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US 6,656,291 B1Granted
Solder paste and soldering method of the same
AssigneeFujitsu Limited
InventorHidefumi Ueda
Life of this patent
Estimating the term…
Abstract
A solder paste including a solder powder; and a flux including at least an activating agent, and acid anhydride obtained by a dehydration reaction of aliphatic carboxylic acid having up to seven carbon atoms. The solder paste provides excellent solderability, high corrosive resistance and a good shelf life, but not an offensive smell, during the soldering operation.
Claims20
A solder paste comprising:
- an Sn—Bi solder powder;
- and
- a flux having at least one activating agent, including acid anhydride obtained by a dehydration reaction of aliphatic carboxylic acid having up to seven carbon atoms, wherein said solder paste is used for soldering a solder alloy having a lower melting point than that of Sn—Pb eutectic solder.
A solder paste comprising:
- an Sn—Bi solder powder;
- and
- a flux containing at least one activating agent including acid anhydride having the following formula:
- (CH3(CH2)nCO)2O
- where n is an integer from 0 to 2.
2 more elements
A soldering method comprising the steps of:
- mixing an Sn—Bi solder powder with a flux having at least one activating agent including acid anhydride obtained by a dehydration reaction of aliphatic carboxylic acid having up to seven carbon atoms so as to form a solder paste;
- choosing said acid anhydride to be acetic anhydride continued in said flux in an amount of from 0.5 to 3.0 percent by weight;
- placing said solder paste in a predetermined position;
- and
- soldering a solder alloy with said solder paste, said solder alloy having a lower melting point than Sn—Pb eutectic solder.
2 more elements
A soldering method comprising the steps of:
- mixing an Sn—Bi solder powder with a flux having at least one activating agent including acid anhydride having the following formula:
- (CH3(CH2)nCO)2O
- where n is an integer from 0 to 2, so as to form a solder paste;
- choosing said acid anhydride to be acetic anhydride contained in said flux in an amount of from 0.5 to 3.0 percent by weight;
- placing said solder paste in a predetermined position, and
- soldering a solder alloy with said solder paste, said solder alloy having a lower melting point than Sn—Pb eutectic solder.
3 more elements
The soldering method as claimed in claimed 7, wherein amine is further contained in said flux.
A soldering method comprising the steps of:
- mixing an Sn—Bi solder powder with a flux having at least one activating agent including acid anhydride obtained by a dehydration reaction of aliphatic carboxylic acid having up to seven carbon atoms so as to form a solder paste;
- choosing said acid anhydride to be acetic anhydride contained in said flux in an amount of from 0.5 to 3.0 percent by weight;
- placing said solder paste in a predetermined position;
- and
- soldering a solder alloy with said solder paste, said solder alloy including from 40 to 60 percent by weight of Sn and from 60 to 40 percent by weight of Bi.
2 more elements
A soldering method comprising the steps of:
- mixing an Sn—Bi solder powder with a flux having at least one activating agent including acid anhydride obtained by a dehydration reaction of aliphatic carboxylic acid having the following formula:
- (CH3(CH2)nCO)2O
- where n is an integer from 0 to 2, so as to form a solder paste;
- choosing said acid anhydride is acetic anhydride contained in said flux in an amount from 0.5 to 3.0 percent by weight;
- placing said solder paste in a predetermined position;
- and
- soldering a solder alloy with said solder paste, said solder alloy including from 40 to 60 percent by weight of Sn and from 60 to 40 percent by weight of Bi.
4 more elements
A solder paste comprising:
- a solder powder;
- and
- a flux having at least one activating agent, including acid anhydride obtained by a dehydration reaction of aliphatic carboxylic acid having up to seven carbon atoms, wherein said solder paste is used for soldering a solder alloy having a lower melting point than that of Sn—Pb eutectic solder,
- wherein said acid anhydride has the following formula:
- (CH3(CH2)nCO)2O
- where n is an integer from 0 to 2, and
- wherein said acetic anhydride is acetic anhydride and is contained in said flux in an amount of from 0.5 to 3.0 percent by weight.
4 more elements
A soldering method comprising the steps of:
- mixing an Sn—Bi solder powder with a flux having at least one activating agent including acid anhydride to form a solder paste;
- placing said solder paste in a predetermined position;
- and
- soldering a solder alloy with said solder paste, said solder alloy including from 40 to 60 percent by weight of Sn and from 60 to 40 percent by weight of Bi.
1 more element
Dependencies are inferred from the claim text.