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Method for encapsulant removal after die attachment for compliant interconnect silicon

IP.com Disclosure Number: IPCOM000012346D
Publication Date: 2003-Apr-30
Document File: 5 page(s) / 358K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for encapsulant removal post die attach for compliant interconnect silicon. Benefits include improved yield.

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Method for encapsulant removal after die attachment for compliant interconnect silicon

Disclosed is a method for encapsulant removal post die attach for compliant interconnect silicon. Benefits include improved yield.

Background

        � � � � � The compliant interconnection must be protected from being over-soldered to the pad and changing the compliance aspect of the bump. It must also be protected from being damaged by the conventional tape-and-reel process used to store die until it is ready for die attachment (see Figure 1).

        � � � � � Dice are placed into a carrier tape that is open at the bottom. They are supported only on the outside edge of the die. The bumps are not contacted. Lateral shifting causes damage.

        � � � � � A portion of the compliant interconnection is coated with a nickel oxide that resists wetting from the solder.

� � � � � During conventional reflow, the lead can become engulfed by the solder. Instead of riding on the top layer of solder, it sinks into the solder. When the solder solidifies during cooling, it has surrounded the lead, removing the compliance.

        � � � � � The conventional method can be implemented using the following steps (see Figure 2):

1.        � � Clean/remove the encapsulant (see Figure 3).

2.        � � Place the die in the holder (see Figure 4).
3.        � � Attach the die (see Figure 5).
4.        � � Reflow the solder.

General description

        � � � � � The disclosed method is the removal of the bump encapsulant after die attachment for compliant interconnect silicon.

        � � � � � The key elements of the method include:

•        � � � � Compliant interconnect die bumps

•        � � � � Encapsulant

•        � � � � Atta...