Methods for inspecting semiconductor wafers
AssigneeBt Imaging Pty Ltd
InventorsThorsten Trupke, Juergen Weber
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Abstract
Methods and systems are presented for analyzing semiconductor materials as they progress along a production line, using photoluminescence images acquired using line-scanning techniques. The photoluminescence images can be analyzed to obtain spatially resolved information on one or more properties of said material, such as lateral charge carrier transport, defects and the presence of cracks. In one preferred embodiment the methods and systems are used to obtain series resistance images of silicon photovoltaic cells without making electrical contact with the sample cell.
Claims20
A method for obtaining series resistance or carrier transport information across a semiconductor material comprising an emitter and a base, said method comprising the steps of:
- illuminating a first portion of said material with a first illumination from a light source suitable for generating a photoluminescence response from said material;
- detecting photoluminescence emitted from a second portion of said material with an image capture device, wherein said first and second portions are at least partially overlapping;
- scanning said first and second portions across a substantial area of said material, said substantial area corresponding to an entire surface of said semiconductor material;
- and
- interrogating said image capture device while said first and second portions are being scanned across said substantial area to acquire an image of photoluminescence emitted from said substantial area,
- wherein an intensity of said first illumination is selected such that there is a significant lateral flow of photo-generated charge carriers out of said first portion, and wherein said method further comprises the step of interpreting said image to identify defects that impede carrier transport in said substantial area.
A system for obtaining series resistance or carrier transport information across a semiconductor material comprising an emitter and a base, said system comprising:
- a light source adapted to illuminate a first portion of said material with a first illumination suitable for generating a photoluminescence response from said material;
- an image capture device adapted to detect photoluminescence emitted from a second portion of said material, wherein said first and second portions are at least partially overlapping;
- a mechanism for scanning said first and second portions across a substantial area of said material, said substantial area corresponding to an entire surface of said semiconductor material;
- and
- a computer programmed to interrogate said image capture device while said first and second portions are being scanned across said substantial area to acquire an image of photoluminescence emitted from said substantial area,
- wherein an intensity of said first illumination is selected such that there is a significant lateral flow of photo-generated charge carriers out of said first portion, and wherein said computer is programmed to interpret said image to identify defects that impede carrier transport in said substantial area.
Dependencies are inferred from the claim text.