Singulation method used in leadless packaging process
A singulation method used in leadless packaging process is disclosed. An array of molded products on an upper surface of a lead frame is utilized in the singulation method. The lead frame has a plurality of dambars between the molded products. The lower surface of the lead frame is attached with a tape. Each of the molded products includes a semiconductor chip encapsulated in a package body and electrically coupled to the upper surface of the lead frame. The singulation method is accomplished by etching the upper surface of the lead frame with the package bodies as mask until each dambar is etched away.
1. An array of molded products, which is formed on a lead frame for making a plurality of leadless semiconductor packages, comprising:
a plurality of product units each comprising a die pad, a semiconductor chip disposed on the die pad, a plurality of contacts arranged at the periphery of the die pad and electrically connected to the semiconductor chip, and a package body encapsulating the die pad, the semiconductor chip and the plurality of contacts;
a plurality of dambars each being located next to the package bodies of two adjacent product units, being completely exposed from the package bodies, and connecting the contacts of the two adjacent product units;
wherein each dambar has at least one groove formed therein; and
wherein the plurality of product units can be individually separated by etching away the dambars through an etching process so as to form the plurality of leadless semiconductor packages.
2. The array of molded products as claimed in claim 1 , wherein the groove is formed by half-etching the dambar.
3. The array of molded products as claimed in claim 1 , wherein each of the dambars has an upper surface, a lower surface and two side surfaces, and all of said surfaces are exposed from the package bodies.
4. The array of molded products as claimed in claim 3 , wherein the at least one groove is formed on one of the upper surface, the lower surface and the two side surfaces.
5. The array of molded products as claimed in claim 4 , wherein said groove has opposite walls each being disposed adjacent one of two singulation lines along which the package bodies of the two adjacent product units are to be separated from each other when the dambar is etched away.
6. The array of molded products as claimed in claim 5 , wherein the opposite side walls of said groove are located between said singulation lines.
7. The array of molded products as claimed in claim 4 , wherein each said dambar comprises two said grooves each being disposed adjacent one of two sigulation lines along which the package bodies of the two adjacent product units are to be separated from each other when the dambar is etched away.
8. The array of molded products as claimed in claim 7 , wherein said grooves are located between said singulation lines.
9. The array of molded products as claimed in claim 7 , wherein both said grooves are formed on the lower surface of said dambar.
10. The array of molded products as claimed in claim 3 , wherein the package bodies of each pair of adjacent product units are separated from each other by a gap located above the exposed upper surface of the respective dambar.
11. The array of molded products as claimed in claim 4 , further comprising a tape removably attached to the lower surfaces of said dambars as well as lower surfaces of said die pads and said bodies.