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US 9,040,317 B2Granted
Methods for achieving width control in etching processes
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsKeng-Ying Liao, Szu-Hung Yang, Chiung Wen Hsu
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Abstract
A method includes performing a patterning step on a layer using a process gas. When the patterning step is performed, a signal strength is monitored, wherein the signal strength is from an emission spectrum of a compound generated from the patterning step. The compound includes an element in the patterned layer. At a time the signal strength is reduced to a pre-determined threshold value, the patterning step is stopped.
Claims17
A method comprising:
- performing a patterning step on a first layer using a process gas, wherein the patterning step comprises:
- an etching step for etching down the first layer;
- and
- after the first layer is etched through, performing a trimming step on the first layer to remove parts of the first layer;
- when the patterning step is performed, monitoring a signal strength from an emission spectrum of a compound generated from the patterning step, wherein the compound comprises a first element in the first layer, and wherein the signal strength is monitored during the trimming step;
- monitoring an additional emission spectrum of an element in a second layer underlying the first layer, wherein the first layer and the second layer are formed of different materials;
- at a time after the additional emission spectrum indicates a presence of the element in the second layer, recording a value of the signal strength;
- determining a threshold value based on the recorded value of the signal strength;
- and
- stopping the patterning step once the signal strength is reduced to the threshold value.
7 more elements
A method comprising:
- forming a gate electrode layer over a substrate, wherein the gate electrode layer comprises silicon;
- forming a hard mask over the gate electrode layer, wherein the hard mask comprises a compound comprising silicon and nitrogen;
- forming and patterning a photo resist over the hard mask;
- etching the hard mask;
- after the hard mask is etched through and at a time point, starting trimming the hard mask using a process gas comprising carbon fluoride;
- after the hard mask is etched through, recording a reference signal strength of an emission spectrum of a compound, wherein the compound comprises nitrogen and carbon;
- calculating a threshold signal strength as a function of the reference signal strength;
- stopping the trimming once the signal strength of the emission spectrum of the compound reduces to the threshold signal strength;
- and
- patterning the gate electrode layer using remaining portions of the hard mask as an etching mask.
7 more elements
A method comprising:
- performing a patterning step on a first layer using a process gas;
- when the patterning step is performed, monitoring a signal strength from a first emission spectrum of a compound, wherein the compound comprises a first element in the first layer and a second element in the process gas;
- monitoring a second emission spectrum of a third element in a second layer, wherein the second layer is underlying the first layer, and wherein the first layer and the second layer are formed of different materials;
- at a time after the second emission spectrum indicates a presence of the third element, recording a first value of the signal strength;
- and
- stopping the patterning step once the signal strength is reduced to a pre-determined second value.
3 more elements
Dependencies are inferred from the claim text.