- Patent Title: Method for sorting silicon wafers according to their bulk lifetime
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Application No.: US16331702Application Date: 2017-09-07
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Publication No.: US11077469B2Publication Date: 2021-08-03
- Inventor: Elénore Letty , Wilfried Favre , Jordi Veirman
- Applicant: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
- Applicant Address: FR Paris
- Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
- Current Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
- Current Assignee Address: FR Paris
- Agency: Pillsbury Winthrop Shaw Pittman LLP
- Priority: FR1658368 20160908
- International Application: PCT/FR2017/052375 WO 20170907
- International Announcement: WO2018/046855 WO 20180315
- Main IPC: B07C5/344
- IPC: B07C5/344 ; H01L31/18 ; H01L21/67

Abstract:
A Czochralski-type method for sorting wafers obtained by cutting a single-crystal silicon ingot, the method being implemented when the wafers are in an as-cut state or in a shaped-surface state. The method includes a) measuring the majority free charge carrier concentration in an area of each wafer; calculating the thermal donor concentration in the area of each wafer, on the basis of the majority free charge carrier concentration; calculating the charge carrier lifetime limited by the thermal donors in the area of each wafer, on the basis of the thermal donor concentration; determining a bulk lifetime value for the charge carriers in each wafer on the basis of the lifetime limited by the thermal donors; comparing the bulk lifetime value or a normalised bulk lifetime value with a threshold value; and discarding the wafer when the bulk lifetime value or the normalised bulk lifetime value is lower than the threshold value.
Public/Granted literature
- US20190247889A1 METHOD FOR SORTING SILICON WAFERS ACCORDING TO THEIR BULK LIFETIME Public/Granted day:2019-08-15
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