Imprint mold for manufacturing a printed wiring board based on imprint technology and method for manufacturing the same

Abstract

The application provides a stamping mold for manufacturing a printed circuit board based on a stamping technology and a preparation method thereof, the stamping mold is prepared based on an mSAP process in a PCB process, and the preparation method comprises the following steps: providing a substrate, preparing a to-be-stamped pattern layer on the substrate, preparing a preset metal plating layer on the to-be-stamped pattern layer, and preparing an anti-sticking treatment layer on the preset metal plating layer. The stamping mold is prepared by using an improved semi-additive process (mSAP), a preset metal plating layer is formed on the surface of the stamping mold, an anti-sticking treatment layer is formed by performing anti-sticking treatment on the preset metal plating layer, the stamping technology is applied to the manufacturing of the PCB, metal circuits are prepared through the PCB process, and the stamping mold is suitable for large-size PCBs. The uniformity of circuits with inconsistent complex feature sizes can be greatly improved, the steepness is high, the process stability is good, batch production can be ensured, and the requirements of hardness, tensile strength and the like of the mold in the PCB stamping process can be easily met.

Description

Technical Field

[0001] This invention belongs to the field of printed circuit board manufacturing technology, and in particular relates to an embossing mold for making printed circuit boards based on embossing technology and its preparation method. Background Technology

[0002] Imprint lithography is a micro-nano manufacturing process that uses a mold to create microscopic patterns on a substrate. It is widely used in optical devices, LED manufacturing, and other fields. It is a high-resolution, high-precision, high-efficiency, and low-cost pattern transfer method, adaptable to the densification of electronic circuits, enabling finer circuit shapes, thinner insulating media, and better electrical performance. The imprint lithography process begins with creating a mold for the featured pattern, i.e., an imprinting template. Then, an imprinting adhesive is applied to the substrate. The template and substrate are placed opposite each other. Depending on the properties of the imprinting adhesive, the applied mechanical pressure, temperature, and time are adjusted to gradually fill the pattern structure on the template with the viscous or liquid imprinting adhesive. Finally, the imprinting adhesive is cured, the template is removed, and the imprinted pattern is formed.

[0003] However, research on imprinting technology for printed circuit boards is still limited, mainly due to the following reasons: First, most stencil sizes on the market are 6-inch, 8-inch, and 12-inch, with almost none larger than 12 inches. PCB prototypes, on the other hand, are typically large, around 20 inches, and the market currently cannot provide large-size stencils to meet the needs of PCB manufacturing. Second, the materials used to make stencils typically include silicon wafers, quartz wafers, silicon carbide, and silicon nitride, but these materials are relatively brittle and cannot meet the hardness and tensile strength requirements of PCB imprinting. Third, current stencil manufacturing processes mainly involve photolithography methods such as electron beam, ion beam, and X-ray. These methods are inefficient and relatively expensive, making them unsuitable for industrial production. Wet etching processes also result in smaller stencil sizes, failing to meet the requirements of PCB prototype sizes. Other non-traditional methods, such as atomic force etching and self-assembly technology, are simple to operate and relatively low-cost for imprinting stencils, but controlling the degree of order over large areas is difficult, making them suitable only for research. Fourth, current template patterns are mostly periodic repeating patterns at the microscopic level, while circuit board patterns are complex and do not have periodic repeating patterns at the microscopic level. This makes template manufacturing more complicated, feature dimensions inconsistent, and it is difficult to control the depth and uniformity of the printing adhesive.

[0004] Therefore, producing high-quality, high-precision embossing stencils is the core issue in applying embossing technology to printed circuit boards. It is essential to provide an embossing mold for manufacturing printed circuit boards based on embossing technology and its preparation method to solve the aforementioned problems in the existing technology. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an embossing mold for manufacturing printed circuit boards based on embossing technology and its preparation method, so as to solve the problems of the complexity of existing template manufacturing, the limitation of template manufacturing size, the high material requirements, and the difficulty in effectively preparing large-area printed circuit boards based on embossing technology.

[0006] To achieve the above and other related objectives, the present invention provides a method for preparing an imprinting mold for printed circuit board manufacturing based on imprinting technology. The imprinting mold is prepared based on the mSAP process in PCB manufacturing, and the preparation method includes the following steps:

[0007] A substrate is provided, which is suitable for PCB fabrication and can be repeatedly imprinted;

[0008] A pattern layer to be imprinted is prepared on at least one side of the substrate, wherein the pattern to be imprinted is prepared in the pattern layer;

[0009] A predetermined metal plating layer is prepared on the side of the pattern layer to be imprinted that is away from the substrate;

[0010] The surface of the preset metal plating layer is subjected to an anti-sticking treatment to form an anti-sticking treatment layer.

[0011] Optionally, the substrate includes at least one of a polymaleimide triazine resin substrate and a ceramic substrate; wherein the ceramic substrate includes any one of an Al2O3 substrate, a BeO substrate, and an AlN substrate.

[0012] Optionally, the coefficient of thermal expansion of the substrate before the glass transition temperature is between 0.1ppm and 20ppm; the coefficient of thermal expansion after the glass transition temperature is between 0.1 and 100ppm; the glass transition temperature of the substrate is greater than 200°C; the thickness of the substrate is greater than 1mm; and the size of the substrate is greater than or equal to 15 inches.

[0013] Optionally, the preset metal coating is prepared using a chemical plating process.

[0014] Optionally, the imprinting mold based on the PCB mSAP process includes: preparing a metallic nickel template through lamination, exposure, development, electroplating, film removal, and electroless nickel plating. The metallic nickel constitutes the preset metal plating layer. The imprinting mold with the preset metal plating layer is conducive to the production of micro-irregular and periodically non-repeating template patterns. Specifically, a copper template is first prepared by the mSAP process to form the substrate, and then a layer of nickel is plated on the copper by electroless nickel plating to form a nickel template.

[0015] Optionally, the preset metal coating is an amorphous nickel-phosphorus alloy material layer, wherein the phosphorus content is between 1% and 4%.

[0016] Optionally, the flatness of the preset metal coating is Ra≤300nm; the thickness of the preset metal coating is between 3 and 5μm.

[0017] Optionally, the anti-sticking layer is formed by liquid phase deposition, and the anti-sticking layer comprises a mesh self-assembled monolayer film.

[0018] Optionally, the step of forming the network self-assembled monolayer includes: hydroxylating the surface of the preset metal coating; immersing the substrate with the preset metal coating in a mixed solution of H2SO4 and H2O2, where hydroxylation occurs on the surface through physical adsorption; directly immersing the hydroxylated substrate in a 0.5%–1.5% solution of a fluorinated organosilicon derivative, and then allowing it to stand at 60–70°C for 0.8–1.2 hours, where the halogen elements undergo hydrolysis, the chlorine atoms surrounding the silicon are replaced, forming Si-OH bonds; finally, the Si-OH bonds on the substrate undergo dehydration through hydrogen bonding with the fluorinated organosilicon derivative, ultimately forming a network self-assembled monolayer in the form of Si-O-Si covalent bonds, wherein the fluorinated organosilicon derivative includes F... 17 -FDTS.

[0019] Optionally, a printed circuit board pattern is prepared based on a dielectric material layer, wherein the side of the imprinting mold having the pattern to be imprinted constitutes an imprinting surface, and the imprinting surface cooperates with the dielectric material layer to perform imprinting.

[0020] Optionally, the dielectric layer material is a polymer film resin containing Si spheres based on epoxy resin, the size of which is between 0.1 and 5 μm; the epoxy resin base contains two types of functional groups to achieve two-stage curing, wherein, during the formation of the imprinted pattern, the semi-curing conditions are controlled based on the first type of functional group as follows: temperature between 100 and 140°C, semi-curing time between 5 and 15 min, and vacuum pump pressure between 0.5 and 5 MPa, so as to facilitate demolding based on the first type of functional group; the curing conditions are controlled based on the second type of functional group as follows: temperature between 160 and 200°C, curing time between 30 and 60 min, so as to improve the uniformity, steepness, and process stability of the imprinted pattern.

[0021] Optionally, the step of forming the patterned layer to be imprinted includes: forming a pad layer on the substrate; forming a patterned dry film on the pad layer, wherein a patterned window exposing the pad layer is formed in the patterned dry film; and preparing electroplated metal lines in the window to obtain the patterned layer to be imprinted.

[0022] The present invention also provides an imprinting mold for manufacturing printed circuit boards based on imprinting technology, preferably prepared by the above-described preparation method of the present invention, wherein the imprinting mold comprises:

[0023] substrate;

[0024] A pattern layer to be imprinted is formed on at least one side of the substrate, wherein the pattern to be imprinted is prepared in the pattern layer to be imprinted;

[0025] A pre-defined metal plating layer is formed on the side of the pattern layer to be imprinted that is away from the substrate;

[0026] An anti-sticking layer is formed on the side of the preset metal plating layer away from the pattern layer to be imprinted.

[0027] Optionally, the preset metal coating is an amorphous nickel-phosphorus alloy material layer, wherein the phosphorus content is 1% to 4%; the flatness of the preset metal coating is Ra≤300nm; and the thickness of the preset metal coating is between 3 and 5μm.

[0028] Optionally, the anti-sticking treatment layer comprises a mesh-like self-assembled monolayer film.

[0029] Optionally, the coefficient of thermal expansion of the substrate before the glass transition temperature is between 0.1ppm and 20ppm; the coefficient of thermal expansion after the glass transition temperature is between 0.1 and 100ppm; the glass transition temperature of the substrate is greater than 200°C; the thickness of the substrate is greater than 1mm; and the size of the substrate is greater than or equal to 15 inches.

[0030] Optionally, the substrate includes at least one of a polymaleimide triazine resin substrate and a ceramic substrate; wherein the ceramic substrate includes any one of an Al2O3 substrate, a BeO substrate, and an AlN substrate.

[0031] As described above, the embossing mold for printed circuit board manufacturing based on embossing technology and its preparation method of the present invention utilize a modified semi-additive process (mSAP) to prepare the embossing mold, form a preset metal plating layer on the surface of the embossing mold and perform anti-sticking treatment to form an anti-sticking layer, apply embossing technology to the manufacturing of PCB boards, and prepare metal lines through PCB processes. It is suitable for large-size PCB boards, can greatly improve the uniformity of lines with inconsistent complex feature dimensions, has high steepness, good process stability, can ensure mass production, and easily meets the requirements of the mold for hardness, tensile strength, etc. in the PCB embossing process. Attached Figure Description

[0032] Figure 1 The diagram shows the process flow for preparing the embossing mold for manufacturing printed circuit boards based on embossing technology according to the present invention.

[0033] Figure 2This is a schematic diagram showing the formation of a pattern layer to be imprinted on a substrate during the preparation of an example imprinting mold according to the present invention.

[0034] Figure 3 The diagram shown is a schematic diagram of the formation of a preset metal coating during the preparation of an example embossing mold according to the present invention.

[0035] Figure 4 The diagram shown is a schematic diagram of the formation of an anti-sticking treatment layer during the preparation of an example embossing mold according to the present invention.

[0036] Figure 5 The diagram shown is a schematic representation of the structure of a substrate to be imprinted, as an example of the present invention.

[0037] Figure 6 The diagram shown is an example of an embossing pattern formed using an embossing mold according to the present invention.

[0038] Figure 7 The diagram shows a mold core plate provided in the preparation of a double-sided embossing mold for a graphic to be embossed, as an example of the present invention.

[0039] Figure 8 The diagram shown is a schematic diagram of the pattern formation during the preparation of a double-sided embossing mold according to an example of the present invention.

[0040] Figure 9 The diagram shows a schematic of the process of removing the film to obtain the embossing mold in the preparation of a double-sided embossing mold for a pattern to be embossed, as an example of the present invention.

[0041] Component designation explanation

[0042] 100 Imprinting Die

[0043] 100a Imprint Surface

[0044] 101 substrate

[0045] 102 Pattern layer to be imprinted

[0046] 103 Preset metal plating

[0047] 104 Anti-sticking treatment layer

[0048] 200 substrate to be imprinted

[0049] 201 substrate

[0050] 202 Dielectric Layer

[0051] 203 Embossed Graphics

[0052] 300 mold core plate

[0053] 301, 302 copper layers

[0054] 303 dry film

[0055] 304 Pattern layer to be imprinted

[0056] 400 Substrate to be imprinted

[0057] Steps S1 to S4 Detailed Implementation

[0058] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0059] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0060] For ease of description, spatial relation terms such as "below," "below," "less than," "below," "above," and "upper" may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there may be one or more layers in between. Additionally, the term "between" as used in this invention includes both endpoint values.

[0061] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0062] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0063] like Figure 1 As shown, the present invention provides a method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology, comprising the following steps:

[0064] S1 provides a substrate;

[0065] S2, a pattern layer to be imprinted is prepared on at least one side of the substrate, wherein the pattern to be imprinted is prepared in the pattern layer;

[0066] S3, a preset metal plating layer is prepared on the side of the pattern layer to be imprinted that is away from the substrate;

[0067] S4, perform an anti-sticking treatment on the surface of the preset metal plating layer to form an anti-sticking treatment layer.

[0068] The following will describe in detail, with reference to the accompanying drawings, the method for preparing an imprinting mold for manufacturing a printed circuit board based on imprinting technology according to the present invention. It should be noted that the above order does not strictly represent the preparation order of the printed circuit board preparation method based on imprinting technology protected by the present invention, and those skilled in the art can change the order of steps according to the actual process. Figure 1 The only example shown is the preparation steps of a method for preparing a printed circuit board based on imprinting technology according to one embodiment of the present invention.

[0069] First, such as Figure 1 S1, S2 and Figure 2 As shown, a substrate 101 is provided, and a pattern layer 102 to be imprinted is prepared on at least one side of the substrate 101. The pattern to be imprinted is prepared in the pattern layer 102 for use in the preparation of the imprinting mold 100. The substrate 101 is preferably a substrate suitable for PCB manufacturing that can be imprinted multiple times.

[0070] As an example, the template body includes a substrate 101 and a pattern layer 102 to be imprinted formed on at least one surface of the substrate 101, wherein the pattern to be imprinted is formed in the pattern layer 102. That is, it can be a single pattern layer to be imprinted, or the pattern layer to be imprinted can be formed on both opposite surfaces of the substrate.

[0071] The substrate 101 can be a polymaleimide triazine resin substrate or a ceramic substrate; wherein the ceramic substrate can be a ceramic substrate of type Al2O3, BeO, AlN, etc. The substrate has good performance, high hardness, and low shrinkage. Before the glass transition temperature, the coefficient of thermal expansion of the substrate is between 0.1ppm and 20ppm, for example, 0.5ppm, 5ppm, or 6ppm; after the glass transition temperature, the coefficient of thermal expansion is between 0.1ppm and 100ppm, for example, 10ppm, 20ppm, or 50ppm. The glass transition temperature of the substrate is greater than 200℃, for example, 300℃ or 500℃. The thickness of the substrate is greater than 1mm, for example, 2mm, 3mm, or 5mm; it is less prone to warping and beneficial for controlling the depth of the imprinted pattern. The size of the substrate is greater than or equal to 15 inches.

[0072] Furthermore, the thickness of the pattern layer 102 to be imprinted is between 10 and 50 μm, such as 20 μm, 25 μm, and 30 μm, and can be selected according to actual needs; the material of the pattern layer 102 to be imprinted can be a copper material layer. The substrate and pattern layer to be imprinted with the above specifications help to ensure the rigidity and dimensional stability of the imprinting mold (such as the nickel template mentioned above), avoiding warping and deformation of the substrate during imprinting and demolding, which would affect the number of times the template can be used and lead to different depths of the imprinted pattern, increasing the difficulty of subsequent PCB electroplating and uniform copper removal.

[0073] As an example, the step of forming the pattern layer to be imprinted includes: forming a pad layer on the substrate 101, as shown in [reference]. Figure 7 As shown, the copper layers 301 and 302 serve as the pads described herein. The pads can be Cu layers with a thickness of 10 oz. A patterned dry film is formed on the pads, and a patterned window is formed in the patterned dry film to expose the pads. Electroplated metal lines are prepared in the window to obtain the patterned layer 102 to be imprinted.

[0074] Next, as Figure 1 S3 and Figure 3 As shown, a preset metal plating layer 103 is prepared on the side of the pattern layer 102 to be imprinted that is away from the substrate 101.

[0075] As an example, the preset metal plating layer 103 is formed on the surface of the pattern to be imprinted. That is, a metal layer, namely the preset metal plating layer 103, is formed on the surface of the pattern layer 102 to be imprinted, thereby achieving imprinting based on the preset metal plating layer 103 and the structure to be imprinted. In one example, the thickness of the preset metal plating layer 103 is between 3 and 5 μm, for example, it can be 3.5 μm, 4 μm, or 4.5 μm. In one example, the preset metal plating layer is an amorphous nickel-phosphorus alloy, wherein the phosphorus content is between 1% and 4% (mass percentage), which is low phosphorus and has a very high HV in the plating state. Of course, in other examples, it can also be a nickel layer. In addition, the plating surface has a very high flatness, Ra≤300nm, for example, 50nm, 100nm, or 200nm.

[0076] In one optional example, the preset metal plating layer 103 is prepared using a chemical plating process, resulting in good chemical stability. Alternatively, in another example, the preset metal plating layer 103 is preferably a nickel layer, which allows for good cooperation with the imprinted pattern layer and subsequent anti-sticking treatment layer, and is also beneficial for use with dielectric layer materials. The nickel plating template has a relatively smooth surface with low roughness, a uniform and dense nickel layer thickness, strong deep plating capability, strong corrosion resistance, and good coating adhesion. Furthermore, the nickel plating template itself also has advantages such as high hardness, low surface energy, and low interfacial tension, exhibiting non-wetting and chemical inertness to the polymer adhesive layer. It will not be damaged by tearing or breaking during subsequent demolding. Even under high-temperature polymer conditions, it does not easily adhere to the template. Specifically, for complex circuits with inconsistent feature dimensions according to the present invention, the chemically plated nickel layer is extremely uniform. As long as the plating solution can immerse the workpiece and ensure sufficient solute exchange, the plating layer will be very uniform, almost achieving a conformal effect. Electroplating cannot plate the entire surface of some complex-shaped workpieces, but chemical nickel plating can plate workpieces of any shape. Phosphorus-containing electroless nickel plating layers are amorphous, preferably low-phosphorus, with no intercrystalline gaps on the plating surface, while electroplating layers are typically crystalline and have a slower plating rate. The adhesion of electroless plating layers is generally higher than that of electroplating layers. Because electroless plating mostly uses food-grade additives and does not use harmful substances such as cyanide, it is more environmentally friendly than electroplating.

[0077] In a specific example, for the above-mentioned fabrication based on the modified semi-additive process (mSAP), a metallic nickel template is obtained through processes such as lamination, exposure, development, electroplating, stripping, and electroless nickel plating. Metal templates fabricated using the PCB mSAP process can have microscopically irregular and non-repeating patterns. A copper template is first fabricated using the mSAP process, and then a layer of nickel is plated onto the copper using an electroless nickel plating process to form a nickel template. Template fabrication using the PCB mSAP process allows for mass production, is highly efficient, low-cost, and can produce irregular and complex patterns. The size and depth of the molds are highly uniform.

[0078] Finally, as Figure 1 S4 and Figure 4 As shown, the surface of the preset metal plating layer 103 is subjected to an anti-sticking treatment to form an anti-sticking treatment layer 104. This results in an imprinting mold 100, where the surface of the anti-sticking treatment layer constitutes an imprinting surface 100a. The imprinting surface 100a refers to the patterned surface of the imprinting mold 100, that is, the surface of the imprinting mold 100 that contacts the structure to be imprinted. This invention uses the mSAP process for PCB fabrication to prepare the imprinting mold. The imprinting mold 100 uses an imprinting process to fabricate a printed circuit board, realizing the application of imprinting technology in PCBs. For example, for a nickel template with a nickel plating layer, after the nickel template is fabricated, an anti-sticking treatment is required on the template surface.

[0079] In the nanoimprinting process, the imprinting mold 100 transfers the pattern to the substrate (such as the dielectric layer mentioned later) through direct contact, and retains the pattern through the curing of the dielectric layer. After demolding, a structural pattern corresponding to the template is obtained on the dielectric layer. Regarding the two contact surfaces of the template-dielectric layer and the dielectric layer-substrate, to ensure successful imprinting, the adhesion force between the template and the dielectric layer must be much smaller than the adhesion force between the substrate and the dielectric layer. This prevents delamination during demolding. The adhesion force between the imprinting template and the dielectric layer is determined by the surface energy of the template and the dielectric layer. Low surface energy facilitates demolding; therefore, the anti-sticking treatment layer 104 constructed in this invention is beneficial for achieving effective demolding.

[0080] In one example, the anti-sticking layer 104 is selected as a fluorosilane self-assembled layer. Fluorinated organosilane derivatives are used for surface modification of the template, forming a fluorosilane self-assembled monolayer film on the template surface, effectively reducing the free surface energy of the template. Further, in an optional example, fluorinated organosilane derivatives are used for surface modification of this nickel template via liquid phase deposition. The fluorosilane self-assembled monolayer film of the present invention, combined with the inherent advantages of the metallic nickel template itself, such as high hardness, low surface energy, and low interfacial tension, will not be damaged by tearing or breaking during subsequent demolding, effectively realizing the fabrication of printed circuit boards. In addition, the low surface energy and low interfacial tension of the metal plating (such as metallic nickel) exhibit non-wetting and chemical inertness to the polymer adhesive layer. It does not easily adhere to the template even under high-temperature polymer conditions. Considering that the metal template is to be used repeatedly 200 times or more, repeated use may damage the surface metal plating. Therefore, in this invention, a liquid-phase deposition method is used to directly immerse the surface-hydroxylated template onto a nickel template in a diluted fluorinated organosilicon derivative, ultimately forming a network-like self-assembled monolayer film, resulting in an anti-adhesion material with properties similar to Teflon. This provides better anti-adhesion performance, allows for repeated use, and produces less contaminants. Furthermore, the combination of the anti-adhesion treatment and the pre-designed metal plating further enhances the anti-adhesion effect.

[0081] In one example, the steps for forming the network self-assembled monolayer film include: hydroxylating the surface of the pre-defined metal coating; immersing the template in a mixed solution of H2SO4 and H2O2, where hydroxylation occurs on the surface through physical adsorption; directly immersing the hydroxylated template in approximately 1% fluorine-containing solution, and then allowing it to stand at 65°C for 1 hour. Halogen elements undergo hydrolysis, chlorine atoms surrounding Si are replaced, forming Si-OH bonds. Finally, the Si-OH bonds on the template bond with fluorine-containing organosilicon derivatives such as F... 17 -FDTS undergoes dehydration due to hydrogen bonding and ultimately bonds together in the form of Si-O-Si covalent bonds to form a network of self-assembled monolayers.

[0082] The imprinting mold 100 is fabricated using a modified semi-additive process (mSAP). Currently, most molds are small, such as 4-inch, 6-inch, 8-inch, and 10-inch, often requiring custom-made molds. However, molds of PCB-sized dimensions (>510mm*410mm) are almost nonexistent. Using PCB technology to fabricate molds allows for large mold sizes, mass production, high efficiency, low cost, and the creation of irregular and complex patterns. This invention, based on PCB mSAP technology, can fabricate large-size molds >15 inches (15-inch, 18-inch, 20-inch…28-inch, etc.), or even larger or smaller, comparable to the size of a PCB board, far exceeding traditional mold sizes. For example, a nickel mold, comprising the substrate 101, the pattern layer 102 (Cu layer) to be imprinted, and the preset metal plating layer 103 (nickel layer) formed on the surface of the pattern layer, is fabricated using a modified semi-additive process (mSAP) through lamination, exposure, development, electroplating, stripping, and nickel plating processes to obtain the nickel mold. The stencil body, consisting of a substrate and a pattern layer to be imprinted, is prepared using the mSAP process. Specific process steps can utilize existing techniques, followed by nickel plating. Metal stencils fabricated using PCB mSAP can exhibit microscopically irregular and non-repeating patterns. Alternatively, a copper stencil is first prepared using the mSAP process, followed by electroless nickel plating to form a nickel stencil. PCB mSAP stencil fabrication allows for mass production, is highly efficient, low-cost, and can produce irregular and complex patterns. The mold size and depth exhibit high uniformity.

[0083] As an example, see Figures 5-6 As shown, a substrate 200 to be imprinted is provided. An imprinting process is performed on the substrate 200 based on the imprinting mold 100 to transfer a pattern from the imprinting mold 100 to the substrate 200, resulting in an imprinted pattern 203. The substrate 200 includes a substrate 201 and a dielectric layer 202 formed on the surface of the substrate 201, and the imprinted pattern 203 is formed in the dielectric layer 202.

[0084] As an example, the dielectric layer material is a polymer film resin based on epoxy resin containing Si spheres, with the Si sphere size ranging from 0.1 to 5 μm, such as 0.8 μm or 3 μm. During the formation of the imprinted pattern, the semi-curing conditions are controlled as follows: semi-curing at a temperature between 100 and 140°C (e.g., 110°C or 120°C) for 5 to 15 minutes (e.g., 8 minutes or 12 minutes), and controlling the vacuum pump pressure between 0.5 and 5 MPa (e.g., 0.8 MPa, 2 MPa, or 3 MPa), which facilitates demolding. The curing conditions are controlled as follows: curing at 160 to 200°C (e.g., 170°C or 180°C) for 30 to 60 minutes (e.g., 40 minutes or 50 minutes), achieving high uniformity, steepness, and process stability in the imprinted pattern, ensuring mass production. In a preferred example, the epoxy resin base is selected to contain two types of functional groups, exhibiting a two-stage curing characteristic. These two types of functional groups facilitate the achievement of the effects described above. Among these, the functional groups that play a role in the semi-curing and curing processes are: the first type of functional groups, which facilitate demolding under semi-curing conditions; and the second type of functional groups, which, under curing conditions, result in embossed patterns with good uniformity, high steepness, and good process stability, ensuring mass production. In one example, the steps for forming the embossed pattern include: imprinting the medium layer based on the embossing mold to form a semi-cured pattern in the medium layer; performing a demolding process to remove the embossing mold; and curing the semi-cured pattern to form the embossed pattern.

[0085] As an example, the steps for forming the embossed pattern 203 include: First, embossing the medium layer 202 based on the embossing mold 100 to form a semi-cured pattern in the medium layer; embossing can be performed after an anti-sticking treatment, and the semi-cured pattern is formed by controlling pressure, temperature, and time, with a curing degree between 40% and 60%, or up to 50%. Then, a demolding process is performed to remove the embossing mold 100. After demolding, the semi-cured pattern is cured to completely cure the material, thereby forming the embossed pattern 203.

[0086] As an example, such as Figures 7-9 As shown, an example of double-layer imprinting is provided, wherein the specific process is as follows: Figure 7 As shown, a mold core plate 300 is provided, and copper layers 301 and 302 are laminated to form copper layers, wherein the thickness can be 1 oz. Then, as... Figure 8 As shown, a dry film 303 is formed by lamination, wherein a pattern window is formed in the dry film, and metal is electroplated in the window to form the pattern to be imprinted 304. The film is then removed, as shown below. Figure 9 As shown, the circuit patterns on both sides of the embossing mold can be the same or different; in addition, a preset metal plating layer is formed on it and an anti-sticking treatment is performed to form an anti-sticking treatment layer, which is not shown in the figure.

[0087] This invention applies imprinting technology to PCBs to create patterned circuits that meet design requirements, producing high-precision and repeatable circuit patterns. A modified semi-additive process (mSAP) is used to prepare a nickel template. The PCB mSAP process enables mass production with high efficiency and low cost, and can create irregular and complex patterns. The size and depth of the mold are highly uniform. The nickel template is obtained through processes such as lamination, exposure, development, electroplating, stripping, and nickel plating. The nickel template's linewidth and spacing meet design requirements, and its depth is uniform, facilitating subsequent imprinting and PCB wet processing. After the nickel template surface undergoes an anti-sticking treatment before imprinting, demolding, and curing, a pattern with uniform depth is obtained. The imprinted board undergoes processes such as desmearing, PTH (partial heat treatment), electroplating, and copper removal to produce complete circuits with uniform linewidth, meeting design requirements. Imprint lithography can produce finer lines (50μm, 40μm, 30μm, 10μm, or even finer). The solution based on this invention helps solve the problems of complex and varied PCB patterns, which are microscopically non-periodic and repetitive, making template fabrication difficult. Furthermore, due to the large size of PCBs, there is a lack of matching imprint lithography and anti-sticking equipment on the market. The solution based on this invention effectively solves these problems. This invention applies imprint lithography technology to PCB manufacturing without requiring complex upgrades to existing equipment, facilitating mass production and promoting the development of the entire process.

[0088] In addition, the present invention also provides an imprinting mold for a process of preparing printed circuit boards based on imprinting technology. The imprinting mold for manufacturing printed circuit boards is preferably prepared using the above-described process of the present invention. The specific structural features and related descriptions can be found in the above description and will not be repeated here. The imprinting mold includes a template body and a preset metal plating layer. The template body has a pattern to be imprinted. The preset metal plating layer is formed on the surface of the pattern to be imprinted. An anti-sticking treatment layer is also formed on the surface of the preset metal plating layer.

[0089] The embossing mold includes:

[0090] substrate 101;

[0091] A pattern layer 102 to be imprinted is formed on at least one side of the substrate 101, and a pattern to be imprinted is prepared in the pattern layer 102.

[0092] A pre-set metal plating layer 103 is formed on the side of the pattern layer 102 to be imprinted that is away from the substrate 101;

[0093] An anti-sticking treatment layer 104 is formed on the side of the preset metal plating layer 103 away from the pattern layer 102 to be imprinted.

[0094] As an example, the preset metal coating 103 is an amorphous nickel-phosphorus alloy material layer, wherein the phosphorus content is between 1% and 4%; the flatness of the preset metal coating is Ra≤300nm; and the thickness of the preset metal coating is between 3 and 5μm.

[0095] As an example, the anti-sticking treatment layer 104 comprises a mesh-like self-assembled monolayer film.

[0096] As an example, the coefficient of thermal expansion of the substrate 101 before the glass transition temperature is between 0.1ppm and 20ppm; the coefficient of thermal expansion after the glass transition temperature is between 0.1 and 100ppm; the glass transition temperature of the substrate is greater than 200°C; the thickness of the substrate is greater than 1mm; and the size of the substrate is greater than or equal to 15 inches.

[0097] As an example, the substrate 101 includes at least one of a polymaleimide triazine resin substrate and a ceramic substrate; wherein the ceramic substrate includes any one of an Al2O3 substrate, a BeO substrate, and an AlN substrate.

[0098] In summary, the present invention provides an embossing mold for printed circuit board (PCB) fabrication based on embossing technology and its preparation method. The embossing mold is prepared using the mSAP process in PCB manufacturing. This invention utilizes a modified semi-additive process (mSAP) to prepare the embossing mold, forming a pre-defined metal plating layer on the mold surface and applying an anti-sticking treatment to form an anti-sticking layer. By applying embossing technology to PCB fabrication and preparing metal circuits using PCB processes, this invention is suitable for large-size PCBs. It can significantly improve the uniformity of circuits with inconsistent dimensions and features, exhibiting high steepness, good process stability, and ensuring mass production. It also easily meets the mold's requirements for hardness, tensile strength, etc., during PCB embossing. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial applicability.

[0099] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology, characterized in that, The imprinting mold is prepared using the mSAP process in PCB manufacturing. The preparation method includes the following steps: A substrate is provided, the substrate comprising at least one of a polymaleimide triazine resin substrate and a ceramic substrate, the substrate being suitable for PCB fabrication and capable of multiple imprinting processes; the coefficient of thermal expansion of the substrate before its glass transition temperature is between 0.1 ppm and 20 ppm; the coefficient of thermal expansion after its glass transition temperature is between 0.1 and 100 ppm; the glass transition temperature of the substrate is greater than 200°C; the thickness of the substrate is greater than 1 mm; and the size of the substrate is greater than or equal to 15 inches. A pattern layer to be imprinted is prepared on at least one side of the substrate, wherein the pattern to be imprinted is prepared in the pattern layer; the thickness of the pattern layer to be imprinted is between 10 and 50 μm. A preset metal plating layer is prepared on the side of the pattern layer to be imprinted that is away from the substrate; the preset metal plating layer is prepared by chemical plating process, and the preset metal plating layer is an amorphous nickel-phosphorus alloy material layer, wherein the phosphorus content is 1%~4%; the flatness of the preset metal plating layer is Ra≤300nm, and the thickness of the preset metal plating layer is between 3~5μm; The surface of the preset metal coating is subjected to an anti-sticking treatment, and an anti-sticking treatment layer is formed based on liquid phase deposition. The anti-sticking treatment layer includes a mesh self-assembled monolayer film.

2. The method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology according to claim 1, characterized in that, in, The ceramic substrate includes any one of Al2O3 substrate, BeO substrate and AlN substrate.

3. The method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology according to claim 1, characterized in that, The fabrication of the embossing mold based on the PCB mSAP process includes: preparing a metallic nickel template through lamination, exposure, development, electroplating, film removal, and electroless nickel plating. The metallic nickel constitutes the preset metal plating layer. The embossing mold with the preset metal plating layer is conducive to the fabrication of micro-irregular and periodically non-repeating template patterns. Specifically, a copper template is first prepared by the mSAP process to form the substrate, and then a layer of nickel is plated on the copper by electroless nickel plating to form a nickel template.

4. The method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology according to claim 1, characterized in that, The steps for forming the network self-assembled monolayer include: hydroxylating the surface of the preset metal coating; immersing the substrate with the preset metal coating in a mixed solution of H2SO4 and H2O2, where hydroxylation occurs on the surface through physical adsorption; directly immersing the hydroxylated substrate in a 0.5%~1.5% solution of a fluorinated organosilicon derivative, and then allowing it to stand at 60~70℃ for 0.8~1.2h, where halogen elements undergo hydrolysis, chlorine atoms around silicon are replaced, forming Si-OH bonds; finally, the Si-OH bonds on the substrate undergo dehydration through hydrogen bonding with the fluorinated organosilicon derivative, ultimately forming a network self-assembled monolayer in the form of Si-O-Si covalent bonds. The fluorinated organosilicon derivative includes F... 17 -FDTS.

5. The method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology according to claim 1, characterized in that, Printed circuit board patterns are prepared based on dielectric material layers, wherein the side of the imprinting mold with the pattern to be imprinted constitutes an imprinting surface, and the imprinting surface cooperates with the dielectric material layer to perform imprinting.

6. The method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology according to claim 5, characterized in that, The dielectric layer material is an epoxy resin-based polymer film resin containing Si spheres, the size of which is between 0.1 and 5 μm. During the formation of the imprinted pattern, the semi-curing conditions are controlled as follows: temperature between 100 and 140°C, semi-curing time between 5 and 15 min, and vacuum pump pressure between 0.5 and 5 MPa. The curing conditions are controlled as follows: temperature between 160 and 200°C, and curing time between 30 and 60 min.

7. The method for preparing an embossing mold for manufacturing printed circuit boards based on embossing technology according to any one of claims 1 to 6, characterized in that, The step of forming the patterned layer to be imprinted includes: forming a pad layer on the substrate; forming a patterned dry film on the pad layer, wherein a patterned window is formed in the patterned dry film to expose the pad layer; and preparing electroplated metal lines in the window to obtain the patterned layer to be imprinted.

8. An embossing mold for manufacturing printed circuit boards based on embossing technology, characterized in that, The die is prepared using the method for preparing an embossing mold for printed circuit board manufacturing based on embossing technology as described in any one of claims 1-6, wherein the embossing mold comprises: The substrate comprises at least one of a polymaleimide triazine resin substrate and a ceramic substrate, wherein the coefficient of thermal expansion of the substrate before the glass transition temperature is between 0.1 ppm and 20 ppm; the coefficient of thermal expansion after the glass transition temperature is between 0.1 and 100 ppm; the glass transition temperature of the substrate is greater than 200°C; the thickness of the substrate is greater than 1 mm; and the size of the substrate is greater than or equal to 15 inches. A pattern layer to be imprinted is formed on at least one side of the substrate, wherein the pattern to be imprinted is prepared in the pattern layer to be imprinted; A preset metal plating layer is formed on the side of the pattern layer to be imprinted that is away from the substrate. The preset metal plating layer is an amorphous nickel-phosphorus alloy material layer, wherein the phosphorus content is 1% to 4%. The flatness of the preset metal plating layer is Ra≤300nm. The thickness of the preset metal plating layer is between 3 and 5μm. An anti-sticking treatment layer is formed on the side of the preset metal plating layer away from the pattern layer to be imprinted, and the anti-sticking treatment layer includes a mesh self-assembled monolayer film.

9. The embossing mold for manufacturing printed circuit boards based on embossing technology according to claim 8, characterized in that, The substrate includes at least one of a polymaleimide triazine resin substrate and a ceramic substrate; wherein the ceramic substrate includes any one of an Al2O3 substrate, a BeO substrate, and an AlN substrate.

Images