Method of alternating grounded/floating poly lines to monitor shorts
View Patent ↗A method for in-line testing of a chip to include multiple independent bit Flash memory devices, includes the steps of: grounding every other polysilicon line on the chip to emulate the multiple independent bit Flash memory devices, where an oxide line reside between every two polysilicon lines; scanning the polysilicon lines with an electron beam; examining voltage contrasts between the polysilicon lines; and determining if there are consecutively grounded polysilicon lines based on the voltage contrasts. If consecutive polysilicon lines appear to be grounded, then this indicates that a bridge defect exists between two of the consecutively grounded polysilicon lines. With this method, bridge defects in multiple independent bit Flash memory devices are better detected, leading to improved yield and reliability of the devices.
1. A method for in-line testing of a chip to comprise multiple independent bit Flash memory devices, comprising the steps of:
(a) grounding every other polysilicon line on the chip to emulate the multiple independent bit Flash memory devices, wherein an oxide line resides between every two polysilicon lines;
(b) scanning the polysilicon lines with an electron beam;
(c) examining voltage contrasts between the polysilicon lines; and
(d) determining if there are consecutively grounded polysilicon lines based on the voltage contrasts.
2. The method of claim 1 , further comprising:
(e) determining that a bridge defect exists between two of the consecutively grounded polysilicon lines, if there are consecutively grounded polysilicon lines.
3. The method of claim 2 , further comprising:
(f) performing further tests to determine between which two of the consecutively grounded polysilicon lines the bridge defect exists.
4. The method of claim 1 , further comprising:
(e) determining that no bridge defect exists, if there are no consecutively grounded polysilicon lines.
5. The method of claim 1 , wherein the examining step (c) is performed using a scanning electron microscope tool.
6. A method for in-line testing of a chip to comprise multiple independent bit Flash memory devices, comprising the steps of:
(a) grounding every other polysilicon line on the chip to emulate the multiple independent bit Flash memory devices, wherein oxide lines reside between each polysilicon line;
(b) scanning the polysilicon lines with an electron beam;
(c) examining voltage contrasts between the polysilicon lines;
(d) determining if there are consecutively grounded polysilicon lines based on the voltage contrasts; and
(e) determining that a bridge defect exists between two of the consecutively grounded polysilicon lines, if there are consecutively grounded polysilicon lines.
7. The method of claim 1 , further comprising:
(f) determining that no bridge defect exists, if there are no consecutively grounded polysilicon lines.
8. The method of claim 1 , wherein the examining step (c) is performed using a scanning electron microscope tool.
9. A method for detecting implant defects in a semiconductor device, comprising the steps of:
(a) providing a plurality of implant lines in a substrate;
(b) scanning the substrate with an electron beam;
(c) examining voltage contrasts in the substrate; and
(d) identifying implant defects from the voltage contrasts.