Liquid immersion doping
AssigneeVarian Semiconductor Equipment Associates, Inc.
InventorsFrank Sinclair, Jay T. Scheuer, William Davis Lee, Peter L. Kellerman
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Abstract
Methods for processing of a workpiece are disclosed. A fluid that contains a desired dopant is prepared. The workpiece is immersed in this fluid, such that the dopant is able to contact all surfaces of the workpiece. The fluid is then evacuated, leaving behind the dopant on the workpiece. The dopant is then subjected to a thermal treatment to drive the dopant into the surfaces of the workpiece. In certain embodiments, a selective doping process may be performed by applying a mask to certain surfaces prior to immersing the workpiece in the fluid. In certain embodiments, the fluid may be in a super-critical state to maximize the contact between the dopant and the workpiece.
Claims16
A method of doping a workpiece, comprising:
- immersing the workpiece in super-critical fluid containing dopant;
- removing the super-critical fluid from the workpiece, wherein residue of the dopant remains on exposed surfaces of the workpiece;
- and
- applying a thermal treatment to drive the dopant into the workpiece, wherein the removing and the applying are performed at least partly simultaneously.
A method of doping a workpiece having a feature length of 5 nm or less, comprising:
- immersing the workpiece in a gas containing a dopant, wherein the gas is compressed by increasing pressure or temperature so that a ratio of mean free path of the gas to the feature length is less than 1;
- removing the gas, wherein residue of the dopant remains on exposed surfaces of the workpiece;
- and
- performing a thermal treatment to drive the dopant into the workpiece, wherein the removing and the performing are performed at least partly simultaneously.
A method of doping a workpiece having a predetermined feature length of 5 nm or less, comprising:
- immersing the workpiece in a fluid having a ratio of a mean free path of the fluid to the predetermined feature length is less than 1, wherein the fluid contains a dopant;
- removing the fluid from the workpiece by changing pressure or temperature, so that the fluid becomes a gas and wherein the dopant remains on exposed surfaces of the workpiece;
- and
- performing a thermal treatment to drive the dopant into the workpiece, wherein the removing and the performing are performed at least partly simultaneously.
Dependencies are inferred from the claim text.