrate from being pulled apart to form stratification, thereby helping to improve the quality of the product.

[0076] Further, forming a copper coating layer at the groove includes:

[0077] After copper plating is performed on the drilled connecting holes, surface copper is plated on the HDI board, and a copper coating layer is formed at the grooves;

[0078] The copper cladding layer extends outward from the opening of the communicating hole, the thickness of the copper cladding is greater than 5 μm, and the minimum distance from the edge of the copper cladding to the edge of the opening of the communicating hole is greater than 25 μm.

[0079] In this application, the size of the clad copper is strictly limited, specifically the thickness is greater than 5μm, and the minimum distance from the edge of the clad copper to the edge of the opening of the connecting hole is greater than 25μm. The design of the clad copper has a large thickness and extension distance, which effectively increases the contact area between the copper layer and the substrate, significantly improves the bonding force between the hole copper and the copper layer on the surface of the substrate, and reduces the risk of delamination. It helps to improve the overall structural strength and electrical performance of the HDI board.

[0080] Furthermore, in this embodiment, a method for making a groove at the opening of a reserved hole is provided. The details are as follows:

[0081] The step of making a groove at the opening of the reserved hole comprises:

[0082] A dry film is attached to the substrate surface of the motherboard, and according to the design requirements, windows are opened on the substrate surface for connecting holes connecting the substrate with other layers of the HDI board, so that the hole positions of the connecting holes are exposed; specifically, the substrate surface of the motherboard is the L1 layer of the HDI board, and the dry film 300 can protect the substrate surface and serve as a mask for subsequent processing.

[0083] The substrate after the window is opened is subjected to copper reduction; the copper reduction removes part of the copper layer at the exposed hole position, so that the thickness of the copper layer at the window is less than the thickness of the copper layer at the position covered by the dry film.

[0084] The substrate after copper reduction is subjected to film stripping treatment, so that grooves are formed at the exposed holes.

[0085] In this embodiment, groove processing is performed on a substrate with thick surface copper, and a positive film processing method is used to form the groove on the surface of the substrate during the processing.

[0086] Further, a connecting hole connecting the substrate and other layers of the HDI board is drilled from the produced groove, and the drilled connecting hole is electroplated, including:

[0087] According to the design requirements, a connecting hole connecting the substrate surface with the other layers is drilled layer by layer from the groove to ensure that the hole penetrates the substrate and connects with the other layers of the HDI board. Specifically, the drilling here can be processed by mechanical drilling.

[0088] The drilled connecting holes are plated with copper and the surface copper is plated to form a cladding copper layer connected to the hole copper of the connecting holes at the grooves. During the electroplating process, the entire HDI board is electroplated, and the copper ions in the plating solution are deposited on the surface of the connecting holes and the grooves to form a uniform copper layer.

[0089] The formed groove is plugged.

[0090] The plugging of holes in this embodiment refers to the use of resin or copper paste to fill the through holes or blind holes. The resin plugging can be done by filling the blind holes and through hole walls with resin and then flattening the pads. The resin plugging has the following advantages: preventing PP glue from flowing into the holes during pressing, avoiding lamination due to lack of glue and explosion of boards; facilitating the reduction of vacuum in lamination, avoiding surface depression problems, and facilitating fine circuit production and characteristic impedance control; achieving arbitrary layer interconnection by using three-dimensional space through hole stacking technology; achieving higher density wiring by patch design on the holes; eliminating impurities from entering the conductive holes, avoiding the involvement of corrosive impurities.

[0091] Copper paste plugging uses copper paste to fill blind holes and through holes. Compared with resin plugging, copper paste plugging has better heat dissipation effect and higher quality, but the production cost is also higher.

[0092] Example 2

[0093] In this embodiment, a method for making a groove at the opening of a reserved hole different from that in Embodiment 1 is provided, which is specifically as follows:

[0094] The step of making a groove at the opening of the reserved hole comprises:

[0095] On the substrate, a dry film is attached to the positions of the connecting holes connecting the substrate and the other layers of the HDI board; the substrate is the LI layer of the asymmetric structure HDI board.

[0096] The surface copper is electroplated on the film-attached substrate; the process of electroplating the surface copper can be carried out using existing electroplating methods.

[0097] The copper-plated substrate is stripped to form grooves at the positions of the connecting holes on the substrate.

[0098] In this embodiment, the grooves are formed on the surface of the substrate by electroplating. This processing method is applied in the negative film processing of HDI boards.

[0099] Furthermore, the method of drilling a connecting hole connecting the substrate and other layers of the HDI board from the produced groove includes:

[0100] plugging the formed groove;

[0101] According to the design requirements, connecting holes connecting the substrate with the remaining layers are drilled layer by layer from the groove behind the plug hole;

[0102] The drilled connecting holes are subjected to copper electroplating and surface copper electroplating.

[0103] In this embodiment, the processing method of plugging the hole and drilling the connecting hole can be the same as the processing method of embodiment 1.

[0104] Furthermore, plugging the formed groove further comprises:

[0105] Before the next connecting hole production process, according to the design requirements, the resin in the groove is removed layer by layer using a laser, and the residual resin is cleaned with a plasma machine to expose the groove;

[0106] A connecting hole is drilled from the exposed groove to connect the substrate with the remaining layers of the HDI board;

[0107] The drilled connecting holes are subjected to copper plating and surface copper plating to form a cladding copper connected to the hole copper of the connecting holes at the grooves.

[0108] In actual applications, HDI boards have multiple layers, such as L1, L2...L12 layers. In the actual manufacturing process, after all the connecting holes are drilled for the first time, the connecting holes of the L1-L3 layers are plated with copper and then plugged with resin according to the design requirements. During the plugging process, all the grooves will be filled with resin. Therefore, before the next copper plating of the connecting holes, the resin in the grooves needs to be cleared. The specific cleaning method can be to use plasma degumming method to remove the glue.

[0109] Example 3

[0110] The present embodiment provides a method for manufacturing an asymmetric HDI board, which includes a motherboard and a daughterboard, wherein the motherboard includes a multi-layer core board and a substrate; in the manufacturing process of the connecting hole, the hole mouth clad copper manufacturing method as described above is adopted to form clad copper at the hole mouth of the connecting hole.

[0111] The HDI board product manufactured by the method has reliable quality and outstanding performance, and is not prone to poor circuit connection.

[0112] Furthermore, the motherboard manufacturing process includes:

[0113] Through holes are drilled on the substrate of the motherboard, and the drilled through holes are electroplated and plugged with resin; the substrate of the present application is the L1 layer of the motherboard.

[0114] Obtain the core boards of each layer of the motherboard, perform copper reduction treatment on the obtained core boards of each layer, and drill, electroplate, plug holes and make circuit patterns on the core boards of each layer;

[0115] Laminating the core board with completed circuit pattern on the substrate layer by layer;

[0116] Wherein, during the pressing process, the above-mentioned method for manufacturing the orifice-coated copper is adopted to make a connecting hole on the substrate that is connected to the pressed core plate;

[0117] After the motherboard is manufactured, the daughterboard is laminated on the motherboard layer by layer, and the laminated daughterboard is drilled, copper plated and circuit patterned to obtain an asymmetric HDI board.

[0118] Furthermore, during the electroplating process of the core board of the motherboard, N rows of cyclic holes 2 are drilled on the edge of a single core board, where N is a natural number greater than or equal to 1;

[0119] Wherein, the diameter of the circulation hole 2 is greater than 0.2 mm;

[0120] When HDI products are electroplated and blind holes are drilled by laser, there are no through holes in the middle of the PCB. During the spraying process, a "pool" will accumulate on the surface of the PCB. This will hinder the uniform distribution of the solution, making the blind holes in the center of the PCB more difficult to electroplate than the blind holes on the edge. The present application drills circulation holes 22 on the edge of the PCB. When drilling, a drill tip of 0.2-0.4mm can be selected for the inner layer board. When there is a large hole of more than 0.4mm in the middle of the outer layer board, the circulation path of the solution can be improved, thereby improving the quality of blind hole electroplating.

[0121] After the daughter board is pressed onto the mother board, it also includes:

[0122] Drilling an improvement hole 1 at the edge of the pressed HDI board, wherein the improvement hole 1 penetrates the motherboard and the daughterboard;

[0123] And along the direction from the center to the edge of the HDI board, the improved holes 1 are arranged in M ​​rows, where M is a natural number greater than 1;

[0124] Wherein, the positions of the improved holes 1 in two adjacent rows are staggered with each other;

[0125] The hole diameter of the improved hole 1 is 0.3mm-0.5mm, and in the same row of improved holes 1, the diameter of the improved hole 1 is greater than the minimum distance between two adjacent improved holes 1; and the hole diameter of the improved hole 1 is related to the material and thickness of the core plate; specifically, the greater the material hardness of the core plate, the larger the hole diameter of the improved hole 1, and the diameter of the improved hole 1 is positively correlated with the thickness of the core plate.

[0126] The inner layer asymmetric structure of the HDI board will be deformed after lamination due to the asymmetry of the board thickness, copper thickness, and pattern distribution, and will be affected by thermal expansion and contraction, resulting in the inability to use the patch later. During the manufacturing process, this application designs a drill bit based on the material of the inner layer board, drills two rows of holes alternately on the edge of each single PCB, cuts off the longitude and latitude lines of the inner layer PCB, releases the stress generated in the Z-axis direction of the sheet material and the PP longitude and latitude lines, improves the deformation of the asymmetric structure HDI board after lamination, and improves product quality.

[0127] More preferably, before the motherboard is manufactured, it also includes engineering graphic design;

[0128] The engineering graphic design includes:

[0129] During the graphic design process of the core board of the motherboard, multiple PCB board graphics of the core board are spliced ​​on a substrate;

[0130] During the splicing process, the pattern of a single PCB board is rotated by a preset angle so that the pattern of the single PCB board and the longitude and latitude of the prepreg are staggered;

[0131] Among them, the preset angle is 10°-45°.

[0132] In the manufacturing process of conventional HDI boards, in order to facilitate design and optimization, the signal lines of the PCB board are usually parallel to the X or Y direction when designing the data according to production requirements. Due to the consistency between the signal lines of the sheet material and the longitude and latitude of the PP, the longitude and latitude will have a certain impact on the transmission of the signal, which can easily cause distortion of high-frequency and high-speed signals. This application rotates the normal PCB board graphics by 10°-45° when assembling asymmetric blind hole boards, and the specific angle can be adjusted according to the shape of the product. The routing direction of the signal graphics required by the design is staggered with the longitude and latitude of the PP, reducing the impact of the signal lines on signal transmission when they are parallel to the longitude or latitude, and improving the distortion of high-frequency and high-speed signals.

[0133] Example 4

[0134] This embodiment describes in detail the manufacturing process of the asymmetric structure HDI board of the present application. The manufacturing method of the hole-clad copper in this embodiment adopts the manufacturing method of the hole-clad copper described in Example 1 for manufacturing.

[0135] The details are as follows:

[0136] The HDI board includes a motherboard and a daughterboard, wherein the motherboard has L1-L6 layers, and the daughterboard has L7-L12 layers.

[0137] Get the L1 layer of the motherboard and reduce the copper on the L1 layer.

[0138] Obtain the core board of the L2 layer, perform copper reduction processing on the core board of the L2 layer, drill holes, electroplate, plug holes, and make circuit patterns on the core board of the L2 layer, and press the L2 layer onto the L1 layer.

[0139] Then drill the holes in the L1-L2 layer and electroplate the holes in the pad to connect the L1-L2 layers. Then plug the holes in the pad with resin to fill them up.

[0140] The circuit patterns of the L2 and L3 layers are made, and the L3 layer is pressed onto the L2 layer.

[0141] A dry film is covered on the surface of the L1 layer, and a window process is performed on the hole positions of the connecting holes between the L1 layer and the L3 layer and the remaining layers, so that the hole positions of the connecting holes are exposed.

[0142] The substrate after the window is opened is subjected to copper reduction, and grooves are formed at the hole positions of the connecting holes exposed after the copper reduction.

[0143] A connecting hole between the L1 layer and the L3 layer is drilled from the groove, and then copper plating is performed, and then the hole is plugged with resin. At this time, the groove without the connecting hole is also filled with resin.

[0144] The circuit pattern of the L4 layer is made, and the made L4 layer is pressed onto the L3 layer. Then, the reserved groove of the L1 layer is obtained, and the position of the connecting hole between the L1 layer and the L4 layer is selected. The resin in the groove is plasma debonded, and then drilling and copper plating are performed after debonding to form a cladding copper layer in the groove. The cladding copper layer makes the hole copper and the surface copper tightly connected.

[0145] By analogy, the L5 and L6 core boards of the motherboard are pressed and manufactured. In the manufacturing process of the motherboard, the holes that are not connected between the motherboard and the daughterboard can be back-drilled to remove the copper in the connecting holes according to the design requirements.

[0146] After the motherboard is made, the L7 layer of the daughterboard will be pressed according to the design requirements based on the L6 layer of the motherboard. The L7 layer can be drilled by laser processing. After the processing is completed, the residual glue in the laser hole is cleaned by plasma and then the blind hole is filled with electroplating. After all the laser blind holes of the L7 layer are filled, the circuit production of the L7 layer is completed.

[0147] Repeat the manufacturing method of the L7 layer, and laminate the L8-L12 layers of the daughter board layer by layer, and finally obtain an HDI board with an asymmetric structure.

[0148] Example 5

[0149] This embodiment describes in detail the manufacturing process of the asymmetric structure HDI board of the present application. The manufacturing method of the hole-clad copper in this embodiment adopts the manufacturing method of the hole-clad copper described in Example 2 for manufacturing.

[0150] The details are as follows:

[0151] Likewise, the HDI board includes a motherboard and a daughterboard, wherein the motherboard has L1-L6 layers, and the daughterboard has L7-L12 layers.

[0152] Get the L1 layer of the motherboard and reduce the copper on the L1 layer. Then drill the hole in the L1 layer, use a small current of 10-15ASF to electroplate 5-7um base copper on the surface of the L1 layer, and obtain an L1 layer base copper plate with a surface copper thickness of 10-15um.

[0153] A dry film is applied to the holes of the L1 layer surface that are connected to the other layers of the HDI board; then the surface copper is electroplated to thicken the surface copper to 30-35um, and then the film is stripped. At this time, the surface copper without dry film is thickened, and the hole position of the connecting hole with dry film cannot be electroplated, so a groove is formed.

[0154] The L2-L6 core boards of the motherboard are made, and the prepared core boards are pressed onto the L1 layer layer by layer. When each core board is pressed, connecting holes between the L1 layer and each core board are made from the groove of the L1 layer, and copper plating is performed, and then the connecting holes are plugged with resin.

[0155] For example, copper plating and resin plugging are performed on the connecting holes between the L1 layer and the L3 layer. At this time, the resin plugging process will fill the groove on the L1 layer. Therefore, before making the next connecting hole, it is necessary to use laser milling to clean the resin in the groove of the corresponding connecting hole, and then use plasma degumming to remove the residual resin, and then make the connecting hole from the groove where the residual resin is removed, and then perform copper plating and resin plugging treatment with a certain thickness.

[0156] By analogy, after the motherboard is manufactured, the production process of Example 4 can be used to process the daughterboard, and finally an HDI board with an asymmetric structure is obtained.

[0157] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings. In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0158] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0159] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this application. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a hole-coated copper, characterized in that: On the surface of the substrate of the HDI board, holes are reserved for connecting the substrate with the remaining layers; The HDI board includes a motherboard and a daughterboard, wherein the motherboard has L1-L6 layers and the daughterboard has L7-L12 layers; Get the L1 layer of the motherboard and reduce the copper on the L1 layer; Obtain the L2 layer core board, perform copper reduction treatment on the L2 layer core board, drill holes, electroplate, plug holes, and make circuit patterns on the L2 layer core board, and press the L2 layer onto the L1 layer; Drill the holes in the L1-L2 layer and electroplate the holes to make the L1-L2 layers connected. Then, fill the holes with resin. The circuit patterns of the L2 and L3 layers are made, and the L3 layer is pressed onto the L2 layer; A dry film is covered on the surface of the L1 layer, and a window is opened at the hole positions of the connecting holes between the L1 layer and the L3 layer and the remaining layers, so that the hole positions of the connecting holes are exposed; The substrate after the window is opened is subjected to copper reduction, and a groove is formed at the hole position of the connecting hole exposed after the copper reduction; Drill a connecting hole between the L1 layer and the L3 layer from the groove, then perform copper electroplating, and then plug the hole with resin after electroplating; Make the circuit pattern of the L4 layer, and press the made L4 layer onto the L3 layer; then obtain the groove reserved for the L1 layer, select the position of the connecting hole between the L1 layer and the L4 layer, perform plasma degumming on the resin in the groove, and after degumming, perform drilling and copper electroplating to form a clad copper layer in the groove.

2. The method for manufacturing a hole-clad copper according to claim 1, characterized in that: The cladding copper layer extends outward from the opening of the communicating hole, the cladding copper has a thickness greater than 5 μm, and a minimum distance from the edge of the cladding copper to the edge of the opening of the communicating hole is greater than 25 μm.

3. A method for manufacturing a hole-coated copper, characterized in that: On the surface of the substrate of the HDI board, holes are reserved for connecting the substrate with the remaining layers; The HDI board includes a motherboard and a daughterboard, wherein the motherboard has L1-L6 layers and the daughterboard has L7-L12 layers; Obtain the L1 layer of the motherboard and reduce the copper on the L1 layer; then drill the hole in the L1 layer, electroplate 5-7um of base copper on the surface of the L1 layer, and obtain an L1 layer base copper plate with a surface copper thickness of 10-15um; A dry film is applied to the holes of the L1 layer surface that are connected to the other layers of the HDI board. Then, the surface copper is electroplated to thicken the surface copper to 30-35um, and then the film is stripped. The surface copper without dry film is thickened, and the hole position of the connecting hole with dry film cannot be electroplated to form a groove. The L2-L6 core boards of the motherboard are manufactured, and the manufactured core boards of each layer are pressed onto the L1 layer layer by layer; when each core board is pressed, connecting holes between the L1 layer and each layer of the core board are made from the groove of the L1 layer, and copper plating is performed, and then the connecting holes are plugged with resin; Before making the next connecting hole, the resin in the groove of the corresponding connecting hole is cleaned by laser milling, and then the residual resin is removed by plasma degumming. Then the connecting hole is made from the groove where the residual resin is removed, and the thickness of copper plating and resin plugging are carried out. A cladding copper layer is formed at the groove.

4. A method for manufacturing an asymmetric HDI board, comprising a motherboard and a daughterboard, wherein the motherboard comprises a multi-layer core board and a substrate, characterized in that: In the process of manufacturing the communicating hole, the method for manufacturing the hole-mouth clad copper as claimed in any one of claims 1 to 3 is adopted to form clad copper at the hole mouth of the communicating hole.

5. The method for manufacturing an asymmetric HDI board according to claim 4, characterized in that: The motherboard production process includes: Drilling through holes on the substrate of the motherboard, and electroplating and plugging the drilled through holes with resin; Obtain the core boards of each layer of the motherboard, perform copper reduction treatment on the obtained core boards of each layer, and drill, electroplate, plug holes and make circuit patterns on the core boards of each layer; Laminating the core board with completed circuit pattern on the substrate layer by layer; Wherein, during the pressing process, a method for manufacturing orifice-coated copper as described in any one of claims 1 to 3 is used to make a connecting hole on the substrate that is connected to the pressed core plate; After the motherboard is manufactured, the daughterboard is laminated on the motherboard layer by layer, and the laminated daughterboard is drilled, copper plated and circuit patterned to obtain an asymmetric HDI board.

6. The method for manufacturing an asymmetric HDI board according to claim 5, Features: Wherein, during the electroplating process of the core board of the motherboard, N rows of cyclic holes are drilled on the edge of a single core board, where N is a natural number greater than or equal to 1; Wherein, the diameter of the circulation hole is greater than 0.2 mm; After the daughter board is pressed onto the mother board, it also includes: Drilling an improvement hole at the edge of the pressed HDI board, wherein the improvement hole penetrates the motherboard and the daughterboard; And along the direction from the center to the edge of the HDI board, the improved holes are arranged in M ​​rows, where M is a natural number greater than 1; Among them, the positions of the improved holes in two adjacent rows are staggered; The diameter of the improved hole is 0.3mm-0.5mm, and in the same row of improved holes, the diameter of the improved hole is greater than the minimum distance between two adjacent improved holes; and the diameter of the improved hole is related to the material and thickness of the core plate.

7. The method for manufacturing an asymmetric HDI board according to claim 5, characterized in that: Before the motherboard is manufactured, it also includes engineering graphic design; The engineering graphic design includes: During the graphic design process of the core board of the motherboard, multiple PCB board graphics of the core board are spliced ​​on a substrate; During the splicing process, the pattern of a single PCB board is rotated by a preset angle so that the pattern of the single PCB board and the longitude and latitude of the prepreg are staggered; Among them, the preset angle is 10°-45°.

Images