US 6,280,291 B1 · Wafer sensor utilizing hydrodynamic pressure differential

Abstract

A wafer sensor includes a wafer holder, a liquid distribution system, and a pressure sensor. The wafer holder has a hole and is configured so that a wafer being held by the wafer holder restricts the flow of liquid from the liquid distribution system through the hole. The pressure sensor has a predetermined threshold and is configured to sense the pressure of the fluid at the hole. When no wafer is present in the wafer holder, the fluid flows essentially unrestricted through the hole in the wafer holder, resulting in a relatively low pressure of the liquid in the hole. When the wafer holder holds a wafer, the restricted flow through the hole causes an increase in pressure of the liquid in the hole. This increased pressure triggers the pressure sensor, thereby indicating the presence of the wafer in the wafer holder.

Claims38

Dependent claims

A system for sensing the presence of a workpiece, the system being incorporated into a workpiece processing machine, used in fabricating integrated circuits, the system comprising:

a holder having a hole, wherein the holder is configured to hold a workpiece in a position to restrict fluid flow through the hole;
a liquid distribution system configured to distribute a liquid through the hole of the holder;
and
a pressure sensor coupled to the liquid distribution system, wherein the pressure sensor is configured to detect whether the liquid in the hole has a pressure exceeding a predetermined threshold.

1 more element

A chemical-mechanical polishing machine comprising:

a workpiece holder having a hole, wherein the holder is configured to hold a workpiece in a position to restrict fluid flow through the hole and positioned so that a first surface of the workpiece is exposed;
a pad assembly configurable to be positioned in an operative relationship with the workpiece holder wherein the first surface of a workpiece held in the workpiece holder is placed in contact with an operative surface of the pad assembly;
a motor configured to impart a motion between the operative surface of the pad assembly and the workpiece holder;
a dispenser system configured to provide a fluid to an interface between the first surface of the workpiece and the operative surface of the pad assembly;
a control system coupled to the workpiece holder, the dispenser, and the motor, wherein the control system is configured to provide control signals used in coordinating the operation of the workpiece holder, the dispenser and the motor;
and
a workpiece sensor system coupled to the control system, the workpiece sensor system comprising:
a liquid distribution system coupled to the workpiece holder, wherein the liquid distribution system is configured to distribute a liquid through the hole of the workpiece holder;
and
a pressure sensor coupled to the liquid distribution system, wherein the pressure sensor is configured to provide a signal to the control system indicating whether a portion of the liquid at the hole has a pressure exceeding a predetermined threshold.

7 more elements

Dependencies are inferred from the claim text.

Wafer sensor utilizing hydrodynamic pressure differential

Life of this patent

Wafer sensor utilizing hydrodynamic pressure differential

Life of this patent

Abstract

Claims38