Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2000-06-09
2003-11-04
Picard, Leo (Department: 2125)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C702S084000, C700S121000
Reexamination Certificate
active
06643557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to semiconductor manufacturing, and, more particularly, to a method and apparatus for automated error correction for wafer-by-wafer processing.
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 factors that affect semiconductor device manufacturing are wafer-to-wafer variations that are caused by manufacturing problems that include start-up effects of manufacturing machine tools, memory effects of manufacturing chambers, and first-wafer effects. One of the process steps that is adversely affected by such factors is the photolithography process. Overlay is one of several important steps in semiconductor manufacturing. Line-widths, or critical dimensions, are important measurements that relate to the quality of the photolithography process. Line-width control in semiconductor manufacturing involves measuring the characteristic dimension of lines/spaces patterned onto the semiconductor wafer that is being processed. Generally, minimization of the deviation of the patterned line-width to the targeted line-width is important to ensure that the multiple layers of the semiconductor devices are connected and functional. As technology facilitates smaller critical dimensions for semiconductor devices, the need for fewer off-target line-widths increases dramatically.
Generally, photolithography engineers currently measure the line-width once per lot immediately following the photolithography (or subsequent etch) process. The measured line-width errors can be used to make manual or automatic updates to exposure tool settings. Some of the problems associated with the current methods include the fact that the exposure tool settings can generally only be updated once per lot.
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. 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 is connected to a machine interface to which the stepper is connected, 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, which can be a software program that automatically retrieves the data needed to execute a manufacturing process. The input parameters that control the manufacturing process are revised periodically in a manual fashion. As the need for higher precision manufacturing processes increases, improved methods are needed to revise input parameters that control manufacturing processes in a more automated and timely manner. Furthermore, wafer-to-wafer manufacturing variations can cause non-uniform quality of semiconductor devices.
A known technique for evaluating the acceptability of the photolithography process involves measuring critical dimensions or other parameters after the photoresist has been developed. One method used to evaluate the developed wafer is to use scatterometry to generate an intensity measurement indicative of the pattern on the wafer. The pattern in the developed photoresist appears as a series of trenches. Light is reflected differently in the trenched versus the non-trenched areas, resulting in a characteristic scattering pattern. The scatterometry measurements may be used to change the photoresist operating parameters, such as exposure time, post exposure bake time, develop time, etc., to affect the pattern formed on subsequent wafers. A limitation of post-develop measurement techniques (such as Scanning Electron Microscopy [SEM]) is that significant time elapses between the measurement and the corrective action, potentially resulting in numerous unusable wafers. Furthermore, due to the measurement time that is required when using these techniques, only a small fraction of each manufacturing lot of semiconductor wafers can be measured. The industry today lacks an efficient manner of utilizing scatterometry techniques to reduce variabilities in processed semiconductor wafers.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a method is provided for using scatterometry to perform feedback and feed-forward control. A processing run of semiconductor devices is performed. Metrology data from the processed semiconductor devices is acquired. Error data is acquired by analyzing the acquired metrology data. A determination is made whether the error data merits modification to the processing of semiconductor devices. A feedback modification of the processing of semiconductor devices is performed in response to the determination that the error data merits modification to the processing of semiconductor devices. A feed-forward modification of the processing of the semiconductor devices is performed in response to the determination that the error data merits modification to the processing of semiconductor devices.
In another aspect of the present invention, an apparatus is provided for using scatterometry to perform feedback and feed-forward control. 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 and modifying at least one control input parameter 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 first processing tool being capable of receiving at least one control input parameter signal from the machine interface; a metrology tool coupled with the first processing tool and the second processing tool, the metrology tool being capable of acquiring metrology data; a metrology data processing unit coupled with the metrology tool, the metrology data processing unit being capable of organizing the acquired metrology data; a feedback/feed-forward controller coupled with the metrology tool and the computer system, wherein the feedback/feed-forward controller is capable of generating feedback and feed-forward adjustment data and sending them to the computer system for modification of the control system parameters.
REFERENCES:
patent: 5511005 (1996-04-01), Abbe et al.
patent: 5629772 (1997-05-01), Ausschnitt
patent: 5719495 (1998-02-01), Moslehi
patent: 5900633 (1999-05-01), Solomon et al.
patent: 5987398 (1999-11-01), Halverson et al.
patent: 6016562 (2000-01-01), Miyazaki et al.
patent: 6051348 (2000-04-01), Marinaro et al.
patent: 6051349 (2000-04-01), Yoshioka et al.
patent: 6245584 (2001-06-01), Marinaro et al.
patent: 6304999 (2001-10-01), Toprac et al.
patent: 6314379 (2001-11-01), Hu et al.
patent: 6433878 (2002-08-01), Niu et al.
pa
Miller Michael L.
Toprac Anthony J.
Advanced Micro Devices , Inc.
Picard Leo
Rao Sheela S.
Williams Morgan & Amerson P.C.
LandOfFree
Method and apparatus for using scatterometry to perform... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for using scatterometry to perform..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for using scatterometry to perform... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3151636