Liquid etchant composition, and etching process in capacitor process of dram using the same
a technology of etching process and liquid etchant, which is applied in the direction of semiconductor devices, chemistry apparatus and processes, and capacitors, can solve the problems of limiting the capacitor height, destroying the structure of tin electrodes, and electrical shorts between memory cells, so as to achieve the effect of increasing the capacitor height and improving the selectivity of etching si to metal materials
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example 1
[0024]A wafer having thereon a TiN layer of about 10 nm, and another wafer having thereon a poly-Si layer of about 1000 nm were provided. A 1.0 wt % HF solution was used to treat the surface of the TiN layer for 60 seconds and to remove any SiOx on the surface of the poly-Si layer for 30 seconds, distill water was used to rinse both wafers for 30 seconds, and a 5 wt % TMAH solution (purchased from Moses Lake Industries) added with a given amount of hydroxylamine (purchased from Sigma Aldrich) was used to etch the TiN layer at 75° C. for 20 minutes and etch the poly-Si at 75° C. for 10 seconds.
[0025]The TMAH solutions having been used to etch the TiN layer and the poly-Si layer respectively were then analyzed by ICP-OES (inductively couple plasma optical emission spectrometry) for respective contents of titanium and silicon. The measured contents were used to derive the respective etching rates of TiN and poly-Si.
[0026]FIG. 2 shows variations of the respective etching rates of poly-S...
example 2
[0028]A wafer having thereon a TiN layer of about 10 nm, and another wafer having thereon a poly-Si layer of about 1000 nm were provided. After a 0.5 wt % HF solution was used to treat the surface of the TiN layer and to remove any SiOx on the surface of the poly-Si layer for 2 minutes, a 5 wt % TMAH solution added with a given amount of a TiN corrosion inhibitor, which was provided by Tokyo Ohka Kogyo Co., Ltd. (TOK) and called ST-B046, was used to etch the TiN layer and the poly-Si layer at 75° C. or 80° C. for 6 minutes. A 0.5 wt % HF solution was then used to remove any TiOx on the surface of the TiN layer and to treat the surface of the poly-Si layer for 1 minute. The thickness of the remaining TiN layer was measured by the ellipsometry technique to derive the loss of the TiN thickness. The thickness of the remaining poly-Si layer was measured with X-section SEM to derive the loss of the poly-Si thickness.
[0029]The results are listed in the following Table 2:
TABLE 2TiNPoly-SiPo...
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