Browse Prior Art Database

Thin Redistributed Package On Package

IP.com Disclosure Number: IPCOM000236561D
Publication Date: 2014-May-02
Document File: 4 page(s) / 384K

Publishing Venue

The IP.com Prior Art Database

Abstract

Package on package or PoP refers to the stacking of one or more semiconductor integrated circuits on top of one another. PoP is well known in the semiconductor industry. There are many semiconductor companies producing stacked packages in mass production or in the process of qualifying them for production. Stacking two or more packages together allows for an increase in functionality that cannot be achieved by a single package. An example is stacking a memory package on top of an ASIC package, which allows the overall stacked package to have dual functionality. This also allows both packages to be tested separately and only known-good tested units are used for stacking.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

TITLE

Thin Redistributed Package On Package

ABSTRACT

Package on package or PoP refers to the stacking of one or more semiconductor integrated circuits on top of one another.  PoP is well known in the semiconductor industry. There are many semiconductor companies producing stacked packages in mass production or in the process of qualifying them for production.  Stacking two or more packages together allows for an increase in functionality that cannot be achieved by a single package.  An example is stacking a memory package on top of an ASIC package, which allows the overall stacked package to have dual functionality. This also allows both packages to be tested separately and only known-good tested units are used for stacking.  

CONTENT

In this paper we present a thin, redistributed package on package. The important components are the use of a copper post and redistribution of metal traces from the die in each of the package.

The copper post allows a package to be stacked on another package, while the trace redistribution offers a path to route the traces from within the die to interconnect to the copper post.  

Figure 1 shows the assembly process steps towards the creation of the PoP.

Figure 1 Single package with copper post formed to connect to another package

The process starts with a strip of copper with a thickness of 8mils. The strip is half etched to create an opening for the die and copper posts.  The strip goes for masking, developing and stripping leaving the opening of the die paddle and copper posts for electroplating. Nickel and gold plating is performed on the exposed area without the masking. Photo resist is applied covering the plated side of the metal strip.

Next, the metal strip goes for etching. This etching step removes the thick copper layer at the bottom, leaving the Cu post and photo resist exposed from the bottom. The strip goes for polyimide tape lamination, follow by photo resist removal by chemical.

A semiconductor device or die is attached to the opening between the copper posts. Once all the dies are attached, the entire strip goe...