Selective Cu deposition process

The selective Cu deposition process was suggested by Ting and Paunovic (13) as an alternative means of fabricating multilevel Cu interconnections (Fig. 19.4). The first step in this through-mask deposition process (14) is the deposition of a Cu seed layer on a Si wafer, and then a resist mask is deposited and patterned to expose the underlying seed layers in vias and trenches. In the next step, Cu is deposited to fill the pattern. After the Cu deposition mask is removed, the surrounding seed layer is etched and dielectric is deposited. Electroless Cu deposition has been suggested for the blanket and selective deposition processes (15). 

A variation of the selective Cu deposition process, limited to electroless Cu deposition, is the lift-ojfprocess, a planarized metallization process (16). Figure 19.5 shows a stepwise process sequence for this technology. 

The selective Cu deposition process was suggested, among others, by Ting and Paunovic. This is an alternative process to... 

The maximal Y value for Cu-PPX catalyst is 1150 [116], It is much more than the activity of all known catalysts of this reaction. For comparison, the same reaction of C-Cl bond metathesis was investigated on the special prepared catalyst containing 1 mass% of high-dispersed metallic Cu deposited on silica. In conditions analogous to those of the reaction with the nanocomposite Cu-PPX film, Y for this catalyst was 4. Moreover, it has low selectivity in this case the formation of by-products from condensation processes takes place along with the main reaction, whereas Cu-PPX catalyst gives monochlorosubstituted decanes only [116]. 

This laser approach three-step approach to patterned Cu deposition on PTFE. Step one is chemical etching of the entire sample with- sodium naphthalenide, a solution step which can be carried out in a fume hood. Step two consists of laser patterning of portions of the etched layer. This step is self reguiatlng and can be carried out in air. Finally, step three can be either Cu CVD or electroless Cu deposition. The Cu CVD reaction giving selective-area nucleation and growth of Cu is carried out in a simple reactor with minimal vacuum requirements. The electroless Cu variation is a solution process extensively used in the electronics industry which can be carried out in an efficient fume hood... 

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