Optimizing IC Interconnection: A Functional Approach to Innovation (Stay updated on the project's progress)

Use silicide passivation instead of a thick Ta barrier layer.

To ensure a small gap between the metal line and ILD. It could be made in different ways, such as using soluble Barriers, we can use a difference in temperature expansion coefficients, etc.

Use ILD with non-uniform density. Actually, we need high density of the material to prevent diffusion of Cu in to ILD

Air daps also prevent the formation of voids within the metal via a metal line - we already have voids. Very strong Cu-electromigration might slightly affect the surface of the via and metal line, but the voids will not be formed within the metal.

In Step 3 - Sacrificial Light Absorbing Layer deposition - use hot air for the material solidification on the wafer during the Spinon process. This will allow the termination of the furnace and additional movements of the wafer. The high pressure above the rotating wafer will prevent the material from contamination.

Regarding the Step 4 - Photo Lithography (PL) operation simplification:

Why do we develop within the costly PL equipment? Developing the exposed resist is just a wet etch/clean process that can be performed with regular cheap wet cleaning equipment.

Another idea regarding Step 4 - Via Patterning simplification:

Why do we need to develop exposed PR at all? Exposed PR is removed by an aqueous solution, meaning it can be removed by plasma. So, the idea is to apply plasma etch directly after exposure.

The cleaning solution dissolves the residue, but the contaminated solution remains on the wafer and should be removed by the wafer rotation. The rotation of the wafer results in the removal of the cleaning solution. I would propose to apply "Other way around" principle. Instead of pour out the solution on the rotating wafer, we could rotate the wafer (face down) in the bath of the solution. It gives a better possibility of managing the temperature and renovating the cleaning solution on the wafer surface.

Etch stop is needed only on the surface of Cu to prevent Cu diffusion from the bottom Cu metal line to the top ILD. Instead of depositing the Etch Stop material with CVD; it is proposed to elaborate a process of selective deposition of PMMA with dissolved SiC or SiN. The liquid can be spined on the wafer and removed from the ILD (SiO2) areas.

To make Dry etch process in pulses to ensure the pump to pump out and to remove SiF4 and all other gaseous by-products

Instead of pouring the solution on the rotating wafer, we can do the opposite and place it face down in the solution bath.

Another direction for development and real innovation is to remove the residue at the previous operation - dry etch. In this case the Wet etch operation will not be necessary and can be eliminated.

"Partial or excessive action" - to make a prewet of the wafer before the inserting into the electrolyte

"Composite materials" is a good principle; maybe we can dip the wafer into another liquid with very low surface tension that is soluble in the electrolyte, such as ethanol or IPA.

To simplify the polish (CMP) operation, it is proposed that the bulk of the Cu be removed at the electroplater just after the completion of the electrodeposition. It is a straightforward process to replace the polarity to make the wafer an anode and give (-) to the anode. It will dissolve the main affected part of the Cu and simplify the following operation - polish.