Trench planarization techniques
First Claim
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1. A method of polishing irregular features of a semiconductor device top surface topography, comprising:
- polishing a sample specimen having first trench features;
measuring the height (h) and width (W) of the first trench features during polishing;
calculating the feature aspect ratio (FAR=h/w) of the first trench features;
measuring the rate of removal (Ri) inside the first trench features and outside (Ro) the first trench features during polishing;
calculating a Relative Polish Rate (RPR=Ri/Ro);
plotting first feature width (W), RPR, and FAR; and
polishing a semiconductor device having second features similar to the first trench features of the sample specimen, based on results graphically observed in the plot of first feature polishing.
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Abstract
Various techniques for quantifying polishing performance are disclosed, and provide insight on the progression from a planarization regime to a smoothing regime to a blanket polish back regime, as well as providing a single, definable parameter (Quality Characteristic) for optimizing polishing performance. With these analytical tools in hand, it is possible to create novel structures which absorb polish rate non-uniformities across a wafer, and it is also possible to define and employ a "quick" polish step to clear high spots which will be followed by a subsequent etch step for rapid removal of material.
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Citations
9 Claims
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1. A method of polishing irregular features of a semiconductor device top surface topography, comprising:
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polishing a sample specimen having first trench features; measuring the height (h) and width (W) of the first trench features during polishing; calculating the feature aspect ratio (FAR=h/w) of the first trench features; measuring the rate of removal (Ri) inside the first trench features and outside (Ro) the first trench features during polishing; calculating a Relative Polish Rate (RPR=Ri/Ro); plotting first feature width (W), RPR, and FAR; and polishing a semiconductor device having second features similar to the first trench features of the sample specimen, based on results graphically observed in the plot of first feature polishing. - View Dependent Claims (2, 3, 4, 5)
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6. A method of forming flush-filled trenches in a semiconductor device, comprising
forming a trench of depth h in a test specimen; - over-filling the trench with trench-fill material, so that the trench is at least full and there is excess material outside of the trench;
measuring the thickness (tout) of the trench-fill material outside of the trench; measuring the thickness (tin) of the trench-fill material inside the trench; defining a figure of merit (67 , where; TI δ
=(tin /h)(1-tout /tin);polishing the test specimen for various intervals of time; at each interval, remeasuring tout and tin ; calculating the standard deviation σ
67 , at each interval of time;compounding the figure of merit δ and
the standard deviation σ
into a Quality Characteristic Q that reflects the overall process performance; andpolishing a semiconductor device having second trenches similar to the trenches in the test specimen based on the Quality Characteristic. - View Dependent Claims (7, 8, 9)
- over-filling the trench with trench-fill material, so that the trench is at least full and there is excess material outside of the trench;
Specification