Method of measuring electron shading damage

• US 5,940,682 A
• Filed: 09/05/1997
• Issued: 08/17/1999
• Est. Priority Date: 09/06/1996
• Status: Expired due to Term

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Tabara, Suguru
• Primary Examiner(s): CHAUDHARI, CHANDRA P
• Application Number:
  US08/926,290
• Time in Patent Office: 711 Days
• Field of Search: 438/10, 438/11, 438/17, 438/18, 438/287, 438/393, 438/591
• US Class Current: 438/17
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 22/34 Circuits for electrically characterising or monitoring manufacturing processes, e. g. whole test die, wafers filled with test structures, on-board-devices incorporated on each die, process control monitors or pad structures thereof, devices in scribe line switching, multiplexing, gating devices G01R19/25; process control with lithography, e.g. dose control, G03F7/20; structures for alignment control by optical means G03F7/70633

Abstract

A method of measuring electron shading damage which includes the steps of: a) preparing a characteristic curve of a flat band voltage change relative to an amount of injected charges, by intentionally flowing current through a first capacitor; b) preparing a second capacitor similar to the first capacitor; c) making a sample by using the second capacitor by forming a lamination of an insulating layer having an opening over the second capacitor, a conductive antenna layer connected to the conductive layer through the opening in the insulating layer, and an insulating mask pattern on the conductive antenna layer, the insulating mask pattern including a looped opening which leaves a separated pattern on the second capacitor; d) performing a dry process of the sample to fully remove the conductive layer under the loop opening; e) measuring a flat band voltage of the second capacitor before and after the dry process and calculating a change in the flat band voltage; and f) estimating from the calculated flat band voltage change an amount of charges injected into the second capacitor during the dry process, by referring to the characteristic curve. The method can reduce manufacture costs of a sample and provide a sufficiently high precision.

Claims

1. A method of measuring electron shading damage comprising the steps of:

a) preparing a characteristic curve showing a flat band voltage change relative to an amount of injected charges, the curve being measured by intentionally flowing current through a first capacitor structure comprising a lamination of a conductive layer, a nitride film and an oxide film respectively formed on a semiconductor substrate;

b) preparing a second capacitor structure comprising a lamination of a conductive layer, a nitride film and an oxide film formed on the semiconductor substrate;

c) forming a sample by forming an insulating layer having an opening over the second capacitor structure on the semiconductor substrate, a conductive antenna layer connected to the conductive layer in the opening on the insulating layer, and an insulating mask pattern on the conductive antenna layer, the insulating mask pattern including a loop opening which leaves a separate pattern on the second capacitor structure;

d) performing a dry process on the sample to fully remove the conductive layer under the loop opening, the dry process being a subject process for which the electron shading damage is measured;

e) measuring a flat band voltage of the second capacitor structure before and after the dry process and calculating a change in the flat band voltage; and

f) estimating from the calculated flat band voltage change an amount of charges injected into the second capacitor structure during the dry process, by referring to the characteristic curve.

2. A method of measuring electron shading damage according to claim 1, wherein the first and second capacitor structures have a same structure.

3. A method of measuring electron shading damage according to claim 1, wherein the measurement of a flat band voltage after the dry process is performed by using the separate pattern of the antenna layer.

4. A method of measuring electron shading damage according to claim 1, wherein the measurement of a flat band voltage before the dry process is performed before the antenna layer is formed.

5. A method of measuring electron shading damage according to claim 1, further comprising the step of annealing the second capacitor structure before the measurement of a flat band voltage before the dry process.

6. A method of measuring electron shading damage according to claim 1, wherein the semiconductor substrate is further formed with a third capacitor structure same as the second capacitor structure, the insulating mask pattern of the sample has a dense pattern in an area including the second capacitor structure, the dense pattern having a plurality of patterns disposed adjacent to each other through spaces, and a continuous pattern without a space in an area including the third capacitor structure, and the flat band voltage change is a difference between a flat band voltage of the second capacitor structure and a flat band voltage of the third capacitor structure.

7. A method of measuring electron shading damage according to claim 1, wherein the dry process is dry etching.

8. A method of measuring electron shading damage according to claim 7, wherein the dry etching is performed using etchant gas which contains chlorine.

9. A method of measuring electron shading damage according to claim 8, wherein the etchant gas contains Cl₂ and BCl₃.

10. A method of measuring electron shading damage comprising the steps of:

a) preparing a characteristic curve showing a flat band voltage change relative to an amount of injected charges, the curve being measured by intentionally flowing current through a first capacitor structure comprising a lamination of a conductive layer and an insulating film respectively formed on a semiconductor substrate;

b) preparing a second capacitor structure comprising a lamination of a conductive layer and an insulting film formed on the semiconductor substrate;

c) preparing a sample by forming an insulating layer having an opening over the second capacitor structure on the semiconductor substrate, forming a conductive antenna layer connected to the conductive layer through the opening in the insulating layer, and forming an insulating mask pattern on the conductive antenna layer, the insulating mask pattern including a looped opening which leaves a separate pattern on the second capacitor structure;

d) performing a dry process on the sample to fully remove the conductive layer under the looped opening, the dry process being a subject process for which the electron shading damage is measured;

e) measuring a flat band voltage of the second capacitor structure before and after the dry process and calculating a change in the flat band voltage; and

f) estimating from the calculated flat band voltage change an amount of charges injected into the second capacitor structure during the dry process, by referring to the characteristic curve.

11. A method of measuring electron shading damage according to claim 10, wherein the first and second capacitor structures have a same structure.