A composite copper foil for embedded thin-film resistors, its preparation method and application

Abstract

This invention relates to a composite copper foil for embedded thin-film resistors, its preparation method, and its application. The composite copper foil is constructed by sputtering resistive layers onto both sides of a carrier dielectric layer, and then forming conductive copper layers on the resistive layers, thus forming a composite structure consisting of a first conductive copper layer, a first resistive layer, a carrier dielectric layer, a second resistive layer, and a second conductive copper layer. The composite copper foil of this invention exhibits excellent overall performance and surface roughness, and possesses stable sheet resistance. It can be used in the manufacture of flexible embedded thin-film resistor PCBs and has promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of electronic materials technology, and specifically relates to a composite copper foil for embedded thin-film resistors, its preparation method, and its application. Background Technology

[0002] Thinness and portability have become important development directions for consumer electronics. The thinner and lighter design of electronic products requires a sufficient number of electronic components within limited internal space, a requirement well met by embedded resistor-capacitor technology. Portable electronic products typically employ flexible circuit board (PCB) technology, which helps reduce the overall size and weight of electronic devices and can adapt to various bending and folding requirements. PCBs, as a mature technology, are widely used in electronic products, such as foldable phones; while embedded resistor-capacitor technology has also been applied in some high-end electronic devices in recent years. Currently, there are no copper foil products in the PCB manufacturing industry that integrate flexible circuit board technology and embedded resistor-capacitor technology. Processing these two technologies into composite copper foil through an integrated production method is expected to further accelerate the miniaturization process of electronic products. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a composite copper foil for embedded thin film resistors, a preparation method thereof, and its application. The composite copper foil has good comprehensive performance and surface roughness, and has stable sheet resistance. It can be used in the manufacture of flexible embedded thin film resistor PCBs and has good application prospects.

[0004] The present invention provides a composite copper foil for embedded thin-film resistors. The composite copper foil is formed by sputtering a resistor layer on both sides of a carrier dielectric layer and then forming a conductive copper layer on the resistor layer, thereby constituting a composite structure of a first conductive copper layer, a first resistor layer, a carrier dielectric layer, a second resistor layer, and a second conductive copper layer.

[0005] Preferably, the carrier medium layer is a polyimide film with a thickness between 5 and 50 μm.

[0006] Preferably, the resistive layer comprises one elemental metal selected from nickel, chromium, platinum, palladium, and titanium, or an alloy composed of two or more elements selected from nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, it can be a nickel-chromium (NiCr) alloy or a nickel-phosphorus (NiP) alloy with low electrical conductivity, or a chromium-silicon (Cr-Si) alloy with high resistivity.

[0007] Preferably, the thickness of the resistive layer is 0.05-2.0 μm, and the metal element content of the resistive layer is ≥70 wt%, while the non-metal element content is between 0 wt% and 30 wt%.

[0008] Furthermore, the composite copper foil has a tensile strength > 300 MPa, an elongation after fracture > 4%, a wettability > 38 mN / m, and a coating adhesion > 2.0 N / mm.

[0009] Furthermore, the final surface roughness (spd) of the composite copper foil is between 13900 and 59000 1 / mm. 2 SPC ranges from 15 to 650 1 / mm, SDR ranges from 5% to 200%, and Rq ranges from 0.2 to 4.0 μm.

[0010] Furthermore, the composite copper foil has a stable sheet resistance of 5-250Ω / □, and the deviation of the embedded resistance value does not exceed ±5%.

[0011] The present invention also provides a method for preparing composite copper foil for embedded thin-film resistors, comprising the following steps:

[0012] (1) First, the carrier medium layer is pretreated by plasma to clean the surface of the carrier medium layer and activate the surface at the same time.

[0013] (2) A resistive layer is formed on the surface of the pretreated carrier dielectric layer by vacuum sputtering. Before sputtering the resistive layer, a chromium layer or a titanium layer is deposited as the underlayer.

[0014] (3) Vacuum sputtering of a seed copper layer on the resistive layer. Sputtering of the seed copper layer is an important step in realizing the metallization of the substrate of the carrier dielectric layer-resistive layer composite material, which lays the foundation for subsequent electroplating to conduct electricity.

[0015] (4) Thicken the copper layer by electrodeposition;

[0016] (5) The copper layer is subjected to nodular treatment in order to ensure sufficient bonding force when the composite copper foil is pressed with the dielectric material;

[0017] (6) Electrochemically depositing an anti-oxidation layer to obtain a composite copper foil for embedded thin-film resistors. Metallic copper is prone to chemical reaction with water vapor and carbon dioxide in the air, which leads to oxidation and discoloration of the copper foil. Anti-oxidation treatment of the surface of the carrier dielectric-resistor layer-conductive copper layer composite material can effectively improve the weather resistance and performance stability of the composite material.

[0018] Preferably, the pretreatment in step (1) makes the surface roughness Ra of the carrier medium layer ≥ 0.08 μm.

[0019] Preferably, the surface roughness Ra of the resistive layer in step (2) is between 0.04 and 0.4 μm.

[0020] Preferably, the thickness of the seed copper layer in step (3) is between 50-100 nm; and the thickness of the copper layer after thickening in step (4) is between 12-35 μm.

[0021] Preferably, the nodulation treatment in step (5) includes roughening treatment and curing treatment.

[0022] Furthermore, the current density of the roughening treatment is 5-20 A / dm. 2 The roughening treatment time is 15-18 seconds; the current density of the curing treatment is 4-10 A / dm³. 2 The curing time is 5-12 seconds.

[0023] Furthermore, the roughening solution used in the roughening treatment contains 5-15 g / L of Cu. 2+ The roughening solution contains 100-150 g / L H2SO4, and the temperature of the solution is 20-30℃; the curing solution used in the curing treatment contains 55-60 g / L Cu. 2+ 90-120 g / L of H2SO4, curing solution temperature 45-60℃.

[0024] Preferably, the anti-oxidation layer in step (6) is metallic chromium or carboxybenzotriazole, and the thickness of the anti-oxidation layer is <3nm.

[0025] The present invention also provides an application of composite copper foil for embedded thin-film resistors in the manufacture of embedded resistors.

[0026] Includes the following steps:

[0027] (1) The first conductive copper layer of the composite copper foil is pre-pressed with the prepreg;

[0028] (2) A first photoresist is laminated onto the outer surface of the second conductive copper layer;

[0029] (3) Expose and shape the first photoresist, define the width of the embedded resistor, and develop it;

[0030] (4) Etch away the second conductive copper layer and the second resistive layer in the developing area.

[0031] (5) Remove the first photoresist from the outer surface of the second conductive copper layer to obtain the conductive circuit pattern;

[0032] (6) Laminating a second photoresist onto the outer surface of the second conductive copper layer;

[0033] (7) Expose and shape the second photoresist, define the length of the embedded resistor, and develop it;

[0034] (8) Etch away the second conductive copper layer at the developing area to expose the second resistive layer;

[0035] (9) Remove the second photoresist from the outer surface of the second conductive copper layer to complete the fabrication of the second resistive layer embedded resistor.

[0036] (10) Peel off the pre-pressed semi-cured sheet and repeat the above steps to complete the preparation of the first resistive layer embedded resistor.

[0037] Preferably, the bonding force after pre-compression in step (1) is between 0.3 N / mm and 1.0 N / mm.

[0038] Preferably, the etching in step (4) uses an acidic full etching solution, or a combination of an alkaline etching solution for etching the copper layer and an acidic etching solution for etching the resistive layer can be used.

[0039] Preferably, in steps (3) and (7), the width and length of the embedded resistor must be etched to compensate.

[0040] Furthermore, the peeling in step (10) specifically involves: pressing the second conductive copper layer of the prepared embedded resistor with the prepreg at high temperature, and mechanically separating the first conductive copper layer from the prepreg.

[0041] Furthermore, the high-temperature pressing temperature is >170℃, the pressing time is >2h, and the bonding force at room temperature after pressing is >0.9N / mm.

[0042] Furthermore, before mechanically separating the first conductive copper layer from the pre-pressed semi-cured sheet, a preheating treatment is performed at a temperature of <150℃ for a time of <30min.

[0043] Beneficial effects

[0044] The composite copper foil of this invention not only possesses the bendable and foldable characteristics of flexible copper-clad laminates, but also incorporates embedded resistor manufacturing technology. Using the composite copper foil of this invention to produce flexible circuit boards allows for the embedding of a large number of passive resistors within the circuit board, further saving surface space and significantly reducing inductive interference between resistor soldering points. Compared to traditional surface-mount resistor rigid circuit boards, the flexible embedded thin-film resistor PCB produced using the composite copper foil of this invention combines the flexibility of flexible circuit boards with the stability advantages of embedded resistors.

[0045] This invention provides a method for preparing composite copper foil, which allows for the flexible sputtering of alloy resistor layers with different combinations onto a dielectric layer. The resistivity and sheet resistance of these resistor layers can be flexibly adjusted. The combination of sputtering and electroplating to thicken the copper layer significantly improves production efficiency. This invention also provides a method for applying composite copper foil in the manufacture of embedded resistors. Compared to the method in patent CN105695993A that uses organic solvents to separate the embedded resistor copper foil, this method employs an integrated processing technology, eliminating the need to remove the PI dielectric layer with organic solvents. This preserves the flexibility of the composite copper foil, and the PI layer, acting as a support layer, ensures the integrity of subsequent flexible circuit board processing. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the composite copper foil of the present invention;

[0047] Figure 2 Schematic diagram for fabricating embedded resistors;

[0048] 11-First conductive copper layer

[0049] 12-First Resistive Layer

[0050] 21-Second conductive copper layer

[0051] 22-Second Resistive Layer

[0052] 31-PI film

[0053] 32-pad

[0054] 33-Signal Line

[0055] 34-Embedded Resistor

[0056] 35 - Grounding layer. Detailed Implementation

[0057] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0058] Example 1

[0059] like Figure 1 As shown, this embodiment provides a composite copper foil for embedded thin-film resistors. The composite copper foil is formed by sputtering resistor layers on both sides of a carrier dielectric layer and then forming a conductive copper layer on the resistor layer, thus constituting a composite structure of a first conductive copper layer, a first resistor layer, a carrier dielectric layer, a second resistor layer, and a second conductive copper layer.

[0060] The specific production process is as follows:

[0061] S1. PI film pretreatment

[0062] A 5μm thick PI film was unwound and transported into a vacuum coating apparatus. Under vacuum conditions, the film surface was pretreated using oxygen plasma. The parameters during the plasma pretreatment process are as follows:

[0063] Vacuum degree: 0.0035Torr;

[0064] Plasma source: oxygen;

[0065] Power: 1000W;

[0066] Time: 100s.

[0067] S2. Splashing to the bottom layer

[0068] Before vacuum sputtering the resistor layer, a chromium or titanium layer of a certain thickness needs to be deposited on the PI film surface as a base layer to enhance the adhesion between the resistor layer and the PI film. The parameters for the base layer deposition process are as follows:

[0069] Target material: Titanium metal (purity: 99.997%);

[0070] Vacuum degree: 0.003Torr;

[0071] Carrier gas: Argon;

[0072] Power: 3000W;

[0073] Time: 500s;

[0074] Sputtering method: Double-sided synchronous sputtering.

[0075] S3. Double-sided sputtered resistive layer

[0076] A resistive layer was deposited on the surface of the PI thin film under sputtering substrate using magnetron sputtering. The parameters during the resistive layer deposition process are as follows:

[0077] Target material: Ni-Cr alloy target material (Ni 55-75 at.%, Cr 25-45 at.%);

[0078] Vacuum degree: 0.003Torr;

[0079] Sputtering power: 5000W;

[0080] Sputtering time: 15 min;

[0081] Sputtering method: Double-sided synchronous sputtering.

[0082] S4. Seed Copper Layer Sputtering

[0083] The conductivity of the PI film surface decreases significantly after sputtering the resistive layer, necessitating surface metallization to provide a conductive substrate for subsequent electrochemical deposition. Therefore, after sputtering the underlayer and resistive layer on the PI film surface, a seed copper layer is deposited to enhance the substrate's conductivity. The parameters during the seed copper layer sputtering process are as follows:

[0084] Target material: Copper target (purity: 99.997%);

[0085] Vacuum degree: 0.0025Torr;

[0086] Sputtering power: 4000W;

[0087] Sputtering time: 10 min;

[0088] Sputtering method: Double-sided synchronous sputtering.

[0089] S5. Electrodeposition to thicken copper layer

[0090] Vacuum sputtering has a relatively low deposition rate. To improve production efficiency, electrochemical deposition is used to thicken the copper layer. The parameters in the electrochemical copper deposition process are as follows:

[0091] Copper pyrophosphate concentration: 150 g / L;

[0092] pH value = 11;

[0093] Additive A (potassium selenite) concentration: 12 mg / L;

[0094] Additive B (2-mercaptobenzothiazole) concentration: 0.003 mg / L;

[0095] Electrolyte temperature: 50℃;

[0096] Electrolyte flow rate: 4.5 m³ / h 3 / h;

[0097] Electrodeposition method: Pulse electrodeposition;

[0098] Duty cycle: 33%;

[0099] Frequency: 1000Hz;

[0100] Average current density: 800 A / m 2 ;

[0101] Electrodeposition time: 60s.

[0102] S6. Tumor treatment

[0103] Roughening treatment: 11 g / L Cu 2+120 g / L H2SO4, temperature 28℃, current density 8 A / dm³ 2 Processing time: 15 seconds;

[0104] Curing treatment: 55g / L Cu 2+ 100 g / L H2SO4, temperature 50℃, current density 6 A / dm³ 2 Processing time: 8 seconds.

[0105] S7. Anti-oxidation treatment

[0106] Metallic copper is chemically reactive and readily reacts with moisture and carbon dioxide in the air, leading to oxidation of the copper foil and negatively impacting the performance of the composite copper foil. Therefore, anti-oxidation treatment is necessary to improve the weather resistance and performance stability of the composite copper foil. The parameters for the anti-oxidation treatment process are as follows:

[0107] Antioxidant: Carboxybenzotriazole (BTA);

[0108] Antioxidant concentration: 1.0 wt.%;

[0109] Processing method: roller coating;

[0110] Processing temperature: 25℃;

[0111] Processing time: 5 seconds;

[0112] Drying temperature: 150℃.

[0113] The parameters of the composite copper foil used for the final embedded thin-film resistor are shown in Table 1.

[0114] Example 2

[0115] The difference between this embodiment and Embodiment 1 is that the thickness of the resistive layer has been adjusted. The parameters during the resistive layer deposition process are as follows:

[0116] Target material: Ni-Cr alloy target material (Ni 55-75 at%, Cr 25-45 at%);

[0117] Vacuum degree: 0.003Torr;

[0118] Sputtering power: 5000W;

[0119] Sputtering time: 150 min;

[0120] Sputtering method: Double-sided synchronous sputtering.

[0121] Example 3

[0122] The difference between this embodiment and Embodiment 1 lies in the adjustment of the composition of the resistive layer and the vacuum deposition process parameters. The parameters during the resistive layer deposition process are as follows:

[0123] Target material: Cr-Si alloy target material (Cr 68-76 at.%, Si 24-32 at.%);

[0124] Vacuum degree: 0.0028Torr;

[0125] Sputtering power: 12000W;

[0126] Sputtering time: 20 min;

[0127] Sputtering method: Double-sided synchronous sputtering.

[0128] Example 4

[0129] The difference between this embodiment and Embodiment 1 is that the thickness of the underlayer is adjusted. The parameters during the underlayer deposition process are as follows:

[0130] Target material: Titanium metal (purity: 99.997%);

[0131] Vacuum degree: 2.5*10 -5 Torr;

[0132] Carrier gas: Argon;

[0133] Power: 3000W;

[0134] Time: 1000s;

[0135] Sputtering method: Double-sided synchronous sputtering.

[0136] Example 5

[0137] The difference between this embodiment and Embodiment 1 lies in the adjustment of the composition of the underlayer. The parameters during the underlayer deposition process are as follows:

[0138] Target material: Metallic Cr target material (purity: 99.99%);

[0139] Vacuum degree: 2*10 -5 Torr;

[0140] Carrier gas: Argon;

[0141] Sputtering power: 4500W;

[0142] Sputtering time: 750s;

[0143] Sputtering method: Double-sided synchronous sputtering.

[0144] Example 6

[0145] The difference between this embodiment and Embodiment 1 is that the thickness of the conductive copper layer has been adjusted. The parameters for the electrochemical copper plating process are as follows:

[0146] Copper pyrophosphate concentration: 150 g / L;

[0147] pH value = 11;

[0148] Additive A (potassium selenite) concentration: 12 mg / L;

[0149] Additive B (2-mercaptobenzothiazole) concentration: 0.003 mg / L;

[0150] Electrolyte temperature: 50℃;

[0151] Electrolyte flow rate: 4.5 m³ / h 3 / h;

[0152] Electrodeposition method: Pulse electrodeposition;

[0153] Duty cycle: 33%;

[0154] Frequency: 1000Hz;

[0155] Average current density: 800 A / m 2 ;

[0156] Electrodeposition time: 117s.

[0157] Example 7

[0158] The difference between this embodiment and Embodiment 1 is that the thickness of the seed copper layer is adjusted. The parameters during the seed copper layer sputtering process are as follows:

[0159] Target material: Copper target (purity: 99.997%);

[0160] Vacuum degree: 0.0025Torr;

[0161] Sputtering power: 4000W;

[0162] Sputtering time: 14 min 18 s;

[0163] Sputtering method: Double-sided synchronous sputtering.

[0164] Example 8

[0165] The difference between this embodiment and Embodiment 1 lies in the adjustment of parameters during the electrochemical copper plating thickening process. The parameters for the electrochemical copper plating thickening process are as follows:

[0166] Copper pyrophosphate concentration: 150 g / L;

[0167] pH value; 11;

[0168] Additive A (potassium selenite) concentration: 12 mg / L;

[0169] Additive B (2-mercaptobenzothiazole) concentration: 0.003 mg / L

[0170] Electrolyte temperature: 50℃;

[0171] Electrolyte flow rate: 4.5 m³ / h 3 / h;

[0172] Electrodeposition method: Pulse electrodeposition;

[0173] Duty cycle: 25%;

[0174] Frequency: 2000Hz;

[0175] Current density: 750A / m 2 ;

[0176] Electrodeposition time: 60s.

[0177] Example 9

[0178] The difference between this embodiment and Embodiment 1 lies in the adjustment of parameters during the electrochemical copper deposition thickening process. The parameters for the electrochemical deposition thickening process are as follows:

[0179] Copper pyrophosphate concentration: 150 g / L;

[0180] pH value: 11;

[0181] Additive A (potassium selenite) concentration: 12 mg / L;

[0182] Additive B (2-mercaptobenzothiazole) concentration: 0 mg / L

[0183] Electrolyte temperature: 50℃;

[0184] Electrolyte flow rate: 4.5 m³ / h 3 / h;

[0185] Electrodeposition method: Direct current electrodeposition;

[0186] Current density: 2400A / m 2 ;

[0187] Electrodeposition time: 60s.

[0188] Example 10

[0189] The difference between this embodiment and Embodiment 1 is that the thickness of the PI film was adjusted. The thickness of the PI film was adjusted from 5 μm to 25 μm.

[0190] Example 11

[0191] The difference between this embodiment and Embodiment 1 is that the thickness of the PI film was adjusted. The thickness of the PI film was adjusted from 5 μm to 50 μm.

[0192] To more intuitively compare the effects of the production samples from different embodiments, the present invention summarizes the performance of the samples from different embodiments. Comparing the data in Table 1, it can be found that: (1) There are obvious differences in the sheet resistance of the composite copper foil with different resistive layer materials. The better the conductivity of the alloy layer, the smaller the sheet resistance of the product; (2) There are obvious differences in the sheet resistance deviation with different resistive layers; (3) There are obvious differences in the adhesion of the plating layer with different seed copper layer thickness or underlayer thickness; (4) There are obvious differences in the elongation after fracture of the composite copper foil with different PI film thickness; (5) There are obvious differences in the surface roughness with different electrochemical copper plating parameters.

[0193] Table 1 Comparison of Implementation Effects of Different Embodiments

[0194]

[0195]

[0196] Example 12

[0197] like Figure 2 As shown, this embodiment provides an application of composite copper foil for embedded thin-film resistors in the manufacture of embedded resistors, including the following steps:

[0198] (1) The first conductive copper layer of the composite copper foil prepared in Example 1 is pre-pressed with a prepreg, and the bonding force is between 0.3 N / mm and 1.0 N / mm;

[0199] (2) A first photoresist is laminated onto the outer surface of the second conductive copper layer;

[0200] (3) Expose and shape the first photoresist, define the width of the embedded resistor, and develop it;

[0201] (4) Etch away the second conductive copper layer and the second resistive layer in the developing area.

[0202] (5) Remove the first photoresist from the outer surface of the second conductive copper layer to obtain the conductive circuit pattern;

[0203] (6) Laminating a second photoresist onto the outer surface of the second conductive copper layer;

[0204] (7) Expose and shape the second photoresist, define the length of the embedded resistor, and develop it;

[0205] (8) Etch away the second conductive copper layer at the developing area to expose the second resistive layer;

[0206] (9) Remove the second photoresist from the outer surface of the second conductive copper layer to complete the fabrication of the second resistive layer embedded resistor.

[0207] (10) The second conductive copper layer of the prepared embedded resistor is pressed together with the prepreg at high temperature (the high temperature of the pressing is >170℃, the pressing time is >2h, and the bonding force at room temperature after pressing is >0.9N / mm). The first conductive copper layer is mechanically separated from the prepreg. Before mechanical separation, a preheating treatment is performed at a temperature <150℃ and a time <30min. The above steps are repeated to complete the preparation of the first resistor layer embedded resistor.

[0208] Furthermore, the etching in step (4) uses an acidic full etching solution, or a combination of an alkaline etching solution for etching the copper layer and an acidic etching solution for etching the resistive layer can be used.

[0209] Furthermore, in steps (3) and (7), the width and length of the embedded resistor must be etched to compensate.

[0210] After the fabrication of the embedded resistor with the first or second resistive layer is completed, the resistance of the conductive pattern of the embedded resistor is tested using a resistance meter, and the length and width of the resistive pattern are tested using a metallographic microscope. Finally, the sheet resistance is calculated. When the designed sheet resistance is below 200Ω / □, the deviation between the actual sheet resistance and the design value is within 2.5%. When the designed sheet resistance is 200Ω / □ or above, the deviation between the actual sheet resistance and the design value is within ±4%.

[0211] Finally, it should be emphasized that 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 can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Use of a composite copper foil for embedded thin film resistors in the manufacture of embedded resistors, characterized in that: The composite copper foil is formed by sputtering a resistive layer on both sides of a carrier medium layer, and then forming a conductive copper layer on the resistive layer, to form a composite structure of a first conductive copper layer, a first resistive layer, a carrier medium layer, a second resistive layer, and a second conductive copper layer; the composite copper foil has a tensile strength > 300 MPa, an elongation after break > 4%, a wettability > 38 mN / m, and a plating layer adhesion > 2.0 N / mm; the composite copper foil has a final surface roughness spd of 13900-59000 1 / mm 2 , a spc of 15-650 1 / mm, an sdr of 5%-200%, and an Rq of 0.2-4.0 μm. the composite copper foil is prepared by the following steps: (1) first, the carrier medium layer is pretreated by plasma; (2) a resistance layer is formed on the surface of the pretreated carrier medium layer by vacuum sputtering, and a chromium layer or a titanium layer is deposited as a primer layer before sputtering the resistance layer; (3) a seed copper layer is vacuum sputtered on the resistance layer; (4) the copper layer is thickened by electrodeposition; potassium selenite and 2-mercaptobenzothiazole are used as additives during the electrodeposition of the thickened copper layer; (5) the copper layer is treated to form nodules; (6) an anti-oxidation layer is electrochemically deposited to obtain a composite copper foil for embedded thin film resistors; the use comprises the following steps: (1) the first conductive copper layer of the composite copper foil is pre-pressed with a prepreg; the bonding force after pre-pressing is between 0.3 N / mm and 1.0 N / mm; (2) a first photoresist adhesive is laminated on the outer surface of the second conductive copper layer; (3) the first photoresist adhesive is exposed and shaped to define the width of the embedded resistor, and developed; (4) the second conductive copper layer and the second resistance layer at the developed part are etched away; (5) the first photoresist adhesive on the outer surface of the second conductive copper layer is removed to obtain a conductive circuit pattern; (6) a second photoresist adhesive is laminated on the outer surface of the second conductive copper layer; (7) the second photoresist adhesive is exposed and shaped to define the length of the embedded resistor, and developed; (8) the second conductive copper layer at the developed part is etched away to expose the second resistance layer; (9) the second photoresist adhesive on the outer surface of the second conductive copper layer is removed to complete the preparation of the second resistance layer embedded resistor; (10) the prepreg is peeled off, and the above steps are repeated to complete the preparation of the first resistance layer embedded resistor; peeling off is specifically: the second conductive copper layer of the prepared embedded resistor is high-temperature pressed with the prepreg, and the first conductive copper layer is mechanically separated from the pre-pressed prepreg; the temperature of the high-temperature pressing is > 170℃, the pressing time is > 2h, and the bonding force after pressing is > 0.9 N / mm at room temperature; before the first conductive copper layer is mechanically separated from the pre-pressed prepreg, pre-heating treatment is performed, the treatment temperature is < 150℃, and the treatment time is < 30 min.

2. Use according to claim 1, characterized in that: The carrier medium layer is a polyimide film with a thickness of 5-50 μm.

3. Use according to claim 1, characterized in that: The resistance layer is composed of one of the following single metals: nickel, chromium, platinum, palladium, and titanium, or an alloy composed of two or more of the following elements: nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum.

4. Use according to claim 1, characterized in that: The thickness of the resistance layer is 0.05-2.0 μm, and the metal element content of the resistance layer is ≥ 70 wt%, and the non-metal element content is between 0 wt% and 30 wt%.

5. Use according to claim 1, characterized in that: The thickness of the seed copper layer in step (3) is between 50 nm and 100 nm; and the thickness of the copper layer after thickening in step (4) is between 12 μm and 35 μm.

6. Use according to claim 1, characterized in that: The nodule treatment in step (5) includes roughening treatment and solidification treatment.

7. Use according to claim 1, characterized in that: The anti-oxidation layer in the step (6) is metal chromium or carboxyl benzene triazole, and the thickness of the anti-oxidation layer is less than 3 nm.

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