CN108754466B - Anti-rat-bite tin deposition liquid for copper-based surface, chemical tin deposition method of anti-rat-bite tin deposition liquid and anti-rat-bite copper substrate - Google Patents
Anti-rat-bite tin deposition liquid for copper-based surface, chemical tin deposition method of anti-rat-bite tin deposition liquid and anti-rat-bite copper substrate Download PDFInfo
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- CN108754466B CN108754466B CN201711429526.1A CN201711429526A CN108754466B CN 108754466 B CN108754466 B CN 108754466B CN 201711429526 A CN201711429526 A CN 201711429526A CN 108754466 B CN108754466 B CN 108754466B
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- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 title claims abstract description 152
- 238000000151 deposition Methods 0.000 title claims abstract description 83
- 230000008021 deposition Effects 0.000 title claims abstract description 60
- 239000010949 copper Substances 0.000 title claims abstract description 58
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 56
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 55
- 239000000758 substrate Substances 0.000 title claims abstract description 43
- 239000000126 substance Substances 0.000 title claims abstract description 25
- 239000007788 liquid Substances 0.000 title claims abstract description 14
- 150000002500 ions Chemical class 0.000 claims abstract description 24
- 150000007524 organic acids Chemical class 0.000 claims abstract description 21
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 10
- 238000007654 immersion Methods 0.000 claims abstract description 10
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims abstract description 8
- 239000002131 composite material Substances 0.000 claims abstract description 7
- 150000001450 anions Chemical class 0.000 claims abstract description 6
- 229910052718 tin Inorganic materials 0.000 claims description 143
- 239000000203 mixture Substances 0.000 claims description 28
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea group Chemical group NC(=S)N UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims description 22
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 11
- 229910052709 silver Inorganic materials 0.000 claims description 10
- 239000004332 silver Substances 0.000 claims description 10
- 238000007747 plating Methods 0.000 claims description 8
- 230000002265 prevention Effects 0.000 claims description 7
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 6
- 238000002791 soaking Methods 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 5
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical group OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 4
- AFVFQIVMOAPDHO-UHFFFAOYSA-N Methanesulfonic acid Chemical compound CS(O)(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-N 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 239000007800 oxidant agent Substances 0.000 claims description 4
- -1 silver ions Chemical class 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 229910017604 nitric acid Inorganic materials 0.000 claims description 3
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 claims description 2
- JALQQBGHJJURDQ-UHFFFAOYSA-L bis(methylsulfonyloxy)tin Chemical group [Sn+2].CS([O-])(=O)=O.CS([O-])(=O)=O JALQQBGHJJURDQ-UHFFFAOYSA-L 0.000 claims description 2
- 230000003628 erosive effect Effects 0.000 claims description 2
- 238000005530 etching Methods 0.000 claims description 2
- CCIVGXIOQKPBKL-UHFFFAOYSA-N ethanesulfonic acid Chemical compound CCS(O)(=O)=O CCIVGXIOQKPBKL-UHFFFAOYSA-N 0.000 claims description 2
- 229910000765 intermetallic Inorganic materials 0.000 claims description 2
- 229940098779 methanesulfonic acid Drugs 0.000 claims description 2
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims 2
- 241000283984 Rodentia Species 0.000 claims 1
- 150000007522 mineralic acids Chemical class 0.000 abstract description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 36
- 229910000679 solder Inorganic materials 0.000 description 29
- 238000012360 testing method Methods 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000000576 coating method Methods 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 9
- 238000005476 soldering Methods 0.000 description 4
- 229910001432 tin ion Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000005137 deposition process Methods 0.000 description 3
- 238000011010 flushing procedure Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000036632 reaction speed Effects 0.000 description 3
- 238000004381 surface treatment Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 238000004383 yellowing Methods 0.000 description 2
- 229910001316 Ag alloy Inorganic materials 0.000 description 1
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- PQIJHIWFHSVPMH-UHFFFAOYSA-N [Cu].[Ag].[Sn] Chemical compound [Cu].[Ag].[Sn] PQIJHIWFHSVPMH-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 229910021655 trace metal ion Inorganic materials 0.000 description 1
Images
Classifications
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- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/48—Coating with alloys
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1646—Characteristics of the product obtained
- C23C18/165—Multilayered product
- C23C18/1651—Two or more layers only obtained by electroless plating
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/18—Pretreatment of the material to be coated
- C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
- C23C18/1824—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by chemical pretreatment
- C23C18/1837—Multistep pretreatment
- C23C18/1844—Multistep pretreatment with use of organic or inorganic compounds other than metals, first
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
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- 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
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
Abstract
The invention relates to the field of tinning of copper substrates, in particular to a rat bite-proof tin immersion liquid for a copper-based surface, a chemical tin immersion method of the rat bite-proof tin immersion liquid, and an obtained rat bite-proof copper substrate. The anti-rat-bite tin deposition solution contains 25g/L to 100g/L of Sn 2+ Ions, 25-100 mL/L of organic or inorganic acid with the same anion as the tin source, 200-400 g/L of composite organic acid, 30-60 g/L of tin-copper counter potential agent, 15-50 ppm of Ag + Ions. The chemical tin deposition method of the anti-rat-bite tin deposition liquid can control the rat-bite depth of the copper-based interface to be less than 4.1 microns, and still has excellent weldability after at least 5 lead-free reflow cycles.
Description
Technical Field
The invention relates to the field of tinning of copper substrates, in particular to a rat bite prevention tin deposition solution for a copper-based surface, a chemical tin deposition method of the solution, and an obtained rat bite prevention copper substrate.
Background
Printed circuit boards, also known as PCB boards, are providers of electrical connections for electronic components, and electroless tin deposition products have been used as one of the alternative end products for PCB boards. However, in the final electroless tin assembly, solderability during use, tin whiskers, and rat-bite problems of electroless tin are involved. In relation to the problem of tin whisker of chemical tin deposition, patent nos. CN103124807B and CN1387465a provide a method for inhibiting tin whisker growth by adding trace metal ions. However, it is known that tin deposited on the surface is rapidly dissolved in the solder paste at high temperature (210-255 ℃) during soldering, and the problem of tin whisker caused by tin deposition is not existed. The tin whisker problem during the use of the equipment device is mainly caused by the problem of the soldering paste. In order to reduce the problem of tin whiskers during use, assembly manufacturers have begun to use a series of tin paste products (tin-copper-silver alloy solder pastes) that can act to inhibit the growth of tin whiskers. Regarding the solderability problem of electroless tin deposition, in patent CN101001980a, a phosphorus-containing organic protective film is used to isolate air and prevent tin surface from oxidation. In addition, increasing the thickness of the tin layer also serves to ensure solderability, ensuring a pure tin layer of at least 0.1 micron ("free" tin) during soldering. Thus, to ensure that there is sufficient "free" tin available at the time of assembly, a minimum tin deposit thickness of 1 micron is specified in the IPC-4554 specification (see IPC-4554, "Specifications for Immerization TinPlatingForPrintedcircutBoards", 2007, IPCBnnockburn, IL).
Compared with the galvanic phenomenon of chemical silver deposition, the rat bite phenomenon of chemical tin deposition has small influence on the electrical performance of the circuit, so that sufficient attention is not paid. However, with the development of communication technology, due to the characteristics of excellent flatness of the chemical immersion tin surface treatment and small attenuation of transmission signals, the chemical immersion tin surface treatment method is widely applied to the surface treatment of communication boards, in particular to the chemical immersion tin of a teflon antenna material. Such electroless tin requires that the material thereof has a small attenuation during signal transmission. At this time, the rat bite problem of tin electroless deposition will have a significant impact on signal transmission and stability.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to greatly reduce the rat bite phenomenon of chemical tin deposition, and according to the rat bite prevention tin deposition liquid and the tin deposition method thereof, the rat bite phenomenon of a tin coating can be effectively controlled, and the rat bite depth is far less than that of other tin deposition processes.
In order to achieve the purpose, the invention provides a tin immersion liquid for preventing the rat bite of a copper-based surface, which comprises the following components:
providing Sn 2+ A source of ionic Sn, said Sn 2+ The concentration of the ions is 25 g/L-100 g/L;
an organic or inorganic acid having the same anion as the tin source, wherein the concentration of the organic or inorganic acid is 25mL/L to 100mL/L;
the concentration of the composite organic acid is 200-400 g/L;
the tin-copper counter potential agent has the concentration of 30 g/L-60 g/L;
providing Ag + Silver source of ions, said Ag + The concentration of the ions is 15ppm to 50ppm.
Further, the method can be used for preparing a novel liquid crystal displayGround, the Sn 2+ The concentration of the ions is preferably 25g/L to 75g/L, more preferably 25g/L to 50g/L. A specific example of a tin source may be stannous methanesulfonate.
Further, the concentration of the organic or inorganic acid having the same anion as the tin source is preferably 25 to 75mL/L. A specific example of the organic acid may be methanesulfonic acid.
Further, the concentration of the complex organic acid is preferably 200g/L to 300g/L. A specific example of the complex organic acid may be a combination of citric acid and ethylsulfonic acid.
Further, the concentration of the tin-copper counter potential agent is preferably 40g/L to 60g/L, and more preferably 40g/L to 50g/L. A specific example of a tin-copper counter potential agent may be thiourea.
Further, the Ag + The concentration of the ion is 15ppm to 40ppm, more preferably 15ppm to 30ppm. The source of Ag + ions is generated by the reaction of metallic silver and nitric acid, and the chemical equation of the reaction is as follows: 3Ag +4HNO 3 ＝3AgNO 3 +NO+2H 2 O。
The above-mentioned tin source in the rat-bite-proof tin-depositing liquor is used for providing Sn required for tin-plating 2+ Ions, organic or inorganic acids having the same anion as the tin source for providing an acid environment required for tin plating, complex organic acids for increasing the reaction speed, counter-potential agents for changing the potential, trace amounts of Ag + The presence of ions can help prevent the formation of microvoids.
In industrial production, copper ions in the tin bath gradually rise, and Sn 2+ The ions are oxidized to form Sn 4+ Ions. When Sn 2+ When the ion concentration is too low (less than 10 g/L), more copper and tetravalent tin are reversely deposited in the tin layer in the production, which causes problems of yellowing in reflow soldering, poor solderability and the like, and too low Sn 2+ The ions also cause the phenomenon of rat bite when tin is deposited more easily. Thus, sn 2+ The concentration of the ions is 25g/L to 100g/L, preferably 25g/L to 75g/L, and more preferably 25g/L to 50g/L.
The organic or inorganic acid having the same anion as the tin source in the present invention can provide an acid environment consumed for the reaction, and the concentration is usually 25mL/L to 100mL/L, preferably 25mL/L to 75mL/L. The existence of the composite organic acid can improve the tin deposition reaction speed and accelerate the tin deposition, and the concentration of the composite organic acid is usually 200 g/L-400 g/L, and preferably 200 g/L-300 g/L. In general, the acidity of the tin deposition bath should be maintained between 4 and 8N, preferably between 5 and 7N. It is noted that the solder dip cannot be doped with sulfuric acid, since the presence of sulfuric acid can damage the solder resist.
In the tin plating reaction, since Cu is more inert than Sn, the exchange reaction does not occur at Sn 2+ Ions and Cu metal. To promote the reaction, a counter-potential agent must be present to deposit tin on the copper. As an alternative to the counter-potential agent, thiourea is effective to reverse the potentials of Sn and Cu to facilitate the exchange reaction. When the concentration of thiourea is high, the reaction speed is accelerated, but under the same condition, the phenomenon of mouse bite is more obvious when the concentration of thiourea is high. If the concentration of thiourea is low, the reaction cannot proceed. Therefore, a reasonable thiourea concentration is from 30g/L to 60g/L, preferably from 40g/L to 60g/L, and more preferably from 40g/L to 50g/L.
Ag in the invention + The ions are generated by the reaction of metallic silver and nitric acid, and the chemical equation of the reaction is as follows: 3Ag +4HNO 3 ＝3AgNO 3 +NO+2H 2 O, ag in the present invention because the surface of tin is blackened by excessively high concentration of silver ions + The ion concentration is 15ppm to 40ppm, more preferably 15ppm to 30ppm.
The invention also provides a chemical tin deposition method of the anti-rat bite tin deposition liquid based on the copper-based surface, which is characterized in that a tin deposition mechanism is used for depositing a tin-based coating on a copper test piece or a molded circuit board with a solder mask, and the tin deposition steps are sequentially subjected to cleaning, flushing, microetching, flushing, presoaking, tin deposition, flushing and drying. The method comprises the following specific steps:
(1) Deoiling, namely deoiling and washing the copper substrate;
(2) Microetching, namely microetching the copper substrate deoiled in the step (1) by using a microetching composition to etch the surface of the copper substrate and obtain required surface textures, and washing the copper substrate clean;
(3) Pre-soaking, namely contacting the copper substrate subjected to the micro-etching in the step (2) with a pre-soaking composition, and depositing a layer of Bao Xi on the exposed copper surface, wherein the pre-soaking composition does not contain silver ions;
(4) Depositing tin, namely contacting the copper substrate deposited with thin tin in the step (3) with the tin deposition solution according to any one of claims 1 to 11, and depositing the copper substrate to a required thickness according to the requirement;
(5) Cleaning and drying to obtain the product.
According to the chemical tin deposition method of the present invention, before the tin deposition step, the substrate needs to be micro-etched to etch the substrate surface and obtain the required surface texture. Microetching compositions known in the art may contain an oxidizing agent, such as hydrogen peroxide or persulfate salts, in addition to the acid. It is well known that the ratio of oxidizing agent to acid determines the texture of the substrate surface. Experimental results to date have shown that rougher surfaces are very suitable for increasing the thickness of tin-based alloys. After the substrate is contacted with the microetching composition, the substrate is contacted with the prepreg composition, and the silver ions are not required to be contained in the prepreg composition, so that the phenomenon of blackening and solder reflow yellowing on the surface of the tin immersion can be avoided. In the pre-dipping step, a layer Bao Xi is deposited on the exposed copper surface, the thickness of the thin tin is between 0.05 and 0.1 micron, and the tin deposition liquid is prepared for tin deposition.
After the substrate is contacted with the prepreg composition and a layer Bao Xi is deposited, the substrate with the thin tin deposited is contacted with the tin deposition solution composition of the present invention. As needed to the desired thickness.
In some embodiments, the deposition time of the above tin deposition step is 5 to 25 minutes, resulting in a tin-based coating having a deposition thickness of 0.3 to 1.5 microns. In some embodiments, the tin layer thickness measured by X-RAY is not the actual pure tin layer thickness, and the thickness of the tin deposition layer is controlled to be more than 0.8 μm to ensure solderability after three reflows.
The invention also provides a rat bite prevention copper substrate obtained based on the chemical tin deposition method, wherein the rat bite prevention copper substrate is provided with a copper substrate on the surface or a substrate with a part of exposed copper surface covered by green oil; and a tin plating layer on the surface of the substrate, wherein the thickness of the tin plating layer is 0.3-1.5 micrometers; and an alloy layer resistant to the formation of copper-tin intermetallic compounds, the alloy layer having a silver ion content of 0.5 to 2.5wt%; the mouse-biting depth of the hole ring and the lateral erosion position of the mouse-biting prevention copper substrate is less than 4.1 microns.
In embodiments where, for example, a tin-based coating is deposited on a copper substrate, for tin deposition where no interface is present, such as tin deposition of bare copper plates or tin deposition where no green oil covers the copper base, the phenomenon of mouse-over hardly occurs. For the tin deposition on the interface, such as the copper-exposed part of the copper base covered by the green oil, the mouse bite phenomenon occurs when the chemical tin deposition is carried out on the copper-exposed part.
Compared with the prior art, the invention has the following advantages:
in the present invention where a tin-deposited tin-based coating is deposited as a coating on a metal-based substrate, the tin-based coating deposited according to the method of the present invention has a much lower mouse-bite depth than other tin deposition processes when tested for mouse-bite depth with green oil stripped. In some embodiments, the methods of the present invention deposit tin-based coatings on copper substrates that maintain solderability over, for example, multiple lead-free reflow cycles, such as after at least 5 lead-free reflow cycles.
Drawings
FIG. 1 is an appearance of the tin deposition in example 1.
FIG. 2 shows the tin thickness measured by X-RAY in example 1.
FIG. 3 is a surface SEM photograph of example 1.
FIG. 4 is the surface EDX chart of example 1.
FIG. 5 is a graph showing the results of the test of the depth of mouse bite in example 1.
Detailed Description
In order to more clearly describe the present invention, the following further description is made with reference to the accompanying drawings.
The following non-limiting examples are provided to further illustrate the invention.
Tin deposition of sample
In each of the following examples, a tin-based coating was deposited on a copper coupon or molded wiring board with solder resist using a conventional method using a tin deposition mechanism. Namely, the cleaning, the rinsing, the microetching, the rinsing, the presoaking, the tin immersion, the rinsing and the drying are carried out in sequence. In order to standardize the hydrodynamic conditions in the bath, the sample coupons were manually tin-plated in a beaker with 10 cycles/minute of reciprocation, with a residence time in the bath of 20 minutes.
Tin thickness measurement
The thickness of the tin-based coating was measured using X-RAY.
Crystal structure of tin surface
Measurement of Crystal Structure of tin layer surface by SEM
Surface composition analysis
Measuring the structural composition of the surface of a tin layer by EDX
Mouse bite test
The green oil was washed out with sodium hydroxide and the depth of the rat bite was measured microscopically at X400.
EXAMPLE 1 tin deposition bath composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
Inspecting the appearance of the precipitated tin, see fig. 1; the tin thickness was measured with an x-ray machine, see FIG. 2; the surface crystal structure of the sample was tested by SEM, see fig. 3; the surface composition of the samples was tested with EDX, see figure 4; the solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 2 tin deposition solution composition
The etched test board with solder mask to be treated is cleaned, rinsed, microetched, rinsed, presoaked, tin-deposited, rinsed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 3 tin deposition solution composition
The etched test board with solder mask to be treated is cleaned, rinsed, microetched, rinsed, presoaked, tin-deposited, rinsed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 4 tin deposition solution composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 5 tin deposition solution composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 6 tin deposition solution composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 7 tin deposition solution composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 8 tin deposition solution composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Example 9 tin deposition bath composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Comparative example 1 tin deposition liquid composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Comparative example 2 tin deposition liquid composition
The test board with the solder resist film is cleaned, washed, micro-etched, washed, pre-soaked, tin-deposited, washed and dried.
The solder resist was removed with sodium hydroxide and the mouse bite depth was observed and measured under a microscope.
Table 1 is a table of data from the mouse bite depth test for examples 1-9 and comparative examples 1-2.
As can be seen from the data in table 1, the minimum mouse-biting depth of examples 1 to 9 is 0.6 micrometers, and the maximum mouse-biting depth is 4.1 micrometers, which indicates that the mouse-biting depth of the technical solution of the present invention is much smaller than that of other tin deposition processes, i.e., the present invention can effectively control the mouse-biting depth of tin deposition.
And, by testing the change rule of the tin ion concentration and the thiourea concentration under different proportions: under the condition that the concentration of tin ions is not changed, the mouse bite depth of tin precipitation is in direct proportion to the content of thiourea; under the condition of constant thiourea content, the mouse biting depth of the precipitated tin is inversely proportional to the tin ions. Thus, the depth of the mouse bite at the interface of the deposited tin layer can be optimized by adjusting the concentrations of thiourea and tin ions.
The above disclosure is only for a few specific embodiments of the present invention, but the present invention is not limited thereto, and any variations can be considered by those skilled in the art to fall within the scope of the present invention.
Claims (9)
1. The utility model provides a protection against rodents stings heavy tin liquor on copper base surface which characterized in that: the rat-bite-preventing tin deposition solution consists of the following components: providing Sn 2+ A source of ionic Sn, said Sn 2+ The concentration of the ions is 25 g/L-100 g/L; an organic acid having the same anion as the tin source, wherein the concentration of the organic acid is 25mL/L to 100mL/L; the concentration of the composite organic acid is 200 g/L-400 g/L; the tin-copper counter potential agent has the concentration of 30 g/L-60 g/L; providing Ag + Silver source of ions, said Ag + The concentration of the ions is 15ppm to 50ppm;
the tin source is selected from stannous methanesulfonate; the organic acid is selected from methanesulfonic acid; the composite organic acid is a combination of citric acid and ethyl sulfonic acid; the tin-copper counter potential agent is selected from thiourea; the Ag is + The ions are prepared by reacting silver and nitric acid.
2. The anti-rat-bite tin immersion liquid for the copper-based surface according to claim 1, characterized in that: the Sn 2+ The concentration of the ions is 25 g/L-75 g/L; the concentration of the organic acid is 25 mL/L-75 mL/L; the concentration of the composite organic acid is 200 g/L-300 g/L; the concentration of the tin-copper counter potential agent is 40 g/L-60 g/L; the Ag is + The concentration of the ions is 15ppm to 40ppm.
3. A chemical tin deposition method of a rat-bite-proof tin deposition solution based on the copper-based surface as claimed in any one of claims 1 to 2, characterized in that: the chemical tin deposition method comprises the following steps: removing oil, namely removing oil from the copper substrate and washing the copper substrate clean; (2) Microetching, namely microetching the copper substrate deoiled in the step (1) by using a microetching composition to etch the surface of the copper substrate and obtain required surface textures, and washing the copper substrate clean; (3) Pre-soaking, namely contacting the copper substrate subjected to the micro-etching in the step (2) with a pre-soaking composition, and depositing a layer of Bao Xi on the exposed copper surface, wherein the pre-soaking composition does not contain silver ions; (4) Depositing tin, namely contacting the copper substrate deposited with thin tin in the step (3) with the tin deposition solution according to any one of claims 1-2, and depositing the copper substrate to a required thickness as required;
(5) Cleaning and drying to obtain the product.
4. The chemical tin deposition method according to claim 3, wherein: the microetching composition in the step (2) is a composition of acid and an oxidant, and the oxidant is hydrogen peroxide or persulfate.
5. The chemical tin deposition method according to claim 3, wherein: the thickness of the thin tin in the step (3) is 0.05-0.1 micron.
6. The chemical tin deposition method according to claim 3, wherein: and (5) the tin deposition solution in the step (4) does not contain sulfuric acid, and the acidity of the tin deposition solution is 5-7N.
7. The electroless tin plating method according to claim 3, wherein: the deposition time in the step (4) is 5-25 minutes, and the deposition thickness is 0.3-1.5 microns.
8. The chemical tin deposition method according to claim 7, wherein: the deposition thickness is 0.8-1.5 microns.
9. A rat-bite-preventing copper substrate obtained based on the chemical tin deposition method according to any one of claims 3 to 8, characterized in that: the rat bite preventing copper substrate is provided with a copper substrate on the surface or a substrate with a part of exposed copper surface covered by green oil; and a tin plating layer on the surface of the substrate, wherein the thickness of the tin plating layer is 0.3-1.5 micrometers; and an alloy layer resistant to the formation of copper-tin intermetallic compounds, the alloy layer having a silver ion content of 0.5 to 2.5wt%; the mouse-biting depth of the hole ring and the lateral erosion position of the mouse-biting prevention copper substrate is less than 4.1 microns.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1683589A (en) * | 2004-04-15 | 2005-10-19 | 清英实业有限公司 | Surface contact improver for copper and copper alloy and its usage |
| CN1837413A (en) * | 2005-03-24 | 2006-09-27 | 广东风华高新科技集团有限公司 | Composition for plating pure tin and electronic component employing the same |
| CN101403112A (en) * | 2008-10-28 | 2009-04-08 | 昆山成利焊锡制造有限公司 | Chemical tin plating liquor for copper and copper alloy |
| CN101705482A (en) * | 2009-11-19 | 2010-05-12 | 广州电器科学研究院 | Alkyl sulfonic acid chemical tinning solution and chemical tinning solution based tinning process |
| CN101899664A (en) * | 2009-05-27 | 2010-12-01 | 比亚迪股份有限公司 | Electroplating method |
| CN105239062A (en) * | 2014-07-07 | 2016-01-13 | 侯霞 | Environment-friendly tin plating solution |
| CN106939417A (en) * | 2017-04-28 | 2017-07-11 | 深圳市创智成功科技有限公司 | The chemical plating stannum formula of printed wiring board |
| CN107365986A (en) * | 2017-07-11 | 2017-11-21 | 东莞市富默克化工有限公司 | A kind of tin plating technique of chemical tin inorganic agent and application the chemical tin inorganic agent |
-
2017
- 2017-12-26 CN CN201711429526.1A patent/CN108754466B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1683589A (en) * | 2004-04-15 | 2005-10-19 | 清英实业有限公司 | Surface contact improver for copper and copper alloy and its usage |
| CN1837413A (en) * | 2005-03-24 | 2006-09-27 | 广东风华高新科技集团有限公司 | Composition for plating pure tin and electronic component employing the same |
| CN101403112A (en) * | 2008-10-28 | 2009-04-08 | 昆山成利焊锡制造有限公司 | Chemical tin plating liquor for copper and copper alloy |
| CN101899664A (en) * | 2009-05-27 | 2010-12-01 | 比亚迪股份有限公司 | Electroplating method |
| CN101705482A (en) * | 2009-11-19 | 2010-05-12 | 广州电器科学研究院 | Alkyl sulfonic acid chemical tinning solution and chemical tinning solution based tinning process |
| CN105239062A (en) * | 2014-07-07 | 2016-01-13 | 侯霞 | Environment-friendly tin plating solution |
| CN106939417A (en) * | 2017-04-28 | 2017-07-11 | 深圳市创智成功科技有限公司 | The chemical plating stannum formula of printed wiring board |
| CN107365986A (en) * | 2017-07-11 | 2017-11-21 | 东莞市富默克化工有限公司 | A kind of tin plating technique of chemical tin inorganic agent and application the chemical tin inorganic agent |
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