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US 11,637,083 B2Granted
Flip-chip package assembly
AssigneeTexas Instruments Incorporated
InventorsRafael Jose Lizares Guevara, John Carlo Cruz Molina, Steffany Ann Lacierda Moreno
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Abstract
In a described example, a method includes: forming cavities in a die mount surface of a package substrate, the cavities extending into the die mount surface of the package substrate at locations corresponding to post connects on a semiconductor die to be flip-chip mounted to the package substrate; placing flux in the cavities; placing solder balls on the flux; and performing a thermal reflow process and melting the solder balls to form solder pads in the cavities on the package substrate.
Claims18
A method, comprising:
- forming cavities in a die mount surface of a package substrate, the cavities extending into the die mount surface of the package substrate;
- placing flux in the cavities;
- placing solder balls on the flux;
- performing a thermal reflow process and melting the solder balls to form solder pads in the cavities on the package substrate;
- and
- mounting a semiconductor die on the solder pads, the semiconductor die having a post connects extending from bond pads at a proximal end to a distal end, the distal ends of the post connects contacting the solder pads, the post connect including a concave recess at the distal end.
3 more elements
A method, comprising:
- forming cavities on a die mount surface of a copper lead frame by laser ablating leads of the copper lead frame, the cavities extending into the die mount surface of the leads;
- depositing a first flux in the cavities by a first stencil process;
- placing solder balls on the cavities by a second stencil process;
- and
- in a first thermal reflow process, melting the solder balls to form solder pads at the cavities to form pre-wetted solder pads at the cavities, the cavities having locations corresponding to the locations of post connects on a semiconductor die to be flip-chip mounted to the copper lead frame, the post connects being copper and having a proximal end on bond pads of the semiconductor die and extending to a distal end, the distal end including a concave recess;
- depositing a second flux on the pre-wetted solder pads;
- mounting the post connects of the semiconductor die on the flux over the pre-wetted solder pads on the copper lead frame;
- performing a second thermal reflow process to form solder joints between the leads of the copper lead frame and the distal end of the post connects;
- and
- covering the semiconductor die, post connects, the solder joints, and a portion of the copper lead frame in a mold compound to form a flip-chip packaged semiconductor device.
7 more elements
Dependencies are inferred from the claim text.