System, method and medium for modeling, monitoring and/or controlling plasma based semiconductor manufacturing processes

#The present invention relates to enhancing process control of plasma based semiconductor manufacturing processes. In particular, at least some embodiments of the present invention relate to modeling and monitoring light spectra emitted by the plasma of a plasma based semiconductor manufacturing process and control the plasma based process based on the light spectra.

#A “plasma based semiconductor process” generally refers to a methodology for fabricating microelectronic devices such as very large scale integration (VLSI) microelectronic chips and/or thin film transistors (TFTs). In particular, plasma based semiconductor processes may be used, for example, in deposition processes (e.g., plasma enhanced chemical vapor deposition, hereinafter “PECVD”) and/or etching processes during the fabrication of microelectronic devices.

#For example, a PECVD run (a particular instance of conducting a PECVD process) includes the following steps: 1) a device to be processed is placed within a chamber; 2) an initial condition is created inside the chamber using control parameters (e.g., RF power, electrode spacing, gas pressure, SiH4 flow, N2O flow, etc.); 3) plasma is ignited; 4) the control parameters are adjusted; 5) a desired end point (e.g., a predetermined thickness of a film being deposited) is reached; and 6) the run is then terminated.

#The detailed description of the present application showing various distinctive features may be best understood when the detailed description is read in reference to the appended drawing in which:

#FIG. 1 is a high-level flow chart representation of example primary steps as contemplated by at least some embodiments of the present invention;

#FIG. 2 is a flow chart representation of example steps in modeling a PECVD recipe;

#Embodiments of the present invention provide proper diagnostics and/or process control to plasma based semiconductor manufacturing processes by conducting one or more of the high-level steps indicated in FIG. 1. Referring now to FIG. 1, these steps include modeling, monitoring, and controlling the plasma based semiconductor manufacturing processes (steps 101, 103, and 105, respectively). These steps can be conducted in a sequence, but (as depicted in FIG. 1) in at least some embodiments of the present invention, one or more of the steps can be conducted independently from each other (e.g., in parallel). Each of these steps is described below in detail in the context of PECVD runs. However, it should be understood that at least some embodiments of the present invention also contemplate applying the same or similar steps in other plasma based semiconductor manufacturing processes (e.g., etching).

#In the modeling step (step 101), characteristics of PECVD runs of a particular recipe are determined. A recipe is a set of control settings for control parameters such as specified ranges and application length of time. Examples of control parameters include RF power, electrode spacing, gas pressure, SiH4 flow, and N2O flow. Thus, for instance, a recipe may specify how much RF power to apply and for how long during a PECVD run. A run is one specific instance of processing a wafer using a specified recipe.

#Detail processes of the modeling step, which includes a number of sub-steps, are described with regard to FIG. 2. Referring now to FIG. 2, a number of PECVD runs are conducted by varying control parameters (step 201). While the PECVD runs are being conducted, spectral data is collected. The collected spectral data is indicative of (e.g., is proportional to) the light emitted by plasma during each of the PECVD runs (step 203). After the spectral data is collected and analyzed, a number of spectral bands are formed (step 205). Subsequently, the collected spectral data is categorized for each formed spectral band (steps 207, 209, 211), which forms the basis to determine diagnostic ratios (step 213). Each of these steps is described in greater detail below.