Appeal No. 2001-1384
Application No. 08/726,229
capacitor bottom electrode, formed via a mask. The mask is made
of small particles which are controlled as to size and
distribution, enabling the formation of a dense, evenly-spaced
micro-villus pattern, optimizing the increase in capacitor
electrode surface area, thereby increasing capacitance.
Representative independent claim 1 is reproduced as follows:
1. A method of forming a dynamic random access memory cell
having a storage capacitor, comprising:
precipitating a plurality of particles in a microemulsion
mixture;
forming a lower electrode layer;
depositing the particles in an evenly spaced layer on the
lower electrode layer;
using the deposited particles as a mask to form a micro-
villus pattern on the lower electrode layer;
removing the particles leaving the micro-villus pattern on
the lower electrode layer;
forming a dielectric overlying the micro-villus pattern; and
forming an upper electrode of the storage capacitor.
The examiner relies on the following references:
Ahn 5,158,905 Oct. 27, 1992
Kavassalis et al. (Kavassalis) 5,209,998 May 11, 1993
Cathey et al. (Cathey) 5,244,842 Sep. 14, 1993
Jun et al. (Jun) 5,256,587 Oct. 26, 1993
-2–
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