Leadless semiconductor package and method of manufacture

Abstract

A leadless semiconductor package includes a package body on a leadframe that includes a die paddle and a plurality of bond pads, none of which extend as far as a lateral face of the body. During manufacture of the package, molding compound is deposited over a face of the leadframe on which the die paddle and bond pads are positioned. After the molding compound is cured, a back side of the leadframe is etched to isolate the die paddle and bond pads, back surfaces of which remain exposed at a back face of the body. During manufacture of the leadframe, a parent substrate is etched to define the die paddle and a plurality of bond pads on one side of the substrate and a plurality of cavities on the opposite face.

Description

BACKGROUND OF THE INVENTION[0001]1. Technical Field[0002]The present disclosure relates to semiconductor packaging, and in particular to leadframe-based packages, to leadframes employed in such packages, and most particularly to flat, leadless type packages and leadframes, such as, e.g., QFN packages.[0003]2. Description of the Related Art[0004]While significant advances have been made in semiconductor packaging, including the development of a very large number of packaging types, the majority of semiconductor devices still employ leadframe based packages. This is due to a number of reasons. In particular, leadframe packages are relatively inexpensive to produce, are well known and understood, the tooling is already in hand or readily available, etc. Additionally, leadframe packages have some advantages over many other packages, including having better thermal transmission characteristics, and more being more robust. As industry demand moves toward smaller packages and higher contac...

AI Technical Summary

Problems solved by technology

One problem associated with leadframe-based packages is that there is a minimum thickness requirement for leadframe material.

Typically, leadframe strips cannot be much less than about 100 μm, because thinner material becomes virtually impossible to handle without damage.

It lacks the strength and rigidity to withstand normal handling and the processes to which it is subjected during typical manufacturing operations.

To the extent that special tooling and procedures could be devised to successfully handle thinner material, this would represent a significant additional expense and would eliminate one of the primary advantages of leadframes over other packaging formats, i.e., the ability of many existing automated systems to perform some or all of the processing steps required for more advanced package designs.

Unfortunately, the processes necessary to manufacture leadframes by metal deposition are expensive and time consuming.

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