Atom probe apparatus and method for working sample preliminary for the same

• US 7,550,723 B2
• Filed: 03/02/2005
• Issued: 06/23/2009
• Est. Priority Date: 03/17/2004
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Science Corporation (Hitachi, Ltd.)
• Original Assignee: SII NanoTechnology Inc. (Hitachi, Ltd.)
• Inventors: Kaito, Takashi
• Primary Examiner(s): Berman; Jack I
• Assistant Examiner(s): PURINTON, BROOKE J
• Application Number:
  US10/592,844
• Publication Number:
  US 20070176099A1
• Time in Patent Office: 1,574 Days
• Field of Search: 250/304, 250/306, 250/307, 250/309, 250/492.21, 250/440.11, 977/840, 977/849, 977/858, 977/864, 977/890
• US Class Current: 250/306
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01N 1/32 Polishing; Etching
• CPC Class Codes: H01J 2237/3109 Cutting

Abstract

A preliminary processing technology for a sample locally cuts out a sample part of a device to be analyzed and processes it into a needle-like projection, and a technology of realizing SAP analysis on an atomic level by ensuring stabilized ion evaporation sequentially even in the case of a sample of multilayer structure including an element layer of small evaporation electric field. The preliminary processing method for a sample used on atom probe apparatus comprises a step for cutting the desired observing part of the sample into a block using an FIB equipment, a step for transferring the sample block onto a sample substrate and fixing the sample block in place, and a step for processing the sample block fixed onto the sample substrate into a needle-point shape by FIB etching. The sample processed into a needle-point shape is shaped such that the layer direction of the multilayer structure becomes parallel to the longitudinal direction of the needle.

Claims

1. A method for working a sample preliminarily for an atom probe apparatus, comprising:

a step of cutting out a desired sample observation part to a block-like form by using an FIB apparatus;

a step of carrying and fixing the block-like cut-out sample onto a sample substrate; and

a step of working the block-like sample fixed onto the sample substrate into a needle tip shape by an FIB etching, wherein the step of fixing the block-like cut-out sample onto the sample substrate includes a step of temporarily bonding it by an FIB-CVD, a step of cutting in a groove over a base part of the block-like sample and the sample substrate by an FIB etching, and a step of applying the FIB-CVD to the cut-in portion, thereby bonding and fixing the sample substrate and the block-like sample.

2. A method for working a sample preliminarily for an atom probe apparatus according to claim 1;

wherein a finish working for working the block-like sample into the needle tip shape by the FIB etching is performed by an acceleration voltage of 10 kV or lower, thereby shallowing a damage layer.

3. A method for working a sample preliminarily for an atom probe apparatus according to claim 2;

further comprising a step of additionally removing, after performing the finish working by the acceleration voltage of 10 kV or lower, the damage layer by a low acceleration Ar ion milling.

4. A sample for an atom probe apparatus, characterized in that the sample worked into a needle tip shape is formed such that a layer direction of a multilayer structure becomes parallel to a longitudinal direction of a needle.

5. A method of preparing a sample for an atom probe apparatus, comprising:

cutting out a sample block from a sample using a focused ion beam;

temporarily fixing a base part of the sample block to a substrate;

etching a groove in the base part of the temporarily fixed sample block and in the substrate using a focused ion beam;

completely fixing the sample block to the substrate by bonding using focused-ion-beam-assisted chemical vapor deposition applied to the groove; and

etching the completely fixed sample block into a needle shape using a focused ion beam.

6. A method according to claim 5;

including etching plural grooves in the base part of the temporarily fixed sample block and in the substrate using a focused ion beam; and

completely fixing the sample block to the substrate by bonding using focused-ion-beam-assisted chemical vapor deposition applied to the plural grooves.

7. A method according to claim 5;

wherein the etching of the completely fixed sample block into a needle tip shape using a focused ion beam includes a finish working in which the etching is performed by the focused ion beam at an acceleration voltage of 10 kV or lower.

8. A method according to claim 7;

further including removing a damage layer from the needle tip shape, caused by the focused ion beam etching, by ion milling.

9. A method according to claim 8;

wherein the ion milling is carried out using Ar ions.

10. A method according to claim 5;

wherein the temporarily fixing a base part of the sample block to a substrate is carried out by bonding using focused-ion-beam-assisted chemical vapor deposition.

11. A multilayer sample for an atom probe apparatus, in which the sample has a needle shape and a multilayer structure, and in which the layer direction of the multilayer structure is parallel to a longitudinal direction of the needle.