Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Reexamination Certificate
2008-07-08
2008-07-08
Vanore, David A. (Department: 2881)
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
C250S492100, C250S492300
Reexamination Certificate
active
11025474
ABSTRACT:
Methods (300, 400) are described for calibrating the implantation angle of an ion implanter utilized in the manufacture of semiconductor products. One method (300) includes implanting (330) phosphorous ions into a pilot wafer held by a wafer platen held at a starting implantation angle in the ion implanter. The phosphorous implantation into a p-doped substrate of the pilot or blank wafer, for example, forms a semiconductive sheet. The method (300) then includes changing the implantation angle (340), and implanting another wafer (330) with phosphorous ions. The angle changing (340) and implanting (330) of other wafers continues in this manner until all wafers or angles are implanted (350) as desired. The phosphorous implanted wafers are then measured (360) with a four-point probe, for example, to obtain the sheet resistance of all the implanted wafers. The difference between the sheet resistances of the wafers at each corresponding implant angle is then obtained (370) to determine a functional relationship between the sheet resistance and the implantation angle. Finally, the functional relationship is then used to calibrate (380) the implantation angle of the implanter. For example, the lowest sheet resistance of the functional relationship may be determined, the relationship normalized to the lowest sheet resistance, then a zero degree implantation angle of the implanter is calibrated to to coincide with the lowest sheet resistance measurement.
REFERENCES:
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patent: 6828572 (2004-12-01), Reece et al.
Silicon Processing for the VLSI Era. vol. 1—Process Technology, “Measurement of the Electrical Properties of Thin Films” S. Wolf and R.N. Tauber, Copyright 1986 by Lattice Press, pp. 119-122 and 267-269.
Ion Implantation Science and Technology, “Modulated Reflectance Maps”, edited by J.F. Ziegler, Copyright 2000, pp. 318-320 & 322.
Ion Implantation science and Technology, edited by J.F. Ziegler, Copyright 2000. pp. 93-94.
Conroy Thomas Patrick
Loewecke Jeffrey
Xu Jie-Jie
Yue Duofeng
Brady III Wade J.
Vanore David A.
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