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EMI Shielding for Die Backside Exposed Flip Chip Package

IP.com Disclosure Number: IPCOM000250209D
Publication Date: 2017-Jun-12
Document File: 4 page(s) / 239K

Publishing Venue

The IP.com Prior Art Database

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 55% of the total text.

EMI Shielding for Die Backside Exposed Flip Chip Package

Background

The traditional method of heat dissipation adopted most nowadays is to install a heat spreader

and a thermal interface material on the back surface of an exposed flip-chip die in an

assembled semiconductor package in Fig. 1. But the package profile is generally more than

250 um; and thus it is still required to develop more efficient heat dissipation methods with

low package profile for portable devices.

Fig. 1The traditional method of heat dissipation in a semiconductor package

Description

The subject invention discloses a more efficient method of heat dissipation by using

deposited metal to cover the back surface of the exposed die and possibly the other outside

surfaces of the package.

The first embodiment of the package produced by the subject method is shown in Fig. 2. The

back surface of the flip-chip die is covered by ground metal; while all the outside surfaces of

the molding and both of the side surfaces of the substrate are covered by covered metal.

Without using the thermal interface material and the heat spreader in Fig. 1, the package

profile is greatly reduced, which is very beneficial to reduce the thickness of portable devices.

In addition, this embodiment has the property of electromagnetic interference (EMI)

shielding because of the electrical connection between the covered metal on the top surface of

the molding and the grounded metal on the back surface of the exposed flip-chip die.

EMI Shielding for Die Backside Exposed Flip Chip Package

Fig. 2 The first embodiment of the package produced by the subject method with the covered metal and the grounded metal

The process flow for the first embodiment is shown in Fig. 3. First, a bare substrate is

prepared; second, a flip-chip die is mounted on the top surface of the substrate; third, film

assistance molding process is performed and the back surface of the flip-chip die is exposed;

fourth, solder balls are mounted on the bottom surface of the substrate; fifth, metal is

deposited on the exposed back surface of the flip-chip die to form the grounded metal; while

metal is also deposited on all the outside surface of the molding and both of the side surfaces

of the substrate to form the covered metal.

Fig. 3 The process flow of the first embodiment

The second embodiment of the package produced by the subject method is shown in Fig. 4.

Only the exposed back surface of the flip-chip die is covered with the grounded metal and the

top surface of the molding is covered with the covered metal. Compared with the first

EMI Shielding for Die Backside Exposed Flip Chip Package

embodiment, the side surfaces of the molding and the side surfaces of the substrate are not

covered by...