1. Field of the Invention
This invention relates generally to semiconductor products, and, more particularly, to a method and apparatus for simultaneously controlling multi-cup semiconductor manufacturing tracks.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today""s manufacturing processes, particularly semiconductor manufacturing processes, call for a large number of important steps. These process steps are usually vital, and therefore, require a number of inputs that are generally fine-tuned to maintain proper manufacturing control.
The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (etching, doping, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing locations that contain different control schemes.
Among the important aspects in semiconductor device manufacturing are RTA control, chemical-mechanical polishing (CMP) control, etching, and overlay control. Overlay is one of several important steps in the photolithography area of semiconductor manufacturing. Overlay process involves measuring the misalignment between two successive patterned layers on the surface of a semiconductor device. Generally, minimization of misalignment errors is important to ensure that the multiple layers of the semiconductor devices are connected and functional.
Generally, process engineers currently analyze the process errors a few times a month. The results from the analysis of the process errors are used to make updates to process tool settings manually. Generally, a manufacturing model is employed to control the manufacturing processes. Some of the problems associated with the current methods include the fact that the process tool settings are only updated a few times a month. Furthermore, currently the process tool updates are generally performed manually. Many times, errors in semiconductor manufacturing are not organized and reported to quality control personal. Often, the manufacturing models themselves incur bias errors that could compromise manufacturing quality.
Generally, a set of processing steps is performed on a lot of wafers on a semiconductor manufacturing tool called an exposure tool or a stepper, followed by processing of the semiconductor wafers in etch tools. The manufacturing tool communicates with a manufacturing framework or a network of processing modules. The manufacturing tool is generally connected to an equipment interface. The equipment interface to which the stepper is connected is also connected to a machine interface, thereby facilitating communications between the stepper and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script based upon a manufacturing model, which can be a software program that automatically retrieves the data needed to execute a manufacturing process. Often, semiconductor devices are staged through multiple manufacturing tools for multiple processes, generating data relating to the quality of the processed semiconductor devices. Many times, errors can occur during the processing of semiconductor devices. Furthermore, semiconductor wafers that are processed in different sections, such as different wafer cups on a manufacturing track, of a manufacturing area often have different characteristics. Often, crucial characteristics, such as critical dimensions, of a semiconductor wafer can be non-uniform due to variations between the different sections of a manufacturing area. The lack of uniformity can cause quality and efficiency problems. In some cases, multiple semiconductor wafer cups are not utilized in a single process to avoid semiconductor wafers that have non-uniform characteristics, resulting in inefficient use of manufacturing resources.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
In one aspect of the present invention, a method is provided for controlling multiple semiconductor wafer cups in photolithography processing tools. At least one process run of semiconductor devices is processed. A multi-wafer-cup process analysis is performed upon the processed semiconductor devices. At least one control parameter is modified for a subsequent process run of semiconductor devices using results from the multi-wafer-cup process analysis.
In another aspect of the present invention, an apparatus is provided for controlling multiple semiconductor wafer cups. The apparatus of the present invention comprises: a computer system; a manufacturing model coupled with the computer system, the manufacturing model being capable of generating at least one control parameter input signal; a machine interface coupled with the manufacturing model, the machine interface being capable of receiving process recipes from the manufacturing model; a processing tool capable of processing semiconductor wafers and coupled with the machine interface, the processing tool being capable of receiving at least one control input parameter signal from the machine interface; a first wafer cup coupled with the processing tool for receiving semiconductor wafers, wherein the first wafer cup is capable of applying a photoresist material onto a semiconductor wafer; a second wafer cup coupled with the processing tool for receiving semiconductor wafers, wherein the second wafer cup is capable of applying a photoresist material onto a semiconductor wafer; a metrology tool coupled with the processing tool, the metrology tool being capable of acquiring metrology data; and a metrology data processing unit coupled with the metrology tool and the computer system, the metrology data processing unit being capable of organizing the acquired metrology data and sending the organized metrology data to the computer system.