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Methods of characterizing semiconductor light-emitting devices based on product wafer characteristics

  • US 8,765,493 B2
  • Filed: 11/20/2012
  • Issued: 07/01/2014
  • Est. Priority Date: 11/20/2012
  • Status: Active Grant
First Claim
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1. A method of characterizing the emission wavelength of a semiconductor light-emitting device structure of a product wafer having a substrate, comprising:

  • establishing a relationship between a device-layer stress S(x,y) and the emission wavelength λ

    E(x,y) for the device structures formed on the product wafer by measuring the device-layer stress S(x,y) of a test product wafer, dicing the test product wafer to form dies, and measuring the emission wavelengths of the dies as a function of their device-layer stress and corresponding device structure locations (x,y);

    measuring a change in curvature Δ

    C(x,y) of the test product wafer based on curvature measurements of the substrate performed before and after substrate processing to form the device structures;

    calculating the device-layer stress S(x,y) in the test product wafer based on the measured changed in curvature Δ

    C; and

    associating the actual emission wavelength λ

    E with the device structures based on the relationship between the device-layer stress S(x,y) and the (x,y) positions on the test product wafer to establish a predicted emission wavelength for the device structures that corresponds to the emission wavelength λ

    E.

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