CN115066097A - Control method for lead-free tin spraying of circuit board - Google Patents
Control method for lead-free tin spraying of circuit board Download PDFInfo
- Publication number
- CN115066097A CN115066097A CN202210568435.0A CN202210568435A CN115066097A CN 115066097 A CN115066097 A CN 115066097A CN 202210568435 A CN202210568435 A CN 202210568435A CN 115066097 A CN115066097 A CN 115066097A
- Authority
- CN
- China
- Prior art keywords
- tin
- circuit board
- tin spraying
- spraying
- hours
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 title claims abstract description 92
- 238000005507 spraying Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 17
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 42
- 229910052802 copper Inorganic materials 0.000 claims abstract description 42
- 239000010949 copper Substances 0.000 claims abstract description 42
- 229910000679 solder Inorganic materials 0.000 claims abstract description 18
- 238000007654 immersion Methods 0.000 claims abstract description 9
- 230000008021 deposition Effects 0.000 claims abstract description 6
- 238000005553 drilling Methods 0.000 claims abstract description 5
- 238000001035 drying Methods 0.000 claims description 24
- 238000003801 milling Methods 0.000 claims description 7
- 230000005587 bubbling Effects 0.000 abstract description 7
- 230000032798 delamination Effects 0.000 abstract description 3
- 238000004880 explosion Methods 0.000 description 5
- 239000011324 bead Substances 0.000 description 4
- 230000000903 blocking effect Effects 0.000 description 4
- 238000003466 welding Methods 0.000 description 3
- 238000005187 foaming Methods 0.000 description 2
- MSNOMDLPLDYDME-UHFFFAOYSA-N gold nickel Chemical compound [Ni].[Au] MSNOMDLPLDYDME-UHFFFAOYSA-N 0.000 description 2
- LQBJWKCYZGMFEV-UHFFFAOYSA-N lead tin Chemical compound [Sn].[Pb] LQBJWKCYZGMFEV-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002035 prolonged effect Effects 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
-
- 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
- H05K3/22—Secondary treatment of printed circuits
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
The invention provides a control method of lead-free tin spraying of a circuit board, which specifically comprises the following steps: MI, drilling, copper deposition, circuit, pattern, AOI, solder mask and tin spraying; in the MI stage, if the circuit board is provided with an outer copper sheet, the distance between the outer copper sheets of the circuit board is required to be larger than or equal to 0.25 mm; in the tin spraying stage, the copper content in the tin furnace needs to be controlled below 0.6 percent; when the copper content is more than 0.6%, performing copper removal treatment on the tin furnace; the tin immersion time is 7 to 10 seconds; solves the problems of solder resist bubbling and delamination.
Description
Technical Field
The invention relates to a control method of lead-free tin spraying of a circuit board.
Background
The tin spraying is used as a common surface treatment process of a circuit board, has the advantages of low cost, good weldability and the like, but has a circuit board, and is characterized in that the thickness of the circuit board is thicker, generally reaches more than 3.2mm, the aperture is 0.4-0.8mm, the temperature of tin in holes is lower than that of a board surface due to the thicker board thickness, so that the phenomenon of tin blocking the holes is caused during tin spraying, the phenomenon of tin blocking the holes is easily caused when small holes with the thickness of 0.4-0.8mm are more than 3.2mm thick, therefore, the tin furnace temperature is higher than that of a board with the common board thickness and the tin immersion time is longer during tin spraying, and other problems can be caused during tin spraying: the problems of solder resistance, bubbling, oil dropping, layered plate explosion and the like of the copper sheet edge are solved.
In the prior art, the prior art mainly changes a plate with more than 3.2MM into other surface treatment processes to replace tin spraying, such as OSP and nickel gold deposition (or lead tin spraying, lead tin spraying is less used due to environmental protection and other problems), but the solderability and reliability of OSP are inferior to tin spraying, the cost of nickel gold deposition is higher, in addition, the problem of tin bead hole blocking is improved by greatly prolonging the tin soaking time or twice tin spraying, but the problems of plate delamination solder resistance bubbling, hole copper insufficiency and the like are generated by greatly prolonging the tin soaking time or twice tin spraying.
Disclosure of Invention
The invention aims to solve the technical problem of providing a control method of lead-free tin spraying of a circuit board; solves the problems of solder resist bubbling and delamination.
The invention is realized by the following steps: a control method for lead-free tin spraying of a circuit board specifically comprises the following steps: MI, drilling, copper deposition, circuit, pattern, AOI, solder mask and tin spraying;
in the MI stage, if the circuit board is provided with an outer copper sheet, the distance between the outer copper sheets of the circuit board is required to be larger than or equal to 0.25 mm;
in the tin spraying stage, the copper content in the tin furnace needs to be controlled below 0.6 percent; when the copper content is more than 0.6%, performing copper removal treatment on the tin furnace; the tin immersion time is 7 to 10 seconds.
Further, before tin spraying, if the circuit board is larger than 18 × 24in, performing board milling operation until the circuit board is smaller than or equal to 18 × 24 in; otherwise, the plate milling operation is not carried out.
Further, the temperature of the tin furnace is 270 to 275 ℃.
Further, if characters are not needed to be carried out during the completion of the solder resist, directly carrying out curing operation, and carrying out tin spraying within two hours; if the time is more than two hours, drying the plate before tin spraying; the temperature of the drying plate is set to be 150 ℃, the time is 30-60 minutes, tin spraying is carried out within two hours after the drying plate is dried, and if the time exceeds two hours, the drying plate needs to be dried again;
if the characters are needed after the solder resist is finished, carrying out curing operation after the characters, and carrying out tin spraying within two hours; if the time is more than two hours, drying the plate before tin spraying; the temperature of the drying plate is set to be 150 ℃, the time is 30-60 minutes, tin spraying is carried out within two hours after the drying plate is dried, and if the time exceeds two hours, the drying plate needs to be dried again.
The invention has the following advantages: the problem of tin hole blockage is solved at a lower temperature and in a shorter time, so that the problems of solder resistance, foaming, oil dropping, layered plate explosion and the like of the copper sheet edge are solved.
Drawings
The invention will be further described with reference to the following examples and figures.
FIG. 1 is a flow chart of a method for controlling lead-free tin spraying of a circuit board according to the present invention.
Fig. 2 is a schematic diagram of the thickness spacing between the outer copper layers in the method for controlling lead-free tin spraying of the circuit board.
Detailed Description
The control method of the lead-free tin spraying of the circuit board solves the problem of tin hole blockage at a lower temperature and in a shorter time, thereby solving the problems of solder resistance foaming and oil dropping at the edge of a copper sheet, layered board explosion of a board and the like, and being capable of producing boards with the thickness of 3.2-5.0 mm; a tin spraying plate with the aperture of 0.4-0.8 mm.
The invention can solve the following problems by properly prolonging the tin immersion time on the basis of optimizing the tin spraying flow and parameters:
1: in order to solve the solder resist bubbling problem, the design requirement is defined, the distance between copper sheets with the thickness of 1OZ copper is more than 0.25mm, and the retention time after tin spraying and plate baking is specified to be within 2 hours
2: the problem of blocking up the holes and layering of tin beads in the holes is as follows: the small jointed boards are milled from the large jointed boards before tin spraying, and the copper removal treatment is carried out on the tin furnace before the thick boards are sprayed, so that the copper content is reduced, the tin immersion time is properly prolonged from conventional 2-5S to 7-10S, the tin beads block holes for too short time, and the problems of solder resistance, blistering, layered board explosion and the like can occur for too long time.
As shown in fig. 1, the method for controlling lead-free tin spraying of a circuit board of the present invention specifically includes: MI, drilling, copper deposition, circuit, pattern, AOI, solder mask and tin spraying;
as shown in fig. 2, in the MI stage, if the circuit board has an outer copper sheet, the distance between the outer copper sheets of the circuit board needs to be set to be greater than or equal to 0.25 mm; if the circuit board does not have an outer copper sheet, the step is not needed; the resistance welding bubbling phenomenon is more serious as the plate thickness is thicker and the outer copper sheet distance is smaller, and the resistance welding bubbling phenomenon is greatly reduced by setting the outer copper sheet distance of 0.25 mm;
in the tin spraying stage, the copper content in the tin furnace needs to be controlled below 0.6 percent; when the copper content is more than 0.6%, performing copper removal treatment on the tin furnace; the tin immersion time is 7 to 10 seconds, and the temperature of the tin furnace is 270 to 275 ℃. If the copper content is higher, the copper removal treatment is carried out on the tin furnace, the high copper content can cause the poor fluidity of tin, and in addition, the higher the copper content is, the higher the melting point is, the higher the required temperature is, and the longer the time is;
before tin spraying, if the circuit board is larger than 18 × 24in, performing board milling operation until the circuit board is smaller than or equal to 18 × 24 in; if not, the plate milling operation is not carried out; the plate milling operation does not affect the production efficiency, the large production jointed plate is maintained from drilling to resistance welding, and the large jointed plate is milled into the small jointed plate according to the size requirement of tin spraying during tin spraying, so that the temperature of a tin furnace required by the small jointed plate is lower, the required tin immersion time is shorter, the plate is heated more uniformly, the occurrence of layered plate explosion can be reduced, the defect that a local hole is blocked by tin beads can not occur, and meanwhile, because the temperature is lower and the immersion time is shorter, the copper biting amount is also reduced by 1-2UM, and the thickness of the hole copper is ensured;
if characters are not needed during the completion of the solder resist, directly carrying out curing operation, and carrying out tin spraying within two hours; if the time is more than two hours, drying the plate before tin spraying; setting the temperature of the drying plate to be 150 ℃, setting the time to be 30-60 minutes, carrying out tin spraying within two hours after the drying plate is dried, and drying the plate again if the time exceeds two hours;
if the character is needed after the solder resist is finished, curing operation is carried out after the character, and tin spraying is carried out within two hours; if the time exceeds two hours, drying the plate before tin spraying; the temperature of the drying plate is set to be 150 ℃, the time is 30-60 minutes, tin spraying is carried out within two hours after the drying plate is dried, and if the time exceeds two hours, the drying plate needs to be dried again.
Although specific embodiments of the invention have been described above, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the appended claims.
Claims (4)
1. A control method of lead-free tin spraying of a circuit board is characterized by comprising the following steps: the method specifically comprises the following steps: MI, drilling, copper deposition, circuit, pattern, AOI, solder mask and tin spraying;
in the MI stage, if the circuit board is provided with an outer copper sheet, the distance between the outer copper sheets of the circuit board is required to be larger than or equal to 0.25 mm;
in the tin spraying stage, the copper content in the tin furnace needs to be controlled below 0.6 percent; when the copper content is more than 0.6%, performing copper removal treatment on the tin furnace; the tin immersion time is 7 to 10 seconds.
2. The method for controlling the lead-free tin spraying of the circuit board as claimed in claim 1, wherein: before tin spraying, if the circuit board is larger than 18 × 24in, performing board milling operation until the circuit board is smaller than or equal to 18 × 24 in; otherwise, the plate milling operation is not carried out.
3. The method for controlling the lead-free tin spraying of the circuit board as claimed in claim 1, wherein: the temperature of the tin furnace is 270 to 275 ℃.
4. The method for controlling the lead-free tin spraying of the circuit board as claimed in claim 1, wherein: if the solder mask is finished and characters are not needed, directly carrying out curing operation, and carrying out tin spraying within two hours; if the time is more than two hours, drying the plate before tin spraying; setting the temperature of the drying plate to be 150 ℃, setting the time to be 30-60 minutes, carrying out tin spraying within two hours after the drying plate is dried, and drying the plate again if the time exceeds two hours;
if the characters are needed after the solder resist is finished, carrying out curing operation after the characters, and carrying out tin spraying within two hours; if the time is more than two hours, drying the plate before tin spraying; the temperature of the drying plate is set to be 150 ℃, the time is 30-60 minutes, tin spraying is carried out within two hours after the drying plate is dried, and if the time exceeds two hours, the drying plate needs to be dried again.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210568435.0A CN115066097A (en) | 2022-05-24 | 2022-05-24 | Control method for lead-free tin spraying of circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210568435.0A CN115066097A (en) | 2022-05-24 | 2022-05-24 | Control method for lead-free tin spraying of circuit board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115066097A true CN115066097A (en) | 2022-09-16 |
Family
ID=83198322
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210568435.0A Pending CN115066097A (en) | 2022-05-24 | 2022-05-24 | Control method for lead-free tin spraying of circuit board |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115066097A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6699306B2 (en) * | 2000-02-24 | 2004-03-02 | Nihon Superior Sha Co., Ltd. | Control method for copper density in a solder dipping bath |
| CN1859828A (en) * | 2005-04-30 | 2006-11-08 | 佢朋股份有限公司 | Copper removing method for lead-free tin spray process in PCB, SMT |
| US20090289102A1 (en) * | 2005-07-19 | 2009-11-26 | Nihon Superior Sha Co., Ltd. | SOLDER FREE FROM LEAD FOR ADDITIONAL SUPPLY AND METHOD OF REGULATING Cu CONCENTRATION AND Ni CONCENTRATION IN SOLDER BATH |
| CN102994795A (en) * | 2011-09-16 | 2013-03-27 | 北大方正集团有限公司 | Copper removing method of Sn-Cu-Ni lead-free solder and PCB (Printed Circuit Board) production method |
| CN107058930A (en) * | 2017-05-15 | 2017-08-18 | 深圳市景旺电子股份有限公司 | A kind of thick pcb board and its spray tin method |
| CN111702273A (en) * | 2020-06-29 | 2020-09-25 | 东莞市星马焊锡有限公司 | Lead-free soldering tin spraying process with uniform thickness |
-
2022
- 2022-05-24 CN CN202210568435.0A patent/CN115066097A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6699306B2 (en) * | 2000-02-24 | 2004-03-02 | Nihon Superior Sha Co., Ltd. | Control method for copper density in a solder dipping bath |
| CN1859828A (en) * | 2005-04-30 | 2006-11-08 | 佢朋股份有限公司 | Copper removing method for lead-free tin spray process in PCB, SMT |
| US20090289102A1 (en) * | 2005-07-19 | 2009-11-26 | Nihon Superior Sha Co., Ltd. | SOLDER FREE FROM LEAD FOR ADDITIONAL SUPPLY AND METHOD OF REGULATING Cu CONCENTRATION AND Ni CONCENTRATION IN SOLDER BATH |
| CN102994795A (en) * | 2011-09-16 | 2013-03-27 | 北大方正集团有限公司 | Copper removing method of Sn-Cu-Ni lead-free solder and PCB (Printed Circuit Board) production method |
| CN107058930A (en) * | 2017-05-15 | 2017-08-18 | 深圳市景旺电子股份有限公司 | A kind of thick pcb board and its spray tin method |
| CN111702273A (en) * | 2020-06-29 | 2020-09-25 | 东莞市星马焊锡有限公司 | Lead-free soldering tin spraying process with uniform thickness |
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