JP3371899B2 - Lithography system, information collecting apparatus, setting apparatus, exposure apparatus, and device manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for automatically controlling various kinds of manufacturing equipment and managing various kinds of information in a lithography system using a plurality of exposure apparatuses.

[0002]

2. Description of the Related Art Manufacturing processes for semiconductor devices and liquid crystal devices usually include a process called lithography. In many cases, this lithography process means an optical process, which starts with applying a photo-sensitized (photoresist) film on a semiconductor wafer or a glass plate to a thickness of about 1 μm, and then masks the resist layer. The process ends by exposing the pattern and then developing it.

At present, at the device manufacturing site, the step of applying a resist to a substrate and the step of developing a substrate after exposure are processed exclusively by an apparatus called a coater / developer, and an exposure apparatus is applied with a resist. It is used to precisely align a mask pattern on a substrate and transfer it with a predetermined resolution.

In a production line handling mass-produced devices, a coater / developer and an exposure apparatus are inlined, and an operator simply sets a cassette containing a plurality of unprocessed substrates in the coater / developer. All are processed automatically.

Further, in order to improve mass productivity, a plurality of exposure apparatuses (and coater / developer) are used in parallel in the production line. In this case, since it is necessary to increase the operation rate for each exposure apparatus, a plurality of exposure apparatuses that form a line are centrally (group) controlled by a host computer that is in a superordinate relationship with the exposure apparatus-side computer. There is.

FIG. 1 is a block diagram schematically showing an example of conventional integrated control. Block EX shown in FIG.
P1, EXP2 ... EXPn represent an exposure apparatus, and CD1,
CD1 ... CDn represents a coater / developer. As a matter of course, a computer CMP / En for controlling the main body is provided in each exposure apparatus EXPn, and a computer CMP / Cn for controlling the main body is also provided in the coater / developer CDn.
Is provided. Further, each exposure apparatus EXPn is provided with reticle libraries RL1, RL2, ... RLn for storing a plurality of predesignated reticles (masks), which are automatically converted into necessary reticles by a command from the computer CMP / En. To be done. Furthermore, the coater / developer CDn has a library WC that stores a lot (usually 25 wafers) of wafers designated in advance in cassette units.
L1, WCL2 ... WCLn are attached. This wafer cassette library WCLn is configured to automatically load a desired wafer cassette by selecting a coater / developer CDn that allows the automatic transfer robot to finish the process in the fastest unmanned production line. , Is not necessarily inline with the coater / developer CDn.

The computer CMP.En of each exposure apparatus EXPn and the computer CMP.Cn of each coater / developer CDn both have a communication function such as an RS232C line, and a medium computer using this line. Are connected to personal computers PC1, PC2 ... PCn. Further, the personal computers PC1, PC2 ... PCn are connected to the host computer H.COM of the upper level. The host computers H and COM are personal computers PC1 and PC2 ...
The PCn is instructed to execute the exposure processing of a predetermined wafer using a predetermined reticle, and information such as the completion of processing from each personal computer is received to control the entire lithography process (including wafer distribution management and reticle management). Do.

The personal computers PC1, PC2 ... PCn are
According to a command from the host computer H / COM, the processing operations of the coater / developer CDn and the exposure apparatus EXPn are managed so as to be optimized, and information such as whether or not a predetermined processing is completed and whether or not there is any trouble To the host computer H.COM. The host computer H / COM performs wafer and reticle supply management (physical distribution management) according to the type of product to be processed, and processing capacity (throughput) of each exposure apparatus EXPn in order to carry out total IC device manufacturing management. Etc., and manage the overall operation so as to maximize the operating rate of each exposure apparatus that constitutes the line.

[0009]

As an exposure apparatus used in the line of the lithography process shown in FIG. 1, a stepper for reducing and projecting a reticle pattern to about 1/5 (or 1/10) is currently the mainstream. Has become. With the miniaturization of semiconductor devices, the processing accuracy required for these steppers also becomes stricter year by year, and the performance margin on the stepper side (difference between the accuracy guaranteed on the specification sheet and the accuracy of stable performance) is also increased. The reality is that it is getting smaller.

For this reason, detailed management as described below has become necessary. (B) In order to maintain the performance of the device (EXPn, CDn) in the best state, the device state is grasped in detail. (B) When deterioration of the device performance is detected, it is promptly restored. (C) The processing condition parameters are optimized for each device or each processing lot.

The above (a), (b), and (c) are typical ones, but when these are managed, a huge amount of data such as performance measurement data of the device and status data during processing are collected. , Analysis, and feedback to the device are required.

It is practically impossible to perform this work manually, and the host computer H shown in FIG.
Incorporating the functions of (a), (b), and (c) into COM causes problems in the following points. (1) The amount of data to be collected is large, and the capacity of the communication line of the host computer H / COM for production control etc. is insufficient. (2) Generally, the host computer H / COM manages all processes, and it is often difficult to incorporate detailed software unique to the device such as data management and analysis only for the lithography process, and the number of data items increases. ,
Improvements in analysis methods (algorithms, etc.) cannot be achieved quickly due to the relationship with other management functions. (3) The load on the host computer H / COM increases,
Squeeze other management functions.

In view of the above-mentioned problems, the present invention performs fine and unique management at least for the exposure apparatus while allowing free construction on the user side of the conventional production management system using a host computer. The purpose is to realize the system. Another object of the present invention is to provide a lithography system, an information collecting apparatus for an exposure apparatus, a measuring instrument setting apparatus, an exposure apparatus, and a semiconductor device manufacturing method capable of stably maintaining a lithography process including an exposure process.

[0014]

In order to achieve the above object, in the present invention according to claim 1, in a lithography system having a plurality of exposure devices arranged in a clean room, the plurality of exposure devices are integrated. Manage e
And an information collecting unit that is connected to a communication unit to which the plurality of exposure apparatuses are connected and that collects and stores operation information of each exposure apparatus from each of the exposure apparatuses via the communication unit. Having, means of collecting information
Is independent of its host computer
In addition, it is characterized by being placed outside the clean room.

According to a second aspect of the present invention, in a lithography system having a plurality of exposure apparatuses arranged in a clean room, the exposure system that integrally controls the plurality of exposure apparatuses is used.
A computer and a plurality of exposure apparatuses are connected to a communication means, and the processing state information of the substrates processed by the respective exposure apparatuses is collected from the respective exposure apparatuses via the communication means. And an information collecting means for storing the information stored in the host computer.
It is characterized in that it is provided independently of the data processing unit and is placed outside the clean room.

According to a tenth aspect of the present invention, in a lithography system using an exposure apparatus, a measuring means for measuring a processing state of a substrate exposed by the exposure apparatus, and an exposure when the substrate is subjected to the exposure processing. Setting means for setting the measurement conditions of the measuring means for the exposed substrate based on the exposure processing information of the apparatus.

The present invention according to claim 18 provides a host computer.
Each of the multiple exposure devices that are collectively controlled by the computer
It is an information collection device that collects operating information of
The information collection device is provided independently of the host computer.
There are multiple exposure devices installed in the clean room.
It is connected from the clean room outside the respective connected communication unit, and to store the operation information of the respective exposure apparatuses collected from each of the respective exposure apparatus via the communication means at its clean room outside .

The present invention according to claim 19 provides a host computer.
Each of the multiple exposure devices that are collectively controlled by the computer
Information collection that collects the processing status information of the processed board
A device, the information collecting device of which is a host computer
Is provided independently of each other, and a plurality of exposure apparatuses arranged in the clean room are connected from outside the clean room to the communication means to which they are respectively connected, and collected from each of the exposure apparatuses via the communication means. The processing state information of the substrate processed by each of the exposure apparatuses is stored outside the clean room.

The present invention according to claim 29 is an exposure apparatus,
The exposure apparatus is connected to a measuring unit that measures the processing state of the substrate that has been subjected to the exposure processing, and based on the exposure processing information of the exposure apparatus when the exposure processing is performed on the substrate, The setting device is characterized by setting the measurement conditions of the measuring means.

The present invention according to a thirty-fifth aspect of the present invention is an exposure apparatus which is arranged in a clean room and is connected to a network, the exposure apparatus including a host exposure apparatus and another exposure apparatus.
It is controlled by the computer, and its host computer
The operation information of the exposure apparatus or the processing information of the substrate processed by the exposure apparatus is transmitted via the network to the information collecting means which is provided independently of the computer and is connected to the network from outside the clean room. It is characterized by having a control means.

The present invention according to claim 36 is an exposure apparatus connected to a network, and a measuring instrument for measuring a processing state of a substrate exposed by the exposure apparatus via the network, and the exposure apparatus. Is connected to a setting device that sets the measurement conditions of the measuring instrument for the substrate that has been subjected to the exposure processing by the exposure apparatus based on the exposure processing information of, and the exposure processing information when the substrate is exposed through the network is displayed. It is characterized by having a control means for transmitting to the setting device.

The present invention according to claim 43 is an exposure apparatus which is controlled by a host computer together with other exposure apparatuses, and has a communication function via a first communication line,
It has a communication function via a second communication line of a different type from the first communication line, is connected to the host computer via the first communication line, and is connected via the second communication line. It is characterized in that it has a control means connected to an information collecting device for collecting operation information of the exposure device or a result of performance evaluation. The present invention according to claim 47, is the exposure
Apparatus and resist for a substrate to be exposed by the exposure apparatus
Contact the coater / developer that performs coating and development.
Connected via the communication means and the dew through the communication means.
Collects error occurrence information of optical equipment and its coater / developer.
The history data of the error occurrence information is collected and stored.
Characterized by generating aggregate information using historical data
It is an information collecting device.

[0023]

According to the present invention as set forth in claims 1, 2, 18, 19, and 35, since the operation information of the exposure apparatus or the processing information of the substrate processed by the exposure apparatus is stored outside the clean room, it can be stored in the clean room. Since the stored information can be confirmed without the operator entering, it becomes possible to stably maintain the lithography process. In addition, claim 1
According to the present invention described in Nos. 0, 29, and 36, since the measurement condition of the measuring instrument for the substrate subjected to the exposure processing by the exposure apparatus is set based on the exposure processing information of the exposure apparatus, the measurement suitable for the exposure processing is performed. Therefore, the lithography process can be stably maintained. further,
In the present invention according to claim 43, the first communication means connected to the host computer and the second communication means connected to the information collecting device.
Since the communication means are different types of communication lines, communication with the information collecting apparatus can be performed without interfering with the host computer, and the lithography process can be stably maintained. Also, in claim 47,
The present invention is directed to the occurrence of error in the exposure apparatus and coater developer.
Stores historical data of information and collects it using the historical data.
Detailed status of each device is generated to generate total information.
Stable lithography process including exposure process
It is possible to maintain.

[0024]

FIG. 2 shows a lithographic information management system (Lithography Information Control System) according to an embodiment of the present invention.
The overall structure of the wafer stepper EXP1, EXP2, ...
XPn shall be used. Also, the host computer H
・ COM, coater / developer CD1, CD2 ... CD
Also, n and the like are the same as conventional ones.

As shown in FIG. 2, in this embodiment, an Ethernet (registered trademark) LAN 50 is used for communication between each device. This LAN (Local Area Network) is a host computer H ・ C in the lithography process.
What was laid for OM may be used, and may be newly laid. Further, a dedicated machine controller (MC) is provided between the host computer H / COM and the exposure unit (a pair of stepper and coater / developer).
100 is provided. The machine controller 100 basically has the same functions as the conventional personal computers PC1, PC2 ... PCn, but additionally has a communication function using the LAN 50 and a function of collecting device information of steppers and coater / developers. ing.

Master Data Processor (MDP) 1
Reference numeral 10 collects and manages information on the operating status report from the MC 100, transmits various information to the MC 100, and the like. The centralized information server (CIS) 120 has the functions of editing, distributing, and collecting information of the stepper process program, and in particular, based on the operation information collected by the MDP 110, M
When the DP 110 collects and analyzes data relating to the performance of the stepper, the historical data necessary for correcting and correcting the operation parameter of the stepper is recorded as necessary in the MDP 110.
Send to. Functions related to this correction and correction are MDP11
It is executed at 0. On the other hand, various measuring instruments 140, 150 and the like are connected to the LAN 50 via the LAN adapter 130. As the measuring instruments 140 and 150, for example, automatic line width measuring instruments such as LAMPAS and lightwave 3I sold by Nikon Corporation, pattern coordinate measuring instruments and the like are used. These measuring devices measure the line width of the resist pattern on the exposed and developed wafer, the coordinate position of a specific resist pattern, and the like, and the measurement data is obtained via the LAN 50 or the MDP 110 (or the recording medium). CIS12
0).

In the above hardware configuration,
The CIS 120 can be installed outside the clean room. Generally, the measuring instruments 140 and 150 are arranged in a clean room where a stepper is installed, so that the MDP
When the measuring instruments 140 and 150 are to be remotely controlled by the 110, it is more convenient for the operation that the MDP 110 is also installed in the clean room.

In the system shown in FIG. 2, the communication between the exposure unit and the LAN 50 is performed via the MC 100, but the computer CMP E1 in each stepper is used.
~ CMP En may have a communication function with a LAN. In this case, the computer CMP of the stepper body
Since the En generally does not store much information about the wafer process, it is preferable to exchange data regarding the operating parameters of the stepper associated with the process progress via the MC 100.

The main services (software) installed in the system described above are roughly classified into the following four items. Auto setup service that automatically sets the operation parameters of each stepper Centrally manages the program that sets the processing conditions of each stepper, and process program management service that distributes to each stepper as necessary Centralized management of the process execution status (operating state) of each stepper The central monitoring service that maintains the operational stability of the stepper by displaying the status of the stepper and saving the history collects the performance data unique to each stepper, and changes the stepper as necessary. Performance Analysis Service for Estimating Operational Parameters Of the above four service functions, three of which are the subject of the present invention are, and the most important of these is the auto setup service.

This automatic setup service (hereinafter A
Called SUS) is the wafer (and reticle) to be processed
The main functions of the stepper are set in advance so as to optimize the accuracy and function of the stepper according to the product type.

In executing this ASUS, the measuring instruments 140, 150 or the stepper EX shown in FIG. 2 are used.
The measurement function using the alignment sensor in Pn will be used.

A typical structure of the stepper EXPn and the coater / developer CDn will be described with reference to FIG. In FIG. 3, WCLn is a wafer cassette library as shown in FIG. 1, and the wafer to be processed is a wafer loader unit compatible with in-line processing through each section (resist coating, prebaking, etc.) in the coater / developer CDn. Then, the wafer is transferred to the WL and then transferred to the wafer stage WST of the stepper EXPn. Also,
Wafers that have been exposed by the stepper are the wafer loader WL
Through the respective sections (wet development, drying, etc.) in the coater / developer CDn, and returns to the library WCLn again.

On the other hand, the stepper EXPn has an illumination system ILS for illuminating the reticle R as a mask, a reticle stage RST, a projection lens PL, and a wafer stage WS.
T, a reticle alignment sensor RA, a TTL type wafer alignment sensor LA, an off-axis type wafer alignment sensor WA, etc. are typically provided, and these controls are performed by a computer CMP / E.
n.

As described above, the system shown in FIG. 3 is merely an example, and does not represent all lithography systems. Now, in order to execute ASUS using the system of FIG. 3, actual exposure processing is performed by using the leading wafer of a lot of 25 or 50 as a pilot wafer, and the processing result of the pilot wafer is measured by a measuring instrument. 140
(Or 150) is required.

The MDP 110 in FIG. 2 also organically participates in the processing using this pilot wafer. First, in the MDP 110, information regarding the exposure processing of the wafer lot is accumulated from the host computer H / COM via the MC 100. So MDP110
It is possible to recognize which exposure unit is processing the wafer lot and set measurement conditions. Here, it is assumed that the measuring instruments 140 and 150 in FIG. 2 are used, and the MDP 110 executes a measuring process / program relating to measurement contents, measuring instrument control data, measurement result determination criteria and the like that can be determined for each product (wafer type) or process. Create and manage (save). That is, the MDP 110 stores and manages a file MPPF that defines the name of the exposure process program (created by H.COM) to which the wafer lot to be processed belongs and the measurement process program content corresponding to the lot. . Here, the flow of the actual pilot wafer processing will be described with reference to FIG.
First, the measuring device 14 is used for the pilot wafer after the development processing.
0 or 150. At this time, measuring instruments 140, 1
Reference numeral 50 designates the registered name of the stepper (EXP1, EXP2 ... EXPn) which exposed the pilot wafer by inputting the keyboard KB or the bar code card BC, and the MDP.
Contact 110 (information flow DA).

From the registered name of the stepper, MDP110
MC1 of the exposure unit that processed the pilot wafer
00 was found from the file STPF and the corresponding 1
Inquires about the exposure process program name to one MC 100 (information flow DB). In response to this, the selected MC100 sets the exposure process program name to MDP11.
Return to 0 (information flow DC). Then, the MDP 110 searches the file MPPF, calls the measurement process program corresponding to the exposure process program name, and loads the program into the measuring instruments 140 and 150 (information flow DD).

As a result, the measuring devices 140 and 150 automatically execute various measurements and evaluations required for the pilot wafer. Items of measurement by the measuring instruments 140 and 150 are
Two examples are the degree of overlay (misalignment) and the accuracy of the pattern line width. Among these, the misalignment measurement evaluates the center deviation of the shot transferred on the wafer by the step-and-repeat method, the rotation deviation of the shot, etc., and the alignment determined by the stepper during wafer global alignment (hereinafter referred to as EGA). A parameter having the same meaning as the parameter for operation (a kind of operation parameter) is calculated.

The alignment parameter and its calculation are as described in detail, for example, in Japanese Patent Laid-Open No. 61-44429. By this parameter calculation, the accuracy of the EGA of the stepper that has exposed the pilot wafer is reviewed, and it is determined whether or not the EGA parameter calculated on the stepper side is corrected (or corrected).

On the other hand, the data of the measured pattern line widths are aggregated for the positions of a plurality of shots on the wafer or a plurality of measurement points within each shot, and the exposure amount during pilot wafer exposure is insufficient or insufficient, and the entire wafer is exposed. The flatness, the flatness within the shot, or the offset with respect to the best focus is estimated. It is generally known that the line width of a line pattern formed on a photoresist becomes thicker or thinner depending on the focus position and the exposure amount.

The above measurement data is sent from the measuring instruments 140 and 150 to the MDP 110 (information flow DE). The MDP 110 calculates the above-mentioned parameters for alignment, calculates necessity of correction, necessity of correction, and correction value at the time of correction based on the data obtained by the misalignment measurement and the line width measurement, and as other operation parameters. , Correction value of exposure amount, correction value of tilt amount of leveling stage provided on wafer stage WST of stepper, offset amount for position setting of wafer in optical axis direction using focus sensor, or error caused by projection magnification or distortion The correction amount and the like are calculated.

When correction or correction of these various parameters is required, the correction amount or correction amount is sent to the MC 100 (information flow DF). As a result, the MC 100 adds a correction amount or a correction amount to the value of the preset parameter, and repairs the deficiency found in the processing of the pilot wafer, thereby providing a more optimized exposure process program in the corresponding MC 100. To generate.

When the MC 100 receives the processing result of the pilot wafer, the MC 100 performs the above-mentioned parameter correction when the processing result has a sufficient value for the accuracy set in the production control. Instead, the second and subsequent wafers in the lot to be processed are continuously processed under the same conditions.

If the pilot wafer is not sufficiently processed, the exposure process
After the parameters in the program are corrected, the pilot wafer is sent to the coater / developer CDn to completely remove the resist, and then the pilot exposure process is performed again for measurement and evaluation. This pilot wafer processing is repeated until the evaluation result is good. However, since it cannot be repeated indefinitely, how many times it is allowed is set in advance.

During the processing (exposure and measurement) of the pilot wafer, the console of the MDP 110 displays the status of each measuring instrument and the latest pilot processing result. Of course, the MDP 110 stores and manages the pilot processing result in association with the file MPPF.

Further, the MDPs are provided on the measuring instruments 140 and 150 side.
When the communication control with 110 is possible, the operation of each measuring instrument can be remotely controlled from the console side of the MDP 110.

FIG. 5 is a flow chart showing the above ASUS function. In FIG. 5, the operating conditions shown in steps 50 and 56 include, for example, the above-described alignment parameters and parameters that define the operation of each unit during the exposure operation.

Other operating conditions include selection of a plurality of alignment sensors mounted on the stepper, selection of various signal processing algorithms by the alignment sensor, selection of alignment mark types on the wafer, and pattern area on the reticle. Position setting of the reticle blind that narrows the irradiation light, various offset settings for the function (field lens fine movement, pressure control, etc.) that corrects the imaging characteristics (magnification, focus) of the projection lens PL of the stepper, and the exposure amount according to the resist film thickness Offset setting etc.

Further, step 52 of pilot wafer measurement
Is a dedicated measuring instrument 140, 150 as shown in FIG.
In addition to measuring at stepper EXP1, EXP2 ... E
There is also a method of measuring with XPn itself, one example of which is JP-A-2
The details are disclosed in JP-A-30112, JP-A-1-187817 and the like.

The ASUS function described above has 1
There are two disadvantages. That is, the next lot processing (step 55) cannot be started until the pilot wafer processing result is good in step 54 of FIG. This disadvantage becomes noticeable as a decrease in throughput when the exposure process is stable and the exposure process of the pilot wafer is completed almost once. Therefore, it is possible to change the whole process as follows.

FIG. 6 shows a flowchart in which the whole process is modified based on the flowchart in FIG. Figure 6
The steps 60 to 69 of FIG. 5 are modified steps, and the steps 52 to 54 and 56 in the figure are the same as the steps in FIG. In this embodiment, in parallel with the pilot processing of the first wafer at the beginning of the lot, the second and subsequent wafers continue the normal lot processing, and only when the result of the pilot processing is defective, It is to stop the lot processing from continuing.

First, in step 60, it is judged whether or not the lot is to be returned. Lot return is an operation of returning the wafers from the leading wafer of the lot to the exposed wafers only when the flag indicating the result of the pilot process is turned on and there is a defect.

For the first wafer at the beginning of the lot,
The process proceeds to steps 60, 61 and 62, and step 63
If so, the process proceeds to steps 52, 53 and 54. If step 52 is executed by another measuring device 140 or 150,
Since the first wafer is taken out from the stepper, the MDP 110 continuously executes steps 60, 61 and 62 to perform the exposure processing on the second wafer.

In the case of the second wafer, the process proceeds from step 63 to step 64, where the wafer is loaded into the library WCLn.
It is stored in the second slot in the cassette. Then, in step 65, it is determined whether or not there are remaining wafers, and if there are remaining wafers, the same processing is repeated from step 60.

On the other hand, when the wafers pilot-processed in steps 52 and 53 are judged to be good in step 54, all wafers in the lot are processed without doing anything and the first wafer is also stored in the cassette. Is stored in the first row of. When the result of step 54 is defective, step 69
Immediately turn on the flag for lot return. If the flag is turned on when the lot processing timing is step 60, the MDP 110 cooperates with the MC 100 to return the entire lot from the first sheet of the lot to the exposed wafer to the coater / developer and complete the resist on the entire surface. Is removed and the resist is applied again. This is called wafer reclamation and is executed in step 66.

Next, the regenerated wafer is returned to the cassette of the unexposed wafer of the library WCLn in step 67, the flag is turned off in step 68, and the operating condition is corrected and corrected in step 56 to execute again. Step 60
Return to.

In the case where such a process is taken, the time spent once a defect occurs becomes long, but if the probability of defect occurrence is sufficiently low, the throughput of the entire process improves. still,
When the flag is turned on in step 69, the operation of the stepper is stopped even while the stepper is exposing several wafers. Immediately after shifting to step 66, that much lot Needless to say, the reprocessing start time of is accelerated.

Next, a method according to the second embodiment using this system (FIG. 2) will be described. The second embodiment is combined with the pilot exposure, but when the pilot exposure is started, the host computers H.COM to M
Instead of directly following the contents of the exposure process program set in C100, the optimal operating conditions are estimated in advance by referring to the operating conditions monitored in the past, and pilot exposure is performed under the estimated operating conditions. It is the one to start. Therefore, the CIS 120 shown in FIG. 2 uses the operating condition information obtained in the pilot processing executed in the past,
Edited and organized for each wafer type to be processed or for each stepper, and centrally stored. Then, when processing a certain wafer lot, the MDP 110 (or MC 100) sets the optimum estimated operating condition to the CIS 120 based on the product type (processing layer etc.) information of the wafer in the lot and the stepper name for processing the wafer. Inquire, correct operating conditions based on this, and then start pilot exposure.

Such an estimation is effective when the operator has set parameters or the like in the host computer H / COM that greatly deviate from the appropriate values, or when the lot processing is performed for the first time for that type.

To exemplify the case of the parameter for alignment as one of the optimum estimation operating conditions, for example, when the mark center position is determined by slicing the signal waveform obtained by the alignment sensor at a certain slice level, The decision requires some trial and error depending on the layer structure of the wafer to be processed and the characteristics of the alignment sensor. However, the optimum slice level can be almost uniquely determined from the empirical judgment of the marks on the wafer surface that have undergone substantially the same process and layers having substantially the same structure. So MDP1
Reference numeral 10 is a past wafer that has been processed under the same exposure process program, rearranges the same type, and creates a slice level histogram (frequency distribution) adopted at the time of alignment. , The most frequently used slice level is determined as the optimum estimated operating condition.

The condition determined as the optimum value is MC1
If it is different from the condition loaded in 00, the optimum value is selected and corrected. By doing so, it is possible to reduce the probability that the evaluation result after the pilot exposure process is defective.

Next, an example of the ASUS function according to the third embodiment will be described. In the third embodiment, a method of evaluating an exposed wafer is used. Normally, when the exposure process for each lot is completed in the lithography process, all the wafers in the lot are inspected, inspected, or extracted before being sent to the next process.
This inspection is actually steps 52 and 5 in FIGS.
When the evaluation result of this inspection is defective, the entire lot is recycled as in step 66. Also, if it does not lead to a defect,
Errors and trends within the permissible range are detected, and the measurement data is transmitted from the measuring instruments 140 and 150 via the MDP 110 to the CI.
Centrally managed in S120.

In this way, the processed data of the evaluated lots are organized and accumulated for each product type and each stepper,
A database of optimum estimated operating conditions described in the second embodiment is constructed. Hereinafter, the operating method is the same as that of the second embodiment.

Next, a fourth embodiment using the system of FIG. 2 of the present invention
Example will be described. In this example, the events generated in each stepper (EXPn) are intensively monitored,
Correction of the sequence of the exposure process program by checking the operating status of each stepper on an event-by-event basis and analyzing the situation where errors occur frequently
The necessity of correction is determined.

In this embodiment, the following information is handled as events that occur in the exposure process. (A) Start reticle reservation process, end (b) Start reticle foreign matter inspection, end (c) Start reticle exchange process, end (d) Start lot process, end (e) Start pilot exposure, end ( f) Start of main exposure, end (g) Start of single development, end (h) Start of waiting state (i) Error occurrence alarm These event information (a) to (i) are sent from MC100 to MDP110 via LAN50. Submitted and aggregated. The MDP 110 analyzes the aggregated event information based on the history of operating states of each stepper.

First, the MDP 110 creates an operating state history for each stepper and displays it in real time on the console. In this embodiment, the following five operating states are handled. (A) Display of the current operating status of each stepper (b) Information display of the current operating status of the specified stepper (c) List of lot processing results for each today's stepper (d) Today's lot processing for the specified stepper Display of results (e) Latest error occurrence information of designated stepper These five history data (a) to (e) are MDP11
It is sequentially stored in the storage medium (hard disk, optical disk, etc.) in 0.

Therefore, the MDP 110 analyzes the occurrence status of the event for each stepper using the stored five history data (a) to (e). This history data is processed on a daily basis, and the MDP 110 has the following three analysis functions as software. (1) An event / trace information generation function that displays all events (a) to (i) that occurred during stepper operation for each stepper and displays them in time series. (2) Event aggregation information generation function that regroups the events that occurred based on the event trace information for each processing unit.

Here, the processing unit and the event are set as follows. (2-1) Reticle replacement process-Start and end times and end status (whether normal or error) -Generation error statistics (2-2) Lot processing-Start and end time and end status (normal or error) ) ・ Lot name, product name, process name, number of processed wafers, generation error statistics (2-3) Standby state, generation error statistics (3) Operation for each machine that generates aggregate operation information based on event aggregation information Information generation function.

Here, information such as the number of processed lots, the number of processed wafers, the number of reticle replacements, the number of reticle foreign matter inspections NG, the number of error occurrences on the stepper side, and the number of error occurrences on the coater / developer side is generated.

The above three functions (1), (2), (3)
By using, the operating status of each stepper on that day can be grasped, and it becomes possible to set up a more efficient process program for the lot processed on the next day.
Especially when an error occurs, it may become a serious problem in device production, and if the same error occurs frequently for a specific stepper or specific processing item, the flow of that processing item or the execution of that processing item It is immediately clear that the functions and accuracy of the involved steppers need to be reviewed and repaired.

Although the respective embodiments of the present invention have been described above, it is also possible to evaluate the performance of a stepper using a test reticle (a device reticle in some cases) by using the system of FIG.

The items of performance evaluation mainly relate to overlay accuracy and alignment accuracy. In addition, the illuminance distribution of illumination light, control accuracy of correction means for heat accumulation of the projection lens, distortion of the projection lens, and image plane are also included. Curved,
Flatness of wafer holder, stepping accuracy of wafer stage, orthogonality, bending of moving mirror for laser interferometer, time required for exposure and alignment, wafer exchange, reticle exchange, baseline (exposure center point and alignment sensor Stability of the distance)
It also includes items related to focus accuracy.

These items are also periodically evaluated, and the evaluation results are sequentially stored in the MDP 110. The evaluation results of these items are mainly organized for each stepper and accumulated as basic data for matching management between steppers, maintenance of each stepper, accuracy maintenance, and the like. The detailed data peculiar to this stepper was conventionally stored by the computer CMP / En on the stepper main body side, but by managing the peculiar data of all the steppers forming the line by the MDP 110, the exposure process program can be stored. It is possible to select the optimal stepper that suits you, or to look over the entire line to build a more efficient stepper operation.

Further, the change in the intrinsic constant on the stepper side is
When the deviation is out of the allowable range, it is monitored continuously during the main exposure (during lot processing) to determine whether it has deviated from the value set by the operator or the value specified in advance in equipment design. Can also correct the operating parameters of the stepper so as to correct the inconvenience caused thereby.

For example, in controlling the light amount during the exposure operation of the stepper, the total exposure amount of one shot irradiated on the wafer is monitored by the light amount integration using a photoelectric sensor, and the shutter is closed when the target value is reached, the integrator control mode. There is a timer control mode in which the light intensity of the light source is measured in advance and the opening time of the shutter corresponding to the required exposure amount is calculated. The integrator mode automatically adjusts the shutter opening time so that the exposure amount per shot will always reach the set target value even when the light intensity of the light source changes. The exposure time (shutter opening time) for each shot may change at the beginning and end of the process due to the change in the light intensity of the light source, which takes time and effort to manage the productivity (throughput).

On the other hand, in the timer mode, since the exposure time per shot is fixed, there is no trouble in throughput control, but the intensity change of the light source is within the allowable range (1
It should be less than ± several% during lot processing.
Therefore, the output value of the photoelectric sensor that monitors the light intensity of the light source as an inherent constant on the stepper side is sequentially checked not only during pilot exposure but also during lot processing, and the output value obtained during pilot exposure is A function (circuit or program) for determining whether or not it is maintained within an allowable range during processing is provided. When a change in the light intensity of the light source is detected during the lot processing by this function, the MDP 110 uses the ASUS function to correct the exposure time for the wafer that enters the exposure operation with the stepper even during the lot processing. The value of the exposure time set in MC100 is corrected. Alternatively, the power supplied to the light source or the like may be finely adjusted so that the light intensity itself of the light source is maintained within an allowable range.

As described above, by sequentially monitoring the change in the device constant peculiar to the stepper by the MDP 110 via the LAN 50, it is possible to prevent deterioration of various kinds of accuracy that may occur during lot processing. . Other,
The constants peculiar to the stepper include changes in the control accuracy (or drive time) of automatic focusing using the focus sensor, changes in the measurement accuracy by the alignment sensor, changes in the magnification of the projection lens, changes in the position of the image plane, or wafers. Changes in the running accuracy of the stage (habits such as yawing) are considered, and the same method can be applied to these constant changes.

As described above, according to the present invention, not only the pilot process at the head of the lot but also the operating conditions can be dynamically corrected during the main exposure process, so that the operating rate and the yield of the entire line are greatly increased. Can be increased.

[0078]

According to the present invention as set forth in claims 1, 2, 18, 19 and 35, the stored information can be confirmed without an operator entering the clean room, so that the lithography process can be stably maintained. It becomes possible. Further, according to the present invention described in claims 10, 29 and 36,
It is possible to perform the measurement corresponding to the exposure process, and it is possible to stably maintain the lithography process. Furthermore, the present invention according to claim 43 can communicate with the information collecting apparatus without interfering with the host computer, and the lithography process can be stably maintained. The invention according to claim 47 is the exposure apparatus and
Data developer status can be grasped in detail,
Stable maintenance of lithographic process including optical processing
It will be possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a conventional process management system used in a semiconductor device manufacturing line,

FIG. 2 is a diagram showing a configuration of a lithography information management system according to an embodiment of the present invention,

FIG. 3 is a perspective view showing the relationship between a stepper and a coater / developer.

FIG. 4 is a block diagram illustrating a flow of various information when executing an auto setup service function.

FIG. 5 is a flow chart for explaining the operation of the first embodiment of the auto setup service function,

FIG. 6 is a flow chart for explaining a modification of the operation of the first embodiment of the auto setup service function.

[Explanation of symbols]

H-COM host computer EXP1, EXP2, EXPn exposure apparatus CD1, CD2, CDn coater / developer RL1, RL2, RLn reticle library WCL1, WCL2, WCLn wafer cassette library CMP / E1, CMP / E2, exposure apparatus CMP / En Side computer 50 Ethernet (registered trademark) LAN 100 Machine controller (MC) 110 Master data processor (MDP) 120 Centralized information server (CIS) 140, 150 Measuring instrument

Continuation of front page (56) Reference JP 62-7129 (JP, A) JP 63-138732 (JP, A) JP 63-312050 (JP, A) JP 6-168863 (JP , A) JP 3-163818 (JP, A) JP 63-249328 (JP, A) JP 2-109315 (JP, A) JP 62-299022 (JP, A) JP 2-89305 (JP, A) JP-A 63-166211 (JP, A) JP-A 2-170520 (JP, A) JP-A 2-230711 (JP, A) JP-A 63-66933 (JP, A) A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (54)

(57) [Claims] 1. In a lithography system having a plurality of exposure apparatuses arranged in a clean room, a host computer that integrally controls the plurality of exposure apparatuses.
And a communication means to which the plurality of exposure apparatuses are connected,
And an information collection unit that collects and stores the operation information of the exposure apparatus from each of the respective exposure apparatus through said communication means, said information collecting means, independent of the host computer
Lithography system with provided, characterized in that it is arranged outside the clean room. 2. In a lithography system having a plurality of exposure apparatuses arranged in a clean room, a host computer that integrally controls the plurality of exposure apparatuses.
And a communication means to which the plurality of exposure apparatuses are connected,
And an information collecting means for collecting and storing the machining status information of the substrate that has been processed by each of the respective exposure apparatuses from each of the respective exposure apparatus through said communication means, said information collection means, said host Independent of computer
Lithography system with provided, characterized in that it is arranged outside the clean room. 3. The lithography system according to claim 1, wherein the operation information includes error occurrence information of each of the exposure apparatuses. 4. The lithography system according to claim 3, wherein the information collecting unit includes a storage unit that stores a history of error occurrence information of each of the exposure apparatuses. 5. The lithography system according to claim 1, wherein the operation information includes information on an operation condition in an exposure process executed by each of the exposure apparatuses in the past. 6. The information collecting means further comprises a measuring instrument which is connected to the information collecting means and which measures a processing state of a substrate exposed by each of the exposure apparatuses, and the information collecting means comprises the communication means. The lithography system according to claim 2, wherein processing state information measured by the measuring instrument is collected via a means. 7. The exposure apparatus according to claim 2, wherein each of the exposure apparatuses measures a processing state of the substrate subjected to the exposure processing, and transmits the measurement result to the information collecting unit via the communication unit. Lithography system. Wherein said machining status information, viewing including the line width data of the pattern formed on the substrate, based on the collected machining state information by said information collecting means
The operating conditions set for each exposure apparatus
The lithographic system according to claim 2, further comprising setting means for performing correction via a receiving means . 9. The dew collected by the information collecting means
Set for each exposure device based on optical device operation information
Further, a setting means for correcting the specified operating conditions should be further provided.
And any one of claims 3 to 5 characterized by
The described lithographic system. 10. A lithography system using an exposure apparatus, based on measurement means for measuring a processing state of a substrate exposed by the exposure apparatus, and exposure processing information of the exposure apparatus when the substrate is subjected to the exposure processing. And a setting unit configured to set a measurement condition of the measuring unit for the substrate subjected to the exposure processing. 11. The lithography system according to claim 10 , wherein the exposure processing information includes information regarding a type of substrate processed by the exposure apparatus. 12. The lithography system according to claim 10, wherein the setting unit remotely controls the measuring unit. 13. The exposure apparatus performs an exposure process on a lot composed of a plurality of substrates, and also performs an exposure process on another substrate in the lot while the measuring unit is measuring the substrate at the top of the lot. It is characterized by the above-mentioned.
A lithographic system according to any one of the items. 14. The exposure apparatus performs an exposure process on a lot composed of a plurality of substrates, and the measuring unit measures all or a total of the substrates in the lot after the exposure process of the lot is completed. Claims 10 to 1 characterized in that
The lithographic system according to any one of 3 above. 15. A lithography system has a plurality of the exposure apparatuses and a host computer that integrally controls the plurality of the exposure apparatuses, and the measuring unit and the plurality of the exposure apparatuses are connected via a communication unit. The lithographic system according to any one of claims 10 to 14, wherein the lithographic system is connected to the setting unit. 16. The communication device is a local area network, and the communication device is a network device.
6. The lithographic system according to any one of 5 above. 17. The local area network comprises:
The lithographic system of claim 16, wherein the lithographic system is Ethernet. 18. Integrated control by a host computer
The operation information of each of the multiple exposure devices
An information collecting device, wherein the information collecting device is provided independently of the host computer.
Each of the exposure apparatuses is connected from outside the clean room to a communication unit to which a plurality of exposure apparatuses arranged in a clean room are respectively connected, and is collected from each of the exposure apparatuses via the communication unit. An information collecting device, characterized in that the operation information of is stored outside the clean room. 19. Integrated control by a host computer
Of the substrate processed by each of the multiple exposure devices
An information collecting device for collecting work state information, wherein the information collecting device is provided independently of a host computer.
Each of the exposure apparatuses is connected from outside the clean room to a communication unit to which a plurality of exposure apparatuses arranged in a clean room are respectively connected, and is collected from each of the exposure apparatuses via the communication unit. An information collecting apparatus, wherein processing state information of a substrate processed by each of the above is stored outside the clean room. 20. The information collecting device collects the collected information.
Each of the plurality of exposure apparatuses or the plurality of exposure apparatuses exposes
Editing, organizing and storing for each type of board to be processed
The information collecting device according to claim 18 , wherein the information collecting device is a device. 21. The information collecting apparatus according to claim 18, wherein the operation information includes error occurrence information of each of the exposure apparatuses. 22. The information collecting apparatus according to claim 21, wherein the information collecting apparatus has a storage unit that stores a history of error occurrence information of each of the exposure apparatuses. 23. The information collecting apparatus according to claim 18, wherein the operation information includes information on an operation condition in an exposure process executed by each of the exposure apparatuses in the past. 24. The information collecting device is connected via a communication unit to a measuring instrument for measuring the processing state of a substrate exposed by each of the exposure apparatuses, and the processing state measured by the measuring instrument. The information collecting apparatus according to claim 19, wherein information is collected via the communication means. 25. The exposure apparatus according to claim 19, wherein the plurality of exposure apparatuses measure a processing state of the substrate subjected to the exposure processing, and transmit the measurement result to the information collecting apparatus via the communication unit. Information collection device. 26. The information collecting apparatus according to claim 19, wherein the processing state information includes line width data of a pattern formed on the substrate. 27. The information collecting apparatus according to claim 18, wherein the communication unit is a local area network. 28. The local area network comprises:
28. The information collecting device according to claim 27, which is an Ethernet (registered trademark). 29. An exposure apparatus and a measuring means for measuring a processing state of a substrate subjected to the exposure processing by the exposure apparatus, and based on exposure processing information of the exposure apparatus when the substrate is subjected to the exposure processing. And a measuring condition of the measuring means for the exposed substrate is set. 30. The setting apparatus according to claim 29, wherein the exposure processing information includes information regarding a type of substrate processed by the exposure apparatus. 31. The setting device according to claim 29, wherein the setting device remotely controls the measuring unit. 32. The setting device according to claim 29, wherein the setting device is connected to a plurality of the exposure devices via a communication unit. 33. The setting device according to claim 32, wherein the communication unit is a local area network. 34. The local area network comprises:
34. The setting device according to claim 33, which is an Ethernet (registered trademark). 35. An exposure apparatus arranged in a clean room and connected to a network, wherein the exposure apparatus is a host computer together with other exposure apparatuses.
The host computer controls the host computer.
Wherein from the clean room outside it is provided independently of the chromatography data
An exposure apparatus comprising: a control unit for transmitting, to the information collecting unit connected to a network, operation information of the exposure apparatus or processing information of a substrate processed by the exposure apparatus via the network. 36. An exposure apparatus connected to a network, the measuring apparatus measuring the processing state of a substrate subjected to the exposure processing by the exposure apparatus via the network, and based on the exposure processing information of the exposure apparatus. Control for connecting to a setting device that sets measurement conditions of the measuring device for a substrate that has been subjected to exposure processing by the exposure device, and transmitting exposure processing information when the substrate has been exposed through the network to the setting device An exposure apparatus comprising means. 37. The exposure apparatus according to claim 35, wherein the operation information includes error occurrence information of the exposure apparatus. 38. The exposure apparatus according to claim 37, wherein the information collection unit has a storage unit that stores a history of error occurrence information of the exposure apparatus. 39. The exposure apparatus according to claim 35, wherein the operation information includes information on an operation condition in an exposure process executed by each of the exposure apparatuses in the past. 40. The exposure apparatus according to claim 36, wherein the exposure processing information includes information regarding a type of substrate processed by the exposure apparatus. 41. The network of claim 35, wherein the network is a local area network.
The exposure apparatus according to any one of 1. 42. The local area network comprises:
The exposure apparatus according to claim 41, which is an Ethernet (registered trademark). 43. An exposure apparatus which is integrally controlled by a host computer together with other exposure apparatuses, wherein a communication function via the first communication line and a second communication line different in type from the first communication line are provided. Information having a communication function via the first communication line, connected to the host computer via the first communication line, and collecting operation information or performance evaluation results of the exposure apparatus via the second communication line. An exposure apparatus having a control means connected to the collecting apparatus. 44. The exposure apparatus according to claim 43, wherein the control unit has an RS232C interface connected to the first communication line. 45. The second communication line is a local area network, according to claim 43 or 4.
The exposure apparatus according to 4. 46. The local area network comprises:
46. The exposure apparatus according to claim 45, which is Ethernet (registered trademark). 47. An exposure apparatus and an exposure process performed by the exposure apparatus.
Coater for coating and developing resist on the substrate
Connected to the developer via communication means,
The exposure device and the coater developer via a communication means.
Error occurrence information is collected and the history data of the error occurrence information is collected.
Data and memorize data, and generate aggregate information using the history data
An information collecting device characterized by: 48. The summary information is an error of the exposure apparatus.
-Number of occurrences and occurrence of errors by the coater developer
48. Information collection according to claim 47, characterized in that it comprises a number.
apparatus. 49. The exposure apparatus and the coater developer
And are inlined.
47. The information collecting device according to 47 or 48. 50. The exposure apparatus together with another exposure apparatus
It further has a host computer for centralized management,
The information collecting device is provided independently of the host computer.
50. Any of claims 47-49 characterized in that
The information collecting device described in paragraph 1. 51. A method of manufacturing a semiconductor device, which comprises manufacturing a semiconductor device using the lithography system according to claim 1. 52. A semiconductor device manufacturing method, characterized in that a semiconductor device is manufactured using the information collecting apparatus according to any one of claims 18 to 28 and 47 to 50 . 53. A semiconductor device manufacturing method, characterized in that a semiconductor device is manufactured using the setting device according to any one of claims 29 to 34. 54. A semiconductor device manufacturing method, characterized in that a semiconductor device is manufactured by using the exposure apparatus according to any one of claims 35 to 46.