# US 10,371,657 B2 · Method for locating a wafer in the ingot of same

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- Number: US 10,371,657 B2
- Document ID: US10371657B2
- Status: Granted
- Kind: B2
- Application number: 14/909,230
- Filed: 2014-08-01
- Published: 2016-06-30
- Granted: 2019-08-06
- Earliest claimed: 2013-08-02
- Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Applicants: Commissariat à L'energie Atomique Et Aux Energies Alternatives
- Inventors: Jordi Veirman; Sébastien Dubois
- Web page: https://patentgrep.com/patent/US10371657B2

## CPC

- G01N 27/041: {of a solid body}
- G01N 21/3504: for analysing gases, e.g. multi-gas analysis
- G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- G01R 31/2601: {Apparatus or methods therefor (G01R31/2607, G01R31/2642 take precedence)}
- H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects}
- H10P 74/207: {Electrical properties, e.g. testing or measuring of resistance, deep levels or capacitance-voltage characteristics}
- H10P 74/23: {characterised by multiple measurements, corrections, marking or sorting processes}
- G01N 33/0095: {Semiconductive materials}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for determining the original position of a wafer in an ingot made from semiconductor material comprises the following steps: measuring the interstitial oxygen concentration in an area of the wafer; measuring the concentration of thermal donors formed in said area of the wafer during a previous solidification of the ingot; determining the effective time of a thermal donor formation anneal undergone by the wafer when solidification of the ingot took place, from the thermal donor concentration and the interstitial oxygen concentration; and determining the original position of the wafer in the ingot from the effective time.

## Claims

### Claim 1

A method for determining an original position of a wafer in an ingot made from semiconductor material, comprising the following steps:
measuring an interstitial oxygen concentration in one area of the wafer;
measuring a concentration of thermal donors formed in said area of the wafer during a previous solidification of the ingot;
determining an effective time of a thermal donor formation anneal undergone by the wafer when solidification of the ingot took place from the thermal donor concentration and the interstitial oxygen concentration; and
determining the original position of the wafer in the ingot from the effective time.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the thermal donor concentration is determined from first and second resistivity values measured in said area of the wafer respectively before and after heat treatment for the purposes of destroying the thermal donors.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the interstitial oxygen concentration is determined from the first resistivity value and a third resistivity value measured in said area of the wafer respectively before and after an additional thermal donor formation anneal.

### Claim 4 (depends on 3)

The method according to claim 3, wherein the thermal donor destruction heat treatment is performed after the additional thermal donor formation anneal.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the original position of the wafer is determined according to the following steps:
selecting a plurality of wafers originating from the same ingot;
determining an effective time value for each wafer;
placing two points corresponding to the minimum and maximum effective time values from the set of previously determined effective time values on an abacus; and
plotting a straight line between the two points.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the minimum and maximum effective time values are associated with original positions equal to 5% and 85% of the total height of the ingot.

### Claim 7 (depends on 2)

The method according to claim 2, wherein the original position of the wafer is determined according to the following steps:
selecting a plurality of wafers originating from the same ingot;
determining an effective time value for each wafer;
placing two points corresponding to the minimum and maximum effective time values from the set of previously determined effective time values on an abacus; and
plotting a straight line between the two points.

### Claim 8 (depends on 3)

The method according to claim 3, wherein the original position of the wafer is determined according to the following steps:
selecting a plurality of wafers originating from the same ingot;
determining an effective time value for each wafer;
placing two points corresponding to the minimum and maximum effective time values from the set of previously determined effective time values on an abacus; and
plotting a straight line between the two points.

### Claim 9 (depends on 4)

The method according to claim 4, wherein the original position of the wafer is determined according to the following steps:
selecting a plurality of wafers originating from the same ingot;
determining an effective time value for each wafer;
placing two points corresponding to the minimum and maximum effective time values from the set of previously determined effective time values on an abacus; and
plotting a straight line between the two points.