Method for making direct chip attach circuit card
AssigneeInternational Business Machines Corporation
InventorsHormazdyar M. Dalal, Kenneth M. Fallon, Gene J. Gaudenzi
Life of this patent
Estimating the term…
Abstract
A structure and a method is disclosed for making a laminated circuit carrier card for the purpose of making a Direct Chip Attached Module (DCAM) with low cost and high reliability. The carrier is made using an organic or an inorganic laminated carrier having at least one surface available for direct chip mount. The chip has at least one solder ball with a cap of low melting point metal. The surface of the carrier has electrical features that are directly connected to the low melting point metal on the solder ball of the chip to form the eutectic and this way the chip is directly attached to the carrier.
Claims36
A method of making a device carrier for directly attaching a device having reflowed solder balls with low melting point metal cap, said method comprising the steps of:
- (a) making at least one opening in a substrate,
- (b) depositing at least one electrically conductive metal on at least one surface of said substrate, and lining at least a portion of said opening with said at least one electrically conductive metal,
- (c) photolithographically defining a circuit pattern on at least a portion of said substrate,
- (d) forming said photolithographically defined circuit pattern on at least a portion of said substrate,
- (e) coating at least a portion of said substrate with at least one insulator material and filling said opening with said insulator material,
- (f) removing a portion of said insulator material and exposing a portion of said circuit pattern, and
- (g) joining a device having said reflowed solder balls with at least one low melting point metal cap to said exposed circuit pattern, such that at least a portion of said cap joins to a portion of said exposed circuit pattern.
The method of claim l, wherein the time at maximum temperature is between about 15 to about 75 seconds.
Dependencies are inferred from the claim text.