Patent ID: 6858452
Filing Date: 2005-02-22
Classification: H01L

Abstract:
1. A method for isolating self-aligned contact pads of a semiconductor device, the semiconductor device including a first pattern having self-aligned contact holes and a second pattern, comprising: forming a test semiconductor device, the test semiconductor device having a first test pattern having self-aligned contact holes and a second test pattern, the first test pattern and the second test pattern being formed in the vicinity of a main pattern; measuring a step difference between the first test pattern and the second test pattern; performing a chemical mechanical polishing process on the test semiconductor device so as to isolate self-aligned contact pads formed in the self-aligned contact holes of the test semiconductor device; measuring a step difference between the first test pattern and the second test pattern after the chemical mechanical polishing process; setting a relationship equation among the step difference between the first test pattern and the second test pattern before the chemical mechanical polishing process, the step difference between the first test pattern and the second test pattern after the chemical mechanical polishing process, and an extent of isolation of the self-aligned contact pads formed in the test semiconductor device; measuring a step difference between the first pattern and the second pattern of the semiconductor device; estimating an appropriate chemical mechanical polishing time corresponding to the measured step difference between the first pattern and the second pattern of the semiconductor device by referring to the relationship equation; performing a chemical mechanical polishing process on the semiconductor device for the estimated chemical mechanical polishing time so as to isolate self-aligned contact pads formed in the self-aligned contact holes of the semiconductor device; measuring a step difference between the first pattern and the second pattern of the semiconductor device after the chemical mechanical polishing process; comparing the measured step difference between the first pattern and the second pattern of the semiconductor device after the chemical mechanical polishing step with a reference value, the reference value being a step difference necessary to achieve a desired extent of isolation of the self-aligned contact pads; and correcting the chemical mechanical polishing time for sufficiently isolating self-aligned contact pads based on the comparison result.