BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing a test wafer in accordance with a preferred embodiment of the present invention;
FIG. 2 illustrates a diagram of curves showing the relationship between time and current applied to optoelectronic elements for reliability analysis in accordance with a preferred embodiment of the present invention; and
FIG. 3 is a schematic diagram showing a conventional apparatus for testing the reliability of optoelectronic elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The foregoing aspects and many of the attendant advantages of this invention are more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings.
Refer to FIG. 1 and FIG. 2. In the method used for analyzing the reliability of optoelectronic elements rapidly of the present invention, one hundred optoelectronic elements 11 which are good elements determined by the electrical probing test are taken out from a wafer 1 to be testing pieces for rapid reliability analysis. Each optoelectronic element 11 is 300 μm in length and 300 μm in width. A spectrum analyzer is used to test and measure NEP and peak of noise power spectrum of the optoelectronic elements 11 at the low frequency, wherein the NEP, the peak of noise power spectrum, and the multiplication product of the NEP and the peak of noise power spectrum of each optoelectronic element respectively respect three standard values. Then, the optoelectronic elements 11 are imposed with the forward bias and reverse bias to generate alternate cycle 2 of positive currents 21 of 100 MA and negative currents 22 of −5 mA. As shown in FIG. 2, the ratio of the duty cycles of the square waves of the current 21 of 100 mA and the square waves of the current 22 of −5 mA is 1:1, and each of the duty cycles of the square waves of the current 21 of 100 mA and the square waves of the current 22 of −5 mA is 5 μs. In a preferred embodiment, the alternate cycle 2 is carried out over 107 cycles. Then, the spectrum analyzer tests and measures the NEP and peak of noise power spectrum of the optoelectronic elements 11, and the NEP, the peak of noise power spectrum and the multiplication product of the NEP and the peak of noise power spectrum of the optoelectronic elements 11 are compared with the aforementioned standard values. Next, distributed curves are illustrated according to the relations between the NEP and the number of the optoelectronic elements, the peak of noise power spectrum and the number of the optoelectronic elements, and the multiplication product of the NEP and the peak of noise power spectrum and the number of the optoelectronic elements. A statistic standard deviation method is used to determine which optoelectronic element 11 is good and which optoelectronic element 11 has some problems of the reliability, wherein fifth standard deviation is the abnormal criterion. With the application of the present method, a rapid analysis of the reliability is achieved. The method is not a destructive test and has high accuracy. The optoelectronic elements 11 may be light-emitting diode chips.
According to the aforementioned description, advantages of the present invention includes:
1. With the application of the rapid reliability analysis of the optoelectronic elements of the present invention, the time of the reliability analysis can be decreased from several days to one hour, so that the shipping time of the products can be effectively reduced.
2. The rapid reliability analysis of the optoelectronic elements of the present invention can be directly applied to the producing line to accurately find out the optoelectronic elements having some problems of the reliability in the producing line.
3. The rapid reliability analysis of the optoelectronic elements of the present invention is not destructive to the optoelectronic element chips.
As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure.
Patent Application
20070268038
