Method and device for applying solder paste flux
AssigneeMycronic AB
InventorJohan BERGSTRÖM
Life of this patent
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Abstract
A method of applying viscous media on a substrate is disclosed. In the method, the substrate is provided, which is arranged for mounting of electronic components thereon. Further, flux is provided on a deposit of solder paste, which deposit is arranged at a predetermined position on the substrate. The flux is provided by a non-contact dispensing process, such as jetting. By providing flux on the deposit prior to reflow, the risk of quality related issues, such as e.g. graping, advantageously is reduced.
Claims25
A method of applying viscous media on a substrate, the method comprising:
- arranging the substrate for mounting of electronic components thereon;
- and
- providing flux on densely packed deposits of solder paste, which deposit is arranged at a certain position on the substrate;
- wherein the flux does not contain any metal particles and is provided by a non-contact dispensing process on top of the small deposits in order to partly or fully cover the deposits prior to reflow without diluting the solder paste deposits, i.e. without increasing concentration of the flux to adversely affect quality of the solder paste deposits, so that at least a part of the flux of said cover may evaporate prior to reflow oxidation and/or is consumed during reflow oxidation instead of part of the flux of the solder paste, thereby reducing risk that a lack or insufficient amount of flux during reflow oxidation may give rise to unreflowed solder particles and/or dry joints without increasing the risk of short-circuiting or bridging of densely packed smaller electronic components mounted on said deposits.
A jetting device for applying viscous medium on a substrate, the device comprising at least one non-contact dispensing head assembly configured to provide flux on densely packed deposits of solder paste containing metal particles, which deposits are arranged at certain positions on the substrate, said jetting device comprises a jetting head assembly and a non contact dispensing head assembly, wherein the jetting head assembly is configured to form jetted deposits of solder paste containing metal particles on predetermined positions on the substrate and the non-contact dispensing head assembly is configured to provide flux not containing metal particles on said deposits, wherein densely packed deposits of solder paste are applied by the jetting head assembly, and wherein the at least one non-contact dispensing head assembly is configured to apply additional flux that does not contain any metal particles on top of the deposits in order to partly or fully cover the deposit prior to reflow without diluting the solder paste deposits, i.e. without increasing flux concentration to adversely affect quality of the solder paste deposits, so that at least a part of the additional flux of said cover may evaporate prior to reflow oxidation and/or is consumed during reflow oxidation instead of part of the flux of the solder paste, said device of combined jetting head assembly and non-contact dispenser head assembly being configured to provide different types of viscous medium on the same substrate is thereby configured to provide for densely packed solder deposits after reflow oxidation without reducing risk that a lack or insufficient amount of flux during reflow oxidation may give rise to unreflowed solder particles and/or dry joints and without increasing the risk of short-circuiting or bridging of densely packed smaller electronic components mounted on said deposits, wherein said non-contact dispensing head assembly is configured so that the additional flux is added in a non-contact process where the additional flux is not simultaneously in contact with both the nozzle and the deposit during application, thereby reducing the risk that the deposits adhere to the added flux.
A screen printer device for applying viscous medium on a substrate, the device further comprising at least one integrated non-contact dispensing head assembly configured to provide flux on densely packed deposits of solder paste, which deposit is arranged at a certain position on the substrate, said screen printer is configured to screen print deposits of solder paste on predetermined positions on the substrate and the integrated non-contact dispensing head assembly is configured to provide flux on said deposits, wherein densely packed deposits of solder paste are provided on the substrate by the screen printer, and wherein the at least one non-contact dispensing head assembly is configured to apply additional flux that does not contain any metal particles on top of the deposits in order to partly or fully cover the deposits prior to reflow without diluting the solder paste deposits, i.e. without increasing flux concentration to adversely affect quality of the solder paste deposits, so that at least a part of the additional flux of said cover may evaporate prior to reflow oxidation and/or is consumed during reflow oxidation instead of part of the flux of the solder paste, said combination of screen printer and non-contact dispenser configured to provide different types of viscous medium on the same substrate is thereby configured to provide for densely packed solder paste deposits on the substrate after reflow oxidation without reducing the risk that a lack or insufficient amount of flux during reflow oxidation may give rise to unreflowed solder particles and/or dry joints and without increasing risk of short-circuiting or bridging of densely packed smaller electronic components mounted on said deposits, wherein said non-contact dispensing head assembly is configured so that the additional flux is added in a non-contact process where the additional flux is not simultaneously in contact with both the nozzle and the deposit during application, thereby reducing the risk that the deposits adhere to the added flux.
Dependencies are inferred from the claim text.