Blank silicon wafer

Figure 5. (a) C Is ESCA spectrum for the blank silicon wafer (Y58). (b) C Is spectrum for IMTEC Star 2000 vapor HMDS-treated silicon wafer. 

Figure 3. (a) C Is ESCA spectra for blank silicon wafer (Y58). 

To observe how a thin film would perform in DBA, several runs of the polymer films on silicon were done. An example of the tan delta values for one 50 nm film can be seen in Figure 4.4-3. The plot closely resembled those of the blank silicon wafers. The instrument appeared not to have the sensitivity to measure these thin films. The transitions of the polymer seemed to be masked by the bulky silicon substrate. The thicker films of 200 nm and 900 nm never gave an accurate initial permittivity and, therefore, the temperature sweeps were not performed. 

Figure 4.5-3 TMA results of 660 nm film superimposed on blank silicon wafer 4.6 Summary of Cooperativity Studies... 

Vapor-phase decomposition and collection (Figs 4.16 to 4.18) is a standardized method of silicon wafer surface analysis [4.11]. The native oxide on wafer surfaces readily reacts with isothermally distilled HF vapor and forms small droplets on the hydrophobic wafer surface at room temperature [4.66]. These small droplets can be collected with a scanning droplet. The scanned, accumulated droplets finally contain all dissolved contamination in the scanning droplet. It must be dried on a concentrated spot (diameter approximately 150 pm) and measured against the blank droplet residue of the scanning solution [4.67-4.69]. VPD-TXRF has been carefully evaluated against standardized surface analytical methods. The user is advised to use reliable reference materials [4.70-4.72]. 

Finally, it is interesting to note that under exposure to krypton fluoride (KrF) excimer laser radiation supplied in several shots of 350 mJ/cm the S-layer is not ablated but carbonized, in the exposed areas [109,156]. This result is already used for high resolution patterning of polymeric resists (Figure 18). S-layers that have been formed on top of a spin-coated polymeric resist (on a silicon wafer) have been first patterned by ArF radiation and subsequently served as a mask for a blank exposure of the resist by irradiation with KrF-pulses. This two-step process was possible because S-layers are less sensitive to KrF radiation than polymeric resists. The thinness of the S-layer mask causes very steep side walls in the developed polymeric resist. 

Figures 4(a-c) show three ESCA Si 2p spectra resulting from the (a) Y58 blank, (b) HMDS (SVG track) and (c) HMDS ( 2000)/Y58 wafer, respectively All spectra were recorded at 5 take-off angle These spectra clearly indicate the evolution of a new peak between the elemental silicon and the SiO peaks The growth is very pronounced in the case of the HMDS ( 2000)/Y58 treated wafer The new Si 2p peak, arising from HMDS treatment of the wafer, is centered at 101 8 eV (see Figures 4b and 4c) The other five peaks present in the spectrum of the blank wafer are assigned to Si, SiO, Si O and SiO species (4) The new peak at 101 8 eV is assigned to (cHp Si-0-type of Si species formed on the surface due to the HMDS reaction.

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