CN114945246A - Palladium removal process of circuit board, palladium passivator with non-metal holes and preparation method of palladium passivator - Google Patents
Palladium removal process of circuit board, palladium passivator with non-metal holes and preparation method of palladium passivator Download PDFInfo
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- CN114945246A CN114945246A CN202210509314.9A CN202210509314A CN114945246A CN 114945246 A CN114945246 A CN 114945246A CN 202210509314 A CN202210509314 A CN 202210509314A CN 114945246 A CN114945246 A CN 114945246A
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- palladium
- passivator
- thio compound
- wetting agent
- metal
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- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 title claims abstract description 275
- 229910052763 palladium Inorganic materials 0.000 title claims abstract description 137
- 238000000034 method Methods 0.000 title claims abstract description 21
- 230000008569 process Effects 0.000 title claims abstract description 18
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 229910052755 nonmetal Inorganic materials 0.000 title claims description 10
- -1 thio compound Chemical class 0.000 claims abstract description 28
- 239000000080 wetting agent Substances 0.000 claims abstract description 24
- 239000011148 porous material Substances 0.000 claims abstract description 17
- OBBCYCYCTJQCCK-UHFFFAOYSA-L copper;n,n-diethylcarbamodithioate Chemical compound [Cu+2].CCN(CC)C([S-])=S.CCN(CC)C([S-])=S OBBCYCYCTJQCCK-UHFFFAOYSA-L 0.000 claims abstract description 10
- XQWBMZWDJAZPPX-UHFFFAOYSA-N pyridine-3-carbothioamide Chemical compound NC(=S)C1=CC=CN=C1 XQWBMZWDJAZPPX-UHFFFAOYSA-N 0.000 claims abstract description 10
- NGCCQISMNZBKJJ-UHFFFAOYSA-N 2,6-dichloro-3-methylquinoline Chemical compound ClC1=CC=C2N=C(Cl)C(C)=CC2=C1 NGCCQISMNZBKJJ-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229920000570 polyether Polymers 0.000 claims description 15
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 13
- 239000008367 deionised water Substances 0.000 claims description 13
- 229910021641 deionized water Inorganic materials 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000002791 soaking Methods 0.000 claims description 11
- 229920005682 EO-PO block copolymer Polymers 0.000 claims description 6
- 239000001509 sodium citrate Substances 0.000 claims description 5
- HRXKRNGNAMMEHJ-UHFFFAOYSA-K trisodium citrate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O HRXKRNGNAMMEHJ-UHFFFAOYSA-K 0.000 claims description 5
- 229940038773 trisodium citrate Drugs 0.000 claims description 5
- 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 claims description 4
- 239000013065 commercial product Substances 0.000 claims description 4
- UEUXEKPTXMALOB-UHFFFAOYSA-J tetrasodium;2-[2-[bis(carboxylatomethyl)amino]ethyl-(carboxylatomethyl)amino]acetate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]C(=O)CN(CC([O-])=O)CCN(CC([O-])=O)CC([O-])=O UEUXEKPTXMALOB-UHFFFAOYSA-J 0.000 claims description 4
- 239000003109 Disodium ethylene diamine tetraacetate Substances 0.000 claims description 3
- 235000019301 disodium ethylene diamine tetraacetate Nutrition 0.000 claims description 3
- DZCAZXAJPZCSCU-UHFFFAOYSA-K sodium nitrilotriacetate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CN(CC([O-])=O)CC([O-])=O DZCAZXAJPZCSCU-UHFFFAOYSA-K 0.000 claims description 3
- 238000005303 weighing Methods 0.000 claims description 3
- 150000002191 fatty alcohols Chemical class 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 23
- 238000002161 passivation Methods 0.000 abstract description 18
- 238000002844 melting Methods 0.000 abstract description 11
- 230000008018 melting Effects 0.000 abstract description 11
- 239000007788 liquid Substances 0.000 abstract description 7
- 230000001988 toxicity Effects 0.000 abstract description 7
- 231100000419 toxicity Toxicity 0.000 abstract description 7
- 239000002699 waste material Substances 0.000 abstract description 7
- 230000036541 health Effects 0.000 abstract description 5
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 description 21
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 16
- 229910052751 metal Inorganic materials 0.000 description 16
- 239000002184 metal Substances 0.000 description 16
- 229910052802 copper Inorganic materials 0.000 description 15
- 239000010949 copper Substances 0.000 description 15
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 12
- 239000003054 catalyst Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 10
- 238000007747 plating Methods 0.000 description 10
- 239000000126 substance Substances 0.000 description 7
- MSNOMDLPLDYDME-UHFFFAOYSA-N gold nickel Chemical compound [Ni].[Au] MSNOMDLPLDYDME-UHFFFAOYSA-N 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 230000002378 acidificating effect Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000001465 metallisation Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229920002120 photoresistant polymer Polymers 0.000 description 2
- 230000008092 positive effect Effects 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- 206010007269 Carcinogenicity Diseases 0.000 description 1
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000007670 carcinogenicity Effects 0.000 description 1
- 231100000260 carcinogenicity Toxicity 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 125000004177 diethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 230000001804 emulsifying effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- NOJNFULGOQGBKB-UHFFFAOYSA-M sodium;3-[3-tert-butylsulfanyl-1-[[4-(6-ethoxypyridin-3-yl)phenyl]methyl]-5-[(5-methylpyridin-2-yl)methoxy]indol-2-yl]-2,2-dimethylpropanoate Chemical compound [Na+].C1=NC(OCC)=CC=C1C(C=C1)=CC=C1CN1C2=CC=C(OCC=3N=CC(C)=CC=3)C=C2C(SC(C)(C)C)=C1CC(C)(C)C([O-])=O NOJNFULGOQGBKB-UHFFFAOYSA-M 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 125000000446 sulfanediyl group Chemical group *S* 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
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
- H05K3/0011—Working of insulating substrates or insulating layers
- H05K3/0055—After-treatment, e.g. cleaning or desmearing of holes
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/32—Alkaline compositions
- C23F1/40—Alkaline compositions for etching other metallic material
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemically Coating (AREA)
Abstract
The invention provides a palladium removing process of a circuit board, a palladium passivator with non-metallic holes and a preparation method thereof. The palladium passivator with non-metallic pores comprises the following components in percentage by weight: 5-100 g/L of alkaline complex, 5-50 g/L of thio compound and 0.1-30 g/L of wetting agent; wherein the thio compound comprises at least one of sodium dibenzyldithiocarbamate, copper diethyldithiocarbamate and thionicotinamide. The palladium passivator belongs to an alkaline palladium passivator, has a high melting point, can resist high temperature, can keep the passivation effect on palladium, has a good palladium removing effect, and ensures the quality of a circuit board. The palladium passivator is low in toxicity, is friendly to the health of workers, and is low in waste liquid treatment difficulty.
Description
Technical Field
The invention relates to the technical field of circuit board processing, in particular to a palladium removing process of a circuit board, a palladium passivator with non-metallic holes and a preparation method thereof.
Background
Electroless Nickel Gold (ENIG) is mainly used for surface treatment of circuit boards to prevent copper on the surfaces of the circuit boards from being oxidized or corroded, and is a solderable surface coating process for Electroless Nickel plating and Electroless Gold plating on bare copper surfaces.
In the process of manufacturing a Plated Through Hole (PTH), palladium is adsorbed in the Hole wall. Before the electroless nickel-gold process is performed, if palladium cannot be effectively removed, the non-through hole is metallized, and the reliability of the PCB board is affected.
In order to remove palladium, an acidic palladium remover containing thiourea substances is generally used to remove palladium plating in non-copper-deposited pores. However, before electroless ni/au, the PCB board is usually subjected to a high temperature baking operation to remove moisture contained in the PCB or absorbed from the outside. And the thiourea has a low melting point and easily loses the passivation effect on the palladium catalyst under a high-temperature condition. After the acidic palladium removing agent containing thiourea substances is used, thiourea can form a film and adsorb and remain on a copper surface, the appearance color of the nickel-gold surface is rough, the bonding force of a nickel layer and the copper surface is influenced, and the risk of throwing nickel quality on the surface can be caused.
Disclosure of Invention
The invention aims to provide a non-metal pore palladium passivator with a good palladium removing effect, a preparation method thereof and a palladium removing process adopting the palladium passivator, so as to solve the problems in the prior art.
In order to solve the technical problems, the invention provides a palladium passivator with non-metallic pores, which comprises the following components in percentage by weight:
5-100 g/L of alkaline complex, 5-50 g/L of thio compound and 0.1-30 g/L of wetting agent; wherein the thio compound comprises at least one of sodium dibenzyldithiocarbamate, copper diethyldithiocarbamate and thionicotinamide.
In one embodiment, the basic complex comprises at least one of disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium nitrilotriacetate, trisodium citrate.
In one embodiment, the wetting agent comprises at least one of the commercial fatty alcohol-capped polyethers LF-221, the commercial isomeric alcohol polyethers LF-901, the commercial ethylene oxide-propylene oxide block copolymer (EO-PO), and the polyether 1740.
In one embodiment, the basic complex is 20-60 g/L, the thio compound is 15-30 g/L, and the wetting agent is 5-20 g/L.
The invention also provides a preparation method of the palladium passivator with non-metallic pores, which comprises the following steps:
weighing the alkaline complex, the thio compound and the wetting agent according to 5-100 g/L of the alkaline complex, 5-50 g/L of the thio compound and 0.1-30 g/L of the wetting agent: wherein the thio compound comprises at least one of sodium dibenzyl dithiocarbamate, copper diethyldithiocarbamate and thionicotinamide;
adding the basic complex, the thio compound and the wetting agent to deionized water and sufficiently dissolving:
and then, fixing the volume to a preset volume through deionized water, and then uniformly mixing to obtain the palladium passivator with the non-metallic pores.
The invention also provides a palladium removing process of the circuit board, which comprises the following steps:
the palladium passivator with non-metallic holes is used for soaking the plate to be subjected to palladium removal for 10-300 s at the temperature of 25-50 ℃.
In one embodiment, the temperature is 30 to 40 ℃.
In one embodiment, the soaking time is 30s to 180 s.
According to the technical scheme, the invention has the advantages and positive effects that:
the palladium passivator disclosed by the invention belongs to an alkaline palladium passivator, has a higher melting point, can resist higher temperature, further can keep the passivation effect on palladium, has a better palladium removing effect, and ensures the quality of a circuit board. The palladium passivator is low in toxicity, is friendly to the health of workers, and is low in waste liquid treatment difficulty.
Drawings
FIG. 1 is a schematic view of the absence of metal in the non-metallic pores of the sheet material of the present invention.
FIG. 2 is a schematic illustration of a sheet of the present invention having a small amount of metal within the non-metallic pores.
FIG. 3 is a schematic illustration of the sheet of the present invention having a substantial amount of metal within the non-metallic pores.
FIG. 4 is a schematic representation of a plate of the present invention after palladium removal by the palladium deactivator of example 4.
FIG. 5 is a schematic illustration of a sheet that has not been subjected to palladium removal.
The reference numerals are explained below:
1. a plate material; 2. a metal.
Detailed Description
Exemplary embodiments that embody features and advantages of the invention are described in detail below. It is to be understood that the invention is capable of various modifications in various embodiments without departing from the scope of the invention and that the description is intended to be illustrative in nature and not to limit the invention.
For further explanation of the principles and construction of the present invention, the preferred embodiments of the present invention will now be described in detail.
It should be noted that a Printed Circuit Board (PCB for short) needs to metalize a through hole before a Circuit is conducted. Hole metallization refers to a process of plating a layer of conductive metal on the wall of an insulating hole to connect circuits. Among them, copper has good conductivity, low resistivity, and strong binding force with a non-metal substrate, and thus is widely used for hole metallization.
The chemical copper plating is to reduce bivalent copper ions into elemental copper under the action of a reducing agent. Usually, a catalyst is added during electroless copper plating to improve the reduction efficiency and improve the directional adhesion of copper atoms. The catalyst is usually colloidal palladium or ionic palladium.
For non-conductive vias that provide only mechanical mounting or mechanical fastening of the component, it is desirable to remove the palladium catalyst adsorbed on the inner wall of the non-conductive via to avoid metallization of the non-conductive via by catalyzing nickel and attaching nickel to the non-conductive via during the subsequent electroless nickel-gold process.
Therefore, it is necessary to remove the palladium at the non-metal holes on the wiring board. Wherein, removing palladium means to deactivate the palladium catalyst to make it lose catalytic activity.
The prior acidic palladium remover containing thiourea substances is generally adopted, and has the following defects of low melting point (171 ℃):
due to thiourea (CH) 4 N 2 S) has certain toxicity and carcinogenicity, and is not friendly to the physical health of staff after being used for a long time. In a wastewater treatment system, the thiourea-containing waste liquid has an inactivation effect on biochemical treatment bacteria, and more cost is consumed for treatment.
Therefore, the invention provides a palladium passivator (hereinafter referred to as palladium passivator) with non-metallic holes, which is suitable for the palladium removal treatment of a board in the PCB manufacturing process. The palladium passivator belongs to an alkaline palladium passivator, has a high melting point, can resist high temperature, can keep the passivation effect on palladium, and ensures the quality of a circuit board. The palladium passivator is low in toxicity, is friendly to the health of workers, and is low in waste liquid treatment difficulty.
The passivation and palladium removal principle of the palladium passivator is specifically described in detail below.
Specifically, the palladium passivator comprises the following components in percentage by weight: 5-100 g/L of alkaline complex, 5-50 g/L of thio compound and 0.1-30 g/L of wetting agent.
Wherein the alkaline complex comprises at least one of disodium ethylene diamine tetraacetate, tetrasodium ethylene diamine tetraacetate, sodium nitrilotriacetate and trisodium citrate. That is, any one of the above-mentioned individual compounds may be used, any two of them may be mixed, and any three or four of them may be mixed.
The alkaline complex is used for complexing metal ions, and further is beneficial to falling off of palladium ions on the surface of the plate.
And when the amount of the alkaline complex is less than 5g/l, the effect is not obvious, and when the amount of the alkaline complex is more than 100g/l, the effect is not large, so that raw materials are wasted.
Further, the alkaline complex is 20-60 g/L.
The thio compound comprises at least one of sodium dibenzyl dithiocarbamate, copper diethyl dithiocarbamate and thionicotinamide.
The thio compound combines with a palladium (Pd) atom in the palladium catalyst layer adsorbed on the inner wall surface of the non-through hole to form a complex (e.g. Pd) 4 S) and the like, and the passivation phenomenon occurs, so that the palladium catalyst loses the catalytic activity permanently.
SODIUM dibenzyldithiocarbamate dibenzithiobamicacid SODIUM SALT with molecular formula C 15 H 14 NNaS 2 The melting point was 235 ℃.
Copper diethyldithiocarbamate (Copper, bis (diethyl lcarbamodithioato-kS, kS') -, (SP-4-1) - (9CI)), having the formula C 10 H 22 CuN 2 S 4 The melting point was 197 ℃.
The molecular formula of Thionicotinamide (Thionicotinamide) is C 6 H 6 N 2 S, the melting point is 185-190 ℃.
The toxicity of the thio compounds is small, so that the subsequent waste liquid treatment is relatively easy. The melting point of the chemical substance is higher than that of thiourea, the chemical substance is more resistant to high-temperature environment, and the passivation effect of the chemical substance on the palladium catalyst is not easy to damage. Thereby being beneficial to the subsequent working procedure. Has no adsorption effect on the surface of copper metal.
When the amount of the thio compound is less than 5g/L, the passivation on the palladium catalyst is incomplete; if the amount of the thio compound is more than 50g/L, the subsequent wastewater treatment is not facilitated. Further, the amount of the thio compound is 15-30 g/L.
The wetting agent comprises at least one of fatty alcohol-terminated polyether commodity LF-221, isomeric alcohol polyether commodity LF-901, ethylene oxide-propylene oxide block copolymer (EO-PO) commodity polyether 1740 (hereinafter referred to as polyether 1740). That is, the wetting agent may be any one of the above-mentioned individual compounds, may be a mixture of any two of them, and may be a mixture of any three or four of them.
The wetting agents in this application are all of the low foam type, suitable for spray application. The wetting agent has better emulsifying, dispersing and wetting capacities, can better wet the surface of the plate and is beneficial to cleaning.
When the amount of the wetting agent is less than 0.1g/L, the effect is not obvious; when the amount of the wetting agent is more than 30g/L, the effect is not more remarkable.
Further, the wetting agent is 5-20 g/L.
The palladium passivator has a high melting point, can resist high temperature, can keep the passivation effect on palladium, and ensures the quality of a circuit board. The palladium passivator is low in toxicity, is friendly to the health of workers, and is low in waste liquid treatment difficulty.
For ease of understanding, the inventors of the present application provide a representation of the metal in the pores of the plate to illustrate the effect of the palladium passivator, and how well it works. Fig. 1 to fig. 3 respectively show schematic diagrams of whether the non-metallic holes of the plate have metal and how much metal is contained, and referring to fig. 1, the non-metallic holes of the plate 1 have no metal 2 at all, which can show that the palladium passivation agent has 100% of palladium passivation removal efficiency, i.e. the palladium passivation agent has very good effect. Referring to fig. 2, the plate 1 has a small amount of metal 2 on the side walls of the non-metallic holes, and the palladium passivator is relatively ineffective. Referring to fig. 3, the plate 1 has a large amount of metal 2 on the side walls of the non-metallic holes, and the palladium passivator is very ineffective.
The preparation method of the palladium passivator comprises the following steps:
weighing the alkaline complex, the thio compound and the wetting agent according to 5-100 g/L of the alkaline complex, 5-50 g/L of the thio compound and 0.1-30 g/L of the wetting agent. Wherein the thio compound comprises at least one of sodium dibenzyl dithiocarbamate, copper diethyl dithiocarbamate and thionicotinamide.
The basic complex, thio compound and wetting agent are added to deionized water and fully dissolved.
And then the volume is determined to the preset volume by deionized water, and then the components are uniformly mixed to obtain the palladium passivator with non-metallic pores.
The invention also provides a palladium removing process of the circuit board, which comprises the following steps:
the palladium passivator with non-metallic holes is used for soaking the plate to be subjected to palladium removal for 10-300 s at the temperature of 25-50 ℃.
Wherein the soaking temperature is 30-40 ℃. The soaking time is 30-180 s.
The inventors of the present application realized the advantages of palladium passivation by a palladium passivating agent by strictly tailoring the content of each component, which is described below by way of examples.
Example 1
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
15g of ethylene diamine tetraacetic acid disodium salt,
25g of sodium dibenzyl dithiocarbamate,
the commercial product of the fatty alcohol terminated polyether is LF-2215 g,
the balance of deionized water.
Example 2
Taking 1L of the prepared palladium passivator as an example, the components and the contents are as follows:
20g of tetrasodium ethylene diamine tetraacetate,
5g of copper diethyldithiocarbamate (II) was added,
17405 g of polyether (I), 17405 g of polyether,
the balance of deionized water.
Example 3
Taking 1L of the prepared palladium passivator as an example, the components and the contents are as follows:
5g of trisodium citrate, namely 5g of trisodium citrate,
5g of thionicotinamide,
17400.1 g of polyether (I), 17400.1 g of polyether,
the balance of deionized water.
Example 4
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
example 5
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
example 6
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
example 7
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
example 8
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
example 9
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
comparative example 1
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
50mL of hydrochloric acid is added into the solution,
10g of thiourea (10),
the balance of deionized water.
Comparative example 2
Taking 1L of the prepared palladium passivator as an example, the components and the contents are as follows:
30mL of hydrochloric acid is added in the reaction kettle,
30g of thiourea,
the balance of deionized water.
Comparative example 3
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
60g of sulfuric acid, namely 60g of sulfuric acid,
40g of hydrogen peroxide solution, namely 40g of hydrogen peroxide solution,
the balance of deionized water.
Comparative example 4
Taking 1L of prepared palladium passivator as an example, the components and the contents are as follows:
60g of nitric acid is added into the mixture,
50g of the fluoboric acid is added,
the balance of deionized water.
The invention also provides a palladium removing process of the circuit board, which comprises the following steps:
the palladium passivator with non-metallic holes is used for soaking the plate to be subjected to palladium removal for 10-300 s at the temperature of 25-50 ℃.
Further, the temperature is 30-40 ℃. The soaking time is 30-180 s.
The inventor of the present application takes the palladium passivator in example 4 as an example, and performs a blank comparison experiment by using the palladium removing process, that is, one plate uses the palladium passivator in example 4 to perform the palladium removing process, the other plate does not use any palladium passivator, and the other conditions of the two plates are the same, and the two plates are compared.
Fig. 4 shows a photograph of a plate treated with a palladium passivator according to example 4 of the present application, and fig. 5 shows a photograph of a plate not treated with any palladium passivator, so that the plate shown in fig. 5 is golden, and by comparing fig. 4 and 5, it can be seen that the plate treated with the palladium passivator according to the present application does not have metals such as nickel and gold. Therefore, the palladium passivator in the present application has a passivation effect of removing palladium.
In order to show that the palladium passivator has a good effect in the application, the following comparison is carried out:
and cutting the insulation board with the same size (10cm multiplied by 10cm), wherein the number of the non-metal through holes on the insulation board is the same. The method comprises the steps of dipping and plating a palladium catalyst through a PTH copper deposition process to form a metal electroless copper plating through hole, then coating a photoresist, and sequentially carrying out exposure → development → electrolytic copper plating → electrolytic tin plating resist → removal of a film photoresist and alkaline etching of copper to form a metal wiring. Through the above processing procedures, the plated palladium catalyst particles still remain on the insulating material of the plate, so the palladium removal catalyst is performed in examples 1 to 9 and comparative examples 1 to 4, the palladium removal process in the application is used for palladium removal, wherein the soaking temperature is 35 ℃, the soaking time is 60 seconds, and the plate after palladium removal is tested and compared.
Specifically, the plate subjected to palladium removal is baked for 4 hours at the temperature of 120 ℃, and then is subjected to electroless nickel-gold processing. And (3) slicing by grinding and polishing, observing whether the non-metal insulation through hole has a gold feeding phenomenon under a metallographic microscope, and measuring the difference of palladium removal effects by the coverage rate of metal adsorbed in the hole. And (3) observing the appearance change of the nickel-gold surface by a scanning electron microscope to evaluate the change evaluation of the palladium passivator on the appearance of the copper surface.
TABLE 1 test results
| Efficiency of palladium passivation removal | Appearance of the product | |
| Example 1 | 100％ | Is normal |
| Example 2 | 100％ | Is normal and normal |
| Example 3 | 100％ | Is normal |
| Example 4 | 100％ | Is normal |
| Example 5 | 100％ | Is normal |
| Example 6 | 100％ | Is normal and normal |
| Example 7 | 100％ | Is normal |
| Example 8 | 100％ | Is normal and normal |
| Example 9 | 100％ | Is normal |
| Comparative example 1 | 50％ | Slight roughness |
| Comparative example 2 | 100％ | Slight roughness |
| Comparative example 3 | 0 | Roughness of |
| Comparative example 4 | 50％ | Roughness of |
As can be seen from the above table, the palladium passivators in examples 1 to 9 have a palladium passivation removal efficiency of 100%, and the appearance after palladium removal is normal, while the appearance in comparative examples 1 to 2 is slightly rough, and the appearances of comparative examples 3 and 4 are rough, which indicates that the palladium passivators in examples 1 to 9 can maintain the passivation effect on palladium, and ensure the quality of the circuit board.
According to the technical scheme, the invention has the advantages and positive effects that:
the palladium passivator disclosed by the invention belongs to an alkaline palladium passivator, has a higher melting point, can resist higher temperature, further can keep the passivation effect on palladium, has a better palladium removing effect, and ensures the quality of a circuit board. The palladium passivator is low in toxicity, is healthy and friendly to workers, and is low in waste liquid treatment difficulty.
While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.
Claims (8)
1. The non-metal-pore palladium passivator is characterized by comprising the following components in parts by weight:
5-100 g/L of alkaline complex, 5-50 g/L of thio compound and 0.1-30 g/L of wetting agent; wherein the thio compound comprises at least one of sodium dibenzyl dithiocarbamate, copper diethyldithiocarbamate and thionicotinamide.
2. The non-metal pore palladium passivator of claim 1 wherein the basic complex comprises at least one of disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium nitrilotriacetate, trisodium citrate.
3. The non-metal pore palladium passivator of claim 1 wherein the wetting agent comprises at least one of fatty alcohol terminated polyether commercial product LF-221, iso-alcohol polyether commercial product LF-901, ethylene oxide-propylene oxide block copolymer (EO-PO) commercial product, polyether 1740.
4. The non-metal pore palladium passivator of claim 1, wherein the basic complex is 20-60 g/L, the thio compound is 15-30 g/L, and the wetting agent is 5-20 g/L.
5. The preparation method of the palladium passivator with non-metallic pores is characterized by comprising the following steps:
weighing the alkaline complex, the thio compound and the wetting agent according to 5-100 g/L of the alkaline complex, 5-50 g/L of the thio compound and 0.1-30 g/L of the wetting agent: wherein the thio compound comprises at least one of sodium dibenzyl dithiocarbamate, copper diethyldithiocarbamate and thionicotinamide;
adding the basic complex, the thio compound and the wetting agent to deionized water to sufficiently dissolve:
and then, fixing the volume to a preset volume through deionized water, and then uniformly mixing to obtain the palladium passivator with the non-metallic pores.
6. A palladium removing process for a circuit board is characterized by comprising the following steps:
soaking the non-metal-hole palladium passivator of any one of claims 1 to 4 at a temperature of 25 to 50 ℃ for 10 to 300 seconds.
7. The palladium removal process according to claim 6, wherein the temperature is 30 to 40 ℃.
8. The palladium removal process according to claim 6, wherein the soaking time is 30s to 180 s.
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| CN202210509314.9A CN114945246A (en) | 2022-05-11 | 2022-05-11 | Palladium removal process of circuit board, palladium passivator with non-metal holes and preparation method of palladium passivator |
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| CN202210509314.9A CN114945246A (en) | 2022-05-11 | 2022-05-11 | Palladium removal process of circuit board, palladium passivator with non-metal holes and preparation method of palladium passivator |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115558932A (en) * | 2022-10-19 | 2023-01-03 | 南通群安电子材料有限公司 | Palladium removing liquid and method for printed circuit board |
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| JP2002069656A (en) * | 2000-08-31 | 2002-03-08 | Daiwa Kasei Kenkyusho:Kk | Dissolving solution for palladium or palladium compound |
| EP1319734A1 (en) * | 2001-12-14 | 2003-06-18 | Shipley Co. L.L.C. | Plating method |
| CN101153395A (en) * | 2006-09-25 | 2008-04-02 | Mec株式会社 | Metal removing solution and metal removing method using the same |
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| JP2000178752A (en) * | 1998-12-15 | 2000-06-27 | Okuno Chem Ind Co Ltd | Palladium catalyst removing agent for electroless plating |
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| JP2002069656A (en) * | 2000-08-31 | 2002-03-08 | Daiwa Kasei Kenkyusho:Kk | Dissolving solution for palladium or palladium compound |
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| CN115558932A (en) * | 2022-10-19 | 2023-01-03 | 南通群安电子材料有限公司 | Palladium removing liquid and method for printed circuit board |
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