Interfacial alloy layer for improving electromigration (em) resistance in solder joints
AssigneeInternational Business Machines Corporation
InventorsHirokazu Noma, Yasumitsu Orii, Kazushige Toriyama
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Abstract
A method of forming a structure for an interfacial alloy layer which is able to improve the electromigration (EM) resistance of a solder joint. More specifically, in this structure, a controlled interfacial alloy layer is provided on both sides of a solder joint. In order to form this structure, aging (maintenance of high-temperature conditions) is performed until an interfacial alloy layer of Cu3Sn has a thickness of at least 1.5 μm.
Claims8
A method of forming a joint between two structures able to control electromigration (EM), the method comprising the steps of:
- preparing a copper (Cu) structure;
- preparing a tin (Sn) based solder structure brought into contact with the copper (Cu) structure;
- forming a solder joint by raising the temperature to the melting-point temperature of the solder structure and forming intermetallic compounds Cu3Sn and Cu6Sn5 inside between the solder structure and the copper (Cu) structure;
- and
- aging the solder joint (maintaining high-temperature conditions) for 10 to 2,000 hours in a temperature range of 150° C. to 200° C. until the thickness of the grown intermetallic compound Cu3Sn (interfacial) alloy layer exceeds 1.5 μm.
A method of forming a joint between two structures able to control electromigration (EM), the method comprising the steps of:
- forming a solder joint by bringing a tin (Sn) based solder structure into contact with a copper (Cu) structure, raising the temperature to the melting-point temperature of the solder structure, and forming intermetallic compounds Cu3Sn and Cu6Sn5 inside between the solder structure and the copper (Cu) structure;
- and
- aging the solder joint (maintaining high-temperature conditions) for 10 to 2,000 hours in a temperature range of 150° C. to 200° C. until the thickness of the grown intermetallic compound Cu3Sn (interfacial) alloy layer exceeds 1.5 μm.
Dependencies are inferred from the claim text.