US 6,441,398 B2Granted

Algorithm for detecting sloped contact holes using a critical-dimension waveform

AssigneeAdvanced Micro Devices, Inc.

InventorsJean Yang, Ian Dudley, Khoi Phan

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method for contact hole formation and inspection during integrated circuit fabrication is disclosed. The method includes defining tolerances for one or more contact hole formation processes, and then performing the formation processes to create at least one contact hole. After at least one of the formation processes is performed, a waveform is generated for the contact hole. A critical dimension (CD) and an edge width value are then generated for the contact hole from the waveform. The CD and the edge width value are then compared to the tolerances to detect and correct variations in the formation process. In a further aspect of the present invention, the edge width is compared to a predetermined limit to automatically detect contact holes having sloped sidewalls.

Claims5

Dependent claims

An integrated circuit comprising:

active-region regions;
interconnect paths electrically connecting the active-regions to implement a desired circuit function;
and
contact holes formed in the active-region regions where connections with the interconnect paths are needed, wherein each of the contact holes are inspected during formation to detect sloped contact holes by,
(a) generating a waveform for the contract hole;
(b) calculating a critical dimension (CD) for the contact hole using the waveform;
(c) calculating a first derivative curve for the waveform;
(d) setting a percentage of slope threshold;
(e) plotting the percentage of slope threshold on the first derivative curve;
(f) locating an inner diameter of the contact hole on the waveform using the percentage of slope threshold on the first derivative curve;
(g) calculating the edge width of the contact hole using the inner diameter;
(h) comparing the edge width with a predetermined limit;
(i) determining that the contact hole has sloped sidewalls if the edge width is outside of the predetermined limit.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/894,670Filed 27 Jun 2001 · division
Priority: 2 Oct 2000
Published: US 2002/0000550 A13 Jan 2002
Granted: 27 Aug 2002
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

H10P 74/238
Characterised by multiple measurements, corrections, marking or sorting processes: comprising acting in response to an ongoing measurement without…
H10P 74/203
Characterised by the properties tested or measured, e.g. structural or electrical properties: structural properties, e.g. testing or measuring…
H10P
Generic processes or apparatus for the manufacture or treatment of devices covered