Split gate flash memory cell and fabrication method thereof
First Claim
1. A method of fabricating a split gate flash memory cell, comprising:
- providing a semiconductor substrate;
forming a first insulating layer, a first conductive layer, a second insulating layer, a second conductive layer, and a cap layer on the semiconductor substrate in sequence;
performing a first etching process to remove a portion of the cap layer, a portion of the second conductive layer and a portion of the second insulating layer to expose a portion of the surface of the first conductive layer, wherein the etched cap layer, the etched second conductive layer and the etched second insulating layer have coplanar sidewalls;
forming a first sidewall spacer and a second sidewall spacer on the sidewalls of the etched cap layer, the etched second conductive layer and the etched second insulating layer, respectively;
performing a second etching, with the first sidewall spacer and the second sidewall spacer as a mask, to remove a portion of the first conductive layer and a portion of the first insulating layer, and thus, a portion of a surface of the semiconductor substrate is exposed, wherein the etched first conductive layer and the etched first insulating layer have coplanar sidewalls;
striping the first sidewall spacer and the second sidewall spacer;
forming a third insulating layer on the semiconductor substrate and the sidewalls of the etched first conductive layer and the etched first insulating layer; and
forming a third conductive layer on the third insulating layer.
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Accused Products
Abstract
A split gate flash memory cell comprising a semiconductor substrate having a first insulating layer thereon and a floating gate with a first width is disclosed. The cell further comprises a second insulating layer, a control gate and a cap on the floating gate in sequence. The cap layer, the control gate and the second insulating layer have a same second width less than the first width. The cell also comprises a third insulating layer over the semiconductor substrate, the sidewalls of the control gate, the second insulating layer, the floating gate, and the first insulating layer. In addition, an erase gate formed on the third insulating layer is provided.
14 Citations
20 Claims
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1. A method of fabricating a split gate flash memory cell, comprising:
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providing a semiconductor substrate;
forming a first insulating layer, a first conductive layer, a second insulating layer, a second conductive layer, and a cap layer on the semiconductor substrate in sequence;
performing a first etching process to remove a portion of the cap layer, a portion of the second conductive layer and a portion of the second insulating layer to expose a portion of the surface of the first conductive layer, wherein the etched cap layer, the etched second conductive layer and the etched second insulating layer have coplanar sidewalls;
forming a first sidewall spacer and a second sidewall spacer on the sidewalls of the etched cap layer, the etched second conductive layer and the etched second insulating layer, respectively;
performing a second etching, with the first sidewall spacer and the second sidewall spacer as a mask, to remove a portion of the first conductive layer and a portion of the first insulating layer, and thus, a portion of a surface of the semiconductor substrate is exposed, wherein the etched first conductive layer and the etched first insulating layer have coplanar sidewalls;
striping the first sidewall spacer and the second sidewall spacer;
forming a third insulating layer on the semiconductor substrate and the sidewalls of the etched first conductive layer and the etched first insulating layer; and
forming a third conductive layer on the third insulating layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A split gate flash memory cell, comprising:
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a semiconductor substrate;
a first insulating layer on the semiconductor substrate;
a floating gate on the first insulating layer, wherein the floating gate has a first width;
a second insulating layer on the floating gate;
a control gate on the second insulating layer;
a cap layer on the control gate, wherein the cap layer, the control gate and the second insulating layer have a same second width less than the first width;
a third insulating layer conformally disposed on sidewalls of the cap layer, the control gate, the second insulating layer, and the floating gate; and
an erase gate on the third insulating layer. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method of fabricating a split gate flash memory cell, comprising:
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forming a first conductive layer on a substrate;
forming a first insulating layer on the first conductive layer;
forming a second conductive layer on the first insulating layer;
forming a patterned cap layer on the second conductive layer;
using the cap layer as a mask to remove a portion of the second conductive layer and a portion of the first insulating layer, and thus, a portion of the surface of the first conductive layer is exposed;
forming a sidewall spacer on sidewalls of the remaining second conductive layer and the remaining first insulating layer;
using the sidewall spacer and the cap layer as a mask to remove a portion of the first conductive layer, and thus, a portion of a surface of the substrate is exposed;
removing the sidewall spacer;
conformally forming a second insulating layer on sidewalls of the remaining second conductive layer, the remaining first insulating layer and the remaining first conductive layer; and
forming a third conductive layer on the second insulating layer. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification