Browse Prior Art Database

A Solder Resist Trench that Increases Underfill Underneath the Die While Restricting the Flow of Underfill to the Corners of the Die

IP.com Disclosure Number: IPCOM000010419D
Publication Date: 2002-Nov-27
Document File: 2 page(s) / 58K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that controls the flow of underfill by directing it underneath the die, and also by inhibiting it on the solder resist surface. Benefits include an increased amount of underfill flowing underneath the die, and reduced mechanical stresses between the cured underfill and the die corners.

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A Solder Resist Trench that Increases Underfill Underneath the Die While Restricting the Flow of Underfill to the Corners of the Die

Disclosed is a method that controls the flow of underfill by directing it underneath the die, and also by inhibiting it on the solder resist surface.� Benefits include an increased amount of underfill flowing underneath the die, and reduced mechanical stresses between the cured underfill and the die corners.

Background

Currently, excessive underfill material accumulates at the corners of the die; also, electrical opens are induced by substrate cracks initiated at the die corner between the fillet and the underfill interface; these are caused by the underfill material wicking up at the die corner.

General Description

The disclosed method uses solder resist trenches to prevent underfill flow into the passive component region of the substrate (see Figure 1). The solder resist trench directs the underfill flow in two ways (see Figure 2):

  • It controls the underfill in a specific area, improving direction of underfill flow to underneath the die
  • It inhibits underfill flow to the corners of the die from the original dispense location

Underfill coverage under the die corners occurs from underfill flow underneath the die and not from the original dispense location.

Advantages

The following are advantages of the disclosed method:

 

  • Ability to use the existing material set and manufacturing process on large die substrates
  • Ability to manipulate underfill flo...