The Shift to Copper Wire Bonding

Transcription

1 The Shift to Copper Wire Bonding E. Jan Vardaman President TechSearch International, Inc.

2 1/3/06 3/4/06 5/3/06 7/2/06 8/31/06 10/30/06 12/29/06 2/27/07 4/28/07 6/27/07 8/26/07 10/25/07 12/24/07 2/22/08 4/22/08 6/21/08 8/20/08 10/19/08 12/18/08 2/16/09 4/17/09 6/16/09 8/15/09 10/14/09 12/13/09 2/11/10 4/12/10 6/11/10 8/10/10 10/9/10 12/8/10 2/6/11 4/7/11 6/6/11 8/5/11 US$ / Troy Ounce Drivers for Cu Wire Bonding Cost, cost, and cost Gold price moved to all time high: Hit around $1,800/oz in Sept Copper: $3.81/lb Early adoption for power devices electrical and thermal properties Source: London Gold Market Fixing, Ltd.

3 QFN Assembly Price Trends Source: TechSearch International, Inc

4 Advantages of Cu WB: Reduced Intermetallic Growth Source: Renesas Electronics Corp. Slow intermetallic growth particularly beneficial for automotive applications.

5 Challenges of Cu Wire Bonding Mechanical properties: Cu hardness causes pad splash, damage to underlying structures Chemical properties: oxidation requires inert environment, interaction with mold compounds Equipment, process, material changes Capillaries Inert gas at EFO Mold compound, pad metallurgy Throughput and yield Capillary lifetime Capillary MTBA

6 Types of Copper Wire Bare Copper Pd Coated Copper Gold Cost of Material Low Higher than Cu, depends on Pd price Extremely High Cost of Wire Manufacturing Higher than Gold Much higher than Copper Low Bonding Gas Forming Gas Forming Gas or N 2 None FAB Hardness Harder than Gold Harder than bare Copper Low 1 st Bond Process Narrow window Narrower window, higher risk of cratering than bare Copper Very Robust 2 nd Bond Process Proven Successful Better than bare Copper Very Robust Reliability (Molded Pkg) Meets Requirement Same or better than bare Copper Proven Good Source: Heraeus and K&S. Organic-coated copper: sampling for N 2 or forming gas. Page 6

7 Factors in Copper HAST Reliability Source: Hitachi Chemical

8 Low end: Markets for Cu Wire Bonding Low lead counts Larger wire diameters (>25μm) Bare Cu wire Leadframe packages QFN, QFP, SO Mid-range: Lead counts to 600 or above Wire diameters down to 18μm in production Pd-coated Cu wire BGA packages High-end, stacked die, DRAM Typically still gold

9 Market Adoption Major contract assembly houses are increasing purchases of copper wire bonders SEMI survey reports 72% of companies are considering switching new products to copper wire Amkor in production for 5 years, with > 60 customers and nearly 300 devices including 65 and 45nm low-k, leadframe and laminate ASE continues major push to Cu wire Japanese companies starting to adopt Cu wire. Fujitsu needs to confirm manufacturing throughput and stable bond quality Some companies are still calculating the total cost of the conversion of Cu, and conversion will depend on additional silicon cost as well as the cost of re-qualification

10 Growth in Copper Wire Bonding Cu wire bond shipments increased from 1.6% of all wire shipments in 2007 to 5.8% of shipments in 2009 K&S projected Cu wire would be 10% of total wire shipments in Tanaka Denshi Kogyo reports sales of copper bonding wire in the first half of 2010 were 9 times the volume in the first half of 2008 Heraeus is engaged with almost every IC assembly house for copper conversion. This shift [to copper] is showing no signs of slowing down.

11 ASE Cu Wire Bond Shipments Shipments by Packaging Revenue Shipments by Packaging Application SO 5% FBGA 14% Networkin g 4% Memory 5% QFN 31% PBGA 24% Communic ation 27% Comsumer 48% QFP 26% Computer 16% Source: ASE

12 ASE Cu Wire Bond Shipments 0.18um 18% Shipments by node >0.25um 13% 45nm 2% 65um 10% 90nm 25% 0.9mil 11% Shipments by wire diameter 1.0mil 18% 1.2mil 2% >1.5mil 1% 0.7mil 17% 0.13um 32% 0.8mil 51% Source: ASE

13 Conclusions Data from assemblers show leadframe packages, specifically QFPs, were implemented in Cu first Some companies project 30 to 50% of all their packages will use Cu wire by the end of 2011 Gold wire expected to remain in legacy products and automotive packages, stacked die Companies developing solutions to improve yield and qualify Cu instead of Au Movement to Cu wire bond will continue

14 Thank you for your attention!