In the paper, chemical mechanical planarization (CMP) of Ge2 Sb2Te5 (GST) is investigated using IC 1010 and Politex reg pads in acidic slurry. For the CMP with blank wafer, it is found that the removal rate (RR)...In the paper, chemical mechanical planarization (CMP) of Ge2 Sb2Te5 (GST) is investigated using IC 1010 and Politex reg pads in acidic slurry. For the CMP with blank wafer, it is found that the removal rate (RR) of GST increases with the increase of pressure for both pads, but the RR of GST polished using IC 1010 is far more than that of Politex reg. To check the surface defects, GST film is observed with an optical microscope (OM) and scanning electron microscope (SEM). For the CMP with Politex reg, many spots are observed on the surface of the blank wafer with OM, but no obvious spots are observed with SEM. With regard to the patterned wafer, a few stains are observed on the GST cell, but many residues are found on other area with OM. However, from SEM results, a few residues are observed on the GST cell, more dielectric loss is revealed about the trench structure. For the CMP with IC1010, the surface of the polished blank wafer suffers serious scratches found with both OM and SEM, which may result from a low hardness of GST, compared with those of IC1010 and abrasives. With regard to the patterned wafer, it can achieve a clean surface and almost no scratches are observed with OM, which may result from the high-hardness SiO2 film on the surface, not from the soft GST film across the whole wafer. From the SEM results, a clean interface and no residues are observed on the GST surface, and less dielectric loss is revealed. Compared with Politex reg, the patterned wafer can achieve a good performance after CMP using IC1010.展开更多
The effect of iron trichloride (FeC13) on chemical mechanical polishing (CMP) of Ge2Sb2Te5 (GST) film is inves- tigated in this paper. The polishing rate of GST increases from 38 nm/min to 144 nm/min when the Fe...The effect of iron trichloride (FeC13) on chemical mechanical polishing (CMP) of Ge2Sb2Te5 (GST) film is inves- tigated in this paper. The polishing rate of GST increases from 38 nm/min to 144 nm/min when the FeC13 concentration changes from 0.01 wt% to 0.15 wt%, which is much faster than 20 nm/min for the 1 wt% H2O2-based slurry. This polish- ing rate trends are inversely correlated with the contact angle data of FeCl3-based slurry on the GST film surface. Thus, it is hypothesized that the hydrophilicity of the GST film surface is associated with the polishing rate during CMP. Atomic force microscope (AFM) and optical microscope (OM) are used to characterize the surface quality after CMP. The chemical mechanism is studied by potentiodynamic measurements such as Ecorr and Icorr to analyze chemical reaction between FeCl3 and GST surface. Finally, it is verified that slurry with FeCl3 has no influence on the electrical property of the post-CMP GST film by the resistivity-temperature (RT) tests.展开更多
Chemical mechanical planarization(CMP) of amorphous Ge_2Sb_2Te_5(a-GST) is investigated using two typical soft pads(politex REG and AT) in acidic slurry.After CMP,it is found that the removal rate(RR) of a-GST...Chemical mechanical planarization(CMP) of amorphous Ge_2Sb_2Te_5(a-GST) is investigated using two typical soft pads(politex REG and AT) in acidic slurry.After CMP,it is found that the removal rate(RR) of a-GST increases with an increase of runs number for both pads.However,it achieves the higher RR and better surface quality of a-GST for an AT pad.The in-situ sheet resistance(R_s) measure shows the higher R_s of a-GST polishing can be gained after CMP using both pads and the high R_s is beneficial to lower the reset current for the PCM cells. In order to find the root cause of the different RR of a-GST polishing with different pads,the surface morphology and characteristics of both new and used pads are analyzed,it shows that the AT pad has smaller porosity size and more pore counts than that of the REG pad,and thus the AT pad can transport more fresh slurry to the reaction interface between the pad and a-GST,which results in the high RR of a-GST due to enhanced chemical reaction.展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2010CB934300,2013CBA01900,2011CBA00607,and 2011CB9328004)the "Strategic Priority Research Program" of the Chinese Academy of Sciences(Grant No.XDA09020402)+2 种基金the Fund from the Science and Technology Council of Shanghai,China(Grant No.13DZ2295700)the Science Fund from the Chinese Academy of Sciences(Grant No.20110490761)the National Natural Science Foundation of China(Grant Nos.61076121,61176122,and 61106001)
文摘In the paper, chemical mechanical planarization (CMP) of Ge2 Sb2Te5 (GST) is investigated using IC 1010 and Politex reg pads in acidic slurry. For the CMP with blank wafer, it is found that the removal rate (RR) of GST increases with the increase of pressure for both pads, but the RR of GST polished using IC 1010 is far more than that of Politex reg. To check the surface defects, GST film is observed with an optical microscope (OM) and scanning electron microscope (SEM). For the CMP with Politex reg, many spots are observed on the surface of the blank wafer with OM, but no obvious spots are observed with SEM. With regard to the patterned wafer, a few stains are observed on the GST cell, but many residues are found on other area with OM. However, from SEM results, a few residues are observed on the GST cell, more dielectric loss is revealed about the trench structure. For the CMP with IC1010, the surface of the polished blank wafer suffers serious scratches found with both OM and SEM, which may result from a low hardness of GST, compared with those of IC1010 and abrasives. With regard to the patterned wafer, it can achieve a clean surface and almost no scratches are observed with OM, which may result from the high-hardness SiO2 film on the surface, not from the soft GST film across the whole wafer. From the SEM results, a clean interface and no residues are observed on the GST surface, and less dielectric loss is revealed. Compared with Politex reg, the patterned wafer can achieve a good performance after CMP using IC1010.
基金Project supported by the National Integrate Circuit Research Program of China(Grant Nos.2011ZX02704-002 and 2009ZX02030-001)the Funds fromthe Science and Technology Council of Shanghai,China(Grant Nos.0952nm00200 and 10QB1403600)the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists
文摘The effect of iron trichloride (FeC13) on chemical mechanical polishing (CMP) of Ge2Sb2Te5 (GST) film is inves- tigated in this paper. The polishing rate of GST increases from 38 nm/min to 144 nm/min when the FeC13 concentration changes from 0.01 wt% to 0.15 wt%, which is much faster than 20 nm/min for the 1 wt% H2O2-based slurry. This polish- ing rate trends are inversely correlated with the contact angle data of FeCl3-based slurry on the GST film surface. Thus, it is hypothesized that the hydrophilicity of the GST film surface is associated with the polishing rate during CMP. Atomic force microscope (AFM) and optical microscope (OM) are used to characterize the surface quality after CMP. The chemical mechanism is studied by potentiodynamic measurements such as Ecorr and Icorr to analyze chemical reaction between FeCl3 and GST surface. Finally, it is verified that slurry with FeCl3 has no influence on the electrical property of the post-CMP GST film by the resistivity-temperature (RT) tests.
基金Project supported by the National Key Basic Research Program of China(Nos.2010CB934300,2011CBA00607,2011CB9328004)the National Integrated Circuit Research Program of China(No.2009ZX02023-003)+2 种基金the National Natural Science Foundation of China(Nos. 60906004,60906003,61006087,61076121,61176122,61106001)the Science and Technology Council of Shanghai(Nos.11DZ2261000,11OA1407800.12nm0503701)the Chinese Academy of Sciences(No.20110490761)
文摘Chemical mechanical planarization(CMP) of amorphous Ge_2Sb_2Te_5(a-GST) is investigated using two typical soft pads(politex REG and AT) in acidic slurry.After CMP,it is found that the removal rate(RR) of a-GST increases with an increase of runs number for both pads.However,it achieves the higher RR and better surface quality of a-GST for an AT pad.The in-situ sheet resistance(R_s) measure shows the higher R_s of a-GST polishing can be gained after CMP using both pads and the high R_s is beneficial to lower the reset current for the PCM cells. In order to find the root cause of the different RR of a-GST polishing with different pads,the surface morphology and characteristics of both new and used pads are analyzed,it shows that the AT pad has smaller porosity size and more pore counts than that of the REG pad,and thus the AT pad can transport more fresh slurry to the reaction interface between the pad and a-GST,which results in the high RR of a-GST due to enhanced chemical reaction.