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US 6,498,099 B1Granted
Leadless plastic chip carrier with etch back pad singulation
AssigneeASAT Ltd.
InventorsNeil McLellan, Nelson Fan
Life of this patent
Estimating the term…
Abstract
A leadless plastic chip carrier is constructed by half etching one or both sides of the package design onto a leadframe strip. After wire bonding and molding, a further etching is performed to isolate and expose contact pads. Singulation of individual chip packages from the leadframe strip may then be performed by saw singulation or die punching.
Claims12
A process for fabricating a leadless plastic chip carrier, comprising the steps of:
- partially etching at least a top surface of a leadframe strip to define a die attach pad and at least one row of contact pads adjacent to said die attach pad of said leadless plastic chip carrier;
- mounting a semiconductor die to said die attach pad on said top surface and wire bonding said semiconductor die to said contact pads;
- encapsulating said top surface of said leadframe strip in a molding material;
- etching back a bottom surface of said leadframe strip such that only portions of the leadframe strip that are interposed between the portions of the leadframe strip that define the die attach pad and the at least one row of contact pads are removed so as to cause said contact pads to be isolated from said die attach pad;
- and
- singulating said leadless plastic chip carrier from said leadframe strip.
3 more elements
A process for fabricating a multi-row leadless plastic chip carrier, comprising the steps of:
- partially etching said top surface of a leadframe strip to define a first level connect array of inner and outer rows of contact pads circumscribing a die attach pad on said top surface of said leadless plastic chip carrier;
- partially etching said top surface and a bottom surface of said leadframe strip to define a second level connect array of inner and outer rows of contact pads circumscribing said die attach pad on said top and bottom surfaces of said leadless plastic chip carrier;
- mounting a semiconductor die to said die attach pad on said top surface and wire bonding said semiconductor die to said inner and outer rows of contact pads;
- encapsulating said top surface of said leadframe strip in a molding material;
- etching back said bottom surface of said leadframe strip to isolate said second level connect array of said contact pads from said die attach pad;
- and
- singulating said leadless plastic chip carrier from said leadframe strip.
4 more elements
A process for fabricating a multi-row leadless plastic chip carrier, comprising the steps of:
- partially etching a top surface of a leadframe strip to define a first level connect array of inner and outer rows of contact pads circumscribing a die attach pad on said top surface of said leadless plastic chip carrier;
- partially etching said top surface and a bottom surface of said leadframe strip to define a second level connect array of inner and outer rows of contact pads circumscribing said die attach pad on said top and bottom surfaces of said leadless plastic chip carrier;
- mounting a semiconductor die to said die attach pad on said top surface and wire bonding said semiconductor die to said inner and outer rows of contact pads;
- encapsulating said top surface of said leadframe strip in a molding material;
- etching back said bottom surface of said leadframe strip such that only portions of the leadframe strip that are interposed between the portions of the leadframe strip that define the die attach pad and the first level connect array of inner and outer rows of contact pads are removed so as to cause said second level connect array of said contact pads to be isolated from said die attach pad, and singulating said leadless plastic chip carrier from said leadframe strip.
2 more elements
Dependencies are inferred from the claim text.