WO1999063128A1

WO1999063128A1 - Contoured sputtering target

Info

Publication number: WO1999063128A1
Application number: PCT/US1999/011604
Authority: WO
Inventors: Paul S. Gilman; Tetsuya Kojima; Chi-Fung Lo; Eiichi Shimizu; Hidemasa Tamura; Norio Yokoyama
Original assignee: Praxair S.T. Technology, Inc.
Priority date: 1998-06-01
Filing date: 1999-05-26
Publication date: 1999-12-09
Also published as: KR100761592B1; US6086735A; JP3979787B2; EP1092050B1; DE69926634D1; AU4314399A; EP1092050A1; KR20010043955A; EP1092050A4; DE69926634T2; JP2002517610A

Abstract

A countoured sputtering target (10) includes a target member (12, 112) of sputtering material having a top surface (18, 118), a bottom surface (20, 120) and an outer peripheral surface (22, 122). One or more contoured annular regions (24, 124, 224) are formed on the top surface (18, 118) of the target member (12, 112) that extend radially inwardly from the outer peripheral surface (22, 122) and away from the bottom surface (20, 120). The target member may further include planar, concave (34, 134) or central recessed regions (38, 138) formed in the top surface (18, 118) that are surrounded by the one or more contoured annular regions (24, 124, 224). The configuration of the target member (12, 112) reduces generation of contaminating particles from nodules that may form near the outer peripheral surface (22, 122) of the target during a sputtering operation. Methods of forming a contoured sputtering target are also disclosed.

Description

CONTOURED SPUTTERING TARGET

Field of the Invention

The present invention relates generally to sputtering

systems and, more particularly, to sputtering targets for use in

processing a substrate or wafer in a sputtering system.

Background of the Invention

Sputter coating refers to a process for coating a

substrate, such as a semiconductor wafer, within a vacuum

processing chamber of a sputtering system. In the sputter coating

process, an applied electric field positively biases the wafer relative

to an oppositely mounted, negatively biased target made of

sputtering material. Once the processing chamber is evacuated, an

inert gas is introduced into the chamber at a low pressure, and the

applied electric field ionizes the process gas. As a result, positive

ions from the gas bombard the target to cause sputtering of the

target material onto the wafer in a thin film. A magnet or electro agnet may be located behind the target to provide a

magnetic field above the surface of the target facing the wafer to

confine the ion "plasma" adjacent the target, and thereby enhance

the sputter coating operation.

Sputtering targets are typically formed as a generally

circular disk of target material, such as aluminum alloys, gold, silver,

copper, titanium, titanium-tungsten or platinum. The disk of target

material may be soldered or otherwise bonded to a supporting

target backplate to form a replaceable sputtering target assembly.

During the sputtering operation, material is sputtered from the top

surface of the target and deposited on the wafer. The sputtering

material typically erodes unevenly across the width or face of the

target exposed to the wafer, with some areas of the target eroding

more quickly than other areas.

To overcome this problem, some sputtering equipment

employs a variation of the magnetic field, or multiple, non-planar

erosion zones on the target, or both, to create a generally uniform

sputtering rate across the face of the target. Typically, the outer

radial region of the target has been made thicker than the central

region of the target. The target may include a concave region

formed in the target face or even a hole formed through the center of the target. Sputtering material is eroded from the target until the

target is no longer able to provide the desired coating features on

the wafer. At that time, the target assembly, consisting of the

eroded target and backplate, is replaced by a new target assembly.

In titanium nitride (TiN) sputtering, for example, a

titanium sputtering target and backplate assembly is mounted in the

vacuum processing chamber with exposed surface of the target

facing a wafer. The vacuum chamber is evacuated, and then filled

with nitrogen gas that ionizes in the presence of the applied electric

field. Positive ions from the plasma process gas bombard the top

surface of the target and cause titanium particles to be sputtered

toward the wafer. During the sputtering process, the titanium

particles chemically react with the nitrogen process gas to form a

thin film of titanium nitride on the wafer surface.

An important aspect in sputter coating of wafers is the

purity of the film deposited onto the wafer. As the amount of

contaminants within the sputter processing chamber increases, the

wafer product yield decreases as impurities are formed on the

wafer. For example, in titanium nitride sputtering, TiN nodules are

known to form on the sputtering face of the target as material from

the central portion of the target is sputtered and redeposited on the outer peripheral edge of the target face rather than on the wafer.

During the sputtering operation, the TiN nodules have a tendency to

flake and generate contaminating particles that adversely affect the

purity of the deposited titanium nitride film on the wafer. Since TiN

particle generation becomes worse with increasing use of the target,

the target must be periodically conditioned to maintain an

acceptable device yield.

Target conditioning is achieved by conducting

titanium-only sputtering on non-product substrates. The titanium-

only sputtering causes the TiN nodules held on the target to be

released and deposited on the non-product substrates. While the

periodic conditioning prolongs the usable life of the target by

removing the contaminating TiN nodules, it requires stoppage of the

wafer coating production line and results in downtime of the

sputtering system. Thus, notwithstanding known contouring of

sputtering targets and modifications to operation of sputtering

systems, nodule formation on targets has been a problem,

particularly in titanium nitride sputter deposition.

In the past, one-piece sputtering targets have been

made that include steep-angled bevels formed adjacent the outer

edge of the target to reduce redeposition of TiN particles near the outer surface of the target. In U.S. Patent No. 5,538,603, for

example, bevels are formed adjacent the outer edge of the target

that taper at an angle of at least 30° with respect to the planar face

of the target, and preferably at a greater angle, i.e., 70°, such that

the trajectory of the backscattered atoms will cause the atoms to

miss the outer surface of the target altogether. The steep angles of

the bevels are also chosen to reduce the thickness of the target

adjacent its outer peripheral edge to increase the sputter deposition

rate near the tapered target edge. Thus, backscattered TiN particles

that collide and redeposit on the target are more likely to be

resputtered onto the wafer or substrate. However, the steep

tapered targets are single-piece targets that do not encounter the

same TiN nodule formation problems associated with sputtering

targets mounted to a target backplate.

Accordingly, there is a need for a sputtering target and

backplate assembly that reduces generation of contaminating

particles from nodules that may form during a sputtering operation.

There is also a need for a sputtering target and backplate assembly

that requires less periodic conditioning during the life of the target,

thereby resulting in less system downtime and a reduction in

preventative maintenance. Summarv of the Invention

The present invention overcomes the foregoing and

other shortcomings and drawbacks of the sputtering targets

heretofore known. While the invention will be described in

connection with certain embodiments, it will be understood that the

invention is not limited to these embodiments. On the contrary, the

invention includes all alternatives, modifications and equivalents as

may be included within the spirit and scope of the present

invention.

In accordance with the principles of the present

invention, a contoured sputtering target is provided that includes a

target member of sputtering material having a top surface or face

designed to be exposed to, and confront, the wafer or substrate

being coated, a planar bottom surface typically bonded or otherwise

joined to a conventional target backplate, and an outer peripheral

surface. During a sputtering operation in a processing chamber,

sputtered material is ejected from the top surface of the target

member and deposited on the substrate in a thin coating or film.

In one embodiment of the present invention, the target

member has a contoured annular region formed on the top surface

that extends radially inwardly a predetermined distance from the outer peripheral surface and away from the bottom surface. The

contoured annular region may include a planar surface, or a

radiused surface that extends radially inwardly and away from the

bottom surface. The target member may further include a planar,

concave or central recessed region formed in the top surface of the

target that is surrounded by the contoured annular region.

In an alternative embodiment of the present invention,

at least two contoured annular regions may be formed on the top

surface of the target member. One of the contoured annular

regions is formed radially inwardly from the other contoured

annular region. One, or both, of the contoured annular regions may

include a planar surface or a radiused surface that extends radially

inwardly and away from the bottom surface. The target member

may further include a planar, concave or central recessed region

formed in the top surface of the target that is surrounded by the

contoured annular regions.

The shape or profile of the contoured annular regions

on the target member is particularly advantageous to reduce

accumulation of redeposition at the target edge. Additionally, the

contoured sputtering target of the present invention is particularly

profiled to reduce the sputtering or erosion rate of the target member near the outer peripheral surface. As nodules (not shown)

form at or near the outer peripheral surface during a sputtering

operation, the lower plasma intensity existing near the formed

annular regions on the target, and the reduced sputtering rate

created by the profile of the target, prevents the nodules from

flaking or resputtering during a sputtering operation. The contoured

annular regions formed on the target member advantageously

stabilize the nodules that may form on the target member to

significantly reduce resputtering or flaking of the nodules during a

sputtering operation.

The contoured sputtering target of the present

invention therefore reduces accumulation of nodules during a

sputtering operation, and further reduces generation of

contaminating particles from any nodules that may form during the

sputtering operation. The contoured sputtering target of the

present invention also requires less periodic conditioning during the

life of the target, thereby resulting in less system downtime and a

reduction in preventative maintenance.

The above features and advantages of the present

invention will be better understood with reference to the

accompanying figures and detailed description. Brief Description of the Drawings

The accompanying drawings, which are incorporated

in and constitute a part of this specification, illustrate embodiments

of the invention and, together with a general description of the

invention given above, and the detailed description of the

embodiments given below, serve to explain the principles of the

present invention.

Fig. 1 is cross-sectional view along a diameter of a

sputtering target in accordance with one embodiment of the

present invention;

Fig. 1 A is an enlarged view of the encircled area of Fig.

1;

Fig. 1 B is a view similar to Fig. 1A showing an

alternative embodiment of the present invention;

Fig. 2 is a top plan view of the sputtering target shown

in Fig. 1 ;

Fig. 3 is a view similar to Fig. 1 , illustrating a sputtering

target in accordance with a second embodiment of the present

invention;

Fig. 3A is an enlarged view of the encircled area shown

in Fig. 3; Fig. 3B is a view similar to Fig. 3A showing an

alternative embodiment of the present invention;

Fig. 4 is a top plan view of the sputtering target shown

in Fig. 3;

Fig. 5 is a view similar to Fig. 1 , illustrating a sputtering

target in accordance with a third embodiment of the present

invention;

Fig. 5A is an enlarged view of the encircled area shown

in Fig. 5;

Fig. 5B is a view similar to Fig. 5A showing an

alternative embodiment of the present invention;

Fig. 5C is a view similar to Fig. 5A showing yet another

alternative embodiment of the present invention;

Fig. 6 is a top plan view of the sputtering target shown

in Fig. 5;

Fig. 7 is a view similar to Fig. 1, illustrating a sputtering

target in accordance with a fourth embodiment of the present

invention; and

Fig. 8 is a top plan view of the sputtering target shown

in Fig. 7. Detailed Description of the Invention

With reference to the figures, and to Fig. 1 in particular,

a contoured sputtering target assembly 10 in accordance with one

embodiment of the present invention is shown. Sputtering target

assembly 10 includes a target member 12 of sputtering material that

may be soldered or otherwise joined to a target backplate 14 for use

in a sputtering system (not shown). As those skilled in the art will

appreciate, sputtering target assembly 10 is mounted within a

vacuum processing chamber (not shown) of the sputtering system

(not shown) through fasteners (not shown) and a centrally threaded

shaft 16. The sputtering system (not shown) may be of the type

shown in U.S. Patent Nos. 4,909,695 and 5,130,005, both assigned

to the assignee of the present invention, which are expressly

incorporated herein by reference in their entirety.

Target member 12 may be formed as a generally

circular disk of sputtering material, including, but not limited to,

titanium, titanium-tungsten, platinum, aluminum alloys, gold, silver,

copper or refractory metal suicides. The diameter of target member

12 will vary, typically between ten and fourteen inches depending

on the size of the wafer to be sputtered. For example, a ten inch

diameter target may be used to sputter coat a six inch diameter wafer, while a twelve inch target may be used to sputter coat an

eight inch wafer. While target member 12 will be described in detail

herein as a circular disk with a diameter of about ten inches, it will

be appreciated by those skilled in the art that other configurations

and sizes of target member 12 are possible without departing from

the spirit and scope of the present invention.

As best understood with reference to Figs. 1 and 2,

target member 12 has a precisely machined face or top surface 18,

a planar bottom surface 20, and an outer peripheral surface 22.

Preferably, as shown in the figures, the outer peripheral surface 22

is formed generally perpendicularly to the planar bottom surface 20.

During a sputtering operation, target member 12 is mounted within

the sputtering process chamber (not shown) with the top surface 18

of the target 12 facing the wafer (not shown). Sputtering material is

caused to be ejected from the top surface 18 of target member 12

and deposited onto the wafer (not shown) in a thin film as is well

known in the art.

In accordance with one embodiment of the present

invention, as best understood with reference to Figs. 1 , 1A and 2,

target member 12 is contoured to reduce generation of

contaminating particles from nodules (not shown) that may form near the outer peripheral surface 22 of the target during a sputtering

operation. Top surface 18 of target member 12 is formed with a

contoured annular region 24 that extends radially inwardly from the

outer peripheral surface 22 and away from the bottom surface 20.

For a ten inch diameter target, for example, the contoured annular

region 24 may extend to an annular boundary 26 that lies radially

inwardly from the outer peripheral surface 22 in a range between

about 0.195 in. and about 0.975 in.

The profile of contoured annular region 24 is

particularly chosen to reduce accumulation of redeposition at or

near the outer peripheral surface 22. The profile of contoured

annular region 24 is also chosen to reduce the sputtering or erosion

rate of target member 12 near the outer peripheral surface 22.

Thus, as nodules (not shown) form at or near that location, the

reduced sputtering rate created by the profile of target member 12

and lower plasma intensity existing near the outer peripheral

surface 22 stabilizes the nodules (not shown) and prevents them

from flaking and generating contaminating particles within the

processing chamber (not shown) that may adversely affect the

sputtered film on the substrate or wafer (not shown). While the

contour of target member 12 reduces generation of contaminating particles from nodules that may form on target member 12,

particularly in titanium nitride sputtering processes, those skilled in

the art will appreciate that the present invention is applicable to

other sputtering processes as well without departing from the spirit

and scope of the present invention.

The contoured annular region 24 is inclined from the

outer peripheral surface 22 to the radially inward annular boundary

26. The contoured annular region 24 may be inclined at an angle

"a" (Fig. 1A) in a range between about 5° and about 20° relative to a

plane 28 (Fig. 1A) that is parallel to the planar bottom surface 20 of

the target. In one embodiment of the present invention, contoured

annular region 24 may include a planar surface 28 (Figs. 1, 1A and

2). Alternatively, as shown in Fig. 1 B, the contoured annular region

24 may include a radiused surface 32 that extends radially inwardly

from the outer peripheral surface 22 to the annular boundary 26 and

away from the bottom surface 20 of the target 12. In either

embodiment of the contoured annual region 24 as shown in Figs.

1 A and 1 B, the configuration of target member 12 reduces

generation of contaminating particles from nodules that may form

near the outer peripheral surface 22 during a sputtering operation. In accordance with the principles of the present

invention, target member 12 may include a planar region (not

shown) formed on the top surface 18 that is surrounded by the

contoured annular region 24. The planar region (not shown) is

formed generally parallel to the planar bottom surface 20 of target

12. In another embodiment of the present invention, as best

understood with reference to Figs. 1 and 2, the target member 12

may include a substantially concave region 34 formed in the top

surface 18 that is surrounded by the contoured annular region 24.

The circumferential edge of the concave region 34 may be

coincident with the annular boundary 26.

In yet another embodiment of the present invention, as

best understood with reference to Figs. 5, 5A, 5B, 5C and 6, the

target member 12 may include a planar region 36 formed in the top

surface 18 that is surrounded by the annular region 24. The planar

region 36 is generally parallel to the planar bottom surface 20 of the

target. The planar region 36 includes a central recessed region 38

formed in the top surface 18 that reduces the thickness of the target

member 12 between the planar region 36 and the bottom surface 20

of the target 12 by about 5% to about 20%. For a ten inch diameter target, for example, central

recessed region 38 is preferably formed in the about 0.195 in. to

about 3.10" central portion of the top surface 18. As best

understood with reference to Figs. 5 and 5A, the central recessed

region 38 may include a 45° step 40 that extends from the planar

region 36 to a recessed planar region 42 formed in the top surface

18. Alternatively, the step transition from the planar region 36 to the

recessed planar region 42 may be formed as a 90° step 44 (Fig. 5B)

or a radiused step 46 (Fig. 5C). The formation of concave region 34

of Figs. 1 and 2, and the central recessed regions 38 of Figs. 5, 5A,

5B, 5C and 6, in combination with the contoured annular region 24,

further reduce generation of contaminating particles from nodules

that may form near the outer peripheral surface 22 of the target 12

during a sputtering operation.

With reference now to Figs. 3, 3A, 3B and 4, an

alternative embodiment of target member 12 is shown, designated

target member 112. Target member 112 has a face or top surface

118, a planar bottom surface 120, and an outer peripheral surface

122 that preferably extends perpendicularly to planar bottom

surface 120. As best understood with reference to Figs. 3 and 4, top

surface 118 of target member 112 is formed with a first contoured

annular region 124 that extends radially inwardly from the outer

peripheral surface 122 and away from the bottom surface 120. For a

ten inch diameter target, for example, the contoured annular region

124 may extend to an annular boundary 126 that lies radially

inwardly from the outer peripheral surface 122 in a range between

about 0.0195 in. and about 0.195 in.

In this embodiment of the present invention, top

surface 118 of target member 112 is also formed with a second

contoured annular region 224 that extends radially inwardly from

the first annular region 124 and away from the bottom surface 120.

For a ten inch diameter target, for example, the second contoured

annular region 224 may extend to an annular boundary 226 that lies

radially inwardly from the annular boundary 126 in a range between

about 0.1755 in. and about 0.995 in.

The contoured annular region 124 is inclined at an

angle "β" (Fig. 3A) in a range between about 30° and about 60°

relative to a plane 128 (Fig. 3A) that is parallel to the planar bottom

surface 120 of the target. In one embodiment of the present

invention, contoured annular region 124 includes a planar surface 130 (Figs. 3 and 3A) that is inclined from the outer peripheral

surface 122 to the radially inward annular boundary 126.

Alternatively, as shown in Fig. 3B, the contoured annular region 124

may include a radiused surface 132 that extends radially inwardly

from the outer peripheral surface 122 to the annular boundary 126

and away from the bottom surface 120.

The contoured annular region 224 is inclined at an

angle " " (Fig. 3A) in a range between about 5° and about 20°

relative to a plane 228 (Fig. 3A) that is parallel to the planar bottom

surface 120 of target 112. In one embodiment of the present

invention, contoured annular region 224 may include a planar

surface 230 (Figs. 3 and 4) that is inclined from the contoured

annular region 124 to the radially inward annular boundary 226.

Alternatively, the contoured annular region 224 may include a

radiused surface (not shown) that extends radially inwardly from the

annular boundary 126 to the annular boundary 226 and away from

the bottom surface 120. In each embodiment of the contoured

annual regions 124 and 224 as shown in Figs. 3A and 3B, the

configuration of target member 112 reduces generation of

contaminating particles from nodules that may form near the outer peripheral surface 122 of the target 112 during a sputtering

operation.

In accordance with the principles of the present

invention, target member 112 may include a planar region (not

shown) formed on the top surface 118 that is surrounded by the

annular regions 124 and 224. The planar region (not shown) is

formed generally parallel to the bottom surface 120. In another

embodiment of the present invention, as best understood with

reference to Figs. 3 and 4, the target member 1 12 may include a

substantially concave region 134 formed in the top surface 118 that

is surrounded by the annular regions 124 and 224. In yet another

embodiment of the present invention, as best understood with

reference to Figs. 7 and 8, the target member 112 may include a

planar region 136 formed in the top surface 118 that is surrounded

by the annular regions 124 and 224. Planar region 136 is formed

generally parallel to the bottom surface 120. The planar region 136

includes a central recessed region 138 formed in the top surface 118

that is similar to the central recess region 38 described in detail

above with reference to Figs. 5, 5A, 5B and 5C.

As best understood with reference to Fig. 7, the

central recessed region 138 may include a 45° step 140 that extends from the planar region 136 to a recessed planar region 142 formed

in the top surface 118. Alternatively, the step transition from the

planar region 136 to the recessed planar region 142 may be formed

as a 90° step (not shown) or a radiused step (not shown) as

described in detail above with reference to Figs. 5B and 5C. The

formation of the concave region 134 of Figs. 3 and 4, and the

central recessed regions 138 of Figs. 7 and 8, further reduce

generation of contaminating particles from nodules that may form

near the outer peripheral surface 122 of the target 112 during a

sputtering operation.

From the above disclosure of the general principles of

the present invention and the preceding detailed description of

preferred embodiments, those skilled in the art will readily

comprehend the various modifications to which the present

invention is susceptible. For example, the central recessed regions

38 and 138 may be replaced with central holes (not shown)

extending through the thickness of the target member. Moreover, it

will be appreciated that for sputtering targets of greater or lesser

diameter than the ten inch diameter target member 12 discussed

herein, the dimensions set forth above with respect to the radially

inward extent of contoured annular regions 24, 124 and 224 will be increased or decreased proportionally. The invention in its broader

aspects is therefore not limited to the specific details and illustrative

example shown and described. Accordingly, departures may be

made from such details without departing from the spirit or scope of

Applicants' general inventive concept. Therefore, Applicants desire

to be limited only by the scope of the following claims and

equivalents thereof:

Having described the invention, WE CLAIM:

Claims

1. A contoured sputtering target (10) for processing a

substrate in a sputtering system, comprising:

a target backplate (14);

a target member (12) of sputtering material mounted to

said backplate (14) and having a top surface (18), a bottom surface

(20) and an outer peripheral surface (22), said sputtering material

being ejected from said top surface (18) and onto the substrate

during a sputtering operation,

said target member (12) including a contoured annular

region formed (24) on said top surface (18) extending radially

inwardly a predetermined distance from said outer peripheral

surface (22) and away from said bottom surface (20) at an angle in a

range between about 5┬░ and about 20┬░ relative to a plane parallel to

said bottom surface (20) whereby said target member (12 ) has a

configuration that reduces generation of contaminating particles

during the sputtering operation.

2. The sputtering target (10) of claim 1 wherein said

target member (12) includes a substantially concave region (34)

formed in said top surface (18) surrounded by said contoured

annular region (24).

3. The sputtering target (10) of claim 1 wherein said

target member (12) includes a central recessed region (38) formed

in said top surface (18) surrounded by said contoured annular

region (24).

4. The sputtering target (10) of claim 1 wherein said

target member (12) includes a planar region (36) formed on said top

surface (18) surrounded by said contoured annular region (24).

5. The sputtering target (10) of claim 1 wherein said

contoured annular region (24) has a planar surface (28).

6. The sputtering target (10) of claim 1 wherein said

contoured annular region (24) has a radiused surface (32).

7. The sputtering target (10) of claim 1 wherein said

contoured annular region (24) extends radially inwardly from said

outer peripheral surface (22) in a range between about 0.195 in. and

about 0.975 in.

8. The sputtering target (10) of claim 1 wherein said outer

peripheral surface (22) is substantially perpendicular to said bottom

surface (20).

9. A contoured sputtering target (10) for processing a

substrate in a sputtering system, comprising:

a target backplate (14);

a target member (112) of sputtering material mounted

to said backplate (14) and having a top surface (118), a bottom

surface (12) and an outer peripheral surface (122), said sputtering

material being ejected from said top surface (118) and onto the

substrate during a sputtering operation,

said target member (112) including a first contoured

annular region (124) formed on said top surface (118) extending

radially inwardly a predetermined distance from said outer

peripheral surface (122) and away from said bottom surface (120) at

an angle in a range between about 30┬░ and about 60┬░ relative to a

plane parallel to said bottom surface (120),

said target member (112) further including a second

contoured annular region (224) formed on said top surface (118)

extending radially inwardly a predetermined distance from said first

annular region (124) and away from said bottom surface (120) at an

angle in a range between about 5┬░ and about 20┬░ relative to a plane

parallel to said bottom surface (120) whereby said target member (112) has a configuration that reduces generation of contaminating

particles during the sputtering operation.

10. The sputtering target (10) of claim 9 wherein said

target member (112) includes a substantially concave region (134)

formed in said top surface (118) surrounded by said first and second

contoured annular regions (124, 224).

1 1. The sputtering target (10) of claim 9 wherein said

target member (112) includes a central recessed region (138)

formed in said top surface (118) surrounded by said first and second

contoured annular regions (124, 224).

12. The sputtering target (10) of claim 9 wherein said

target member (112) includes a planar region (136) formed on said

top surface (118) surrounded by said first and second contoured

annular regions (124, 224).

13. The sputtering target (10) of claim 9 wherein said first

contoured annular region (124) has a planar surface (130).

14. The sputtering target (10) of claim 9 wherein said first

contoured annular region (124) has a radiused surface (132).

15. The sputtering target (10) of claim 9 wherein said first

contoured annular region ( 124) extends radially inwardly from said

outer peripheral surface (122) in a range between about 0.0195 in.

and about 0.195 in.

16. The sputtering target (10) of claim 9 wherein said

second contoured annular region (224) has a planar surface (230).

17. The sputtering target (10) of claim 9 wherein said

second contoured annular region (224) includes has a radiused

surface (132).

18. The sputtering target (10) of claim 9 wherein said

second contoured annular region (224) extends radially inwardly

from said first contoured annular region (124) in a range between

about 0.1755 in. and about 0.955 in.

19. The sputtering target (10) of claim 9 wherein said outer

peripheral surface (122) is substantially perpendicular to said

bottom surface (120).

20. A method of manufacturing a contoured sputtering

target, comprising:

forming a target member (112) of sputtering material

having a top surface (118), a bottom surface (120) and an outer

peripheral surface (122); and

forming a contoured annular region (124) on said top

surface (118) extending radially inwardly from said outer peripheral

surface (122) and away from said bottom surface (120) at an angle in

a range between about 5┬░ and about 20┬░ relative to a plane parallel

to said bottom surface (120) whereby said target member (112) has

a configuration that reduces generation of contaminating particles

during a sputtering operation.

21. The method of claim 20 further comprising forming a

planar surface (130) on said contoured annular region (124).

22. The method of claim 20 further comprising forming a

radiused surface (132) on said contoured annular region (124).

23. A method of manufacturing a contoured sputtering

target, comprising:

forming a target member (112) of sputtering material

having a top surface (118), a bottom surface (120) and an outer

peripheral surface (122);

forming a first contoured annular region (124) on said

top surface (118) extending radially inwardly from said outer

peripheral surface (122) and away from said bottom surface (120) at

an angle in a range between about 30┬░ and about 60┬░ relative to a

plane parallel to said bottom surface (120); and

forming a second contoured annular region (224) on

said top surface (118) extending radially inwardly from said first

contoured annular region (124) and away from said bottom surface

(120) at an angle in a range between about 5┬░ and about 20┬░ relative

to a plane parallel to said bottom surface (120) whereby said target

member (112) has a configuration that reduces generation of

contaminating particles during a sputtering operation.

24. The method of claim 23 further comprising forming a

planar surface (130) on said first contoured annular region (124).

25. The method of claim 23 further comprising forming a

radiused surface (132) on said first contoured annular region (124).

26. The method of claim 23 further comprising forming a

planar surface (230) on said second contoured annular region (224).

27. The method of claim 23 further comprising forming a

radiused surface (132) on said first contoured annular region (124).

28. A method of reduced-contamination sputter coating of

a wafer comprising the steps of:

installing in a sputtering system process chamber a

target member (112) of sputtering material having a top surface

(118), a bottom surface (120) and an outer peripheral surface (122),

said sputtering material being ejected from said top surface (118)

and onto the substrate during a sputtering operation, said target

member (112) having a contoured annular region (124) formed on

said top surface (118) extending radially inwardly a predetermined

distance from said outer peripheral surface (122) and away from

said bottom surface (120) at an angle in a range between about 5┬░

and about 20┬░ relative to a plane parallel to said bottom surface

(120);

creating a vacuum in said processing chamber;

introducing an inert gas into said processing chamber;

and

applying a voltage potential between the wafer and

said target member (112).

29. A method of reduced-contamination sputter coating of

a wafer comprising the steps of:

installing in a sputtering system process chamber a

target member (112) of sputtering material having a top surface

(118), a bottom surface (120) and an outer peripheral surface (122),

said sputtering material being ejected from said top surface (118)

and onto the substrate during a sputtering operation, said target

member (112) having a first contoured annular region (124) formed

on said top surface (118) extending radially inwardly a

predetermined distance from said outer peripheral surface (122) and

away from said bottom surface (120) at an angle in a range between

about 30┬░ and about 60┬░ relative to a plane parallel to said bottom

surface (120), said target member (112) further having a second

contoured annular region (224) formed on said top surface (118)

extending radially inwardly a predetermined distance from said first

annular region (124) and away from said bottom surface (120) at an

angle in a range between about 5┬░ and about 20┬░ relative to a plane

parallel to said bottom surface (120);

creating a vacuum in said processing chamber;

introducing an inert gas into said processing chamber;

and applying a voltage potential between the wafer and

said target member (112).