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Browse Prior Art Database

Self-Limited C4 Process

IP.com Disclosure Number: IPCOM000106230D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Kan, Y: AUTHOR [+4]

Abstract

Disclosed is a process to form fine pitch solder bumps on semiconductor device by electro-plating solder. The electro-plating solder is reflowed into solder balls for following flip chip bonding process. The proposed process is shown in Figure as follows:

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This is the abbreviated version, containing approximately 100% of the total text.

Self-Limited C4 Process

      Disclosed is a process to form fine pitch solder bumps on
semiconductor device  by electro-plating solder.  The electro-plating
solder is reflowed into solder  balls for following flip chip bonding
process.  The proposed process is shown in Figure as follows:

o   Depositing Pad Limited Metal(PLM) 3  blanket on semiconductor
    device 1 after protection film 2 applied.

o   Applying polyimide 4 and patterning I/O pad (Step a).

o   Electro-plating solder 5 onto I/O pad (Step b).

o   Reflowing back solder 5 to shrink pad's diameter (Step c).

o   Stripping polyimide 4 and etching out PLM 3 by using the solder
    ball 5 as the mask (Step d).

The process eliminates conventional metal mask to provide solder
ball.  This process can make fine pitch I/O products by avoiding the
restriction of the metal mask hole size limitation.