Composite substrate and preparation method therefor, and circuit board

Abstract

The present application relates to a composite substrate and a preparation method therefor, and a circuit board. The composite substrate comprises a base layer and a first resistor layer, which is arranged on at least one surface of the base layer, wherein the thickness of the first resistor layer satisfies the following relational expression: d=1.2 / R+K, where d is the thickness of the first resistor layer, R is sheet resistance, and the value range of K is -0.3 to 3. In the present application, by means of controlling the resistance value R of a resistor layer and the thickness d of the resistor layer to satisfy a certain linear relational expression, a composite substrate, which satisfies the equation, has good resistance stability; moreover, the preparation of the composite substrate by using the method disclosed in the present application has a simple process flow, which simplifies a preparation process, thereby improving the production efficiency of the composite substrate.

Description

Composite substrate, preparation method thereof, and circuit board

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on July 25, 2023, with application number 202310914376.2 and invention name “A composite substrate, its preparation method and circuit board”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of thin film devices, and in particular to a composite substrate, a preparation method thereof, and a circuit board. Background Art

[0004] Composite substrate is a commonly used raw material for preparing embedded resistor elements. However, in the prior art, the resistance stability of composite substrates prepared with specific resistance values ​​is poor, and it is often necessary to stop the running preparation process and directly measure the resistance of the product of this process section to see whether the prepared composite substrate has reached the expected resistance value. When the expected resistance value is not reached, the composite substrate is continued to be processed until the expected resistance value is reached. However, the uncertainty factors in the above-mentioned preparation process are very large, and continued processing often easily leads to a large deviation between the resistance value of the resistor layer and the standard value, resulting in the eventual scrapping of the product. In addition, in order to obtain a composite substrate with an ideal resistance value, conventional preparation requires uninterrupted shutdown testing, and this process also leads to a reduction in work efficiency and a waste of resources. Therefore, there is an urgent need to provide a composite substrate that can reduce the resistance detection process in the preparation process.

[0005] Summary of the Invention

[0006] In view of the problems existing in the prior art, the present application provides a composite substrate, a preparation method thereof, and a circuit board. By limiting the relationship between the resistivity ρ and thickness of the first resistance layer in the composite substrate, a composite substrate with an ideal resistance value R is prepared. The obtained composite substrate has stable performance, simplifies the preparation process, and improves production efficiency.

[0007] To achieve this goal, this application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a composite substrate comprising a base layer and a first resistive layer disposed on at least one surface of the base layer;

[0009] The thickness of the first resistance layer satisfies the following relationship:

[0010] d=1.2 / R+K

[0011] Wherein, d is the thickness of the first resistor layer; R is the square resistance; the value range of K is -0.3 to 3; and the unit of 1.2 is μΩ·m.

[0012] Optionally, the value range of d is 5 nm to 3 μm.

[0013] Optionally, the value range of R is 5 to 100Ω.

[0014] Optionally, the material of the first resistance layer includes any one of NiCrSi, NiCrAlSi, NiP, NiCr, AlN, TiN, Pt, Cr, Cr-SiO, Cr-Si, Ti-Si, Ti-W, TaN, Mo or Ni-Sn, or a combination of at least two of them.

[0015] Optionally, the composite substrate further includes a film layer disposed on a surface of the first resistor layer away from the base layer.

[0016] Optionally, the material of the film layer includes any one or a combination of at least two of polystyrene thermoplastic resin, vinyl acetate thermoplastic resin, polyester thermoplastic resin, polyethylene thermoplastic resin, polyamide thermoplastic resin, rubber thermoplastic resin, acrylic thermoplastic resin, phenolic thermosetting resin, epoxy thermosetting resin, thermoplastic polyimide thermosetting resin, urethane thermosetting resin, melamine thermosetting resin, alkyd thermosetting resin or ABF resin.

[0017] Optionally, a conductive layer is provided on a surface of the film layer away from the first resistance layer.

[0018] Optionally, the conductive layer includes a single layer or multiple layers.

[0019] Optionally, the conductive layer is made of a foil containing at least one of copper, aluminum, titanium, zinc, iron, nickel, chromium, cobalt, silver or gold.

[0020] Optionally, the thickness of the conductive layer is 8 μm to 35 μm.

[0021] Optionally, a second resistance layer is provided between the film layer and the conductive layer.

[0022] Optionally, the thickness of the second resistance layer is 5 nm to 3 μm.

[0023] In a second aspect, the present application provides a method for preparing a composite substrate, for preparing the composite substrate as described in the first aspect, the preparation method comprising the following steps:

[0024] Step 1: setting the resistance value R of the first resistor layer in the composite substrate layer;

[0025] Step 2: Based on the resistance value R set in step 1 and the formula d = 1.2 / R + K, calculate the thickness d of the first resistor layer:

[0026] Step 3: Surface treatment of the base layer;

[0027] Step 4: forming a first resistance layer on the surface of the base layer described in step 3 to prepare a composite substrate.

[0028] Optionally, the first resistor layer is formed by any one of electroplating, chemical plating, physical vapor deposition, or chemical vapor deposition, or a combination of at least two of them. Optionally, after providing the first resistor layer, the method further includes: providing a film layer on a surface of the first resistor layer away from the base layer.

[0029] Optionally, after providing the film layer, the method further includes: providing a second resistance layer on a surface of the film layer away from the first resistance layer.

[0030] Optionally, after providing the second resistance layer, the method further includes: providing a conductive layer on a surface of the second resistance layer on a side away from the film layer.

[0031] In a third aspect, the present application provides a circuit board, comprising the composite substrate as described in the first aspect.

[0032] According to the above technical solution, the beneficial effects of this application are as follows:

[0033] The present application designs a sheet-like stacked composite substrate and controls the resistivity ρ, resistance R and thickness d of the resistor layer to satisfy a certain linear relationship, so that the composite substrate that satisfies the equation has good resistance stability. In addition, the method disclosed in the present application is used to prepare the composite substrate, which has a simple process flow, simplifies the preparation process, and improves the production efficiency of the composite substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic structural diagram of the composite substrate described in Example 1.

[0035] FIG2 is a schematic structural diagram of the composite substrate described in Example 2.

[0036] FIG3 is a schematic structural diagram of the composite substrate described in Example 3.

[0037] FIG4 is a schematic structural diagram of the composite substrate described in Example 4.

[0038] Among them: 1-base layer, 2-first resistance layer, 3-film layer, 4-second resistance layer, 5-conductive layer, 6-first conductive layer, 7-second conductive layer. DETAILED DESCRIPTION

[0039] The technical solution of the present application is further described below through specific implementation methods. However, the following examples are merely simplified examples of the present application and do not represent or limit the scope of protection of the present application. The scope of protection of the present application shall be subject to the claims.

[0040] After extensive data testing, the researchers discovered a linear relationship between the resistance value (R), resistivity (ρ), and thickness of the composite substrate. Maintaining this linear relationship resulted in a relatively stable sheet resistance, simplified the fabrication process, and improved production efficiency.

[0041] According to one aspect of the present application, a composite substrate is provided, comprising a base layer and a first resistor layer disposed on at least one surface of the base layer;

[0042] The thickness of the first resistance layer satisfies the following relationship:

[0043] d=1.2 / R+K

[0044] Wherein, d is the thickness of the first resistor layer, R is the square resistance, the unit of 1.2 is μΩ·m, and the value range of K is -0.3 to 3, for example, it can be -0.3, 0, 1, 2 or 3, or a range between any two of the above values.

[0045] The inventors of this application have discovered that within a certain range, the thickness of the resistor layer has a certain linear correlation with its resistance value, and the thickness of the resistor layer can be controlled by d = 1.2 / R + K. In order to obtain a resistor layer with a certain resistance value, the thickness of the resistor layer needs to be continuously adjusted during the actual preparation process of the resistor layer. For example, every time a resistor layer of a certain thickness is obtained by sputtering, its resistance value needs to be tested to see if it meets the required requirements. The sputtering and resistance value testing are repeatedly stopped until the resistor layer reaches the target resistance value, thereby reducing production efficiency. However, by using the relationship d = 1.2 / R + K, a resistor layer with the desired resistance value can be obtained in one go, eliminating the need for repeated testing during the preparation process, saving production time and improving production efficiency.

[0046] In some embodiments, the value range of the first resistance layer d is 5 nm to 3 μm, for example, it can be 5 nm, 10 nm, 80 nm, 100 nm, 300 nm, 500 nm, 1 μm, 2 μm, 2.5 μm or 3 μm, or a range between any two of the above values. Optionally, the value range of the first resistance layer d is 5 nm to 100 nm.

[0047] In some embodiments, the resistance R of the first resistor layer is in the range of 5 to 100Ω. On the basis of satisfying the above range, the thickness relationship of the first resistor layer also needs to be satisfied. For example, it can be 5Ω, 10Ω, 15Ω, 20Ω, 25Ω, 30Ω, 35Ω, 40Ω, 45Ω, 50Ω, 55Ω, 60Ω, 65Ω, 70Ω, 75Ω, 80Ω, 85Ω, 90Ω, 95Ω or 100Ω, or a range between any two of the above values. Optionally, the resistance R of the first resistor layer is in the range of 20 to 80Ω.

[0048] The thickness of the resistor layer determines its resistance. This application specifies the thickness of the first resistor layer d to be within the range of 5 nm to 3 μm, which allows the resistance of the resistor layer to exhibit the aforementioned linear relationship within the range of 5 to 100 Ω. The thickness of any resistor layer with a resistance within this range can be calculated using the aforementioned linear equation. This allows the preparation process to produce a resistor layer with this resistance value in a single pass, eliminating the need for repeated sputtering and measurement. It should be noted that the material of the first resistor layer includes any one of NiCrSi, NiCrAlSi, NiP, NiCr, AlN, TiN, Cr-SiO, Cr-Si, Pt, Cr, Ti-Si, Ti-W, TaN or Ni-Sn, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of NiCrSi and NiCrAlSi, a combination of NiCrAlSi and NiP, a combination of NiP and NiCr, a combination of NiCr and AlN, a combination of AlN and TiN, a combination of TiN and Pt, a combination of Pt and Cr, a combination of Cr and Cr-SiO, a combination of Cr-SiO and Cr-Si, a combination of Cr-Si and Ti-Si, a combination of Ti-Si and Ti-W, a combination of Ti-W and TaN, a combination of TaN and Mo, and a combination of Mo and Ni-Sn.

[0049] It should be further explained that the material of the base layer is a conductive material or a dielectric material, and the base layer can be a single-layer structure or a stacked multi-layer structure.

[0050] The conductive material includes but is not limited to at least one of copper, aluminum, titanium, zinc, iron, nickel, chromium, cobalt, silver and gold. Specifically, the base layer can be at least one of copper foil, aluminum foil, titanium foil, zinc foil, iron foil, nickel foil, chromium foil, cobalt foil, silver foil or gold foil. It can also be an alloy foil containing at least two of copper, aluminum, titanium, zinc, iron, nickel, chromium, cobalt, silver and gold. It can also be a composite foil composed of at least two of copper foil, aluminum foil, titanium foil, zinc foil, iron foil, nickel foil, chromium foil, cobalt foil, silver foil and gold foil.

[0051] The dielectric material includes but is not limited to PET, PP, PS, ABF film, BT resin, polyacrylic acid, polyurethane, polyimide, etc. In the base layer with a multi-layer structure, the materials of different layers can be the same or different.

[0052] The thickness of the base layer is 3 to 20 μm, for example, 3 μm, 5 μm, 10 μm, 15 μm or 20 μm, or a range between any two of the above values.

[0053] In some embodiments, the composite substrate further includes a film layer disposed on a surface of the first resistor layer away from the base layer.

[0054] In some embodiments, the film layer has a thickness of 0.5 to 100 μm. For example, the film layer may have a thickness of 2 μm, 5 μm, 7 μm, 10 μm, 12 μm, 15 μm, 20 μm, 30 μm, 40 μm, 55 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, or a range between any two of the above values.

[0055] In some embodiments, the material of the film layer includes any one or a combination of at least two of a polystyrene-based thermoplastic resin, a vinyl acetate-based thermoplastic resin, a polyester-based thermoplastic resin, a polyethylene-based thermoplastic resin, a polyamide-based thermoplastic resin, a rubber-based thermoplastic resin, an acrylic-based thermoplastic resin, a phenolic-based thermosetting resin, an epoxy-based thermosetting resin, a thermoplastic polyimide-based thermosetting resin, a urethane-based thermosetting resin, a melamine-based thermosetting resin, an alkyd-based thermosetting resin, or an ABF resin. Exemplarily, the film layer is selected from at least one of modified epoxy resin, modified acrylic resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, polystyrene, polyvinyl chloride, polysulfone, polyphenylene sulfide, polyetheretherketone, polyphenylene oxide, polytetrafluoroethylene, liquid crystal polymer, polyoxaline, epoxy glass cloth, or BT resin. The specific thickness and material of the film layer are selected and set by those skilled in the art according to actual needs.

[0056] In some embodiments, a conductive layer is provided on the surface of the film layer away from the first resistor layer. The conductive layer further forms a foil-clad plate containing the first resistor layer. The foil-clad plate has a four-layer structure and can be directly applied to a hard board or a soft board. Specifically, the conductive layer can be a single-layer structure or a multi-layer structure. That is, the conductive layer can be copper foil, aluminum foil, titanium foil, zinc foil, iron foil, nickel foil, chromium foil, cobalt foil, silver foil or gold foil, or an alloy foil containing at least two of copper, aluminum, titanium, zinc, iron, nickel, chromium, cobalt, silver and gold, or a composite foil composed of at least two of copper foil, aluminum foil, titanium foil, zinc foil, iron foil, nickel foil, chromium foil, cobalt foil, silver foil and gold foil. The material of the conductive layer can be the same as or different from the material of the base layer, and those skilled in the art can make the arrangement according to actual needs.

[0057] The thickness of the conductive layer is 8 to 35 μm, for example, 8 μm, 10 μm, 20 μm, 30 μm or 35 μm, or a range between any two of the above values.

[0058] In an optional embodiment, a second resistor layer is disposed between the film layer and the conductive layer, thereby forming an asymmetric structure. The material and thickness of the second resistor layer may be the same as or different from those used for the first resistor layer, and those skilled in the art can adjust the thickness based on actual needs. The thickness of the second resistor layer is 5 nm to 3 μm, for example, 5 nm, 10 nm, 50 nm, 100 nm, 500 nm, 1 μm, 2 μm, or 3 μm, or a range between any two of the aforementioned values.

[0059] According to another aspect of the present application, a preparation method is provided for preparing the above-mentioned composite substrate, the preparation method comprising the following steps:

[0060] Step 1: setting the resistance value R of the first resistor layer in the composite substrate layer;

[0061] Step 2: Calculate the thickness d of the first resistor layer based on the resistance value R set in step 1 and the formula d = 1.2 / R + K;

[0062] Step 3: Surface treatment of the base layer;

[0063] Step 4: forming a first resistance layer on the surface of the base layer described in step 3 to prepare a composite substrate.

[0064] It should be noted that the first resistive layer can be formed by any one of electroplating, electroless plating, physical vapor deposition, or chemical vapor deposition, or a combination of at least two. Surface treatment methods include corona treatment, plasma treatment, electroplating, electroless plating, sputtering, application of a coupling agent or adhesive, etching, polishing, or other techniques that can implement this solution, which are not listed in detail here. The specific surface treatment method or combination of surface treatment methods is at the discretion of those skilled in the art based on actual needs.

[0065] In some embodiments, after providing the first resistor layer, the process further includes providing a film layer on a surface of the first resistor layer facing away from the base layer. This film layer protects the first resistor layer from damage by external forces. Furthermore, when the composite metal foil is attached to a circuit board, the film layer adheres to the first resistor layer and the circuit board, further enhancing the peel strength between the composite foil and the circuit board. This prevents the composite metal foil from being easily peeled off the circuit board, facilitating the subsequent preparation of a resistor layer with a specific shape. Furthermore, the film layer can be used to produce a foil-clad laminate or directly applied to a flexible printed circuit board.

[0066] According to another aspect of the present application, a circuit board is provided, comprising the composite substrate.

[0067] The technical solution of the present application will be further explained below with reference to the accompanying drawings and through specific implementation methods.

[0068] Example 1

[0069] This embodiment provides a composite substrate, the structure of which is shown in FIG1 , which includes a base layer 1 , a first resistor layer 2 , a film layer 3 , a second resistor layer 4 and a conductive layer 5 stacked in sequence from bottom to top.

[0070] The base layer 1 is made of PET with a thickness of 5 μm; the film layer 3 is made of polystyrene thermoplastic resin with a thickness of 8 μm; the conductive layer 5 is made of copper with a thickness of 10 μm.

[0071] The materials of the first resistance layer 2 and the second resistance layer 4 are independently NiCr, and their thicknesses independently satisfy the following relationship:

[0072] d=1.2 / R+K

[0073] Where d is the thickness of the resistor layer, 5 nm, R is 5Ω, and K is -0.235.

[0074] Example 2

[0075] This embodiment provides a composite substrate having a symmetrical structure as shown in FIG2 , wherein a first resistance layer 2 , a film layer 3 , a second resistance layer 4 and a conductive layer 5 are formed on both sides of a base layer 1 .

[0076] The base layer 1 is made of BT resin with a thickness of 20 μm; the film layer 3 is made of polyamide thermoplastic resin with a thickness of 7 μm; the conductive layer 5 is made of aluminum with a thickness of 15 μm.

[0077] The materials of the first resistance layer 2 and the second resistance layer 4 are independently NiCr, and their thicknesses independently satisfy the following relationship:

[0078] d=1.2 / R+K

[0079] Wherein, d is the thickness of the resistance layer, which is 21.8 nm, R is 50Ω, and K is -0.0022.

[0080] Example 3

[0081] This embodiment provides a composite substrate, the structure of which is shown in FIG3 , which includes a base layer 1 , a first resistance layer 2 , a film layer 3 , a second resistance layer 4 , a first conductive layer 6 , and a second conductive layer 7 stacked in sequence from bottom to top.

[0082] The base layer 1 is made of polyimide and has a thickness of 3 μm. The film layer 3 is made of acrylic thermoplastic resin and has a thickness of 100 μm. The first conductive layer 6 is made of aluminum and has a thickness of 15 μm. The second conductive layer is made of zinc and has a thickness of 35 μm.

[0083] The materials of the first resistance layer 2 and the second resistance layer 4 are independently NiP, and their thicknesses independently satisfy the following relationship:

[0084] d=1.2 / R+K

[0085] Where d is the thickness of the resistor layer, 3 μm, R is 60 Ω, and K is 2.98.

[0086] Example 4

[0087] This embodiment provides a composite substrate having a symmetrical structure as shown in FIG4 , wherein a first resistance layer 2 , a film layer 3 , a second resistance layer 4 , a first conductive layer 6 and a second conductive layer 7 are formed on both sides of a base layer 1 .

[0088] The base layer 1 is made of aluminum with a thickness of 10 μm; the film layer 3 is made of polybutylene terephthalate with a thickness of 40 μm; the first conductive layer 6 and the second conductive layer 7 are made of copper with a thickness of 15 μm respectively;

[0089] The materials of the first resistance layer 2 and the second resistance layer 4 are independently NiP, and their thicknesses independently satisfy the following relationship:

[0090] d=1.2 / R+K

[0091] Wherein, d is the thickness of the first resistance layer 3 μm, R is 100Ω, and K is 2.985.

[0092] It should also be noted that the thickness and material of the first resistance layer 2 and the second resistance layer 4 of the present application can be the same or different, and the thickness and material of the first conductive layer 6 and the second conductive layer 7 can be the same or different, and can be adjusted according to actual needs.

[0093] Comparative Example 1

[0094] This embodiment provides a composite substrate, which differs from embodiment 1 in that the thickness d of the first resistance layer is 1 nm, and R is 3Ω.

[0095] Comparative Example 2

[0096] This embodiment provides a composite substrate, which differs from embodiment 1 in that the thickness d of the first resistance layer is 5 μm, and R is 150Ω.

[0097] The composite foils obtained above were subjected to resistance stability testing. The test method was as follows: the composite foils obtained in the above examples and comparative examples were tested at room temperature using a four-probe resistance tester, and then the resistance of the composite foils was measured at 100°C. The resistance stability was calculated using the following formula:

[0098] Wherein, R1 is the resistance value of the foil measured at room temperature, and R2 is the resistance value of the foil measured at 100°C.

[0099] The test results are shown in Table 1.

[0100] Table 1

[0101] As shown in Table 1, by controlling the thickness d, resistance R, and K range of the resistor layer, the thickness d of the resistor layer satisfies the linear relationship of d = 1.2 / R + K. This ensures that the composite substrate exhibits good resistance stability. Furthermore, during the manufacturing process, the thickness and resistance of the resistor layer are adjusted using this linear relationship, reducing the number of resistance measurement steps required in the prior art and improving process efficiency and yield.

[0102] In addition, after a large number of tests in this application to optimize the linear relationship between the thickness of the resistor layer and its resistance value, it was confirmed that when the value range of the resistor layer d is 5nm to 3μm, the resistance value of the resistor layer can be well regulated. At the same time, it was unexpectedly found that the resistance of the resistor layer obtained by the above linear relationship also has good stability (Examples 1 to 4). This may be because the resistor layer obtained by regulating the linear relationship of this application is formed in one step, and there is no need to repeatedly stop sputtering (or electroplating) and testing in the middle, and the internal atoms (or molecules) of the resistor layer are arranged more uniformly. However, Comparative Examples 1 and 2 are outside the scope of this application and do not show the linear relationship between the thickness of the resistor layer and the resistance value in this application. Therefore, repeated testing and sputtering (or electroplating) are required to form the resistor layer of the required resistance value during the preparation process. Therefore, stratification will occur inside the resistor layer, resulting in uneven arrangement of the internal atoms (or molecules) of the resistor layer, thereby affecting the stability of the resistance value of the resistor layer.

[0103] The present application uses the above-mentioned embodiments to illustrate the detailed structural features of the present application. However, the present application is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present application must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present application, equivalent replacements of selected components of the present application, addition of auxiliary components, selection of specific methods, etc., all fall within the scope of protection and disclosure of the present application.

Claims

1. A composite substrate, characterized in that The composite substrate comprises a base layer and a first resistor layer disposed on at least one surface of the base layer; The thickness of the first resistance layer satisfies the following relationship: d=1.2 / R+K Wherein, d is the thickness of the first resistor layer, R is the square resistance, and the value range of K is -0.3 to 3.

2. The composite substrate according to claim 1, characterized in that The value range of d is 5nm~3μm; Optionally, the value range of R is 5 to 100Ω.

3. The composite substrate according to claim 1 or 2, characterized in that The material of the first resistance layer includes any one of NiCrSi, NiCrAlSi, NiP, NiCr, AlN, TiN, Pt, Cr, Cr-SiO, Cr-Si, Ti-Si, Ti-W, TaN, Mo or Ni-Sn, or a combination of at least two of them.

4. The composite substrate according to any one of claims 1 to 3, characterized in that: The composite substrate further comprises a film layer disposed on a surface of the first resistor layer away from the base layer; Optionally, the film layer has a thickness of 0.5 to 100 μm.

5. The composite substrate according to claim 4, characterized in that A conductive layer is provided on a surface of the film layer away from the first resistance layer; Optionally, the conductive layer includes a single layer or multiple layers.

6. The composite substrate according to claim 5, characterized in that A second resistance layer is arranged between the film layer and the conductive layer.

7. A method for preparing a composite substrate, for preparing the composite substrate as claimed in any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: Step 1: setting the resistance value R of the first resistance layer in the composite substrate layer; Step 2: According to the resistance value R set in step 1 and the formula d = 1.2 / R + K, calculate the first The thickness of the resistor layer d; Step 3: Surface treatment of the surface of the base layer; Step 4: forming a first resistance layer on the surface of the base layer described in step 3 to prepare a composite substrate.

8. The method for preparing a composite substrate according to claim 7, characterized in that: The first resistance layer is formed by any one of electroplating, chemical plating, physical vapor deposition or chemical vapor deposition, or a combination of at least two of them.

9. The method for preparing a composite substrate according to claim 7 or 8, characterized in that: After the first resistor layer is provided, the further step includes: providing a film layer on a surface of the first resistor layer away from the base layer; Optionally, after providing the film layer, the method further comprises: providing a second resistance layer on a surface of the film layer on a side away from the first resistance layer; Optionally, after providing the second resistance layer, the method further includes: providing a conductive layer on a surface of the second resistance layer on a side away from the film layer.

10. A circuit board, characterized in that: The circuit board comprises the composite substrate according to any one of claims 1 to 6.

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