ASE Kaohsiung

Wafer Bumping

Solder Bumping
Gold Bumping
12" Bumping
Ultra CSP

Product Overview

Wafer Bumping Service

ASE’s wafer bumping service currently provides printed eutectic (63Sn/37Pb), high lead (90/10), low alpha (< 0.02 cph/cm2) eutectic solder bumping on 6” and 8” silicon wafers. The capacity will be 30000 pcs/month by the end of 2001. The fine-pitch capability of printed eutectic solder bumping is 160um for area array and 150um for peripheral type of devices.

To improve joint reliability and process yield of the wafer bumping on very fine peripheral bond pad, the redistribution process is needed. Redistribution technology, which allows the re-layout of the interconnection from the locations of peripheral bond pads to new area pad array without changing the die design. This method widens the very fine pad pitch, and allows wider under bump metallurgy (UBM) for larger bumps. The advantages are extended thermal cycle fatigue life, better underfill flow, and greater tolerance of board flatness variation. ASE’s redistribution process will be in service by 2001 Q3.

Other bumping processes, like the electroplated Au bumping which are targeted at the LCD drivers by tape automated bonding (TAB) or tape carrier package (TCP), will be ready in 2001 Q3.

Packaging Capability

Wafer Bumping Outgoing Criteria

FC-CSP (Flip Chip Chip Scale Package) offers chip scale capability for I/Os of 200 and less. FC-CSP provides better protection for chip and better solder joint reliability compared with direct chip attach (DCA) or chip on board (COB). FC-CSP is more superior to known good die (KGD) in low-cost test and burn-in, and performs comparable electrical function with KGD. FC-CSP features thin and small profile, and lightweight packages.

Applications include RFICs and memory ICs. ASE provides packaging service for any customer-designed size at ball pitches ranging from 0.5 to 1.0mm, and no. of I/Os from 16 to 200. The types of encapsulation are underfill and overmold.

Ceramic FC-BGA/PGA - Ceramic substrate offers better moisture resistance, electrical insulating property and higher thermal conductivity than organic substrate. High Pb solder ball with eutectic solder paste improves board level reliability performance of ceramic packages.

FC-BGA & High performance FC-BGA (HFC-BGA) - These two packages cater to I/Os of 100 to over 1500 with BT laminate or sophisticated multi-layer build-up substrates. HFC-BGA is thermally enhanced through adding a metal stiffener and heat spreader on the substrate. This method can effectively remove the heat and improve the thermal performance.

Complete Flip Chip Solutions

Test item	Condition	Sample size	Criteria
Bump height	Optical Microscope (500X) or Bump Height Scanner	25bumps/wafer 5 wafers/lotX3	Bump height?5um
Shear strength	Blade 25 um height & Shear speed 175 um/sec	5 bumps/wafer 5 wafers/lotX3	> 2g / (mil² of UBM area)
Void detection	X-ray Photography	250 bumps/wafer 2 wafers/lotX3	All voids must be 30% smaller than bump diameter for eutectic solder bump
Final inspection	Automatic Inspection Tool & Microscope (50X)	100%inspection (August tool) Manual Sample Inspection	Following ASE Workmanship Standard