Multiple tier collimator system for enhanced step coverage and uniformity

• US 5,643,428 A
• Filed: 02/01/1995
• Issued: 07/01/1997
• Est. Priority Date: 02/01/1995
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Bang, David S., Krivokapic, Zoran
• Primary Examiner(s): NGUYEN, NAM X
• Application Number:
  US08/382,366
• Time in Patent Office: 881 Days
• Field of Search: 204/192.12, 204/298.11
• US Class Current: 204/298.11
• CPC Class Codes: H01J 37/34 operating with cathodic sputtering H01J37/36 takes precedence ; methods of cathodic sputtering C23C14/34
• CPC Class Codes: H01J 37/3447 Collimators, shutters, apertures

Abstract

A collimator system for use in PVD sputtering of semiconductor wafers having multiple tiers provided between a target and wafer substrate. The collimator system prevents target atoms from contacting the wafer at substantially oblique angles, thereby providing good step coverage uniformity over the surface of the wafer. Additionally, the presence of more than one tier prevents localized build-up of target atoms that occurs in conventional single tier collimators, thereby providing good flat coverage uniformity over the surface of the wafer.

Claims

1. A physical vapor deposition collimator system for preventing dislodged target particles from a target from contacting a surface of a substrate at substantially oblique angles, the collimator system comprising:

a first tier capable of being provided between the target and substrate, with said first tier provided substantially parallel to the surface of said substrate, said first tier including a plurality of collimators; and

a second tier capable of being provided between the target and substrate, with said second tier provided adjacent and in fixed and constant relation to said first tier and being substantially parallel to said first tier, said second tier including a plurality of collimators;

wherein said first tier overlaps said second tier such that a collimator of said plurality of collimators from said first tier is staggered with respect to a closest collimator of said plurality of collimators from said second tier; and

wherein said first and second tiers together cause the target particles to be deposited in a substantially flat layer with a substantially uniform film thickness on the surface of the substrate.

2. A physical vapor deposition collimator system as recited in claim 1, wherein the substrate comprises a semiconductor wafer.

3. A physical vapor deposition collimator system as recited in claim 1, wherein each collimator of said plurality of collimators from said first and second tiers have a hexagonal cross section.

4. A physical vapor deposition collimator system as recited in claim 1, wherein collimators of said plurality of collimators from said first and second tiers have a rectangular cross section.

5. A physical vapor deposition collimator system as recited in claim 1, wherein collimators of said plurality of collimators from said first and second tiers have a triangular cross section.

6. A physical vapor deposition collimator system for preventing dislodged target particles from a target from contacting a surface of a substrate at substantially oblique angles, the collimator system comprising:

a plurality of collimator tiers, each tier of said plurality of collimator tiers including a plurality of adjacent collimators, said each tier provided with major surfaces generally parallel to each other and capable of being provided parallel to the surface of the substrate, and said each tier overlapping each other tier from a perspective perpendicular to said major surfaces and said each tier being in a fixed and constant relation to each other tier;

wherein said each tier overlaps each other tier such that a collimator from a first tier of said plurality of tiers is staggered with respect to a closest collimator of a second tier of said plurality of tiers adjacent to said first tier; and

wherein said first and second tiers together cause the target particles to be deposited in a substantially flat layer with a substantially uniform film thickness on the surface of the substrate.

7. A physical vapor deposition collimator system as recited in claim 6, wherein said plurality of tiers comprises greater than or equal to two tiers and less than or equal to two five tiers.

8. A physical vapor deposition collimator system as recited in claim 6, wherein said plurality of tiers comprises two tiers.

9. A physical vapor deposition collimator system as recited in claim 6, wherein collimators from said each tier have a rectangular cross section.

10. A physical vapor deposition collimator system as recited in claim 6, wherein collimators from said each tier have a triangular cross section.