WO1993009276A1 - Age resistant solder coatings - Google Patents
Age resistant solder coatings Download PDFInfo
- Publication number
- WO1993009276A1 WO1993009276A1 PCT/US1992/009134 US9209134W WO9309276A1 WO 1993009276 A1 WO1993009276 A1 WO 1993009276A1 US 9209134 W US9209134 W US 9209134W WO 9309276 A1 WO9309276 A1 WO 9309276A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- lead
- accordance
- metal substrate
- solder
- aromatic aldehyde
- Prior art date
Links
- 229910000679 solder Inorganic materials 0.000 title claims abstract description 62
- 238000000576 coating method Methods 0.000 title claims abstract description 52
- 239000000758 substrate Substances 0.000 claims abstract description 69
- 239000002184 metal Substances 0.000 claims abstract description 54
- 229910052751 metal Inorganic materials 0.000 claims abstract description 54
- 239000011248 coating agent Substances 0.000 claims abstract description 48
- 150000003934 aromatic aldehydes Chemical class 0.000 claims abstract description 39
- 230000032683 aging Effects 0.000 claims abstract description 25
- 238000007747 plating Methods 0.000 claims description 23
- 239000000654 additive Substances 0.000 claims description 21
- 230000000996 additive effect Effects 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 10
- 239000000956 alloy Substances 0.000 claims description 10
- HUMNYLRZRPPJDN-UHFFFAOYSA-N benzenecarboxaldehyde Natural products O=CC1=CC=CC=C1 HUMNYLRZRPPJDN-UHFFFAOYSA-N 0.000 claims description 10
- AFVFQIVMOAPDHO-UHFFFAOYSA-N Methanesulfonic acid Chemical compound CS(O)(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-N 0.000 claims description 8
- -1 nitro, amino Chemical group 0.000 claims description 8
- 125000000217 alkyl group Chemical group 0.000 claims description 7
- 150000003935 benzaldehydes Chemical class 0.000 claims description 7
- QNGNSVIICDLXHT-UHFFFAOYSA-N para-ethylbenzaldehyde Natural products CCC1=CC=C(C=O)C=C1 QNGNSVIICDLXHT-UHFFFAOYSA-N 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 4
- 238000000151 deposition Methods 0.000 claims description 3
- HUMNYLRZRPPJDN-KWCOIAHCSA-N benzaldehyde Chemical group O=[11CH]C1=CC=CC=C1 HUMNYLRZRPPJDN-KWCOIAHCSA-N 0.000 claims 4
- 238000005260 corrosion Methods 0.000 abstract description 14
- 230000007797 corrosion Effects 0.000 abstract description 14
- 230000003647 oxidation Effects 0.000 abstract description 10
- 238000007254 oxidation reaction Methods 0.000 abstract description 10
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 abstract description 3
- 238000003860 storage Methods 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000000080 wetting agent Substances 0.000 description 5
- 230000007774 longterm Effects 0.000 description 4
- 238000005476 soldering Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- LLMLNAVBOAMOEE-UHFFFAOYSA-N 2,3-dichlorobenzaldehyde Chemical compound ClC1=CC=CC(C=O)=C1Cl LLMLNAVBOAMOEE-UHFFFAOYSA-N 0.000 description 3
- FPYUJUBAXZAQNL-UHFFFAOYSA-N 2-chlorobenzaldehyde Chemical compound ClC1=CC=CC=C1C=O FPYUJUBAXZAQNL-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000010943 off-gassing Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- WMOOOIUXYRHDEZ-UHFFFAOYSA-N 2,3,4-trichlorobenzaldehyde Chemical compound ClC1=CC=C(C=O)C(Cl)=C1Cl WMOOOIUXYRHDEZ-UHFFFAOYSA-N 0.000 description 2
- FXWFZIRWWNPPOV-UHFFFAOYSA-N 2-aminobenzaldehyde Chemical compound NC1=CC=CC=C1C=O FXWFZIRWWNPPOV-UHFFFAOYSA-N 0.000 description 2
- CMWKITSNTDAEDT-UHFFFAOYSA-N 2-nitrobenzaldehyde Chemical compound [O-][N+](=O)C1=CC=CC=C1C=O CMWKITSNTDAEDT-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 description 2
- 239000012964 benzotriazole Substances 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- JSIAIROWMJGMQZ-UHFFFAOYSA-N 2h-triazol-4-amine Chemical class NC1=CNN=N1 JSIAIROWMJGMQZ-UHFFFAOYSA-N 0.000 description 1
- LRUDIIUSNGCQKF-UHFFFAOYSA-N 5-methyl-1H-benzotriazole Chemical compound C1=C(C)C=CC2=NNN=C21 LRUDIIUSNGCQKF-UHFFFAOYSA-N 0.000 description 1
- AFVFQIVMOAPDHO-UHFFFAOYSA-M Methanesulfonate Chemical compound CS([O-])(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-M 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000010273 cold forging Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- LQBJWKCYZGMFEV-UHFFFAOYSA-N lead tin Chemical compound [Sn].[Pb] LQBJWKCYZGMFEV-UHFFFAOYSA-N 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- MYWUZJCMWCOHBA-VIFPVBQESA-N methamphetamine Chemical compound CN[C@@H](C)CC1=CC=CC=C1 MYWUZJCMWCOHBA-VIFPVBQESA-N 0.000 description 1
- BTFQKIATRPGRBS-UHFFFAOYSA-N o-tolualdehyde Chemical compound CC1=CC=CC=C1C=O BTFQKIATRPGRBS-UHFFFAOYSA-N 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
-
- 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
- C25D3/56—Electroplating: Baths therefor from solutions of alloys
- C25D3/60—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of tin
-
- 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
- H05K3/3457—Solder materials or compositions; Methods of application thereof
- H05K3/3473—Plating of solder
Definitions
- the present invention relates to an electronic lead- in metallic substrate coated with a fusible solder coating possessing enhanced resistance to loss of solderability due to aging.
- an aromatic aldehyde selected from a group including aminobenzaldehyde , benzaldehyde , chlorobenzaldehyde, dichlorobenzaldehyde, meth lbenzaldehyde , nitrobenzaldehyde and trichlorobenzaldehyde.
- a further object of the present invention is to provide a novel method of depositing and controlling a Sn/Pb solder coating onto the electronic lead-in metal substrate to provide lead-in metal substrates which resist corrosion and oxidation, thus rendering the metal substrate resistant to the loss of solderability due to natural aging.
- a further object of the present invention is the novel method of depositing and controlling an alloy solder coating onto a electronic lead-in metal substrate which consist of plating the Sn/Pb solder alloys from a fluoborate or methylsulfonic acid solution containing aromatic aldehydes, to provide a tin-lead solder coating containing molecules of the organic material included or entrapped therein.
- the phrase electronic lead-in wire or metallic substrate is used to designate the current carrying conductor containing the solder coating.
- solder coating will be referred to as including the elements Sn/Pb.
- the electronic lead-in metal substrate useful as a electronic lead-in component which possesses increased resistance to the loss solderability due to natural or accelerated steam aging, is first cleaned utilizing conventional methods and then a Sn/Pb solder coating is applied to the lead-in metal substrate with the solder coating containing between about 0.5-20 x 10 "4 weight per cent of an aromatic aldehyde.
- the aromatic aldehyde may be selected from a group which includes a inobenzaldehyde, chlorobenzaldehyde, benzaldehyde, dichlorobenzaldehyde, methy 1 be n z a 1 d yd e , n i tr o be n z a 1 d e hyd e , and trichlorobenzaldehyde.
- the method of applying the fusible Sn/Pb solder coating to the electronic lead-in metal substrate consists of plating the solder coating from either a fluoborate or methylsulfonate plating solution containing the selected aromatic aldehyde.
- the plating solution may include a long chain alcohol and wetting agents, as is known in the art.
- a typical fluoborate solder plating bath preferably includes, between about 100-400 grams per liter of stannous (Sn) fluoborate, between about 20-100 grams per liter of lead (Pb) fluoborate, between about 100-300 grams per liter fluoboric acid and between about 0.1-0.5 grams per liter of the age resistant additive or aromatic aldehyde.
- the bath may further include a long chain alcohol and wetting agent.
- the resultant coating may be applied to the lead-in metal substrate at a thickness of between 5-800 micro inches.
- the wire may be coated with a solder coating at a thickness of about 350 micro inches and then the wire may be drawn through a die such that the wire drawn fusible soldered coating has a reduced thickness relative to the applied thickness.
- solder acts as a lubricant and the entrapped or included organic aromatic aldehyde molecules that are randomly and uniformly distributed throughout the deposited solder coating do not detract from the ability of the coated lead-in substrate to be drawn to a reduced size nor does drawing the wire detract from the solder coatings effectiveness in reducing the loss of solderability due to natural aging or steam aging.
- the fusible Sn/Pb solder coating must contain between about 0.5-20 x 10 "4 weight per cent aromatic aldehyde in the solder coating deposit or the enhanced and superior corrosion and oxidation resistance of the lead metal substrate is not achieved. If the concentration of the aromatic aldehyde in the coating is below the given range, the resultant coated lead-in metal substrate does not exhibit satisfactory long term resistance to normal aging conditions, and if the concentration of the aromatic aldehyde is above a given range, the resultant lead-in metal substrate severely out gasses upon soldering thereby adversely effecting the solderability of the lead-in metal substrate.
- the present invention is directed to a novel lead-in metallic substrate possessing superior resistance to corrosion and oxidation and to the loss of solderability due to aging.
- the resultant lead-in metallic substrate is coated with a fusible solder coating containing between about 0.5-20 x 10 "4 weight per cent of an aromatic aldehyde.
- the aromatic aldehyde preferably, is selected from a group comprising nitro, amino, alkyl, halogenated substituted and normal benzaldehydes.
- the aromatic aldehydes that are particularly applicable in steam aged solder coatings include aminobenzaldehyde, benzaldehyde, chlorobenzaldehyde, dichlorobenzaldehyde, trich1orobenza 1dehyde , methyl benzaldehyde, nitrobenzaldehyde.
- the age resistant material may be a mixture of single ring aromatic aldehydes.
- the method of applying the fusible Sn/Pb solder coating to the lead-in metal substrate consists of first cleaning the metal substrate and then plating the solder coating from a fluoborate or methylsulfonic acid plating solution containing the selected age resistant additive or aromatic aldehyde.
- the fluoborate plating solution may include a long chain alcohol and a wetting agent, as is known in the art.
- typical fluoborate solder plating bath includes between about 100-400 grams per liter of stannous(Sn) fluoborate, between about 20-100 grams per liter of lead(Pb) fluoborate, between about 100-300 grams per liter fluoboric acid and between about 0.1.5 gram per liter of the age resistant additive or aromatic aldehyde.
- the bath may further include a long chain alcohol and a wetting agent.
- a typical methylsulfonic acid solder plating bath preferably includes, between about 150-400 grams per liter of stannous(Sn) methylsulfonic acid, between about 80-150 grams per liter of lead(Pb) methylsulfonic acid, between about 100-400 grams per liter of ethonesulfonic acid and between about 0.2-1.0 grams per liter of the age resistant additive or aromatic aldehyde.
- the plating solution may include a long chain alcohol and a wetting agent, as is known in the prior art.
- either the fluoborate or methylsulfonic coating may be applied to the lead-in metal substrate at a thickness of between 5-800 micro inches.
- the wire may be coated with a solder coating at a thickness of about 350 micro inches. Then, the wire may be drawn through a die such that the wire drawn fusible soldered coating has a reduced thickness relative to the applied thickness.
- solder acts as a lubricant and it is believed that the entrapped " or included organic aromatic aldehyde molecules that are randomly and uniformly distributed or occluded throughout the deposited solder coating layer and on the surface thereof do not detract from the ability of the coated lead-in substrate to be drawn to a size thickness nor does drawing the wire detract from the solder coating's effectiveness in reducing the loss of solderability due to natural aging or steam aging.
- solder coating to a lead- in metal substrate is the working of plated lead-in metal substrate by cold forging to change the shape and, as a consequence, thereby thinning the solder coating to approximately 5 micro inches.
- the fusible Sn/Pb solder coating must contain between about 0.5-20 x 10 "4 weight per cent aromatic aldehyde in the solder coating deposit layer or the enhanced and superior corrosion and oxidation resistance of the lead-in metal substrate is not achieved. If the concentration of the aromatic aldehyde in the coating is below this predetermined range, the resultant coated lead-in metal substrate does not exhibit satisfactory long term resistance to normal aging conditions and possesses very poor solderability, and if the concentration of the.
- the preferred range of weight per cent aromatic aldehyde in the solder coating deposit layer is about 1.0-10.0 x 10 " to provide superior corrosion and oxidation resistance.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating With Molten Metal (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Chemically Coating (AREA)
Abstract
The present invention is directed to a lead-in metal substrate possessing superior resistance to corrosion and oxidation and to the loss of solderability due to aging. The resultant lead metal substrate is coated with a fusible solder coating containing between about 0.5-20 x 10-4 weight per cent of an aromatic aldehyde.
Description
AGE RESISTANT SOLDER COATINGS Background of the Invention
The present invention relates to an electronic lead- in metallic substrate coated with a fusible solder coating possessing enhanced resistance to loss of solderability due to aging.
In the electronic manufacturing industry of printed circuit boards, active and passive devices and other components, it is necessary that the electronic lead-in wires or metal substrates utilized in such manufacture be resistant to deterioration of solderability from external environmental agents. The loss in device solderability of the metal substrates and the consequent deterioration in printed circuit board manufacturing yields due to oxidation and corrosion under storage conditions is a primary concern to the electronics industry. Although storage conditions vary considerably, it will be appreciated that under ideal conditions, superb and excellent solderability must be maintained for long periods of time. It is generally considered commercially acceptable to require the electronic lead-in components to provide excellent solderability even after the components have been stored for a minimum of three years.
Several prior treatments and processes to prevent oxidation and corrosion of electronic lead-in components during storage have been disclosed. For example, benzotriazole and other aminotriazoles have been used extensively in the industry to provide a corrosion free and oxygen free metal surface that is amenable to subsequent soldering and usage as electronic lead-in metallic substrates. These chemicals act as corrosion and oxidation inhibitors when coated directly onto the copper, silver or other metal conductor in the metal substrate. However, such chemical coatings tend to have a limited-shelf life and interfere with the subsequent solderability of the electronic lead-in metallic substrate.
A further attempt to improve the aging and produce a corrosion oxygen free surface on a electronic lead-in metal
substrate is reported in the U.S. Patent 4,395,294, which relates to a deposit on copper and other metals of 5-methyl benzotriazole material, which material reportedly does not interfere with subsequent soldering of the treated copper substrate. Although, it is reported that this material provides superior aging over benzotriazole, such chemicals provide only limited corrosion resistance for periods of several days. Also, such materials are somewhat difficult to apply to the metal substrate which results in interference with the subsequent soldering of the treated metal surfaces. Additionally, the use of organic compounds for corrosion and oxygen inhibition of the metal substrate requires additional processing steps beyond the conventional steps of removing contamination from the metal substrate and applying the organic coating to the metal substrate to prevent corrosion and oxidation of the metal substrate. Such additional coating steps necessarily results in increase costs of processing such treated metal substrates.
Summary of the Invention It is one object of the present invention to provide an electronic lead-in metallic substrate possessing resistance to the loss of solderability due to aging wherein the lead-in metallic substrate is coated with a fusible solder coating containing between about 0.5-20 x 10"4 weight per cent of an aromatic aldehyde selected from a group including aminobenzaldehyde , benzaldehyde , chlorobenzaldehyde, dichlorobenzaldehyde, meth lbenzaldehyde , nitrobenzaldehyde and trichlorobenzaldehyde.
It is a further object of the present invention to provide a novel electronic lead-in metal substrate possessing superior resistance to the loss of solderability due to accelerated steam aging wherein the solder coating on the substrate includes an aromatic aldehyde included therein, with the resultant solder coated metal substrate exhibiting long term resistance to normal storage conditions and natural aging.
A further object of the present invention is to provide a novel method of depositing and controlling a Sn/Pb solder coating onto the electronic lead-in metal substrate to provide lead-in metal substrates which resist corrosion and oxidation, thus rendering the metal substrate resistant to the loss of solderability due to natural aging.
A further object of the present invention is the novel method of depositing and controlling an alloy solder coating onto a electronic lead-in metal substrate which consist of plating the Sn/Pb solder alloys from a fluoborate or methylsulfonic acid solution containing aromatic aldehydes, to provide a tin-lead solder coating containing molecules of the organic material included or entrapped therein.
As used within the present specification, the phrase electronic lead-in wire or metallic substrate is used to designate the current carrying conductor containing the solder coating. Also, as used herein, the solder coating will be referred to as including the elements Sn/Pb.
The electronic lead-in metal substrate useful as a electronic lead-in component, which possesses increased resistance to the loss solderability due to natural or accelerated steam aging, is first cleaned utilizing conventional methods and then a Sn/Pb solder coating is applied to the lead-in metal substrate with the solder coating containing between about 0.5-20 x 10"4 weight per cent of an aromatic aldehyde. The aromatic aldehyde may be selected from a group which includes a inobenzaldehyde, chlorobenzaldehyde, benzaldehyde, dichlorobenzaldehyde, methy 1 be n z a 1 d yd e , n i tr o be n z a 1 d e hyd e , and trichlorobenzaldehyde.
The method of applying the fusible Sn/Pb solder coating to the electronic lead-in metal substrate consists of plating the solder coating from either a fluoborate or methylsulfonate plating solution containing the selected aromatic aldehyde. The plating solution may include a long chain alcohol and wetting agents, as is known in the art. A typical fluoborate solder plating bath, preferably includes,
between about 100-400 grams per liter of stannous (Sn) fluoborate, between about 20-100 grams per liter of lead (Pb) fluoborate, between about 100-300 grams per liter fluoboric acid and between about 0.1-0.5 grams per liter of the age resistant additive or aromatic aldehyde. As set forth above, the bath may further include a long chain alcohol and wetting agent.
It has been found that the resultant coating may be applied to the lead-in metal substrate at a thickness of between 5-800 micro inches. For example, if the plating is done upon a lead-in wire substrate, the wire may be coated with a solder coating at a thickness of about 350 micro inches and then the wire may be drawn through a die such that the wire drawn fusible soldered coating has a reduced thickness relative to the applied thickness. The solder acts as a lubricant and the entrapped or included organic aromatic aldehyde molecules that are randomly and uniformly distributed throughout the deposited solder coating do not detract from the ability of the coated lead-in substrate to be drawn to a reduced size nor does drawing the wire detract from the solder coatings effectiveness in reducing the loss of solderability due to natural aging or steam aging.
It has been found that the fusible Sn/Pb solder coating must contain between about 0.5-20 x 10"4 weight per cent aromatic aldehyde in the solder coating deposit or the enhanced and superior corrosion and oxidation resistance of the lead metal substrate is not achieved. If the concentration of the aromatic aldehyde in the coating is below the given range, the resultant coated lead-in metal substrate does not exhibit satisfactory long term resistance to normal aging conditions, and if the concentration of the aromatic aldehyde is above a given range, the resultant lead-in metal substrate severely out gasses upon soldering thereby adversely effecting the solderability of the lead-in metal substrate.
The present invention consist of certain novel features and details hereinafter fully described and particularly pointed out in the appended claims, it being
understood that various changes in the details may be made without departing from the spirit and scope thereof or sacrificing any advantages of the present invention. Description of the Preferred Fmhnd-iτng»nt_
For the purpose of facilitating and understanding the scope of the present invention, the present invention is directed to a novel lead-in metallic substrate possessing superior resistance to corrosion and oxidation and to the loss of solderability due to aging. The resultant lead-in metallic substrate is coated with a fusible solder coating containing between about 0.5-20 x 10"4 weight per cent of an aromatic aldehyde.
The aromatic aldehyde, preferably, is selected from a group comprising nitro, amino, alkyl, halogenated substituted and normal benzaldehydes. Specifically, the aromatic aldehydes that are particularly applicable in steam aged solder coatings include aminobenzaldehyde, benzaldehyde, chlorobenzaldehyde, dichlorobenzaldehyde, trich1orobenza 1dehyde , methyl benzaldehyde, nitrobenzaldehyde. It is within the scope of the present invention that the age resistant material may be a mixture of single ring aromatic aldehydes.
The method of applying the fusible Sn/Pb solder coating to the lead-in metal substrate consists of first cleaning the metal substrate and then plating the solder coating from a fluoborate or methylsulfonic acid plating solution containing the selected age resistant additive or aromatic aldehyde. The fluoborate plating solution may include a long chain alcohol and a wetting agent, as is known in the art. A. typical fluoborate solder plating bath includes between about 100-400 grams per liter of stannous(Sn) fluoborate, between about 20-100 grams per liter of lead(Pb) fluoborate, between about 100-300 grams per liter fluoboric acid and between about 0.1.5 gram per liter of the age resistant additive or aromatic aldehyde. As set forth above, the bath may further include a long chain alcohol and a wetting agent.
A typical methylsulfonic acid solder plating bath, preferably includes, between about 150-400 grams per liter of stannous(Sn) methylsulfonic acid, between about 80-150 grams per liter of lead(Pb) methylsulfonic acid, between about 100-400 grams per liter of ethonesulfonic acid and between about 0.2-1.0 grams per liter of the age resistant additive or aromatic aldehyde. The plating solution may include a long chain alcohol and a wetting agent, as is known in the prior art.
It has been found that either the fluoborate or methylsulfonic coating may be applied to the lead-in metal substrate at a thickness of between 5-800 micro inches. For example, if the plating is done upon a lead-in wire substrate, the wire may be coated with a solder coating at a thickness of about 350 micro inches. Then, the wire may be drawn through a die such that the wire drawn fusible soldered coating has a reduced thickness relative to the applied thickness. The solder acts as a lubricant and it is believed that the entrapped" or included organic aromatic aldehyde molecules that are randomly and uniformly distributed or occluded throughout the deposited solder coating layer and on the surface thereof do not detract from the ability of the coated lead-in substrate to be drawn to a size thickness nor does drawing the wire detract from the solder coating's effectiveness in reducing the loss of solderability due to natural aging or steam aging.
An additional example of a solder coating to a lead- in metal substrate is the working of plated lead-in metal substrate by cold forging to change the shape and, as a consequence, thereby thinning the solder coating to approximately 5 micro inches.
Much work has been conducted and published within the past few years to establish an accelerated aging test capable of predicting long term resistance to normal storage conditions. An 8 or 16 hour exposure of the fusible coated metal substrate to steam at 85-100°C and at atmospheric pressure followed by solderability testing has resulted in a test which predicts resistance to aging in storage. An
acceptable solderability test result is indicative of a satisfactory fusible coated metal substrate storage for a minimum of three years. The published literature shows a relationship between accelerated aging in steam' and natural aging in storage under various conditions. See for example
Printed Circuit Assembly, Vol. 2, No. 6, June 1988. It is believed that approximately 16 hours under steam aging equals to approximately 3 years of natural storage under conditions considered normal for electronic devices.
TABLE I
Solderability After Steam Aging 16 hrε for Various Age Resistant Additive Occlusion Levels {Additive: dichlorbenzaldhyde) in al 90 10 Sn Pb Allo Plated Connector Pins
(Acceptable)
Excellent Moderate
(Acceptable)
341 3.71 89 37.40x10 Dewetting Unacceptable due to out- gassing
284 3.21 93 38.21x10 Dewetting Unacceptable due to out- gassing
It has been found in Table I that the fusible Sn/Pb solder coating must contain between about 0.5-20 x 10"4 weight per cent aromatic aldehyde in the solder coating deposit layer or the enhanced and superior corrosion and oxidation resistance of the lead-in metal substrate is not achieved. If the concentration of the aromatic aldehyde in the coating is below this predetermined range, the resultant coated lead-in metal substrate does not exhibit satisfactory long term resistance to normal aging conditions and possesses very poor solderability, and if the concentration of the. aromatic aldehyde is above this given range, the resultant lead-in metal substrate results in severe out gassing thereby adversely effecting the solderability of the lead metal substrate. Thus, the preferred range of weight per cent aromatic aldehyde in the solder coating deposit layer is about 1.0-10.0 x 10" to provide superior corrosion and oxidation resistance.
Claims
1. A lead-in metal substrate possessing resistance to the loss of solderability due to aging wherein the substrate is coated with a fusible solder coating containing between about 0.5-20 x 10"4 weight per cent of an age resistant additive.
2. The lead-in metal substrate in accordance with claim 1 wherein said age resistant additive is an aromatic aldehyde.
3. The lead-in metal substrate in accordance with claim 2 wherein said aromatic aldehyde is benzaldehyde.
4. The lead-in metal substrate in accordance with claim 2 wherein said aromatic aldehyde is selected from a group comprising nitro, amino, alkyl, and halogenated substituted benzaldehydeε.
5. The lead-in metal substrate in accordance with claim 1 wherein said solder coating is obtained from a fluoborate plating bath containing said age resistant additive.
6. The lead-in metal substrate in accordance with claim 1 wherein said solder coating is obtained from a methylsulfonic acid plating bath containing said age resistant additive.
7. The lead-in metal substrate in accordance with claim l wherein said solder coating has a coating thickness of between about 5-800 micro inches.
8. The lead-in metal substrate in accordance with claim 4 wherein said aromatic aldehyde is a mixture of age resistant additives selected from said group comprising nitro, amino, alkyl and halogenated substituted benzaldehydes.2
9. The lead-in metal substrate in accordance with claim 1 wherein said solder coating is a nominal 90/10 weight per cent Sn/Pb.
10. The lead-in metal substrate in accordance with claim 9 with said solder coating containing between about 1.0-10 x 10"4 weight per cent of an age resistant aromatic aldehyde.
11. The lead-in metal substrate in accordance with claim 10 wherein said aromatic aldehyde is benzaldehyde.
12. The lead-in metal substrate in accordance with claim 10 wherein said aromatic aldehyde is selected from a group comprising nitro, amino, alkyl, and halogenated substituted benzaldehydes.
13. The lead-in metal substrate in accordance with claim 9 wherein said solder coating has a coating thickness of between about 50-500 micro inches.
14. A method of depositing a fusible Sn/Pb solder coating onto a cleaned lead-in metal substrate, including the step of plating the lead-in metal substrate from a Sn/Pb solder plating bath containing between about 0.5-20 x 10"4 weight per cent of an age resistant additive to provide the solder plated substrate with resistance to the loss of solderability due to aging.
15. The method according to claim 14 wherein said age resistant additive in an aromatic aldehyde.
16. The method according to claim 15 wherein said aromatic aldehyde is benzaldehyde.2
17. The method according to claim 15 wherein said aromatic aldehyde is selected from a group comprising nitro, amino, alkyl and halogenated substituted benzaldehydes.
18. The method in accordance with claim 17 wherein said aromatic aldehyde is a mixture of age resistant additives selected from said group comprising nitro, amino, alkyl and halogenated substituted benzaldehydes.
19. The method in accordance with claim 14 wherein said solder plating bath is a fluoborate plating bath containing said age resistant additive.
20. The method in accordance with claim 14, wherein said solder plating bath is a methylsulfonic acid plating bath containing said age resistant additive.
21. A fusible Sn/Pb solder alloy containing between about 0.5-20 x lθ"4 weight per cent of an age resistant additive for use as a coating on a lead-in metal substrate to provide resistance to the loss of solderability due to aging.
22. The solder alloy in accordance with claim 21 wherein said age resistant additive is an aromatic aldehyde.
23. The solder alloy in accordance with claim 22 wherein said aromatic aldehyde is benzaldehyde.
24. The solder alloy in accordance with claim 22 wherein said aromatic aldehyde is selected from a group comprising nitro, amino, alkyl and halogenated substituted benzaldehydes.
25. The solder alloy in accordance with claim 1 wherein said solder coating is obtained from a fluoborate plating bath containing said age resistant additive.
26. The solder alloy in accordance with claim 21 wherein said solder coating is obtained from a methylsulfonic acid plating bath containing said age resistant additive.
27. The solder alloy in accordance with claim 21 wherein said Sn/Pb solder is a nominal 90/10 weight per cent.
28. The solder alloy in accordance with claim 24 wherein said aromatic aldehyde is a mixture of age resistant additives selected from said group comprising nitro, amino alkyl and halogenated substituted benzaldehydes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US78659491A | 1991-11-01 | 1991-11-01 | |
| US786,594 | 1991-11-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1993009276A1 true WO1993009276A1 (en) | 1993-05-13 |
Family
ID=25139043
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1992/009134 WO1993009276A1 (en) | 1991-11-01 | 1992-10-28 | Age resistant solder coatings |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU2927392A (en) |
| WO (1) | WO1993009276A1 (en) |
Cited By (10)
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| WO2007137227A1 (en) | 2006-05-22 | 2007-11-29 | Vanda Pharmaceuticals, Inc. | Treatment for depressive disorders |
| WO2008121899A2 (en) | 2007-03-29 | 2008-10-09 | Vanda Pharmaceuticals Inc. | Method of predicting a predisposition to qt prolongation |
| WO2010117943A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to qt prolongation based on bai3 gene sequence or product thereof |
| WO2010117937A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to qt prolongation |
| WO2010117941A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to qt prolongation based on abcc2 gene sequence or product thereof |
| WO2010117931A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of treatment based on polymorphisms of the kcnq1 gene |
| US8652776B2 (en) | 2007-09-10 | 2014-02-18 | Vanda Pharmaceuticals, Inc. | Prediction of QT prolongation based on SNP genotype |
| EP3075865A2 (en) | 2007-05-18 | 2016-10-05 | Vanda Pharmaceuticals Inc. | Genetic markers for efficacy of iloperidone in the treatment of psychotic symptoms |
| US10570453B2 (en) | 2007-03-29 | 2020-02-25 | Vanda Pharmaceuticals Inc. | Method of predicting a predisposition to QT prolongation |
| WO2023201182A1 (en) | 2022-04-13 | 2023-10-19 | Vanda Pharmaceuticals Inc. | Treatment of parkinson's disease and parkinson's disease psychosis |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007137227A1 (en) | 2006-05-22 | 2007-11-29 | Vanda Pharmaceuticals, Inc. | Treatment for depressive disorders |
| WO2008121899A2 (en) | 2007-03-29 | 2008-10-09 | Vanda Pharmaceuticals Inc. | Method of predicting a predisposition to qt prolongation |
| US10570453B2 (en) | 2007-03-29 | 2020-02-25 | Vanda Pharmaceuticals Inc. | Method of predicting a predisposition to QT prolongation |
| US9074254B2 (en) | 2007-03-29 | 2015-07-07 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| EP3075865A2 (en) | 2007-05-18 | 2016-10-05 | Vanda Pharmaceuticals Inc. | Genetic markers for efficacy of iloperidone in the treatment of psychotic symptoms |
| US8652776B2 (en) | 2007-09-10 | 2014-02-18 | Vanda Pharmaceuticals, Inc. | Prediction of QT prolongation based on SNP genotype |
| US9072742B2 (en) | 2009-04-06 | 2015-07-07 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| EP3023506A1 (en) | 2009-04-06 | 2016-05-25 | Vanda Pharmaceuticals Inc. | Method of treatment based on polymorphisms of the kcnq1 gene |
| WO2010117931A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of treatment based on polymorphisms of the kcnq1 gene |
| US9074256B2 (en) | 2009-04-06 | 2015-07-07 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| WO2010117941A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to qt prolongation based on abcc2 gene sequence or product thereof |
| US9074255B2 (en) | 2009-04-06 | 2015-07-07 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| US9157121B2 (en) | 2009-04-06 | 2015-10-13 | Vanda Pharmaceuticals, Inc. | Method of treatment based on polymorphisms of the KCNQ1 gene |
| US8999638B2 (en) | 2009-04-06 | 2015-04-07 | Vanda Pharmaceuticals, Inc. | Method of treatment based on polymorphisms of the KCNQ1 gene |
| WO2010117937A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to qt prolongation |
| EP3354753A1 (en) | 2009-04-06 | 2018-08-01 | Vanda Pharmaceuticals Inc. | Method of treatment based on polymorphisms of the kcnq1 gene |
| US10563261B2 (en) | 2009-04-06 | 2020-02-18 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| US10563259B2 (en) | 2009-04-06 | 2020-02-18 | Vanda Pharmeceuticals, Inc. | Method of treatment based on polymorphisms of the KCNQ1 gene |
| US10563260B2 (en) | 2009-04-06 | 2020-02-18 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| WO2010117943A1 (en) | 2009-04-06 | 2010-10-14 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to qt prolongation based on bai3 gene sequence or product thereof |
| US10570452B2 (en) | 2009-04-06 | 2020-02-25 | Vanda Pharmaceuticals, Inc. | Method of predicting a predisposition to QT prolongation |
| WO2023201182A1 (en) | 2022-04-13 | 2023-10-19 | Vanda Pharmaceuticals Inc. | Treatment of parkinson's disease and parkinson's disease psychosis |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2927392A (en) | 1993-06-07 |
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