In-situ monitoring of chemical vapor deposition process by mass spectrometry

• US 7,094,614 B2
• Filed: 01/16/2001
• Issued: 08/22/2006
• Est. Priority Date: 01/16/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cheek, Roger W., Reath, Mark L., Armbrust, Douglas S., DiMilia, Doreen D., Baker, John M., Ballantine, Arne W., Rice, Michael B.
• Primary Examiner(s): Jackson, Jerome
• Assistant Examiner(s): DIAZ, JOSE R
• Application Number:
  US09/681,126
• Publication Number:
  US 20020094681A1
• Time in Patent Office: 2,044 Days
• Field of Search: 438/14, 118/708, 118/712, 118/715, 427/255.23, 427/255.28, 427/255.392
• US Class Current: 438/14
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence

Abstract

A method and apparatus are provided for controlling a CVD process used to deposit films on semiconductor substrates wherein the by-products of the reaction are measured and monitored during the reaction preferably using mass spectrometry and the results used to calculate the concentrations of the by-products and to control the CVD reaction process based on the by-product concentrations. An exemplary CVD process is the deposition of tungsten metal on a semiconductor wafer. A preferred method and apparatus uses a capillary gas sampling device for removing the by-product gases of the reaction as a feed for the mass spectrometer. The capillary gas sampling device is preferably connected to a differential pump.

Claims

1. A method of chemical vapor deposition comprising the steps of:

providing a semiconductor substrate in a chemical vapor reaction chamber;

positioning a capillary tube proximate the semiconductor substrate for removal of a gas sample;

providing measuring and monitoring means for measuring and monitoring one or more properties of one or more gaseous-by-products formed in the chemical vapor reaction chamber;

providing a pump outside the chamber in communication with the capillary tube and measuring and monitoring means and positioned between the capillary tube and the measuring and monitoring means;

introducing reactant materials into the chamber;

effectuating a reaction between the reactant materials to produce a desired end product and at least one gaseous by-product;

forming the desired end product on a surface of the substrate;

removing with the pump a sample of the gases from the chamber including at least one gaseous by-product through the capillary tube and passing the pumped sample to the measuring and monitoring means; and

measuring and monitoring one or more properties of one or more of the gaseous by-products during the reaction and controlling the deposition method based on the measured and monitored gaseous by-product properties.

2. The method of claim 1 wherein the removing step is performed using a differential pump.

3. The method of claim 2 wherein the sample is monitored using a mass spectrometer.

4. The method of claim 1 wherein the desired end product is tungsten and one of the reactant materials is WF6.

5. The method of claim 1 wherein an isotope is incorporated into one or more of the reactant materials.

6. The method of claim 1 wherein the monitored property is concentration of the gaseous by-product.

7. The method of claim 6 wherein the concentration of the gaseous by-product is monitored using a mass spectrometer.

8. The method of claim 7 wherein all the gaseous by-products are measured to obtain a mass spectrum and simultaneously monitored so that variations in the process are readily detected.

9. The method as recited in claim 1, further comprising the step of determining a gaseous by-product to be monitored by determining an extent to which a change in a monitored property of such gaseous by-product indicates a change in a concentration of a reactant material.