US 6,551,487 B1Granted

Methods and apparatus for controlled-angle wafer immersion

AssigneeNovellus Systems, Inc.

InventorsJonathan D. Reid, Steven T. Mayer, Seshasayee Varadarajan, David C. Smith, Evan E. Patton, Dinesh S. Kalakkad, Gary Lind

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Abstract

The orientation of a wafer with respect to the surface of an electrolyte is controlled during an electroplating process. The wafer is delivered to an electrolyte bath along a trajectory normal to the surface of the electrolyte. Along this trajectory, the wafer is angled before entry into the electrolyte for angled immersion. A wafer can be plated in an angled orientation or not, depending on what is optimal for a given situation. Also, in some designs, the wafer's orientation can be adjusted actively during immersion or during electroplating, providing flexibility in various electroplating scenarios.

Claims16

Dependent claims

A method of immersing a wafer into an electrolyte of an electroplating cell, the method comprising:

(a) positioning the wafer above the electrolyte surface while holding the wafer in a wafer holder having a proximal end that engages the wafer;
(b) directing a distal end of the wafer holder along an arced track, thereby pivoting the wafer about a pivot point, without substantially translating the wafer, to tilt the wafer at an angle such that the planar plating surface of the wafer is not substantially parallel to the plane defined by the surface of the electrolyte;
(c) moving the wafer toward the electrolyte along a trajectory substantially normal to the plane defined by the surface of the electrolyte;
and
(d) immersing the wafer into the electrolyte while the wafer is tilted.

2 more elements

Dependencies are inferred from the claim text.