Targets for 300 mm Wafer Applications – "300mm Targets"

Introduction

The transition to 300 mm wafers is proceeding in earnest. It is driven by the proven improvement in productivity and the decrease in manufacturing costs by 25-40% and offers IC producers output capacity improvements of 2.0 to 2.5 times that of a 200mm wafer fab.

TODAY, MRC targets are fully QUALIFIED and are being successfully utilized in PRODUCTION in the world’s first functional 300 mm wafer fab. As more and more major producers bring on-line pilot and production fabs, MRC is providing state of the art sputtering target materials and designs. The transition to 300 mm poses new challenges to the target producer and MRC has proved that it can meet these opportunities. These targets are significantly larger than previous generations, requiring proper material selection for mechanical stability to minimize or eliminate bow and deflection. In addition such target assemblies have to maintain the target metallurgy to the same consistency and reproducibility as previously established with targets for 200 mm wafer applications.

MRC has had active programs aimed at producing these new target designs since 1997. Even before OEM designs were finalized, our engineers worked on assuring that MRC ‘s technology was easily transferred to the 300 mm designs. At the early stages, prototypes were produced demonstrating that our CCH™ technology could be applied to these larger target blanks to assure that fine grained microstructures with controlled crystallographic texture could be maintained. Our unique bonding technology, IntegraBond™ for high recryallization target materials (e.g., Ti and Ta) and MightyBond™ for target materials that recrystallize at low temperatures (e.g., Al and Cu ) has been proven to be successful for these new designs.


MRC’s first prototype 300 mm titanium target produced in 1997.

Since 1996 MRC has made investments in equipment at each of its three manufacturing sites to allow it to manufacture targets for 300 mm sputtering systems. This has included CNC mills, presses, furnaces, cutting technologies and bonding facilities. These tools are all capable of handing the current range of targets for the 200 mm fabs while enabling MRC to continue to meet the requirements of the future 300 mm generation of sputtering tools.

Target Materials For 300 mm Wafer Applications

Working with leading OEMs such as Applied Materials, Novellus, Anelva, Ulvac, TEL and others has enabled MRC to develop 300 mm target designs. Target designs utilizing MRC’s experience in engineered metallurgy and backing plate material selection has enabled the successful evolution of 300 mm target assemblies.

Materials and designs currently available from MRC include :

Applied Materials ALPS
SIP
 
Novellus Q300
HCM
Al alloys and Ti
Cu and Ta
Anelva
Ulvac
1201
Cosmos
 
TEL iPVD  

 

Backing Plate Material Selection

Finite Element Analysis(FEA) is routinely conducted to evaluate the degrees of bow and deflection for new target designs. Today, the selection of such commercial alloys as Cu-1%Cu and Al 6061 as well as many others and are being evaluated for applications with 300 mm target designs. Not only are the mechanical properties considered but their response to high electric field is key to their proper selection.

 

 

   

Targets

   

Copper

Tantalum

Backing Plate Material

Surface Temp. (oC)

Max. Deflect. (mm)

Max. Deflect. (mm)

Cu-1.0Cr

100

0.75

0.38

200

1.32

0.60

Al 6061-T6

100

1.06

0.52

200

1.87

0.82

Cu

100

0.78

0.42

200

1.37

0.62

 

Target Microstructures

The CCH process technology that is applied to MRC target materials assures controlled, consistent microstructures to yield the highest possible performance. Based upon more than a decade of development work, structures are tuned to the exacting applications required for the next generation of devices.

Material

Grain Structures

Texture

Al

<50 m m

Random, weak (100)

Ti

<10 m m

Mild (1013)

Cu

<50 m m

Random

Ta

30 to 60 m m

Random

 

From many years of experience with data storage Co-based media alloys, it has been identified that the key factor for cobalt is its magnetic properties. The lowest possible permeability or the highest possible magnetic leakage flux, MLF, (commonly referred to as the pass through flux or PTF) allows for thicker longer lasting targets.

 

Permeability

Magnetic Leakage Flux

Co

7.5 to 9.0

> 250 Gauss

 

Bonding Technology

MRC’s patented IntegraBond technology assures high strength metallurgical bonding for metal and alloy targets that recystallize at high temperatures. A diffusion bonding process which provides a sharp interface enables targets to be embedded into backing plates in order to extend target lives well beyond standard designs. As 300 mm wafer fabs enter into full production and cost of ownership becomes a critical parameter, the processes proven to so successful for smaller formats will prove equally beneficial on the larger 300 mm targets.

In applications utilizing copper or aluminum alloys, MRC’s rapid thermal MightyBond technology maintains the fine grain CCH structures while developing a high strength metallurgical bond.

Summary

With production proven CCH thermo-mechanical technologies, manufacturing facilities properly equipped and with the sales and service organization to support you, MRC is ready to supply all target designs for 300 mm applications. On-going programs and associations with OEM suppliers allows us to meet all new design concepts in a timely manner. MRC engineering is well equipped to provide design improvements through material selection and modeling to predict target performance. As 300 mm fabs go into full production, MRC’s REAliTY™ program of enhancing existing target designs is easily applied to the new 300 mm family of targets promoting further decreases in CoO.