Loading patent…
AssigneeApplied Materials, Inc.
InventorsBryan Y. Pu, Hongching Shan, Claes Bjorkman, Kenny Doan, Mike Welch, Richard Raymond Mett
Estimating the term…
Apparatus and method for inductively coupling electrical power to a plasma in a semiconductor process chamber. In a first aspect, an array of wedge-shaped induction coils are distributed around a circle. The sides of adjacent coils are parallel, thereby enhancing the radial uniformity of the magnetic field produced by the array. In a second aspect, electrostatic coupling between the induction coils and the plasma is minimized by connecting each induction coil to the power supply so that the turn of wire of the coil which is nearest to the plasma is near electrical ground potential. In one embodiment, the hot end of one coil is connected to the unbalanced output of an RF power supply, and the hot end of the other coil is connected to electrical ground through a capacitor which resonates with the latter coil at the frequency of the RF power supply.
A circuit for coupling a pair of induction coils to an RF power supply, comprising:
A circuit for coupling a plurality of induction coils to an RF power supply, comprising:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of inductively coupling electrical power to the interior of a plasma chamber, comprising the steps of:
A method of coupling a pair of induction coils to an RF power supply, comprising the steps of:
A method of coupling a pair of induction coils to an RF power supply, comprising the steps of:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Backward citations are indexed for grants only.
Radio frequency generated discharge: the radio frequency energy being inductively coupled to the plasma
Electric discharge tubes or discharge lamps
Term end not estimated
This invention relates to inductively coupled plasma sources for semiconductor process chambers.
Many processes for fabricating semiconductors, such as etching and deposition, are plasma-enhanced or plasma-assisted; that is, they employ process reagents excited to a plasma state within a vacuum chamber. Generally, the plasma is excited by coupling radio frequency (RF) electrical power to the process gas mixture. The RF electrical field dissociates atoms in the process gas mixture to form the plasma.
One method of coupling RF power to the process gases is inductive coupling, in which an RF power supply is connected to an induction coil which is mounted either inside the chamber or just outside a portion of the chamber wall which is dielectric. In comparison with a capacitively coupled plasma source, an advantage of an inductively coupled plasma source is that it permits adjusting the RF power supplied to the plasma independently of the DC bias voltage on the semiconductor workpiece.
FIG. 1 is a partially schematic, sectional, side view of a plasma chamber employing the invention.
FIG. 2 is a schematic top view of the array of induction coils in the chamber.
FIG. 3 is a partially schematic, perspective view of the induction coil array of FIG. 2.
FIG. 1 shows a plasma chamber utilizing the present invention. The illustrated chamber is intended for plasma-enhanced etching of dielectric films on silicon wafers, but the invention is equally useful in any plasma chamber used for semiconductor fabrication processes such as etching, chemical vapor deposition, or sputter deposition.
The vacuum chamber has a cylindrical aluminum side wall 12, a circular aluminum bottom wall 14, and a circular top wall or lid 10 composed of a dielectric material such as aluminum oxide (Al2O3, commonly called alumina), aluminum nitride, or silicon carbide. We prefer alumina, primarily because it has been used successfully as a dielectric in many other plasma chamber designs, and also because it is much less expensive than the other contemplated dielectric materials.
The chamber side wall and bottom wall are electrically grounded. An aluminum cathode electrode 16 is oriented perpendicular to the cylindrical axis of the chamber and is electrically insulated from the grounded chamber walls by dielectric support shelf 18. A semiconductor workpiece such as a silicon wafer (not shown) is mounted on the top face of the cathode electrode by conventional means such as a mechanical clamp ring or an electrostatic chuck. Such chamber construction is completely conventional.