Method of fabricating module having stacked chip scale semiconductor packages
Stacked CSP (chip scale package) modules include a molded first (“top”) chip scale package having a molding side and a substrate side, and a second (“bottom”) package affixed to the substrate side of the top chip scale package, the second package being electrically connected to the first package by wire bonding between the first and second package substrates.
1. A method for making a stacked package module, comprising
providing a first chip scale package including at least one first package die affixed to and electrically interconnected with a die attach side of a first package substrate, the first CSP being molded and without solder balls;
providing a singulated second package including at least one second package die affixed to and electrically interconnected with a die attach side of a second package substrate, the second package being molded and without solder balls;
affixing the second package onto a land side of the first package substrate, employing an adhesive between a surface of a molding of the second package and the land side of the first package substrate;
forming wire bond interconnections between the land side of the second package substrate and sites in a marginal area of the land side of the first package substrate; and
performing an operation to enclose the marginal areas of the land side of the first substrate, the z-interconnection wire bonds and wire loops, the edges of the second package, and the marginal area on the land side of the second package, leaving exposed an area of the land side of the second substrate located within a marginal area.
2. The method of claim 1 , wherein employing an adhesive comprises dispensing adhesive on the land side of the first package substrate.
3. The method of claim 1 , wherein employing an adhesive comprises dispensing adhesive on the second package molding.
4. The method of claim 1 , further comprising at least partially curing the adhesive.
5. The method of claim 1 , further comprising fully curing the adhesive.
6. The method of claim 1 , further comprising attaching second level interconnect solder balls to sites on the exposed area of the second package substrate.
7. The method of claim 1 , wherein providing the first package comprises providing a strip of first packages, and further comprising saw singulating to complete a unit assembly.
8. The method of claim 1 , wherein providing the first package comprises providing a strip of first packages, and further comprising punch singulating to complete a unit assembly.