Browse Prior Art Database

Stud Bump Pin Interconnect Via Flex Through Hole Flip Chip Package

IP.com Disclosure Number: IPCOM000011427D
Publication Date: 2003-Feb-19
Document File: 2 page(s) / 49K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a stud-bumped die with wire “tails” to form the interconnect pin. The flex substrates with plated through holes mirror the bump layout, rather than mirroring the substrate bump pads. Benefits include finer bump/pad pitch and reduced z-height.

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 99% of the total text.

Stud Bump Pin Interconnect Via Flex Through Hole Flip Chip Package

Disclosed is a method for a stud-bumped die with wire “tails” to form the interconnect pin. The flex substrates with plated through holes mirror the bump layout, rather than mirroring the substrate bump pads. Benefits include finer bump/pad pitch and reduced z-height.

Background

Currently, z-height is reduced by the following:

 

  1. Die thinning; however, there is limited capability for this on a Flip Chip die
  2. Use of a thinner core to reduce substrate thickness
  3. Use of eutectic bumps to eliminate the need for a bumping substrate

General Description

The following are the steps required for the disclosed method:

 

  1. The flip chip die are stud bumped.
  2. Solder or conductive paste is printed onto the flex substrates with PTH lands.
  3. The die are pick and placed onto the substrate.
  4. The unit is reflown or cured depending upon the use of the solder or conductive paste.

Figure 1 shows the steps of the disclosed method, and Figure 2 shows the completed unit.

Advantages

The following are advantages of the disclosed method:

 

  • Reduces 2-4 mil of z-height, depending on design
  • Reduction of material interfaces reduces possibility of process errors and marginal material compatibility, thus improving reliability.
  • Reducing bump pitch allows for a reduction of die size or increased I/O count.
  • A direct/straight line joint from die bump to the substrate ball enables high-speed interconnects.

 
 

Stud Bumped Die

 
 

       
   
 
   

Paste Squeegee

 
 

Fig. 1

Fig. 2

Disclo...