Non-contact method for determining quality of semiconductor dielectrics

• US 6,664,800 B2
• Filed: 01/08/2001
• Issued: 12/16/2003
• Est. Priority Date: 01/08/2001
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Chacon, Carlos M., Chetlur, Sundar, Roy, Pradip K.
• Primary Examiner(s): Nguyen, Vinh P.
• Application Number:
  US09/756,965
• Publication Number:
  US 20020121914A1
• Time in Patent Office: 1,072 Days
• Field of Search: 324/750, 324/751, 324/752, 324/501, 324/765, 324/537, 250/492.2, 438/14, 438/17, 438/18
• US Class Current: 324/754.05
• CPC Class Codes: G01R 31/129 of components or parts made of semiconducting materials; of LV components or parts G01R31/18 takes precedence
• CPC Class Codes: G01R 31/2648 Characterising semiconductor materials testing of materials or semi-finished products G01R31/2831; testing during manufacture H01L22/00

Abstract

A non-contact method for determining a quality of a semiconductor dielectric. The method includes depositing a charge on a dielectric to achieve a high voltage on the dielectric, measuring a voltage drop of the dielectric as a function of time, and determining a soft breakdown voltage of the dielectric from the voltage drop as a function of time. The amount of charge that is deposited may vary. For example, the charge may be deposited until a voltage that ranges from about 4 megavolts to about 16 megavolts is achieved on the dielectric. The amount of charge may also depend on the thickness of the dielectric. For example, applying a charge as a function of the thickness may include applying 4 megavolts when the thickness is about 1.2 nm or applying 16 megavolts when the thickness is about 5.0 nm.

Claims

1. A non-contact method for determining a quality of a semiconductor dielectric, comprising:

depositing a charge on a dielectric to achieve a high voltage on the dielectric;

measuring a voltage drop of the dielectric as a function of time; and

determining a soft breakdown voltage of the dielectric from the voltage drop as a function of time.

2. The method as recited in claim 1 further including determining a stress-induced leakage current within the dielectric from the voltage drop as a function of time.

3. The method as recited in claim 1 wherein depositing a charge includes depositing a charge with a corona source.

4. The method as recited in claim 1 wherein depositing a charge includes depositing a charge to achieve a high voltage that ranges from about 4 megavolts to about 16 megavolts.

5. The method as recited in claim 4 wherein depositing a charge includes depositing a charge to achieve a high voltage of about 8 megavolts.

6. The method as recited in claim 1 wherein the dielectric has a thickness ranging from about 1.2 nm to about 5.0 nm.

7. The method as recited in claim 6 wherein depositing a dielectric includes depositing a dielectric having a thickness of about 3.0 nm.

8. The method as recited in claim 1 wherein said measuring is performed with a Kelvin probe.

9. The method as recited in claim 1 wherein depositing a charge includes depositing a charge as a function of a thickness of the dielectric.

10. The method as recited in claim 9 wherein depositing a charge as a function of the thickness includes depositing 4 megavolts when the thickness is about 1.2 nm or depositing 16 megavolts when the thickness is about 5.0 nm.

11. The method as recited in claim 1 wherein the dielectric is a gate oxide and said determining the soft breakdown voltage includes determining the soft breakdown voltage during an in-line process of fabricating the semiconductor device.

12. The method as recited in claim 1 wherein said measuring a voltage drop includes measuring the voltage on the dielectric once every 1 ms.