Arrhenius Characterization of ILD and Copper CMP Processes

Abstract

To date, chemical mechanical planarization ͑CMP͒ models have relied heavily on parameters such as pressure, velocity, slurry, and pad properties to describe material removal rates. One key parameter, temperature, which can impact both the mechanical and chemical facets of the CMP process, is often neglected. Using a modified definition of the generalized Preston's equation with the inclusion of an Arrhenius relationship, thermally controlled polishing experiments are shown to quantify the contribution of temperature to the relative magnitude of the thermally dependent and thermally independent aspects of copper and interlayer dielectric ͑ILD͒ CMP. The newly defined Preston's equation includes a modified definition of the activation energy parameter contained in the Arrhenius portion, the combined activation energy, which describes all events ͑chemical or mechanical͒ that are impacted by temperature during CMP. Studies indicate that for every consumable set combination ͑i.e., slurry and polishing pad͒ a characteristic combined Arrhenius activation energy can be calculated for each substrate material being polished.

A wafer-scale material removal rate profile model for copper chemical mechanical planarization

“…According to the Arrhenius equation and Sorooshian's study [10], the process temperature in the copper CMP process affects the chemical reaction rate. To study the relation between polishing temperature and chemical reaction rate, we measured the static etch rates at various slurry temperatures, and the results are shown in Fig.…”

“…The static etch rates were measured at five points in each sample, and it was found that the rate increased with the slurry temperature. The Arrhenius equation for the static etch rate can be rewritten for the CMP process as follows [10]:…”

“…Based on the experimental analysis and the energy flow in the copper CMP, the average MRR for copper CMP can be represented as [10]:…”

Analysis of Interaction Structure Among Multiple Functional Process Variables for Process Control in Semiconductor Manufacturing

“…The focused thermal zone was selected on the polishing pad adjacent to the wafer-pad interface to record the average temperature. Since the temperature in this interface between wafer and polishing pad cannot be obtained directly, the selected zone is the best approximation of the average process temperature [20]. These three process variables are good indicators of chemical-mechanical polishing conditions [21], [22].…”

Detailed Placement for Enhanced Control of Resist and Etch CDs

“…The slurry acts as a coolant material at the interface of the pad and wafer contact and takes away a significant part of the heat through convective heat transfer [42], [55], [56], [66]. The dissipated heat changes the chemical kinetics and the physical properties of the polishing pad [42], [55], [66].…”