CN116288544A - Ultra-low profile copper foil production method applied to high-frequency high-speed PCB - Google Patents
Ultra-low profile copper foil production method applied to high-frequency high-speed PCB Download PDFInfo
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- CN116288544A CN116288544A CN202310073032.3A CN202310073032A CN116288544A CN 116288544 A CN116288544 A CN 116288544A CN 202310073032 A CN202310073032 A CN 202310073032A CN 116288544 A CN116288544 A CN 116288544A
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 165
- 239000011889 copper foil Substances 0.000 title claims abstract description 140
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- 239000000654 additive Substances 0.000 claims abstract description 49
- 230000000996 additive effect Effects 0.000 claims abstract description 46
- 238000000034 method Methods 0.000 claims abstract description 34
- 238000002161 passivation Methods 0.000 claims abstract description 28
- 239000000126 substance Substances 0.000 claims abstract description 28
- 239000011888 foil Substances 0.000 claims abstract description 25
- 239000011347 resin Substances 0.000 claims abstract description 22
- 229920005989 resin Polymers 0.000 claims abstract description 22
- 238000007788 roughening Methods 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims abstract description 11
- 238000004070 electrodeposition Methods 0.000 claims abstract description 10
- 238000012545 processing Methods 0.000 claims abstract description 8
- 238000005498 polishing Methods 0.000 claims abstract description 5
- 238000003780 insertion Methods 0.000 claims description 36
- 230000037431 insertion Effects 0.000 claims description 36
- 239000010949 copper Substances 0.000 claims description 32
- 229910052802 copper Inorganic materials 0.000 claims description 25
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- 230000001105 regulatory effect Effects 0.000 claims description 17
- 239000003792 electrolyte Substances 0.000 claims description 13
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- 238000003825 pressing Methods 0.000 claims description 11
- 238000007731 hot pressing Methods 0.000 claims description 9
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- 229920001609 Poly(3,4-ethylenedioxythiophene) Polymers 0.000 claims description 6
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- 229910052755 nonmetal Inorganic materials 0.000 claims description 6
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
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- 238000004458 analytical method Methods 0.000 claims description 5
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- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
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- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 claims description 4
- 238000004090 dissolution Methods 0.000 claims description 4
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 claims description 4
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- 239000001509 sodium citrate Substances 0.000 claims description 4
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims description 4
- 239000001763 2-hydroxyethyl(trimethyl)azanium Substances 0.000 claims description 3
- 235000019743 Choline chloride Nutrition 0.000 claims description 3
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 3
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- SGMZJAMFUVOLNK-UHFFFAOYSA-M choline chloride Chemical compound [Cl-].C[N+](C)(C)CCO SGMZJAMFUVOLNK-UHFFFAOYSA-M 0.000 claims description 3
- 229960003178 choline chloride Drugs 0.000 claims description 3
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 3
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 3
- 239000003112 inhibitor Substances 0.000 claims description 3
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- LJCNRYVRMXRIQR-OLXYHTOASA-L potassium sodium L-tartrate Chemical compound [Na+].[K+].[O-]C(=O)[C@H](O)[C@@H](O)C([O-])=O LJCNRYVRMXRIQR-OLXYHTOASA-L 0.000 claims description 3
- 229940074439 potassium sodium tartrate Drugs 0.000 claims description 3
- 235000011006 sodium potassium tartrate Nutrition 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- OBDVFOBWBHMJDG-UHFFFAOYSA-M 3-sulfanylpropane-1-sulfonate Chemical compound [O-]S(=O)(=O)CCCS OBDVFOBWBHMJDG-UHFFFAOYSA-M 0.000 claims description 2
- 239000004593 Epoxy Substances 0.000 claims description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 2
- 239000002253 acid Substances 0.000 claims description 2
- 230000002378 acidificating effect Effects 0.000 claims description 2
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- 125000004368 propenyl group Chemical group C(=CC)* 0.000 claims description 2
- 229910052708 sodium Inorganic materials 0.000 claims description 2
- 229960001790 sodium citrate Drugs 0.000 claims description 2
- 235000011083 sodium citrates Nutrition 0.000 claims description 2
- XMVONEAAOPAGAO-UHFFFAOYSA-N sodium tungstate Chemical compound [Na+].[Na+].[O-][W]([O-])(=O)=O XMVONEAAOPAGAO-UHFFFAOYSA-N 0.000 claims description 2
- FRTIVUOKBXDGPD-UHFFFAOYSA-M sodium;3-sulfanylpropane-1-sulfonate Chemical compound [Na+].[O-]S(=O)(=O)CCCS FRTIVUOKBXDGPD-UHFFFAOYSA-M 0.000 claims description 2
- 125000005504 styryl group Chemical group 0.000 claims description 2
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 claims description 2
- 125000003396 thiol group Chemical class [H]S* 0.000 claims description 2
- 229940045136 urea Drugs 0.000 claims description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims description 2
- 229920002554 vinyl polymer Polymers 0.000 claims description 2
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims 1
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- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 8
- 238000002360 preparation method Methods 0.000 description 8
- 229910000077 silane Inorganic materials 0.000 description 8
- 239000002585 base Substances 0.000 description 6
- ZGTMUACCHSMWAC-UHFFFAOYSA-L EDTA disodium salt (anhydrous) Chemical compound [Na+].[Na+].OC(=O)CN(CC([O-])=O)CCN(CC(O)=O)CC([O-])=O ZGTMUACCHSMWAC-UHFFFAOYSA-L 0.000 description 5
- 230000002500 effect on skin Effects 0.000 description 5
- 239000000178 monomer Substances 0.000 description 5
- 150000003071 polychlorinated biphenyls Chemical class 0.000 description 5
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 4
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- GKWLILHTTGWKLQ-UHFFFAOYSA-N 2,3-dihydrothieno[3,4-b][1,4]dioxine Chemical compound O1CCOC2=CSC=C21 GKWLILHTTGWKLQ-UHFFFAOYSA-N 0.000 description 2
- KAESVJOAVNADME-UHFFFAOYSA-N Pyrrole Chemical compound C=1C=CNC=1 KAESVJOAVNADME-UHFFFAOYSA-N 0.000 description 2
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- XDLMVUHYZWKMMD-UHFFFAOYSA-N 3-trimethoxysilylpropyl 2-methylprop-2-enoate Chemical compound CO[Si](OC)(OC)CCCOC(=O)C(C)=C XDLMVUHYZWKMMD-UHFFFAOYSA-N 0.000 description 1
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- 239000003109 Disodium ethylene diamine tetraacetate Substances 0.000 description 1
- 229920002560 Polyethylene Glycol 3000 Polymers 0.000 description 1
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Images
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-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D1/00—Electroforming
- C25D1/04—Wires; Strips; Foils
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/38—Electroplating: Baths therefor from solutions of copper
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D9/00—Electrolytic coating other than with metals
- C25D9/02—Electrolytic coating other than with metals with organic materials
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D9/00—Electrolytic coating other than with metals
- C25D9/04—Electrolytic coating other than with metals with inorganic materials
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F3/00—Electrolytic etching or polishing
- C25F3/16—Polishing
- C25F3/22—Polishing of heavy metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2202/00—Metallic substrate
- B05D2202/40—Metallic substrate based on other transition elements
- B05D2202/45—Metallic substrate based on other transition elements based on Cu
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
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- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Laminated Bodies (AREA)
Abstract
The invention discloses a production method of an ultralow-profile copper foil applied to a high-frequency high-speed PCB, which belongs to the technical field of electrolytic copper foil and aims to realize that the produced ultralow-profile (HVLP) copper foil can ensure the integrity in signal transmission and the reliability in processing a CCL product. The method comprises the steps of electrolytic ultralow-profile foil, electrochemical polishing pretreatment, additive assisted ultrafine roughening treatment and curing treatment, electrodeposition of nonmetallic passivation layer construction and chemical bonding layer construction. The invention can reduce the roughness of the surface of the copper foil serving as a raw material, and can meet the bonding strength between the electrolytic copper foil and the resin base material, so that a high-quality CCL can be produced, and the reliability of a PCB product and the integrity of signal transmission can be ensured.
Description
Technical Field
The invention belongs to the technical field of electrolytic copper foil, and particularly relates to a production method of an ultralow-profile copper foil applied to a high-frequency high-speed PCB.
Background
In recent years, thinning and high integration have become mainstream trends in the development of high-frequency high-speed PCBs. The PCB product is designed and processed by a copper clad laminate CCL, and is formed by laminating and hot-pressing a prepreg PP and a copper foil.
In the subject research of guaranteeing the integrity of signals in the PCB transmission process, on one hand, the attenuation problem of a PCB circuit in the signal transmission process needs to be overcome; on the other hand, the stability of the performance of the copper clad laminate CCL serving as a raw material, namely the bonding strength between the prepreg PP and the copper foil, is also considered. Only if both are compatible, the longevity and stability of the PCB in signal transmission can be ensured.
In the study of the first aspect, the transmission process of electronic information in the PCB circuit is inevitably affected by the dielectric constant of the dielectric material and the resistance of the conductor material. Therefore, the transmission loss of the electric signal in the PCB board can be mainly divided into dielectric loss alpha C And conductor loss alpha C . Wherein the dielectric loss alpha D Then the dielectric constant D of the dielectric material is equal to the frequency f of the signal k And dielectric loss factor D f The values are closely related; conductor loss alpha of PCB board C Mainly related to the roughness of the copper foil of the conductor material.
In addition, the high-frequency signals can be influenced by skin effect in the transmission process of the PCB. Skin effect refers to the electrical signal that follows the transmission of a conductorWith a gradual increase in the signal frequency f, a greater proportion of the current will be concentrated in the surface or near-surface region of the signal transmission line for conduction. Skin depth (delta) of high frequency signal in PCB board transmission process s ) Closely related to the permeability (mu) of the conductor, the conductivity (sigma) of the conductor and the frequency (f) of the signal, exhibit the correlation as shown in equation 1-1.
From equation 1-it can be seen that the higher the signal frequency f, the skin depth is delta s The smaller the current is, the more concentrated the current is correspondingly conducted in the surface region of the line. Skin depth δ of copper foil at room temperature when frequency f=1 GHz s About 2.09 μm; when the signal frequency f increases to 4GHz, the skin depth delta of the copper foil s Further reduced to below 1.0 μm.
Therefore, when the roughness of the copper foil is too large, the high frequency signals are concentrated in the roughened layer of the copper foil having relatively low conductivity for transmission. The uneven distribution of current in the circuit caused by the rough layer of the copper foil can further cause resistance increase, the increase of the resistance can cause the high-frequency signal transmitted in the copper foil to be increased in the form of heat energy dissipation proportion, and finally, the signal is severely attenuated.
Skin effect induced signal loss (alpha H ) Not only by the signal frequency f, but also by the wire width w. Signal loss (alpha) caused by skin effect H ) There is a correlation between the signal frequency f and the wire width w as shown in equations 1-2.
It can be seen that in order to reduce the attenuation of signals during the transmission of PCB boards, the adverse effect of skin effect on signal transmission must be reduced as much as possible, which is also directed to reducing the roughness of the copper foil surface.
It is seen from the above factors that reducing the roughness of the copper foil surface as a raw material is an important implementation way to improve the signal integrity of high frequency high speed PCB products.
However, in the second aspect of the study, CCL is a resin matrix composite material formed by performing glass transition of a resin material in PP at high temperature and performing physical-chemical reaction with copper foil during hot pressing, and the bonding strength between an electrolytic copper foil and a resin matrix directly determines the processability of CCL and the reliability of PCB product.
The bonding force between the electrolytic copper foil and the resin base material can be classified into physical bonding force and chemical bonding force according to the difference of the form of the applied force. Wherein, the physical binding force is mainly realized by the mutual occlusion between the roughened copper foil and the resin, and the chemical binding force is mainly realized by the chemical bond formed between the coupling agent on the surface of the copper foil and the resin.
The conventional electrolytic raw foil has rough surfaces which are mostly undulating mountain-like microscopic morphology and have certain roughness, and when the CCL is manufactured, the physical binding force of mutual occlusion between the copper foil and resin is large, so that the strength of hot-press bonding of the copper foil and resin can be ensured.
However, if the research in the first aspect is followed, the reduction of the roughness of the surface of the copper foil as a raw material tends to affect the physical bonding force between the copper foil and the resin, and when the bonding force is insufficient, the bonding strength between the electrolytic copper foil and the resin base material tends to be affected, thereby affecting the CCL and the PCB product in turn.
Based on the above problems in the background art, a method must be found that can reduce the roughness of the surface of the copper foil as a raw material, and can also satisfy the bonding strength between the electrolytic copper foil and the resin substrate to yield a high quality CCL, ensuring the reliability of the PCB product, and thus, research and development personnel have proposed a production method of an ultra-low profile copper foil applied to a high frequency and high speed PCB.
Disclosure of Invention
The invention aims to provide a production method of an ultralow-profile copper foil applied to a high-frequency high-speed PCB (printed Circuit Board) so as to realize that the produced ultralow-profile (HVLP) copper foil can ensure the integrity in signal transmission and the reliability in processing a CCL product.
In order to solve the problems, the technical scheme of the invention is as follows:
the ultra-low profile copper foil production method applied to the high-frequency high-speed PCB comprises the following steps:
s1, electrolyzing ultra-low profile foil;
adding a brightening agent and an inhibitor into the acidic copper sulfate electrolyte, regulating and controlling the concentration of the additive, and electrolyzing under the action of direct current to prepare the ultra-low profile green foil;
s2, electrochemical polishing pretreatment;
running the ultra-low profile raw foil prepared in the step S1 into a pretreatment tank, and carrying out microetching pretreatment on the surface of the copper foil by means of chemical reaction between the pretreatment liquid and oxide on the surface of the copper foil and dissolution action of reverse pulse current on the copper layer;
first through H 2 SO 4 With CuO and Cu 2 (OH) 2 CO 3 Chemical reaction between them, converting the oxide layer on the surface of the green foil into Cu 2+ The method comprises the steps of carrying out a first treatment on the surface of the Further at H 2 O 2 Under the oxidation of Cu and the electrochemical dissolution of reverse pulse current to Cu, microetching pretreatment is carried out on the electrolytic green foil smooth surface, so that the nucleation active site density of the smooth surface is improved;
s3, auxiliary superfine roughening treatment and curing treatment of the additive;
s3.1, auxiliary superfine coarsening treatment is carried out by the additive;
transferring the copper foil pretreated in the step S2 into a roughening electrolytic tank for carrying out ultra-fine roughening treatment of pulse electrochemical deposition; the introduction of pulsed electrochemical deposition may serve two purposes: (1) The electrochemical polarization overpotential in the electrochemical deposition process is effectively increased, the formation of crystal nuclei is promoted, and the grain size is effectively reduced; (2) Concentration polarization is reduced, fluctuation of ion concentration on the surface of an electrode is reduced, and stability of electrochemical reduction is improved;
the coarsening electrolytic tank is characterized in that an additive with grain refinement and leveling functions is added into coarsening liquid; the method is used for reducing the size of coarsening particles and improving the uniformity of the foil surface coarsening particles in height;
in this step, the coarsening particle size and the profile of the copper foil are significantly reduced under the synergistic effect of the additive and the pulsed electrochemical deposition;
s3.2, curing treatment;
the electrolytic copper foil subjected to superfine roughening treatment in the step S3.1 is subjected to water washing and water squeezing, and then is transferred into a curing tank for curing treatment;
s4, constructing an electrodeposited nonmetallic passivation layer;
in order to improve the oxidation resistance of the electrolytic copper foil in the downstream processing process, carrying out nonmetal passivation treatment on the smooth surface and the rough surface of the copper foil obtained in the step S3 by an electrochemical reduction or electrochemical polymerization method, and forming a nonmetal passivation layer with a blocking effect on the treated surface of the electrolytic copper foil; the adverse effect of metal components on high-frequency high-speed signal transmission is fundamentally eliminated;
s5, constructing a chemical bonding layer;
the copper foil after nonmetallic passivation treatment in the step S4 is operated to a chemical bonding layer treatment tank, a chemical bonding layer is further constructed on the rough surface of the electrolytic copper foil in a spraying mode, and finally, an ultralow-profile (HVLP) copper foil applied to a high-frequency high-speed PCB is obtained;
because the extremely low roughness of ultra low profile (HVLP) copper foil determines that the contribution rate of the physical bonding force to the peel strength is relatively limited, the bonding strength between the copper foil and the prepreg is further improved by means of the chemical bonding force in order to ensure the stability of the copper foil in the downstream processing.
Further, the additive in the step S1 is at least 2 combinations of sodium polydithio-dipropyl sulfonate (SPS), sodium 3-mercapto-1-propane sulfonate (MPS), polyethylene glycol (PEG), and Polyethylenimine (PEI). The electrochemical reduction process of copper ions is regulated and controlled by using the additive with grain refinement and leveling effects, so that the profile of the foil is reduced, and the electrolytic foil with ultralow profile is prepared.
Further, in the step S1, the roughness Rz of the ultra-low profile green foil is 0.5-1.0um, and the interface expansion area ratio Sdr is 5-10%.
Further, the pulse of the pulse-oriented current in step S2The impact frequency is between 200 and 2000Hz, and the average current density is between 5 and 10A/dm 2 The duty cycle is between 25 and 50 percent, and the treatment time is between 5 and 10 seconds.
Further, the additives used in the ultra-fine roughening process of step S3.1 are urea, choline chloride, sodium citrate, potassium sodium tartrate, sodium tungstate, potassium permanganate, malic acid, disodium ethylenediamine tetraacetate (EDTA-2 Na), vanadium pentoxide (V) 2 O 5 ) One or a combination of several of them; the additive concentration is between 5 and 50 ppm.
Further, specific parameters in the pulsed electrochemical deposition process in step S3.1 are as follows: the frequency is between 1000 and 3000Hz, and the average current density is between 25 and 50A/dm 2 The duty cycle is between 25 and 50 percent, and the treatment time is between 5 and 10 seconds.
Further, in the step S4, the component of the nonmetallic passivation layer is one or a combination of several of reduced graphene oxide (rGO), polyethylene dioxythiophene (PEDOT), polypyrrole (PPy), and Polyaniline (PANI).
Further, in S5, the chemical bonding layer is water glass or a silane coupling agent, where:
the molecular formula of the water glass is M 2 O·xSiO 2 ·nH 2 Alkali metal silicate of O (m=na or K, x=2 to 4);
the silane coupling agent is one of vinyl, epoxy, styryl, methylpropenyl, propenyl, amino, ureido and mercapto.
The chemical bonding layer with water glass or a silane coupling agent as an effective component is constructed on the copper foil treatment surface, so that the peeling strength between the copper foil and the plate is improved. And compensating the part with low contribution rate of weak physical binding force of the HVLP copper foil to peel strength, and ensuring the quality of the copper clad laminate CCL by ensuring the binding strength between the copper foil and the prepreg.
Further, the ultra low profile (HVLP) copper foil applied to the high frequency high speed PCB obtained in step S5 has the following performance indexes:
coarsened particles in the form of dendrites, hemispheres, cones and spheres were observed when the microscopic morphology characterization was performed at 8000 x using a scanning electron microscope SEM at a 40 degree tilt angle; gaps exist between adjacent coarsening particles to form coarsening tissues with porosity;
the average size of coarsened particles is between 200 and 600nm measured at 8000 times at 0 degree angle using scanning electron microscope SEM;
when microscopic parameter analysis is carried out by using a laser confocal microscope, the volume Vvp of the valley area of coarsened particles is measured to be between 0.03 and 0.06 mu m 3 /μm 2 Between 0.23-0.65 μm in nuclear space volume 3 /μm 2 Between them;
when a laser confocal microscope is used for microscopic parameter analysis, the roughness Rz of the treated surface is measured to be between 1.0 and 2.0 mu m, and the peak density Spd is between 25000 and 45000mm -2 Between them, the peak curvature Spc is 20-80mm -1 The interfacial expansion area ratio Sdr is between 5 and 15 percent.
Further, the ultra low profile (HVLP) copper foil applied to the high frequency high speed PCB obtained in step S5 has the following performance indexes:
the insertion loss of the PCB plate formed by pressing and processing the ultra-low profile (HVLP) copper foil and PPO resin at 16GHz is between-0.81 dB/in and-1.75 dB/in;
the peel strength of the ultra low profile (HVLP) electrolytic copper foil with the thickness of 18 mu m after hot pressing with the PPO resin-based sheet material is not lower than 0.50N/mm.
The beneficial effects of the invention are as follows:
1. the invention provides a production technology of an ultra-low profile electrolytic copper foil, which is used for producing an HVLP electrolytic copper foil with excellent performance by combining an ultra-low profile rough foil electrolysis technology and an ultra-fine roughening surface treatment technology, and the copper foil has the following characteristics:
(1) Controllable microcosmic appearance (the coarsened structure is dendritic, hemispherical, conical and spherical), and different microcosmic appearances can meet the requirements of different resin systems on the bonding strength of the copper foil;
(2) Ultra-fine coarsening particles, wherein the average particle size of coarsening tissues is between 200 and 600 nm;
(3) Very low profile: the non-contact roughness Rz of the treated surface is 1.0-2.0 μm, and the peak density Spd is 25000-45000mm -2 Between them, the peak curvature Spc is 20-80mm -1 The interfacial expansion area ratio Sdr is between 5 and 15 percent, the valley void volume Vvv is between 0.03 and 0.06 mu m 3 /μm 2 Between them, the nuclear space volume Vmp is between 0.23 and 0.65 mu m 3 /μm 2 Between them.
2. Because the HVLP electrolytic copper foil produced by the invention has low surface roughness, the bonding strength between the electrolytic copper foil and the resin base material is sufficient when the CCL product of the copper clad laminate is processed, and the HVLP electrolytic copper foil can be used as the raw material of the PCB product, so that the attenuation of signals in the PCB transmission process can be reduced, and the signal integrity can be ensured.
In order to evaluate and verify the reliability and signal transmission performance of the copper foil in the processing process, respectively performing a peel strength test on the CCL after hot pressing, and performing an insertion loss test on a PCB processed by the CCL.
And (3) hot pressing of the CCL: first, referring to a sandwich structure, the HVLP copper foil produced in the present invention was laminated with prepregs (4 prepregs with a glass transition temperature of 200 ℃ were placed between upper and lower copper foils). Then hot-pressing, wherein the hot-pressing temperature is 220-250deg.C, and the surface pressure is 20-25kg/m 2 The time is between 90 and 150 minutes. The following tests were performed on the copper clad laminate CCL produced by lamination:
(1) Peel strength test: firstly, cutting the copper-clad plate after hot pressing forming into a spline with the width of 3.0mm by using a cutter; then stripping the copper foil at one side of the copper-clad plate by 1-2cm by means of a craft knife, and fixing the stripped copper foil at one end of the weight; and finally, driving the copper foil to test the peeling strength by moving the weight on a peeling strength testing instrument.
The stable stripping resistance is provided between the 18 mu m finished foil and the PPO resin-based sheet material, and the stripping resistance PS is more than or equal to 0.5N/mm.
(2) Transmission characteristics test: a sample for measuring transmission characteristics was prepared using a thermally pressed copper-clad laminate, and transmission loss in a high frequency bandwidth was measured. In the evaluation of the transmission characteristics, the transmission loss at 16GHz was measured by using a strip line resonator method (a method of measuring S21 parameters in a microstrip structure in which the thickness of an electrolyte is 50 μm, the length of a conductor is 1.0mm, the thickness of a conductor is 18 μm, the width of a conductor circuit is 120 μm, the characteristic impedance is 50Ω, and there is no cover film). Each sample was tested 5 times separately, with the average of 5 tests being the final test result for that sample.
Through test, the insertion loss of the signal with the frequency of 16GHz can reach-0.81 dB/in. The larger the transmission loss is, the larger the negative absolute value is, and the fact that the heat-pressed copper-clad plate CCL has excellent signal transmission performance is proved to benefit from the construction of a nonmetallic passivation layer, so that adverse effects of non-copper metal elements on signal transmission can be thoroughly eliminated, the signal attenuation degree is further reduced, and the transmission loss value at 16GHz is extremely low.
3. The invention solves the problems in the background technology, not only can reduce the roughness of the surface of the copper foil serving as a raw material, but also can meet the bonding strength between the electrolytic copper foil and the resin base material, so that a CCL with high quality can be produced, and the reliability and the signal transmission integrity of a PCB product can be ensured.
Drawings
FIG. 1 shows the microscopic morphology of the HVLP finished foil electron microscope produced by the various embodiments;
wherein (A) example 1; (B) example 2; (C) example 3; (D) example 4;
FIG. 2 is a microscopic morphology under a HVLP finished foil section super depth of field microscope produced by different embodiments;
wherein (A) example 1; (B) example 2; (C) example 3; (D) example 4;
FIG. 3 is a schematic illustration of a HVLP finished foil laser copolymerization Jiao Yuntu produced by the various embodiments;
wherein (A) example 1; (B) example 2; (C) example 3; (D) example 4.
Detailed Description
For the purpose of making 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 clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.
Thus, the following detailed description of the embodiments of the invention, as 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
The ultra-low profile copper foil production method applied to the high-frequency high-speed PCB comprises the following steps:
s1, electrolyzing ultra-low profile foil;
adding brightening agent and inhibitor into acid copper sulfate electrolyte, regulating the concentration of additive, and electrolyzing under the action of DC to obtain ultra-low profile foil with thickness of 18 microns and roughness Rz of less than or equal to 1.0 microns.
Parameters during electrolysis of the ultra-low profile foil are as follows:
Cu 2+ concentration: 80g/L;
H 2 SO 4 concentration: 200g/L;
SPS concentration: 20ppm;
PEG-3000 concentration: 10ppm;
cl-concentration: 15ppm;
electrolyte temperature: 55 ℃;
electrolyte flow rate: 40m 3 /h；。
Current density: 80A/dm 2 。
S2, electrochemical polishing pretreatment;
running the ultra-low profile raw foil prepared in the step S1 into a pretreatment tank, and carrying out microetching pretreatment on the surface of the copper foil by means of chemical reaction between the pretreatment liquid and oxide on the surface of the copper foil and dissolution action of reverse pulse current on the copper layer;
the parameters during the electrochemical polishing pretreatment are as follows:
duty cycle: 25%;
pulse frequency: 2000Hz;
average current density: 5.0A/dm 2 ；
H 2 SO 4 Concentration: 100g/L;
H 2 O 2 concentration: 30wt%;
pretreatment liquid temperature: 30 ℃;
the flow rate of the pretreatment liquid is 2.5m 3 /h；
Pretreatment time: 10s.
S3, auxiliary superfine roughening treatment and curing treatment of the additive;
s3.1, auxiliary superfine coarsening treatment is carried out by the additive;
transferring the copper foil pretreated in the step S2 into a roughening electrolytic tank for carrying out ultra-fine roughening treatment of pulse electrochemical deposition, and adding an additive with grain refinement and leveling effects into the roughening liquid in the roughening electrolytic tank, wherein specific parameters in the pulse electrochemical deposition process are as follows:
Cu 2+ ion concentration: 15g/L;
H 2 SO 4 concentration: 150g/L;
Na 2 WO 4 concentration: 25ppm;
EDTA-2Na concentration: 10ppm;
electrolyte temperature: 30 ℃;
coarsening liquid flow rate: 5.0m 3 /h；
Average current density: 25A/dm 2 ；
Duty cycle: 33%;
frequency: 1000Hz;
the treatment time is as follows: 10s.
S3.2, curing treatment;
the electrolytic copper foil subjected to superfine roughening treatment in the step S3.1 is subjected to water washing and water squeezing, and then is transferred into a curing tank for curing treatment; the specific parameters of the curing stage are as follows:
Cu 2+ ion concentration: 50g/L;
H 2 SO 4 concentration: 100g/L;
curing liquid temperature: 50 ℃;
flow rate of curing liquid: 10.0m 3 /h；
Curing current density: 40A/dm 2 ；
The treatment time is as follows: 10s.
S4, electrodepositing a nonmetallic passivation layer;
in order to improve the oxidation resistance of the electrolytic copper foil in the downstream processing process, carrying out nonmetal passivation treatment on the smooth surface and the rough surface of the copper foil obtained in the step S3 by an electrochemical reduction or electrochemical polymerization method, and forming a nonmetal passivation layer with a blocking effect on the treated surface of the electrolytic copper foil; the adverse effect of metal components on high-frequency high-speed signal transmission is fundamentally eliminated; parameters in the preparation process of the nonmetallic passivation layer are as follows:
graphene oxide concentration: 50mg/L (reduced graphene oxide is formed after electrochemical reduction treatment of the part): 0.5A/dm 2 ；
Electrolyte temperature: 25 ℃;
the treatment time is as follows: 10s.
S5, construction of chemical bonding layer
And (3) running the copper foil subjected to nonmetallic passivation treatment to a chemical bonding layer treatment tank, and further constructing a chemical bonding layer on the rough surface of the electrolytic copper foil in a spraying mode. The parameters during the construction of the chemical bond layer were as follows:
Na 2 O·xSiO 2 ·2H 2 o concentration: 1.0g/L.
Treatment fluid temperature: 30 ℃.
Flow rate of treatment fluid: 4.0m 3 /h。
Oven temperature: 180 ℃.
After the above-mentioned processing steps, an ultra low profile (HVLP) copper foil product 1 applied to a high frequency high speed PCB is finally obtained.
The HVLP copper foil product 1 was tested with the following physical parameters:
the non-contact roughness Rz is 1.23 mu m, the interface expansion area ratio Sdr is 8.21%, and the peak curvature Spc is 80mm -1 Peak density Spd of 45000mm -2 Valley void volume Vvp is 0.03 μm 3 /μm 2 The nuclear space volume Vmp is 0.23 μm 3 /μm 2 。
And pressing the HVLP copper foil product 1 and the IT-988G prepreg to prepare a copper clad laminate CCL product 1, and testing the peel strength of the CCL product 1, wherein the peel strength is 0.52N/mm.
The insertion loss test is performed on the PCB product 1 processed from the CCL product 1:
the insertion loss measured at a frequency of 8GHz was-0.74 dB/in;
the insertion loss measured at 16GHz was-0.81 dB/in.
Example 2
The difference from example 1 is that:
the additive components and the content in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated, and part of process parameters in the treatment process are regulated;
the additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
urea concentration: 20ppm;
choline chloride concentration: 10ppm;
average current density: 50A/dm 2 ；
Duty cycle: 25%;
frequency: 2000Hz;
the treatment time is as follows: 5s.
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 2 for use in high frequency high speed PCBs.
The HVLP copper foil product 2 was tested with the following physical parameters:
the non-contact roughness Rz is 1.52 mu m, the interface expansion area ratio Sdr is 14.63%, and the peak curvature Spc is 72mm -1 Peak density Spd of 39000mm -2 Valley void volume Vvp is 0.054 μm 3 /μm 2 The nuclear space volume Vmp is 0.65 μm 3 /μm 2 。
And pressing the HVLP copper foil product 2 and an IT-988G prepreg to prepare a copper clad laminate CCL product 2, and testing the peel strength of the CCL product 2 to obtain the peel strength of 0.50N/mm.
The insertion loss test is performed on the PCB product 2 processed from the CCL product 2:
the insertion loss measured at a frequency of 8GHz was-0.95 dB/in;
the insertion loss measured at 16GHz was-1.23 dB/in.
Example 3
The difference from example 1 is that:
(1) The additive components and the content in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated, and part of process parameters in the treatment process are regulated;
(2) The electrolyte composition and content of the nonmetallic passivation layer in step S4 are adjusted.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
KMnO 4 concentration: 5ppm;
sodium citrate concentration: 50ppm;
average current density: 40A/dm 2 ；
Duty cycle: 50%;
frequency: 3000Hz;
the treatment time is as follows: 8s.
The parameters in the preparation process of the nonmetallic passivation layer in S4 are as follows:
polyethylene dioxythiophene EDOT monomer concentration: 25mg/L;
current density: 1.0A/dm 2 。
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 3 that is applied to a high frequency high speed PCB.
The HVLP copper foil product 3 was tested with the following physical parameters:
the non-contact roughness Rz is 1.67 mu m, the interface expansion area ratio Sdr is 10.17%, and the peak curvature Spc is 63mm -1 Peak density Spd of 29500mm -2 Valley void volume Vvp was 0.06 μm 3 /μm 2 The nuclear space volume Vmp is 0.58 μm 3 /μm 2 。
And pressing the HVLP copper foil product 3 and the IT-988G prepreg to prepare a copper clad laminate CCL product 3, and carrying out peel strength test on the CCL product 3, wherein the peel strength is 0.51N/mm.
The insertion loss test is performed on the PCB product 3 processed from the CCL product 3:
the insertion loss measured at a frequency of 8GHz was-1.08 dB/in;
the insertion loss measured at 16GHz was-1.37 dB/in.
Example 4
The difference from example 1 is that:
(1) Part of process parameters in the treatment process of the step S2 are adjusted;
(2) The components and the content of the additive in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated;
(3) The electrolyte composition and content of the nonmetallic passivation layer in step S4 are adjusted.
The pulse frequency of the reverse pulse current in S2 is 200Hz, and the average current density is 10A/dm 2 The duty cycle was 50% and the processing time was 5s.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
V 2 O 5 concentration: 10ppm; sodium citrate concentration: 25ppm.
The parameters in the preparation process of the nonmetallic passivation layer in S4 are as follows:
aniline ANI monomer concentration: 30mg/L;
current density: 2.5A/dm 2 。
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 4 that is applied to a high frequency high speed PCB.
The HVLP copper foil product 4 was tested with the following physical parameters:
the non-contact roughness Rz is 1.41 mu m, the interface expansion area ratio Sdr is 5.08%, and the peak curvature Spc is 25mm -1 Peak density Spd of 30850mm -2 The valley void volume Vvp was 0.032 μm 3 /μm 2 The nuclear space volume Vmp is 0.25 μm 3 /μm 2 。
And pressing the HVLP copper foil product 4 and the IT-988G prepreg to prepare a copper clad laminate CCL product 4, and testing the peel strength of the CCL product 4, wherein the peel strength is 0.50N/mm.
The insertion loss test is performed on the PCB product 4 processed from the CCL product 4:
the insertion loss measured at a frequency of 8GHz was-0.92 dB/in;
the insertion loss measured at 16GHz was-1.19 dB/in.
Example 5
The difference from example 1 is that:
(1) Part of process parameters in the treatment process of the step S2 are adjusted;
(2) The components and the content of the additive in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated;
(3) The composition and content of the chemical bonding layer in step S5 are adjusted.
The pulse frequency of the reverse pulse current in S2 is 1000Hz, and the average current density is 8A/dm 2 The duty cycle was 35% and the processing time was 8s.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
Na 2 WO 4 concentration: 20ppm;
malic acid concentration: 20ppm.
The parameters during the construction of the chemical bond layer in S5 are as follows:
silane name: KH-792;
silane concentration: 1.0wt%.
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 5 that is applied to a high frequency high speed PCB.
The HVLP copper foil product 5 was tested with the following physical parameters:
the non-contact roughness Rz is 1.35um, the interface expansion area ratio Sdr is 9.16 percent, and the peak curvature Spc is 68mm -1 Peak density Spd of 42500mm -2 Valley void volume Vvp is 0.036 μm 3 /μm 2 The nuclear space volume Vmp is 0.37 μm 3 /μm 2 。
And pressing the HVLP copper foil product 5 and the IT-988G prepreg to prepare a copper clad laminate CCL product 5, and testing the peel strength of the CCL product 5, wherein the peel strength is 0.50N/mm.
The insertion loss test is performed on the PCB product 5 processed from the CCL product 5:
the insertion loss measured at a frequency of 8GHz was-0.83 dB/in;
the insertion loss measured at 16GHz was-0.92 dB/in.
Example 6
The difference from example 1 is that:
(1) The components and the content of the additive in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated;
(2) The electrolyte composition and content of the nonmetallic passivation layer in step S4 are adjusted.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
KMnO 4 concentration: 5ppm;
potassium sodium tartrate concentration: 25ppm.
The parameters in the preparation process of the nonmetallic passivation layer in S4 are as follows:
parameters in the preparation process of the nonmetallic passivation layer are as follows:
pyrrole Py monomer concentration: 20mg/L;
current density: 1.5A/dm 2 。
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 6 that is applied to a high frequency high speed PCB.
The HVLP copper foil product 6 was tested with the following physical parameters:
the non-contact roughness Rz is 1.78 mu m, the interface expansion area ratio Sdr is 11.25%, and the peak curvature Spc is 76mm -1 Peak density Spd of 35080mm -2 Valley void volume Vvp is 0.045 μm 3 /μm 2 The nuclear space volume Vmp is 0.52 μm 3 /μm 2 。
And pressing the HVLP copper foil product 6 and the IT-988G prepreg to prepare a copper clad laminate CCL product 6, and testing the peel strength of the CCL product 5, wherein the peel strength is 0.51N/mm.
The insertion loss test is performed on the PCB product 6 processed from the CCL product 6:
the insertion loss measured at a frequency of 8GHz is-1.03 dB/in;
the insertion loss measured at 16GHz was-1.29 dB/in.
Example 7
The difference from example 1 is that:
(1) The components and the content of the additive in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated;
(2) The electrolyte composition and content of the nonmetallic passivation layer in step S4 are adjusted.
(3) The composition and content of the chemical bonding layer in step S5 are adjusted.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
V 2 O 5 concentration: 10ppm;
EDTA-2Na concentration: 20ppm.
The parameters in the preparation process of the nonmetallic passivation layer in S4 are as follows:
polyethylene dioxythiophene EDOT monomer concentration: 10mg/L;
current density: 2.5A/dm 2 。
The parameters during the construction of the chemical bond layer in S5 are as follows:
silane name: KH-560;
silane concentration: 0.5wt%.
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 7 for use in high frequency high speed PCBs.
The HVLP copper foil product 7 was tested with the following physical parameters:
the non-contact roughness Rz is 1.66 mu m, the interface expansion area ratio Sdr is 9.51%, and the peak curvature Spc is 59mm -1 Peak density Spd of 33250mm -2 Valley void volume Vvp is 0.038 μm 3 /μm 2 The nuclear space volume Vmp is 0.43 μm 3 /μm 2 。
And pressing the HVLP copper foil product 7 and the IT-988G prepreg to prepare a copper clad laminate CCL product 7, and testing the peel strength of the CCL product 7, wherein the peel strength is 0.50N/mm.
The insertion loss test is performed on the PCB product 7 processed from the CCL product 7:
the insertion loss measured at a frequency of 8GHz was-0.97 dB/in;
the insertion loss measured at 16GHz was-1.25 dB/in.
Example 8
The difference from example 1 is that:
(1) The components and the content of the additive in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated;
(2) The electrolyte composition and content of the nonmetallic passivation layer in step S4 are adjusted.
(3) The composition and content of the chemical bonding layer in step S5 are adjusted.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
malic acid concentration: 25ppm;
EDTA-2Na concentration: 5ppm.
The parameters in the preparation process of the nonmetallic passivation layer in S4 are as follows:
aniline ANI monomer concentration: 20mg/L;
current density: 1.5A/dm 2 。
The parameters during the construction of the chemical bond layer in S5 are as follows:
silane name: KBM-503;
silane concentration: 0.75wt%.
This embodiment ultimately results in an ultra low profile (HVLP) copper foil product 8 that is applied to a high frequency high speed PCB.
The HVLP copper foil product 8 was tested with the following physical parameters:
the non-contact roughness Rz is 1.52 mu m, the interface expansion area ratio Sdr is 9.07%, and the peak curvature Spc is 47mm -1 Peak density Spd of 39500mm -2 Valley void volume Vvp is 0.042 μm 3 /μm 2 Nuclear spaceVolume Vmp of 0.45 μm 3 /μm 22 。
And pressing the HVLP copper foil product 8 and an IT-988G prepreg to prepare a copper clad laminate CCL product 8, and testing the peel strength of the CCL product 8, wherein the peel strength is 0.51N/mm.
The insertion loss test is performed on the PCB product 8 processed from the CCL product 8:
the insertion loss measured at a frequency of 8GHz was-0.94 dB/in;
the insertion loss measured at 16GHz was-1.34 dB/in.
Comparative example 1
The difference from example 1 is that:
(1) Adjusting part of process parameters of pretreatment of the wool foil in the step 2;
(2) The additive components and the content in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated, and part of process parameters are regulated;
(3) The composition and content of the chemical bonding layer in step S5 are adjusted.
The parameters during the pretreatment of S2 are as follows:
H 2 SO 4 concentration: 100g/L;
H 2 O 2 concentration: 30wt%.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
V 2 O 5 concentration: 5ppm;
KMnO 4 concentration: 10ppm.
The parameters during the construction of the chemical bond layer in S5 are as follows:
water glass composition: k (K) 2 O·xSiO 2 ·3H 2 O；
Concentration of water glass: 0.5g/L.
The comparison results in an ultra low profile (HVLP) copper foil product 9 for high frequency high speed PCBs.
The HVLP copper foil product 9 was tested with the following physical parameters:
the non-contact roughness Rz is 1.97 μm,the interfacial expansion area ratio Sdr is 21.37%, and the peak curvature Spc is 93mm -1 Peak density Spd of 35200mm -2 Valley void volume Vvp is 0.078 μm 3 /μm 2 The nuclear space volume Vmp is 0.77 μm 3 /μ 22 。
And pressing the HVLP copper foil product 9 and the IT-988G prepreg to prepare a copper clad laminate CCL product 9, and carrying out peel strength test on the CCL product 9, wherein the peel strength is 0.51N/mm.
The insertion loss test is performed on the PCB product 9 processed from the CCL product 9:
the insertion loss measured at a frequency of 8GHz was-1.23 dB/in;
the insertion loss measured at 16GHz was-2.06 dB/in.
Comparative example 2
The difference from example 1 is that:
(1) The additive components and the content in the additive auxiliary superfine coarsening treatment in the step S3.1 are regulated, and part of process parameters are regulated;
(2) The composition and content of the chemical bonding layer in step S5 are adjusted.
The additive with grain refinement and leveling effects in S3.1 has the concentration as follows:
KMnO 4 concentration: 5ppm;
EDTA-2Na concentration: 10ppm.
The parameters during the construction of the chemical bond layer in S5 are as follows:
silane name: KH-792;
silane concentration: 0.5wt%.
The comparison results in an ultra low profile (HVLP) copper foil product 10 that is applied to a high frequency high speed PCB.
The HVLP copper foil product 10 was tested with the following physical parameters:
the non-contact roughness Rz is 2.05 mu m, the interface expansion area ratio Sdr is 24.51 percent, and the peak curvature Spc is 108mm -1 Peak density Spd of 3050 mm -2 Valley void volume Vvp is 0.089 μm 3 /μm 2 The nuclear space volume Vmp is 0.91 μm 3 /μm 22 。
The HVLP copper foil product 10 and the IT-988G prepreg were laminated to produce a copper clad laminate CCL product 10, and the CCL product 10 was tested for peel strength, which was 0.55N/mm.
The insertion loss test was performed on the PCB product 10 processed from the CCL product 10:
the insertion loss measured at a frequency of 8GHz was-1.47 dB/in;
the insertion loss measured at 16GHz was-2.38 dB/in.
In order to more intuitively reflect the implementation effect of the present invention, the products 1 to 4 produced in examples 1 to 4 were respectively subjected to analysis and characterization of microscopic morphology and parameters by means of a scanning electron microscope (SEMTESCAN, VEGA), a super depth-of-field microscope (Keyence, VR 6000) and a laser confocal microscope (0 lympus, ols 5100), and the results are as follows:
1. the rough surface conditions of the products 1 to 4 produced in examples 1 to 4 were analyzed under an electron microscope, and FIG. 1 was obtained.
From the SEM images shown in (a) - (D) of fig. 1, it can be clearly observed that:
from example 1 to example 4, the roughened structures exhibited dendritic, hemispherical, conical and spherical morphologies, respectively, that is: by changing the combination and concentration of the additives with grain refinement and leveling effects in the step S3.1, coarsened tissues with different morphologies can be obtained. And certain gaps exist between adjacent coarsening particles, so that the contact area between the coarsening particles and the resin is increased, and a certain space is provided for the infiltration of the resin during CCL preparation.
Further measuring the size of the coarsened particles, it was possible to obtain coarsened particles having an average particle diameter of 0.6-0.8 μm. On the one hand, submicron ultra-fine coarsening particles are beneficial to improving the etching efficiency in the downstream processing process; on the other hand, the risk of short circuits due to etching residues is also significantly reduced.
2. The products 1 to 4 produced in examples 1 to 4 were each sliced, and the sectional morphology and copper tooth conditions were analyzed under a super depth of field microscope to obtain FIG. 2.
From the super depth of field microscope images shown in fig. 2 (a) - (D), it can be clearly observed that: the profile of the base copper layer of the products 1-4 is low, and a large number of copper teeth grow on the surface of the base copper layer. Wherein: in products 1 and 2, the average height of the copper teeth was about 1.5 μm; in products 3 and 4, the average height of the copper teeth was about 2.0 μm.
3. Samples of products 1-4 produced in examples 1-4 were analyzed under a laser confocal microscope to obtain FIG. 3.
From the confocal laser cloud diagrams shown in (a) - (D) of fig. 3, it is clear that:
the uniformity of the roughened structures of the rough surfaces of the products 1-4 can be intuitively judged under different color distribution conditions.
The color in example 1 is mainly green, and the uniformity is relatively good;
in examples 2 to 4, which are also mainly green, a part of blue region appears, which indicates that the roughness uniformity of the roughened structure is slightly lower than that of example 1, but is also preferable.
Other parameters for confocal laser measurements are shown in table 1.
From Table 1, it can be found that the method of the present invention represented by examples 1 to 8 and the conventional surface treatment method represented by comparative examples 1 to 2 can produce an HVLP electrolytic copper foil having low roughness, stable peel strength and excellent signal transmission performance.
But further alignment will find that:
the copper foil products produced in examples 1 to 8 have lower optical roughness, lower peak curvature, lower expansion area ratio, lower valley void volume, lower core void volume, no obvious difference in peel strength, and lower insertion loss at both 8GHz and 16GHz, that is, the method for producing ultra-low profile copper foil applied to high-frequency high-speed PCBs provided by the invention can obtain high-performance HVLP electrolytic copper foil with lower profile (about 40% reduction in noncontact roughness Rz) and higher signal integrity (about 65.9% reduction in insertion loss) under the condition of keeping the peel strength unchanged significantly.
Finally, it should be emphasized that the foregoing description is merely illustrative of the preferred embodiments of the invention, and that various changes and modifications can be made by those skilled in the art without departing from the spirit and principles of the invention, and any such modifications, equivalents, improvements, etc. are intended to be included within the scope of the invention.
Claims (10)
1. The ultra-low profile copper foil production method applied to the high-frequency high-speed PCB comprises the following steps: the method comprises the following steps:
s1, electrolyzing ultra-low profile foil;
adding a brightening agent and an inhibitor into the acidic copper sulfate electrolyte, regulating and controlling the concentration of the additive, and electrolyzing under the action of direct current to prepare the ultra-low profile green foil;
s2, electrochemical polishing pretreatment;
running the ultra-low profile raw foil prepared in the step S1 into a pretreatment tank, and carrying out microetching pretreatment on the surface of the copper foil by means of chemical reaction between the pretreatment liquid and oxide on the surface of the copper foil and dissolution action of reverse pulse current on the copper layer;
s3, auxiliary superfine roughening treatment and curing treatment of the additive;
s3.1 additive assisted ultra-fine roughening treatment
Transferring the copper foil pretreated in the step S2 into a roughening electrolytic tank for carrying out ultra-fine roughening treatment of pulse electrochemical deposition;
the coarsening electrolytic tank is characterized in that an additive with grain refinement and leveling functions is added into coarsening liquid;
s3.2, curing treatment;
the electrolytic copper foil subjected to superfine roughening treatment in the step S3.1 is subjected to water washing and water squeezing, and then is transferred into a curing tank for curing treatment;
s4, constructing an electrodeposited nonmetallic passivation layer;
carrying out nonmetal passivation treatment on the smooth surface and the rough surface of the copper foil obtained in the step S3 by an electrochemical reduction or electrochemical polymerization method, and forming a nonmetal passivation layer with a blocking effect on the treated surface of the electrolytic copper foil;
s5, constructing a chemical bonding layer;
and (3) running the copper foil subjected to the nonmetallic passivation treatment in the step (S4) to a chemical bonding layer treatment tank, and further constructing a chemical bonding layer on the rough surface of the electrolytic copper foil in a spraying mode to finally obtain the ultralow-profile (HVLP) copper foil applied to the high-frequency high-speed PCB.
2. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 1, wherein: the additive in the step S1 is at least 2 combinations of sodium polydithio-dipropyl sulfonate (SPS), sodium 3-mercapto-1-propane sulfonate (MPS), polyethylene glycol (PEG) and Polyethyleneimine (PEI).
3. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 2, wherein: the roughness Rz of the ultra-low profile green foil in the step S1 is 0.5-1.0 mu m, and the interface expansion area ratio Sdr is 5-10%.
4. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 1, wherein: the pulse frequency of the reverse pulse current in the step S2 is between 200 and 2000Hz, and the average current density is between 5 and 10A/dm 2 The duty cycle is between 25 and 50 percent, and the treatment time is between 5 and 10 seconds.
5. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 1, wherein: the additives used in the ultra-fine roughening process of the step S3.1 are urea, choline chloride, sodium citrate, potassium sodium tartrate, sodium tungstate, potassium permanganate, malic acid and ethylenediamine tetraethylDisodium acid (EDTA-2 Na), vanadium pentoxide (V) 2 O 5 ) One or a combination of several of them; the additive concentration is between 5 and 50 ppm.
6. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 5, wherein: the specific parameters in the pulsed electrochemical deposition process in step S3.1 are as follows: the frequency is between 1000 and 3000Hz, and the average current density is between 25 and 50A/dm 2 The duty cycle is between 25 and 50 percent, and the treatment time is between 5 and 10 seconds.
7. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 1, wherein: the component of the nonmetallic passivation layer in the step S4 is one or a combination of several of reduced graphene oxide (rGO), polyethylene dioxythiophene (PEDOT), polypyrrole (PPy), and Polyaniline (PANI).
8. The method for producing ultra-low profile copper foil applied to high frequency and high speed PCB as claimed in claim 1, wherein: in the step S5, the chemical bonding layer is water glass or a silane coupling agent, wherein:
the molecular formula of the water glass is M 2 O·xSiO 2 ·nH 2 Alkali metal silicate of O (m=na or K, x=2 to 4);
the silane coupling agent is one of vinyl, epoxy, styryl, methylpropenyl, propenyl, amino, ureido and mercapto.
9. The method for producing an ultra-low profile copper foil applied to a high frequency and high speed PCB according to any one of claims 1 to 8, wherein: the ultra-low profile (HVLP) copper foil applied to the high-frequency high-speed PCB, which is obtained in the step S5, has the following performance indexes:
coarsened particles in the form of dendrites, hemispheres, cones and spheres were observed when the microscopic morphology characterization was performed at 8000 x using a scanning electron microscope SEM at a 40 degree tilt angle; gaps exist between adjacent coarsening particles to form coarsening tissues with porosity;
the average size of coarsened particles is between 200 and 600nm measured at 8000 times at 0 degree angle using scanning electron microscope SEM;
when microscopic parameter analysis is carried out by using a laser confocal microscope, the volume Vvp of the valley area of coarsened particles is measured to be between 0.03 and 0.06 mu m 3 /μm 2 Between 0.23-0.65 μm in nuclear space volume 3 /μm 2 Between them;
when a laser confocal microscope is used for microscopic parameter analysis, the roughness Rz of the treated surface is measured to be between 1.0 and 2.0 mu m, and the peak density Spd is between 25000 and 45000mm -2 Between them, the peak curvature Spc is 20-80mm -1 The interfacial expansion area ratio Sdr is between 5 and 15 percent.
10. The method for producing an ultra-low profile copper foil applied to a high frequency and high speed PCB according to any one of claims 1 to 8, wherein: the ultra-low profile (HVLP) copper foil applied to the high-frequency high-speed PCB, which is obtained in the step S5, has the following performance indexes:
the insertion loss of the PCB plate formed by pressing and processing the ultra-low profile (HVLP) copper foil and PPO resin at 16GHz is between-0.81 dB/in and-1.75 dB/in;
the peel strength of the ultra low profile (HVLP) electrolytic copper foil with the thickness of 18 mu m after hot pressing with the PPO resin-based sheet material is not lower than 0.50N/mm.
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| CN202310073032.3A CN116288544A (en) | 2023-02-06 | 2023-02-06 | Ultra-low profile copper foil production method applied to high-frequency high-speed PCB |
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