Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-05-29
2003-02-04
Black, Thomas (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S109000
Reexamination Certificate
active
06516237
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system for preparing and managing manufacturing-process specifications, and particularly, to a system for preparing manufacturing-process specifications, capable of efficiently designing the conditions of individual manufacturing processes.
2. Description of the Prior Art
Manufacturing processes are manually designed by skilled engineers, and simulation is used only to supplement the engineers. Manufacturing-process specifications designed for, for example, a semiconductor large-scale integrated circuit device (LSI) must be edited and checked to see whether or not they are correct according to accumulated knowledge. Then, simulation is carried out according to the specifications, to test the structure of a semiconductor wafer, impurity distributions, and the characteristics of the LSI.
To assist these tasks, several systems have been developed and used in practice in, for example, an LSI manufacturing line. The LSI manufacturing line has a production control system that needs process specifications to specify and control apparatuses that work in the manufacturing line. The process specifications are huge to precisely control the manufacturing line and improve the quality and yield of products. To reduce manpower, time, and careless input mistakes in preparing the process specifications, an assisting system is used.
Also used to assist the preparation of the process specifications are process simulators, device simulators, and circuit simulators. These simulators simulate the manufacturing, electric characteristics, and circuit characteristics of LSIs, and such simulation work is essential before actually manufacturing LSIs to find the problems thereof.
Conventional production control systems control apparatuses for carrying out manufacturing processes according to specifications, independently of simulation. The simulation, however, must use actual manufacturing conditions, to determine or evaluate the manufacturing processes and the electric characteristics of products manufactured through the processes under various conditions. Instead of using every piece of data set for actual manufacturing processes, the conventional simulation uses only part thereof. For example, the prior art simulates a diffusion process only with specifications for charging and discharging a wafer into and from a diffusion furnace, as well as diffusion temperature, diffusion atmosphere, and diffusion time.
Simulation needs specific data such as discretization data for numerical calculations. Such simulation data qualitatively differs from process specification data. Due to this, a prior art of
FIG. 1
employs a tool for converting process specification data into simulation data, and simulation data into process specification data. This prior art employs different databases for preparing the process specification data and simulation data. Namely, a database A stores data for a production control system and is used to prepare the process specification data, and a database B stores data for a simulation system and is used to prepare the simulation data. This kind of prior art is disclosed in, for example, Japanese Unexamined Patent Publication Nos. 9-34533 and 6-260380.
LSIs are integrating, adding more values, and improving yield and productivity. This tendency is heightening requirements for reduction in process variations and margins. It is important, therefore, to improve simulation accuracy so that a simulation result conforms to actual manufacturing processes. To faithfully simulate actual manufacturing processes, some prior art tries to adjust existing models of manufacturing processes to reflect actual conditions.
The prior art prepares models and parameters for every process. For example, the prior art prepares a model of impurity diffusion and parameters for a diffusion process according to diffusion temperature, time, and atmosphere.
In practice, each process involves variations due to apparatuses to carry out the process. For example, the operating conditions of a diffusion furnace are influenced by manufacturing variations specific to a heat source of the furnace and by changes in the flow rates and velocities of gases in the furnace. The prior art is incapable of considering these variations because the prior art fixes models and parameters for each process.
Specification data for each process contains data about apparatuses to carry out the process and data for controlling the apparatuses. When preparing simulation data from the specification data, the prior art does not usually pick up the data about apparatuses and data for controlling them.
In this way, the prior art handles the process specification data and the simulation data independently of each other, and therefore, must prepare different databases to store them. Process specifications are usually prepared for each process or for a process sequence, and an engineer is assigned to prepare specifications for a process sequence. An engineer of a given sequence prepares process specifications for the sequence, tests the specifications, and improves them through simulation. Sometimes, the engineer who tests the specifications of a given process sequence differs from the engineer who simulates the process sequence. To complete specifications for the process sequence, many pieces of specification data and simulation data are prepared and tested. These pieces of data are kept by the engineers in charge. When the other engineers want to have technical information such as process specification data, simulation data, prototype evaluation results, and simulation results, they must refer to the engineers in charge.
This hinders the quick transfer and sharing of information, to thereby deteriorate the efficiency of developing LSIs.
To share information, it is necessary to make a collective database of technical know-how and prototype evaluation results obtained from groups of manufacturing processes. Since the process specification data and simulation data of the prior art are separately prepared by engineers, the process specification data, data obtained from manufacturing processes that are based on the process specification data, simulation input data, and simulation resultant data have different formats. As a result, it is difficult to make a collective database of them.
Like the process specification data, the simulation data is based on production and simulation know-how. Accordingly, it is beneficial to make a database of the simulation data. Since the process specification data and simulation data are independent of each other, it is difficult for the prior art to combine them together and utilize them for new simulation.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a system for preparing and controlling manufacturing-process specifications, capable of equally handling production control and simulation and effectively utilizing simulation results. The present invention also provides a method of preparing process data for the system, and a method of manufacturing semiconductor devices with the use of the system.
In order to accomplish the objects, the present invention provides a system for preparing manufacturing-process specifications. The system has a database for storing process data that includes manufacturing-process specifications applied to apparatuses to carry out manufacturing processes and parameters used to simulate the manufacturing processes; a production control system for controlling the apparatuses according to the process data, and collecting data measured through the manufacturing processes; a simulation system for simulating the manufacturing processes according to the process data; and an editing unit for correcting the parameters according to the collected data and amending the manufacturing-process specifications according to a result of the simulation.
The database may collect data for each of the apparatuses and be amended so as to reflect dependence among the apparatuses in carrying out the man
Aoki Nobutoshi
Kanemura Takahisa
Black Thomas
Foley & Lardner
Hartman Jr. Ronald D
Kabushiki Kaisha Toshiba
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