CN113973437A - Surface treatment method of copper foil for high-speed high-frequency signal transmission circuit board - Google Patents
Surface treatment method of copper foil for high-speed high-frequency signal transmission circuit board Download PDFInfo
- Publication number
- CN113973437A CN113973437A CN202111057189.4A CN202111057189A CN113973437A CN 113973437 A CN113973437 A CN 113973437A CN 202111057189 A CN202111057189 A CN 202111057189A CN 113973437 A CN113973437 A CN 113973437A
- Authority
- CN
- China
- Prior art keywords
- copper foil
- copper
- treatment
- layer
- signal transmission
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
- H05K3/18—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material
- H05K3/188—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material by direct electroplating
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing Of Printed Wiring (AREA)
- Electroplating Methods And Accessories (AREA)
- Laminated Bodies (AREA)
Abstract
The invention discloses a surface treatment method of copper foil for a high-speed high-frequency signal transmission circuit board, which provides a raw material copper foil with lower profile degree and meeting the requirement of stripping resistance for a printed circuit board for high-speed high-frequency signals, and provides a copper foil which does not contain ferromagnetic metal elements and has excellent PIM performance for 5G communication. The method comprises the following steps: and adding a dispersing agent and nano alumina particles into the copper-containing electrolytic solution, fully mixing the dispersing agent and the nano alumina particles, and performing electrochemical codeposition on the surface of the copper foil to form a metal composite deposition layer with a high specific surface area structure. And sequentially electroplating a copper layer, a zinc layer and a chromium layer on the composite layer, and then coating a silane coupling agent to form a complete treatment layer. The treatment layer has the characteristics of small thickness, large specific surface area, low roughness and high peel strength. The method has simple process, can meet the passive intermodulation PIM function of high-frequency high-speed signals, and has considerable application prospect in the field of 5G high-frequency high-speed communication.
Description
Technical Field
The invention belongs to the technical field of copper foil surface treatment, and particularly relates to a surface treatment method of a copper foil for a high-speed high-frequency signal transmission circuit board.
Background
When high-speed high-frequency alternating current signals are transmitted on the circuit of the printed circuit board, the current inside the copper foil is not uniformly distributed, and the current is concentrated on a thin layer on the outer surface of the conductor, which is called skin effect. The research shows that: the higher the frequency of the transmitted signal, the more pronounced the skin effect. Due to the skin effect, high-frequency signals are concentrated on the surface of the outer layer of the copper foil, and the effective cross-sectional area of transmission is reduced, which increases the resistance of the surface layer of the copper foil and increases signal transmission loss. Meanwhile, the surface resistance of the copper foil is increased, so that the dissipation proportion of high-frequency signals transmitted in the copper foil in a heat energy form is increased.
Therefore, high-speed high-frequency signal transmission is focused on the surface layer of the copper foil, and in order to reduce the adverse effect of the skin effect on signal transmission, the copper foil is required to have low surface roughness and the thickness of the surface treatment layer is as small as possible. The factors limiting the reduction of the roughness of the copper foil are mainly because:
in order to increase the bonding capability of the copper foil and the board in the printed circuit board, the surface of the copper foil needs to be roughened and enhanced, and the thickness of the processing layer is generally not less than 5 μm. However, the greater the roughness of the copper foil surface, the greater the transmission loss of the high-frequency signal. In order to reduce the signal transmission loss of the high frequency circuit, the conventional method generally uses a low profile copper foil, but this treatment causes another problem that the lower the roughness of the copper foil, the lower the adhesion strength (peel strength) of the copper foil to the substrate.
That is, if the roughness of the surface of the copper foil is too large, the signal fidelity of the high-speed and high-frequency ac signal transmitted through the circuit of the printed circuit board cannot be satisfied, and if the roughness of the surface of the copper foil is reduced for a small loss of the high-frequency signal transmission, the adhesive strength between the copper foil and the substrate may be reduced. These two problems cannot be solved simultaneously.
In addition to the influence of the roughness of the copper foil on high-speed and high-frequency alternating-current signals, the processing layer for performing roughening enhancement treatment on the surface of the copper foil is composed of various metals and metal oxides, the resistance of the processing layer is higher than that of a pure copper matrix, and when the resistance of the surface layer of the copper foil is increased, the signal loss is further increased.
Particularly, in the surface treatment process of the classic copper foil, ferromagnetic metal elements such as nickel, cobalt and the like are introduced into the surface treatment layer, and the ferromagnetic elements can generate adverse effects on the passive inter-modulation (PIM) performance of the substrate to a certain extent. The copper foil used for the radio-frequency-microwave circuit substrate (such as the substrate for millimeter wave vehicle radar) for 5G communication requires that the surface treatment layer does not contain ferromagnetic elements such as nickel, cobalt, iron, etc.
Based on the fact that the traditional copper foil surface treatment method can not provide a raw material copper foil which has lower profile and simultaneously meets the requirement of stripping resistance for a printed circuit board for high-speed high-frequency signals, and can not provide a copper foil which does not contain ferromagnetic metal elements and has excellent PIM performance for 5G communication, the technical personnel in the field develop a surface treatment method of the copper foil for the high-speed high-frequency signal transmission circuit board.
Disclosure of Invention
The invention aims to provide a surface treatment method of copper foil for a high-speed high-frequency signal transmission circuit board, which aims to solve the problems in the background technology.
In order to solve the above problems, the technical scheme of the invention is divided into the following steps:
a surface treatment method of copper foil for a high-speed high-frequency signal transmission circuit board comprises the following steps:
step A, preparing a roughening electrolyte:
the method comprises the steps of filtering a main electrolyte in a copper dissolving tank in multiple stages, preparing a dispersion liquid (2) by using a dispersing agent (1) of nano alumina particles, dispersing the nano alumina particles in the dispersion liquid (2) to obtain a nano alumina particle dispersion liquid (3), fully mixing the nano alumina particle dispersion liquid and the nano alumina particle dispersion liquid uniformly, and adding the nano alumina particle dispersion liquid into the main electrolyte to prepare a coarsening electrolyte.
Step B, coarsening treatment:
and C, uniformly feeding the coarsening electrolyte obtained in the step A into an electrolytic bath, and electrodepositing a copper-aluminum trioxide composite treatment layer on the rough surface of the copper foil by taking the copper foil to be treated as a cathode.
Step C, curing treatment:
in order to prevent the granular crystals formed on the rough surface in the step B from falling off, the surface of the copper-aluminum oxide composite treatment layer is further subjected to layered copper plating, so that a compact copper layer with a stable structure is covered on the surface of the copper-aluminum oxide composite treatment layer;
step D, ashing treatment:
in order to improve the chemical resistance and the high temperature resistance of the copper foil in the step C, a zinc layer is plated on the rough surface and the smooth surface of the copper foil simultaneously;
step E, passivation treatment:
in order to improve the oxidation resistance of the copper foil in the step D, the rough surface and the smooth surface of the copper foil coated with the zinc layer are simultaneously coated with the chromium layer, so that the weather resistance of the copper foil is improved;
step F, coating treatment:
in order to improve the chemical bonding force between the copper foil and the base material in the step E, coating a silane coupling agent on the rough surface of the copper foil subjected to copper-aluminum oxide composite treatment;
step G, drying treatment;
and E, drying the residual moisture of the copper foil subjected to the multi-layer surface treatment in the step E and the silane coupling agent in an oven.
Further, the main component of the main electrolyte in the step A is acid copper sulfate or copper pyrophosphate.
Further, the dispersant (1) of the nano alumina particles in the step A is one or more of Sodium Dodecyl Benzene Sulfonate (SDBS), Sodium Dodecyl Sulfate (SDS), trisodium citrate, cetyl trimethyl ammonium bromide (CBTA) and polyethylene glycol.
Further, the dispersant (1) for the nano aluminum trioxide particles in the step A is used in an amount of 1.5 to 5.5% by weight based on the nano aluminum trioxide particles.
Further, the concentration of the dispersant in the dispersion (2) in the step A is 20 to 30% by weight.
Further, the concentration of the nano alumina in the nano alumina particle dispersion liquid (3) prepared in the step A is between 5 and 25wt percent.
Further, the temperature of the roughening electrolyte in the electrolytic cell of step B is controlled between 25-40 deg.C, preferably 30-35 deg.C.
Further, the current density in step B is 1500-2The treatment time is 2-6 s.
Further, the aluminum trioxide nano particles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil obtained in the step B are in a spherical uniformly-dispersed state, and the particle size is 20-50 nm; the content of aluminum trioxide in the layer is 0.5-5 wt%.
Further, the thickness of the copper foil treated in the step B is 12-105 μm.
The invention has the following beneficial effects:
(1) according to the method, the copper-aluminum trioxide composite treatment layer is electrodeposited on the rough surface of the copper foil, so that the surface roughness of the copper foil is increased; further adding a curing treatment link on the roughened rough surface to enhance the bonding strength between the copper nodule treatment layer and the matrix copper layer; the light surface and the hair surface of the copper foil are subjected to ashing zinc plating layer treatment, so that the chemical resistance and the high temperature resistance of the copper foil are further improved; then, the passivated chromium layers on the smooth surface and the rough surface are plated, so that the weather resistance of the copper foil at room temperature is improved, and the quality guarantee period of the copper foil is prolonged; finally, the rough surface is coated with a silane coupling agent, so as to improve the bonding performance between the treated surface and the resin substrate, and the structural model is shown in figure 1.
Through the matching use of the series of process methods, the performance of the copper foil is greatly improved, the improvement of the surface roughness and the peeling resistance can be considered, and the copper foil is more suitable for the requirements of a printed circuit board for high-speed and high-frequency signals on the copper foil, namely the copper foil has lower profile and simultaneously meets the peeling resistance requirement.
(2) The copper foil produced by the method has obviously improved performance, compared with the copper foil adopting the traditional surface treatment process, the same raw electrolytic foil (semi-finished product before surface treatment) raw material is adopted, the surface of the copper foil treated by the method can achieve 50% reduction of roughness, the thickness of the surface treatment layer is reduced by 30%, and the peel strength is kept unchanged.
(3) Because the method does not use ferromagnetic metal elements such as nickel, cobalt, iron and the like in the whole process, the PIM performance is better, the process is simpler and the safety is higher. The final product can also be applied to the radio-frequency-microwave circuit substrate for 5G communication. Greatly expands the market applicability of the product and has obvious economic benefit.
Drawings
FIG. 1 is a model of a composite copper foil structure of the present invention;
fig. 2 is SEM images of the copper foil prepared in example at 1000 times and 5000 times magnification.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
Example 1
A thickness of 12 μm and a basis weight of 102 g/m were used2The raw foil is pretreated according to an acid washing program, and the acid washing process has the following control indexes: cu2+The concentration is 12 g/L, H2SO4The concentration is 100 g/L, the temperature is 35 ℃, and the flow rate is 8 m3/h。
Step A, preparing a roughening electrolyte:
and (3) carrying out multi-stage filtration on the main electrolyte in the copper dissolving tank, adding the nano alumina particle dispersion liquid into the main electrolyte, and fully and uniformly mixing to obtain the coarsening electrolyte.
The dispersing agent selected in the steps is trisodium citrate, the mass of the dispersing agent is 3% of the mass of the nano aluminum oxide powder, the trisodium citrate is dissolved by pure water, and the concentration of the aqueous solution of the trisodium citrate is 20 wt%; adding the weighed nano aluminum oxide particles into a trisodium citrate aqueous solution to ensure that the concentration of nano aluminum trioxide in the nano aluminum oxide particle dispersion liquid is 5 wt%; ultrasonic stirring and mixing for 1 hour, adding into the main electrolyte, and mixing to obtain coarsening electrolyte containing Cu2+The concentration is 12 g/L; h2SO4The concentration was 110 g/L.
Step B, coarsening treatment:
and C, uniformly feeding the coarsening electrolyte obtained in the step A into an electrolytic bath, and electrodepositing a copper-aluminum trioxide composite treatment layer on the rough surface of the copper foil by taking the copper foil to be treated as a cathode.
The key technical indexes in the step are as follows:
Cu2+the concentration is 12 g/L; h2SO4The concentration is 110 g/L; the flow rate is 24 m3H; the temperature is 25 ℃; the current density is 2500A/m2(ii) a The electrolysis time was 6 s.
After completion: the aluminum trioxide nanoparticles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil are in a spherical uniformly-dispersed state, the particle size of the aluminum trioxide nanoparticles in the composite treatment layer is 50 nm, and the following results are found after sampling analysis: the content of aluminum trioxide in the treated layer was 5 wt%.
Step C, curing treatment:
and C, in order to prevent the granular crystals formed in the step B from falling off, further carrying out layered copper plating on the surface of the copper-alumina composite treatment layer, so that a compact copper layer with a stable structure is covered on the surface of the copper-alumina composite treatment layer.
The key technical indexes in the step are as follows:
Cu2+the concentration is 45 g/L, H2SO4The concentration is 110 g/L, and the flow rate is 10 m3At 45 ℃ and a current density of 2800A/m2 。
Step D, ashing treatment:
and D, plating a zinc layer on the rough surface and the smooth surface of the copper foil simultaneously in order to improve the chemical resistance and the high-temperature resistance of the copper foil in the step C.
The key technical indexes in the step are as follows:
K4P2O7the concentration is 85 g/L, Zn2+The concentration is 4.5 g/L, the pH value is 8.5, the temperature is 25 ℃, and the flow rate is 10 m3H, the current density of the light surface is 50A/m2The current density of the matte surface is 200A/m2。
Step E, passivation treatment:
and D, in order to improve the oxidation resistance of the copper foil in the step D, plating a chromium layer on the rough surface and the smooth surface of the copper foil simultaneously, and improving the weather resistance of the copper foil.
The key technical indexes in the step are as follows:
Cr6+the concentration of the (chromic anhydride) is 1.5 g/L; the pH concentration is 11; the flow rate is 6 m3H; the temperature is 32 ℃; the current density of the light surface is 10A/m2(ii) a The current density of the rough surface is 50A/m2。
Step F, coating treatment:
and E, coating a silane coupling agent on the rough surface of the copper foil subjected to the copper-aluminum oxide composite treatment in order to improve the chemical bonding force between the copper foil and the base material in the step E.
The key technical indexes in the step are as follows:
the concentration of the KH-560 silane coupling agent is 0.45 wt%; the temperature was 25 ℃.
Step G, drying treatment;
and E, drying the residual moisture of the copper foil subjected to the multi-layer surface treatment in the step E and a silane coupling agent in an oven to finally obtain a product of the copper foil for the high-speed high-frequency signal transmission circuit board.
The product is subjected to performance detection, and is mainly observed by an electron microscope image and an enlarged image, so that the following effects are obtained: the rough surface of the copper foil has uniform particles, the thickness of a treatment layer is 2 mu m, the roughness Rz is 2.2 mu m, and the peel strength is 1.25N/mm.
Example 2
Using a substrate having a thickness of 15 μmThe weight is 102 g/m2The raw foil is pretreated according to an acid washing program, and the acid washing process has the following control indexes: cu2+The concentration is 12 g/L, H2SO4The concentration is 100 g/L, the temperature is 35 ℃, and the flow rate is 8 m3/h。
The difference from the embodiment 1 is that:
step A, preparing a roughening electrolyte:
the selected nano alumina particle dispersant (1) is Sodium Dodecyl Benzene Sulfonate (SDBS), and the mass of the nano alumina particle dispersant is 1.5 percent of the mass of the nano alumina powder;
dissolving the Sodium Dodecyl Benzene Sulfonate (SDBS) with pure water, wherein the concentration of the aqueous solution is 22 wt%;
adding the weighed nano alumina particles into a Sodium Dodecyl Benzene Sulfonate (SDBS) aqueous solution to ensure that the concentration of nano aluminum trioxide in the nano alumina particle dispersion liquid is 10 wt%;
step B, a coarsening processing link:
the temperature is 30 ℃; the current density is 2400A/m2(ii) a The electrolysis time was 5 s.
After completion: the aluminum trioxide nanoparticles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil are in a spherical uniformly-dispersed state, the particle size of the aluminum trioxide nanoparticles in the composite treatment layer is 40 nm, and the following results are found after sampling analysis: the content of aluminum trioxide in the treated layer was 4 wt%.
The rest of the procedure was the same as in example 1.
The performance detection of the product obtained after the implementation shows that: the rough surface of the copper foil has uniform particles, the thickness of a treatment layer is 2.0 mu m, the roughness Rz is 2.8 mu m, and the peel strength is 1.39N/mm.
Example 3
With a thickness of 18 μm and a basis weight of 102 g/m2The raw foil is pretreated according to an acid washing program, and the acid washing process has the following control indexes: cu2+The concentration is 12 g/L, H2SO4The concentration is 100 g/L, the temperature is 35 ℃, and the flow rate is 8 m3/h。
The difference from the embodiment 1 is that:
step A, preparing a roughening electrolyte:
the selected nano alumina particle dispersant (1) is Sodium Dodecyl Sulfate (SDS), and the mass of the dispersant is 2.5 percent of the mass of the nano alumina powder;
dissolving the Sodium Dodecyl Sulfate (SDS) with pure water to obtain an aqueous solution with a concentration of 25 wt%;
adding the weighed nano aluminum oxide particles into a Sodium Dodecyl Sulfate (SDS) aqueous solution to ensure that the concentration of nano aluminum trioxide in the nano aluminum oxide particle dispersion liquid is 12 wt%;
step B, a coarsening processing link:
the temperature is 35 ℃; the current density is 2300A/m2(ii) a The electrolysis time was 4 s.
After completion: the aluminum trioxide nanoparticles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil are in a spherical uniformly-dispersed state, the particle size of the aluminum trioxide nanoparticles in the composite treatment layer is 30 nm, and the following results are found after sampling analysis: the content of aluminum trioxide in the treated layer was 3 wt%.
The rest of the procedure was the same as in example 1.
The performance detection of the product obtained after the implementation shows that: the rough surface of the copper foil has uniform particles, the thickness of the treatment layer is 1.9 mu m, the roughness Rz is 3.4 mu m, and the peel strength is 1.42N/mm.
Example 4
With a thickness of 35 μm and a basis weight of 102 g/m2The raw foil is pretreated according to an acid washing program, and the acid washing process has the following control indexes: cu2+The concentration is 12 g/L, H2SO4The concentration is 100 g/L, the temperature is 35 ℃, and the flow rate is 8 m3/h。
The difference from the embodiment 1 is that:
step A, preparing a roughening electrolyte:
the selected nano alumina particle dispersant (1) is cetyl trimethyl ammonium bromide (CBTA), and the mass of the nano alumina particle dispersant is 3.5 percent of the mass of the nano alumina powder;
dissolving the Cetyltrimethylammonium Bromide (CBTA) with pure water to obtain an aqueous solution with a concentration of 26 wt%;
adding the weighed nano aluminum oxide particles into a cetyl trimethyl ammonium bromide (CBTA) aqueous solution to ensure that the concentration of nano aluminum trioxide in the nano aluminum oxide particle dispersion liquid is 15 wt%;
step B, a coarsening processing link:
the temperature is 40 ℃; the current density is 2100A/m2(ii) a The electrolysis time was 3 s.
After completion: the aluminum trioxide nanoparticles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil are in a spherical uniformly-dispersed state, the particle size of the aluminum trioxide nanoparticles in the composite treatment layer is 35 nm, and the following results are found after sampling analysis: the content of aluminum trioxide in the treated layer was 2.5 wt%.
The rest of the procedure was the same as in example 1.
The performance detection of the product obtained after the implementation shows that: the rough surface of the copper foil has uniform particles, the thickness of the treatment layer is 1.8 mu m, the roughness Rz is 5.5 mu m, and the peel strength is 1.87N/mm.
Example 5
With a thickness of 70 μm and a basis weight of 102 g/m2The raw foil is pretreated according to an acid washing program, and the acid washing process has the following control indexes: cu2+The concentration is 12 g/L, H2SO4The concentration is 100 g/L, the temperature is 35 ℃, and the flow rate is 8 m3/h。
The difference from the embodiment 1 is that:
step A, preparing a roughening electrolyte:
the selected nano alumina particle dispersant (1) is polyethylene glycol, and the mass of the nano alumina particle dispersant is 4.0 percent of the mass of the nano alumina powder;
dissolving the polyethylene glycol with pure water, wherein the concentration of the aqueous solution is 28 wt%;
adding the weighed nano alumina particles into a polyethylene glycol aqueous solution, and ensuring that the concentration of nano aluminum trioxide in the nano alumina particle dispersion liquid is 20 wt%;
step B, a coarsening processing link:
the temperature is 28 ℃; the current density is 1800A/m2(ii) a The electrolysis time was 2 s.
After completion: the aluminum trioxide nanoparticles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil are in a spherical uniformly-dispersed state, the particle size of the aluminum trioxide nanoparticles in the composite treatment layer is 25nm, and the following results are found after sampling analysis: the content of aluminum trioxide in the treated layer was 1.5% by weight.
The rest of the procedure was the same as in example 1.
The performance detection of the product obtained after the implementation shows that: the rough surface of the copper foil has uniform particles, the thickness of the treatment layer is 1.6 mu m, the roughness Rz is 8.4 mu m, and the peel strength is 2.45N/mm.
Example 6
With a thickness of 105 μm and a basis weight of 102 g/m2The raw foil is pretreated according to an acid washing program, and the acid washing process has the following control indexes: copper pyrophosphate is used, wherein: cu2+：20 g/L ；Cu2P2O7: 125 g/L, 35 ℃ and 8 m flow3/h。
The difference from the embodiment 1 is that:
step A, preparing a roughening electrolyte:
the selected nano alumina particle dispersant (1) is trisodium citrate, SDS and polyethylene glycol which are mixed according to the proportion of 1:1:2, and the mass of the nano alumina particle dispersant is 5.5 percent of the mass of the nano alumina powder;
dissolving the mixed nano alumina particle dispersant (1) by pure water, wherein the concentration of the aqueous solution is 30 wt%;
adding the weighed nano alumina particles into the aqueous solution of the nano alumina particle dispersing agent (1) to ensure that the concentration of nano aluminum trioxide in the nano alumina particle dispersing solution is 25 wt%;
step B, a coarsening processing link:
the temperature is 33 ℃; the current density is 1500A/m2(ii) a The electrolysis time was 2 s.
After completion: the aluminum trioxide nanoparticles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil are in a spherical uniformly-dispersed state, the particle size of the aluminum trioxide nanoparticles in the composite treatment layer is 20nm, and the following results are found after sampling analysis: the content of aluminum trioxide in the treated layer was 0.5 wt%.
The rest of the procedure was the same as in example 1.
The performance detection of the product obtained after the implementation shows that: the rough surface of the copper foil has uniform particles, the thickness of the treatment layer is 1.4 mu m, the roughness Rz is 10.6 mu m, and the peel strength is 2.63N/mm.
In the above examples 4 to 6, the raw foil having a large thickness was selected, and the roughness Rz value before the surface treatment was large, the raw foil itself could provide a high peel strength. The secondary roughening degree in the subsequent surface treatment process is not required to be very high, and the requirement of peeling resistance can also be met.
However, higher roughness means longer transmission paths during signal transmission, and thus more serious signal delay and attenuation.
Therefore, for the green foil with larger thickness, the part of coarsening parameters in the surface treatment process can be properly reduced to reduce the adverse effect of the overlarge roughness Rz on the signal transmission.
The copper foils prepared in examples 1-6 were sampled and observed randomly, and 2 SEM images thereof were selected as shown in FIG. 2, showing that: the surface treatment is uniform and stable.
Comparative example:
the same copper foil surface treatment procedure with a thickness of 12 μm as in example 1 was employed, and no nano-alumina composite treatment technique was used in the roughening treatment.
(1) Acid pickling
H2SO4The concentration is 100 g/L; cu2+The concentration is 12 g/L; the temperature of the pickling solution is 35 ℃; the flow rate of the pickling solution is 8 m3/h。
(2) Roughening treatment:
H2SO4the concentration is 110 g/L; cu2+The concentration is 12 g/L, the temperature of the roughing solution is 28 ℃, and the flow rate of the roughing solution is 8 m3H; the current density is 2100A/m2。
(3) Curing treatment:
H2SO4the concentration is 110 g/L; cu2+The concentration is 45 g/L; the temperature of the curing liquid is 45 ℃; the flow rate of the curing liquid is 8 m3H; the current density is 2500A/m2。
(4) Ashing treatment:
K4P2O7the concentration is 85 g/L: zn2+The concentration is 4.5 g/L, and the pH value is 8.5; the temperature of the ashing liquid is 28 ℃; the current density of the light surface is 50A/m2(ii) a The current density of the rough surface is 200A/m2。
(5) Passivating:
the concentration of hexavalent chromium is 1.5 g/L; the pH value is 11; the temperature of the passivation solution is 32 ℃; the current density of the light surface is 10A/m2(ii) a The current density of the rough surface is 50A/m2，
(6) Spraying a silane coupling agent:
KH-560 with a concentration of 0.5 wt%; the temperature of the silane coupling agent was 25 ℃.
As a result: the copper foil surface-treated by this example had a treated layer thickness of 2.6 μm, a roughness Rz of 3.5 μm and a Tg140 peel strength of 1.18N/mm.
The results of the performance tests of the copper foil products produced in examples 1 to 6 and the copper foil products produced in the comparative example are summarized as shown in Table-1.
TABLE-1 comparison of copper foil properties prepared in examples and comparative examples
Description of the drawings: the peel strength data will vary from manufacturer to manufacturer depending on the resin formulation.
PIM was measured at 1900 MHz signal input, 43 dBm input power.
Table-1 shows the surface parameters and passive intermodulation performance of the final copper foil products of examples 1-6.
From the table, it can be observed that the copper foil products produced by the surface treatment processes of examples 1 to 6 not only had a lower treatment layer thickness and roughness Rz than those of the surface-treated copper foils of the comparative examples, but also did not show a significant decrease in peel resistance.
The surface treatment method provided by the invention can reduce the roughness of the copper foil surface, simultaneously keep better peeling resistance, and better meet the stability and reliability of the high-speed high-frequency printed circuit board.
It is noted that the green foils of the same thickness after the example surface treatment had a larger interfacial expansion area ratio Sdr than the comparative examples.
The calculation formula of Sdr is as follows:
wherein S is the surface area of the object, and Sp is the projection area of the object.
In general, a larger Sdr indicates a larger specific surface area of the object. The copper foil subjected to surface treatment in the examples has a larger specific surface area than the copper foil subjected to surface treatment in the comparative examples, and is favorable for increasing the contact area between the copper foil and the resin base material and improving the peel strength of the copper foil.
Passive Intermodulation (PIM) performance is an important metric for measuring high frequency PCBs. In general, the lower the PIM value of the PCB for 5G communication, the better the passive intermodulation performance. From Table-1, it can be found that the PIM values of the copper foils treated by the copper foils of examples 1-6 are below-156 dBm, and the copper foils show good passive intermodulation performance. Therefore, the copper foil produced by the method is suitable for being applied to a radio frequency-microwave circuit substrate for 5G communication.
The surface treatment method of the copper foil for the high-speed high-frequency signal transmission circuit board provided by the invention can be used for reducing the thickness and the roughness of the treatment layer, maintaining excellent stripping resistance and passive intermodulation performance, and having wide market prospect and considerable economic benefit.
Claims (10)
1. A surface treatment method of copper foil for a high-speed high-frequency signal transmission circuit board, characterized by comprising: the method comprises the following steps:
step A, preparing a roughening electrolyte:
carrying out multi-stage filtration on the main electrolyte in a copper dissolving tank, firstly preparing a dispersion solution (2) by using a dispersing agent (1) of nano alumina particles, then dispersing the nano alumina particles in the dispersion solution (2) to obtain a nano alumina particle dispersion solution (3), fully and uniformly mixing the nano alumina particle dispersion solution and the nano alumina particle dispersion solution, and adding the nano alumina particle dispersion solution into the main electrolyte to prepare a coarsening electrolyte;
step B, coarsening treatment:
b, uniformly feeding the coarsening electrolyte obtained in the step A into an electrolytic bath, and electrodepositing a copper-aluminum trioxide composite treatment layer on the rough surface of the copper foil by taking the copper foil to be treated as a cathode;
step C, curing treatment:
in order to prevent the granular crystals formed on the rough surface in the step B from falling off, the surface of the copper-aluminum oxide composite treatment layer is further subjected to layered copper plating, so that a compact copper layer with a stable structure is covered on the surface of the copper-aluminum oxide composite treatment layer;
step D, ashing treatment:
in order to improve the chemical resistance and the high temperature resistance of the copper foil in the step C, a zinc layer is plated on the rough surface and the smooth surface of the copper foil simultaneously;
step E, passivation treatment:
in order to improve the oxidation resistance of the copper foil in the step D, the rough surface and the smooth surface of the copper foil coated with the zinc layer are simultaneously coated with the chromium layer, so that the weather resistance of the copper foil is improved;
step F, coating treatment:
in order to improve the chemical bonding force between the copper foil and the base material in the step E, coating a silane coupling agent on the rough surface of the copper foil subjected to copper-aluminum oxide composite treatment;
step G, drying treatment;
and E, drying the residual moisture of the copper foil subjected to the multi-layer surface treatment in the step E and the silane coupling agent in an oven.
2. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the main component of the main electrolyte in the step A is acid copper sulfate or copper pyrophosphate.
3. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: and the dispersing agent (1) of the nano alumina particles in the step A is one or a combination of more of Sodium Dodecyl Benzene Sulfonate (SDBS), Sodium Dodecyl Sulfate (SDS), trisodium citrate, hexadecyl trimethyl ammonium bromide (CBTA) and polyethylene glycol.
4. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 4, characterized in that: the amount of the dispersant (1) of the nano aluminum trioxide particles in the step A is 1.5 to 5.5 percent of the weight of the nano aluminum trioxide particles.
5. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the concentration of the dispersing agent in the dispersion liquid (2) in the step A is 20-30 wt%.
6. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the concentration of the nano alumina in the nano alumina particle dispersion liquid (3) prepared in the step A is between 5 and 25wt percent.
7. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the temperature of the roughening electrolyte in the electrolytic cell of the step B is controlled between 25 ℃ and 40 ℃, preferably between 30 ℃ and 35 ℃.
8. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the current density in the step B is 1500-2The treatment time is 2-6 s.
9. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the aluminum trioxide nano particles in the copper-aluminum trioxide composite treatment layer deposited on the surface of the copper foil obtained in the step B are in a spherical uniformly-dispersed state, and the particle size is 20-50 nm; the content of aluminum trioxide in the layer is 0.5-5 wt%.
10. The method for surface treatment of copper foil for high-speed high-frequency signal transmission wiring board according to claim 1, characterized in that: the thickness of the copper foil treated in the step B is 12-105 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111057189.4A CN113973437B (en) | 2021-09-09 | 2021-09-09 | Surface treatment method of copper foil for high-speed high-frequency signal transmission circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111057189.4A CN113973437B (en) | 2021-09-09 | 2021-09-09 | Surface treatment method of copper foil for high-speed high-frequency signal transmission circuit board |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113973437A true CN113973437A (en) | 2022-01-25 |
| CN113973437B CN113973437B (en) | 2022-09-09 |
Family
ID=79586468
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111057189.4A Active CN113973437B (en) | 2021-09-09 | 2021-09-09 | Surface treatment method of copper foil for high-speed high-frequency signal transmission circuit board |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113973437B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115044947A (en) * | 2022-06-17 | 2022-09-13 | 山东金宝电子股份有限公司 | Surface treatment method for improving adhesive force of copper foil and resin |
| CN115305540A (en) * | 2022-09-08 | 2022-11-08 | 广东嘉元科技股份有限公司 | Surface treatment method of copper foil |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1683601A (en) * | 2005-02-24 | 2005-10-19 | 上海交通大学 | Composite electroforming preparing process for nano aluminium oxide particle reinforced copper base composite material |
| CN102618902A (en) * | 2012-04-24 | 2012-08-01 | 山东金宝电子股份有限公司 | Surface treatment process of copper foil for flexible copper-clad plate |
| CN104694939A (en) * | 2015-04-07 | 2015-06-10 | 河南红日铜箔科技有限公司 | Surface treatment technology for ultralow-surface-roughness copper foil |
| CN112455020A (en) * | 2020-11-23 | 2021-03-09 | 无锡嘉瑞元通新材料科技有限公司 | High-frequency high-speed PCB copper-clad laminate and preparation method thereof |
-
2021
- 2021-09-09 CN CN202111057189.4A patent/CN113973437B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1683601A (en) * | 2005-02-24 | 2005-10-19 | 上海交通大学 | Composite electroforming preparing process for nano aluminium oxide particle reinforced copper base composite material |
| CN102618902A (en) * | 2012-04-24 | 2012-08-01 | 山东金宝电子股份有限公司 | Surface treatment process of copper foil for flexible copper-clad plate |
| CN104694939A (en) * | 2015-04-07 | 2015-06-10 | 河南红日铜箔科技有限公司 | Surface treatment technology for ultralow-surface-roughness copper foil |
| CN112455020A (en) * | 2020-11-23 | 2021-03-09 | 无锡嘉瑞元通新材料科技有限公司 | High-frequency high-speed PCB copper-clad laminate and preparation method thereof |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115044947A (en) * | 2022-06-17 | 2022-09-13 | 山东金宝电子股份有限公司 | Surface treatment method for improving adhesive force of copper foil and resin |
| CN115044947B (en) * | 2022-06-17 | 2023-09-29 | 山东金宝电子有限公司 | Surface treatment method for improving adhesion of copper foil and resin |
| CN115305540A (en) * | 2022-09-08 | 2022-11-08 | 广东嘉元科技股份有限公司 | Surface treatment method of copper foil |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113973437B (en) | 2022-09-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113973437B (en) | Surface treatment method of copper foil for high-speed high-frequency signal transmission circuit board | |
| CN102560584B (en) | Additive for electrolytic copper foil and surface treatment process of very low profile electrolytic copper foil | |
| JP5871426B2 (en) | Surface treated copper foil for high frequency transmission, laminated plate for high frequency transmission and printed wiring board for high frequency transmission | |
| KR101998923B1 (en) | Treated copper foil for low dielectric resin substrate, and copper-clad laminate and printed writing board using the same | |
| WO2013047272A1 (en) | Copper foil excellent in adhesion with resin, method for manufacturing same, and printed wiring board or battery negative electrode material using electrolytic copper foil | |
| JPH07233497A (en) | Non-cyan copper-zinc electroplating bath, surface treatment of copper foil for printed circuit board using the bath, and the copper foil for printed circuit board | |
| CN107109663B (en) | Surface-treated copper foil for forming high-frequency signal transmission circuit, copper-clad laminate, and printed wiring board | |
| CN110453252B (en) | Manufacturing method of HVLP copper foil for high-frequency high-speed copper-clad plate | |
| CN110724979A (en) | Additive for electrolytic copper foil, ultralow-peak-value HVLP copper foil and preparation method thereof | |
| JP2006210689A (en) | Copper foil for high frequency printed wiring board and its production method | |
| KR20180112769A (en) | A surface-treated copper foil and a copper clad laminate produced using the same | |
| CN105603480A (en) | Black surface treatment method for rolled copper foil | |
| CN112981481B (en) | Ultrathin copper foil and preparation method thereof | |
| CN103469267A (en) | Process method for carrying out surface treatment on electrolysis copper foil, and cooper foil treated by using the same | |
| JP7019876B1 (en) | Surface-treated copper foil for printed wiring boards, and copper-clad laminates and printed wiring boards for printed wiring boards using this | |
| EP3882378A1 (en) | Surface-treated copper foil for high-frequency circuit and method for producing the same | |
| JP6550196B2 (en) | Surface-treated copper foil, and copper-clad laminate and printed wiring board using the same | |
| CN114086227B (en) | Surface treatment process for improving peel strength of low-profile electrolytic copper foil | |
| CN113981494B (en) | Surface treatment process for reducing heat loss rate of electrolytic copper foil in peel strength | |
| CN107645852B (en) | Double-sided copper foil surface treatment process for high-frequency printed circuit board | |
| CN115261942A (en) | Electrolytic copper foil surface treatment method for PCB | |
| CN114214623B (en) | Method for processing copper foil by RTF inversion | |
| CN116334698A (en) | Ultralow-profile reversal processing electrolytic copper foil and preparation method of printed circuit board thereof | |
| CN118166407A (en) | Surface treatment method of electronic copper foil | |
| CN116180174A (en) | Micro roughening surface treatment method for electrolytic copper foil |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CB03 | Change of inventor or designer information | ||
| CB03 | Change of inventor or designer information |
Inventor after: Jin Rongtao Inventor after: Zhang Jie Inventor after: Yang Hongguang Inventor after: Wang Xiaodong Inventor before: Qi Pengwei Inventor before: Lv Jiqing Inventor before: Wang Xiaodong Inventor before: Zhang Jie Inventor before: Yang Hongguang Inventor before: Jin Rongtao |