US 2001/0034083 A1 · Method of fabricating a molded package for micromechanical devices

Abstract

A plastic land-grid array package, a ball-grid array package, and a plastic leaded package for micromechanical components are fabricated by a molding process characterized by lining the cavity surfaces of the top and bottom mold halves with a protective plastic film, which also protects the surfaces of the components during the molding phase, selectively encapsulating the bonding pads and coupling members of the chip while leaving empty space above the components, and attaching a lid over the components. A molding method as well as a molding apparatus are provided compatible with the sensitivity of the micromechanical devices, yet flexible with regard to the technique used to assemble the chip and the substrate. Furthermore, the method disclosed is flexible with regard to the material and the properties of the substrate. It is an aspect of the present invention to be applicable to a variety of different semiconductor micromechanical devices, for instance actuators, motors, sensors, spatial light modulators, and deformable mirror devices. In all applications, the invention achieves technical advantages as well as significant cost reduction and yield increase.

Claims18

Dependent claims

A method of fabricating a molded device by encapsulating a semiconductor chip having an integrated circuit including a plurality of micromechanical components, configured in a plane in the central area of said chip, and a plurality of bonding pads, disposed in peripheral areas of said chip, comprising the steps of:

forming an electrically insulating substrate, having a plurality of conductive routing lines, first and second surfaces, and a plurality of terminals on said second surface, said terminals electrically connected with said routing lines, respectively;
assembling said chip onto said first substrate surface;
providing a mold for encapsulating said assembled chip, said mold having top and bottom halves;
lining said top and bottom halves with a protective plastic film;
loading said substrate including said assembled chip into said mold;
introducing an encapsulation material into said mold;
curing said encapsulation material at least partially, thereby forming a molded frame around said chip, while leaving empty space above said components, said frame having a flat surface in a plane parallel to said plane of said components;
removing said substrate together with said encapsulated chip from said mold;
attaching a lid to said flat surface of said molded frame, thereby positioning said lid in a plane parallel to said plane of said components;
and
attaching an array of solder balls to said substrate terminals.

8 more elements

forming a leadframe, having a chip mount pad for an integrated circuit chip and a plurality of lead segments, each segment having a first end near said mount pad and a second end remote from said mount pad;
assembling said chip onto said mount pad;
providing a mold for encapsulating said assembled chip, said mold having top and bottom halves;
lining said top and bottom halves with a protective plastic film;
loading said leadframe including said assembled chip into said mold;
introducing an encapsulation material into said mold;
curing said encapsulation material at least partially, thereby forming a molded frame around said chip, while leaving empty space above said components, said frame having a flat surface in a plane parallel to said plane of said components;
removing said substrate together with said encapsulated chip from said mold;
attaching a lid to said flat surface of said molded frame, thereby positioning said lid in a plane parallel to said plane of said components;
and
trimming and forming said second segment ends of said leadframe.

8 more elements

Dependencies are inferred from the claim text.

Method of fabricating a molded package for micromechanical devices

Life of this patent

Method of fabricating a molded package for micromechanical devices

Life of this patent

Abstract

Claims18