| 摘要 |
An apparatus and method is presented for a DRAM memory cell array exhibiting improved alignment tolerance for bit line contact formation and utilizing closely-spaced double-sided stacked capacitors for increased overall feature density on the circuit die. The use of a sacrificial insulating layer, an etch-stop insulating layer, and insulating spacers surrounding the bit line contact plug permits wet etching of the sacrificial layer to enable double-sided capacitors to be formed close together. In the resulting structure, only the bit line contact plug and insulating sidewall spacers separates adjacent capacitors and hence DRAM cells can be more tightly packed on the circuit die. Another aspect of the invention is improved alignment tolerance of the bit line contact plug. Because the bit line contact plug is formed prior to the double-sided capacitors, and then the double sided capacitors are formed to occupy all of the space laterally surrounding the bit line contact plug and its insulating spacers, mask alignment errors are less likely to affect this arrangement.
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