Method for measuring the electrical potential in a semiconductor element

• US 6,091,248 A
• Filed: 03/02/1998
• Issued: 07/18/2000
• Est. Priority Date: 08/29/1994
• Status: Expired due to Term

• Current Assignee: IMEC International
• Original Assignee: IMEC International
• Inventors: Vandervorst, Wilfried, Trenkler, Thomas, De Wolf, Peter, Hellemans, Louis C.
• Primary Examiner(s): Do, Diep N.
• Application Number:
  US09/032,906
• Time in Patent Office: 869 Days
• Field of Search: 324/715, 324/717, 324/718, 324/719, 324/722, 324/724, 324/754, 324/756, 324/758, 324/762, 324/765, 73/105, 250/306, 250/307
• US Class Current: 324/719
• CPC Class Codes: G01Q 60/30 Scanning potential microscopy
• CPC Class Codes: G01R 1/06711 Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins
• CPC Class Codes: G01R 31/2648 Characterising semiconductor materials testing of materials or semi-finished products G01R31/2831; testing during manufacture H01L22/00
• CPC Class Codes: G01R 31/2831 Testing of materials or semi-finished products, e.g. semiconductor wafers or substrates G01R31/318511 takes precedence; testing during manufacture H01L22/00
• CPC Class Codes: H01L 22/14 for electrical parameters, e.g. resistance, deep-levels, CV, diffusions by electrical means
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: Y10S 977/854 Semiconductor sample

Abstract

Measuring an electrical potential in a semiconductor element by applying one or more voltages over the semiconductor element, placing at least one conductor in contact with the semi-conductor element using a scanning proximity microscope while injecting a substantially zero current in the semiconductor element with the conductor, measuring an electrical potential in the conductor while injecting a substantially zero current in the semiconductor element with the conductor, changing the position of the conductor, and repeating the measuring and changing steps.

Claims

1. A method of measuring an electrical potential distribution in a semiconductor element, comprising the steps of:

(a) applying at least one voltage over said semiconductor element;

(b) placing at least one conductor in contact with said semiconductor element using a scanning proximity microscope while injecting a substantially zero current in said semiconductor element with said conductor;

(c) measuring the electrical potential on said conductor while injecting a substantially zero current in said semiconductor element with said conductor;

(d) changing the position of said conductor; and

(e) repeating steps (c) and (d).

2. The method as recited in claim 1 further comprising the step of holding said conductor in contact with said semiconductor element while changing the position of said conductor.

3. The method as recited in claim 1 wherein said contact includes electrical and mechanical contact.

4. The method as recited in claim 3 further comprising the step of monitoring a contact parameter while executing steps (b)-(e).

5. The method as recited in claim 4 further comprising the step of calibrating said contact parameter, thereby obtaining at least one calibrated contact parameter value.

6. The method as recited in claim 4, wherein said contact parameter is contact force.

7. The method as recited in claim 5 further comprising the step of executing steps (b)-(e) at said calibrated contact parameter value.

8. The method as recited in claim 1 adapted for measuring said electrical potential on a cross-section of said semiconductor element.

9. The method as recited in claim 8, wherein said cross-section is formed by cleaving said semi-conductor element.

10. The method as recited in claim 8, wherein said cross-section is formed by polishing said semi-conductor element.

11. The method as recited in claim 8, wherein said cross-section is formed by chemical etching said semi-conductor element.

12. The method as recited in claim 8, wherein said cross-section is formed by ion-beam milling said semi-conductor element.

13. The method as recited in claim 8, wherein said cross-section is formed by sawing said semi-conductor element.

14. The method as recited in claim 8, wherein said cross-section is formed by sputter-etching said semi-conductor element.

15. The method as recited in claim 8, wherein said cross-section is formed by bevel etching said semi-conductor element.

16. The method as recited in claim 6, wherein said step of calibrating the contact force between said conductor and said semiconductor element comprises the steps of:

placing said conductor in contact with said semiconductor element in a region with a known electrical potential;

monitoring the electrical potential measured with said conductor; and

increasing the contact force between said conductor and said semiconductor element until a first substantial change in the force characteristic of said conductor is recorded and until a first substantial change in said monitored electrical potential is recorded, whereby the monitored electrical potential attains substantially the same value as said known electrical potential, the corresponding contact force being the calibrated contact force.

17. The method as recited in claim 1, further comprising the step of:

oscillating said conductor in a direction substantially perpendicular to the surface of said semiconductor element during step (c).

18. The method as recited in claim 1, wherein said voltage is applied by applying a voltage between two or more contacts arranged on said semiconductor element.

19. The method as recited in claim 1, wherein said voltage is applied by placing said semiconductor element in a magnetic field.

20. The method as recited in claim 1, wherein said voltage is applied by placing said semiconductor element in an electromagnetic field.

21. The method is recited in claim 1, wherein said voltage is applied by subjecting said semiconductor element to electromagnetic radiation.

22. The method as recited in claim 1, wherein said scanning proximity microscope is an atomic force microscope.

23. The method as recited in claim 1, wherein said conductor is an electrically conducting, relatively hard probe.

24. The method as recited in claim 23, wherein at least the tip of said probe is made of a material selected from the group consisting of diamond, boron implanted diamond, tungsten coated diamond, diamond-like-carbon, silicon, diamond-coated silicon, silicide-coated silicon, cubic boron-nitride and nitride-coated silicon.

25. The method as recited in claim 6, adapted for measuring a characteristic of said semiconductor element, further comprising the steps of:

establishing a relation between said electrical potential and said characteristic;

mapping the electrical potential distribution in said semiconductor element; and

converting said potential distribution to said characteristic using said relation.

26. The method as recited in claim 25, wherein said characteristic is the charge carrier distribution in said semiconductor element.

27. The method as recited in claim 25, wherein said conductor is moved substantially perpendicular over a surface of said semiconductor element in which is situated a p-n junction.

28. A method of measuring an electrical potential distribution in a semiconductor element, comprising the steps of:

(a) applying at least one voltage over said semiconductor element;

(b) placing at least one conductor in contact with said semiconductor element using a scanning proximity microscope while injecting a substantially zero current in said semiconductor element with said conductor, thereby establishing a contact force between said conductor and said semiconductor element;

(c) calibrating said contact force between said conductor and said semiconductor element to thereby obtain a calibrated contact force; and

thereafter

(d) holding said conductor in contact with said semiconductor element while establishing said calibrated contact force between said conductor and said semiconductor element;

(e) measuring the electrical potential on said conductor while injecting a substantially zero current in said semiconductor element with said conductor;

(f) changing the position of said conductor;

and

(g) repeating steps (e) and (f).

29. A method of measuring an electrical potential distribution in a semiconductor element, comprising the steps of:

(a) applying at least one voltage over said semiconductor element;

(b) placing at least one conductor in contact with said semiconductor element using a scanning proximity microscope while injecting a substantially zero current in said semiconductor element with said conductor;

(c) measuring the electrical potential on said conductor while injecting a substantially zero current in said semiconductor element with said conductor;

(d) changing the position of said conductor;

(e) repeating steps (c) and (d);

(f) monitoring a contact parameter while executing steps (b)-(e);

(g) calibrating said contact parameter, thereby obtaining at least one calibrated contact parameter value;

(h) executing steps (b)-(e) at said calibrated contact parameter value;

(i) establishing a relation between said electrical potential and a characteristic of said semiconductor;

(j) mapping the electrical potential distribution in said semiconductor element; and

(k) converting said potential distribution to said characteristic using said relation.

30. The method as recited in claim 29, wherein said conductor is moved substantially perpendicular over a surface of said semiconductor element in which is situated a p-n junction.

31. The method as recited in claim 29, wherein said semiconductor element comprises a transistor structure.