Browse Prior Art Database

Process to Form Decal Transfer for Organic Bridge and uBGA Rework Process

IP.com Disclosure Number: IPCOM000245407D
Publication Date: 2016-Mar-07
Document File: 2 page(s) / 24K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a process to form a decal transfer for an organic bridge and ultra fine-line Ball Grid Arrays (uBGAs) rework process. The novel solution is the creation of a quad sputter layer and a dual sputter layer onto which the method directly plates solder without an Under Bump Metallization (UBM) system.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 51% of the total text.

Page 01 of 2

Process to Form Decal Transfer for Organic Bridge and uBGA Rework Process


For Chip Scale Package (CSP)/Memory Chip Controller (MCC) rework, it is necessary to transfer solder to the ultra fine-line Ball Grid Arrays (uBGAs) after each site has been dressed following the uBGAs removal. Else, there is not enough solder to join the next CSP.

For a mixed Under Bump Metallization (UBM) system, a dual chip module, or for de-coupling capacitors between the processor and laminate, it might be necessary to add more pre-solder to the laminate in order to tailor the height of the pre-solder to obtain the correct gap or match height during chip join.

The novel solution is the creation of a quad sputter layer (e.g., Titanium (Ti) Tungsten (W)/Copper (Cu)/TiW/Cu, or a combination of metals with the same base properties) and a dual sputter layer (e.g., TiW/Cu or a combination of metals with the same base properties) onto which the method directly plates solder without a UBM.

After the resist is stripped, the top Cu (if any) is etched away. The wafer is then diced, which provides plated solder on the pattern of interest. After the decal is made as listed above, the wafer is diced.

The die are then aligned onto the laminate that will receive the transfer of the pre-solder. The die and laminate are sent through a reflow furnace so that the solder melts and dissolves the top Cu seed layer (if it is present).

For the quad layer, there is either no top Cu so that the solder is plated directly onto the TiW, or the top Cu is les...