CF4-O2 plasmas

Figure 23. The normalized etch rate of Si (bJ and F-atom emission intensity 60 in a CF4/O2 plasma as a function of O2 concentration in the feed. (Reproduced with permission from Ref. 42 J...

It has been found, however, that the etch rate of PBS can be reasonably controlled in both oxygen and CF4/O2 plasmas if the substrate temperature is kept below room temperature (9). This fact has been utilized to reduce the defect density in the manufacture of chrome photomasks by exposing the developed PBS pattern to a low-temperature oxygen plasma (descum) prior to wet-etching the chrome. We have now found that the plasma-etch resistance of PBS in a CF4/O2 plasma can be markedly enhanced at room temperature simply by exposing the resist to a short oxygen plasma pretreatment prior to exposure to the fluorinated plasma. This effect can be used in a variety of pattern transfer processes to controllably generate submicron features on wafers and masks. This paper examines the parameters associated with this effect, proposes a mechanism to account for the results and delineates some possible pattern transfer processes. 

The plasma etch rates of the SOG films were determined In an MRC Model 51 RIE parallel plate etcher which had 6 in. diameter electrodes. The electrode spacing was 2 in. and the substrates were placed on the powered electrode which was water cooled. The chamber pressure was about 200 mTorr for plasma etching and 10-15 mTorr for reaction ion etching (RIE). A net total power of 50W was used in each experiment. In contrast to their wet etch behavior, the SOG films etch only slightly faster than thermal Si02 in CF4 + O2 plasmas. This Is so since plasma etch rates are determined to a greater... 

Strictly speaking, the dry-process compatibility for a resist is very process dependent, and must be measured for the specific process involved. A general idea of compatibility, however, can be obtained by doing a CF4/O2 plasma etch test vs Si02 and/or PMMA references, and this test has been adopted as a quick screen test for dry-process compatibility for new resists. The relative etch ratios vs these references usually, but not always, remain constant when the process requiring resist masking is changed (e.g., PE to RIE), thus, what is measured is resist compositionally-dependent. 

Hole injection from the anode into the HTL depends upon the energy barrier at this interface. The higher the barrier, the larger the voltage required to induce injection. Therefore, in order to reduce the barrier (i.e., increase anode work function) and facilitate hole injection, for the typical anode material, indium tin oxide (ITO), various treatments of the surface are used, such as oxygen (O2) plasma treatment UV/ozone treatment treatment with polymerization of and CF4/O2 plasma treatment. ... 

Figure 18 Residue from a CF4/O2 plasma on Si (after reference 51).

Gracias s group utilized a dry etch technique for the fabrication of conical nanopores in Si substrates." They dispersed gold nanoparticles (GNPs) on the surface of a single Si crystal wafer and etched GNPs containing Si wafers with CF4/O2 plasma. They obtained conical pores with a small pore diameter as small as 20 nm with this method. The enhancement of the etch rate in the vicinity of Au NPs was explained by... 

The pattern in Figure 3 demonstrates the potential of organometallic polymers as etch resists. The top half of the AFM image corresponds to the untreated pattern of polyferrocenyldimethylsilane (PFS). The bottom half displays the same pattern after it has been exposed to a CF4/O2 plasma treatment. 

The lines shown in Figure 5 demonstrate the very high etch resistance of these organometallic polymers. The initial PFS film thickness was approximately 30 nm. After the plasma etching treatment (10 min in CF4/O2 plasma) the features exhibited a height of approximately 250 nm. 

Figure 5 Pattern of PFS on silicon fabricated by direct stamping using a ozoneAJV-cleaned PDMS stamp. Subsequently, the pattern was etched into the substrate by a CF4/O2 plasma. The features of the resulting pattern consisted primarily of hnes narrowed by dewettmg.

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