JP2003115445A - Exposure apparatus management system and device manufacturing method - Google Patents

Abstract

(57) [Summary] [Problem] Even if a position detection target is burned in a place other than a position corresponding to a target provided on a reference wafer, positioning can be performed with high accuracy and high throughput can be easily achieved. The present invention provides an exposure apparatus management system and a device manufacturing method that enable alignment to be obtained. SOLUTION: A position detection target provided on a reference wafer is detected, a deviation amount of the position detection target from a predetermined position is detected in step S104, and a correction value relating to the position deviation on the wafer stage is calculated in step S106. The apparatus further includes means for storing the correction value obtained in step S106 as a pre-alignment correction value unique to the apparatus, and reflects the pre-alignment correction value in product wafer alignment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor chip such as IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head,
The present invention relates to an exposure apparatus management system for manufacturing a device having a fine pattern such as a micromachine and a device manufacturing method using the management system.

[0002]

2. Description of the Related Art Conventionally, in an exposure apparatus such as a stepper for manufacturing a semiconductor element, relative alignment between an original plate such as a mask and an exposed substrate such as a wafer is used to manufacture a highly integrated semiconductor element. It is an important factor. In aligning the mask and the wafer at this time, first, pre-alignment is performed to align the wafer at a predetermined position on a PA (pre-alignment) stage with high accuracy. Then, after the pre-alignment operation is completed, the wafer is transferred onto the wafer stage, and a wafer chuck on the wafer stage vacuum-sucks the wafer to correct the surface, and the subsequent wafer process processing is performed.

Generally, the position reproducibility of prealignment is high, and there is relatively no problem when all the steps for processing the wafer are processed by the same apparatus. However, since the mounting positions of the sensor and the pressing mechanism, which are the reference for pre-alignment, are different between the devices, the alignment of the wafer with respect to the wafer chuck varies among the devices.

On the other hand, when a semiconductor device is manufactured through various semiconductor manufacturing processes using a plurality of devices, it is unlikely that the device that processed the previous process and the device that processes the next process are the same. As a result, when the wafer on the wafer chuck and the mask are precisely aligned after the completion of pre-alignment, the position detection target provided on the wafer surface may not fall within the field of view of the target detection microscope. At this time, processing for searching for a position detection target is added.

In contrast to the conventional alignment method, a single wafer containing a target for alignment (this wafer is used as a reference wafer) is fed to a predetermined position on a wafer chuck with good reproducibility, The proposal to print the position detection target at a position corresponding to the target provided in JP-A-7-22101 is described in detail in Japanese Patent Laid-Open No. 221010/1995.

[0006]

However, in the above-mentioned conventional technique, it is attempted to eliminate the variation between the apparatuses and perform the printing at the position corresponding to the target provided on the reference wafer in any apparatus. When the target is located in a different place, there is a problem that it cannot be included in the field of view of the microscope for detecting the target as usual.

The present invention has been made in view of the above-mentioned problems in the prior art. Even if the position detection target is printed at a position other than the position corresponding to the target provided on the sample such as the reference wafer, it is highly accurate. It is an object of the present invention to provide a position aligning apparatus and a position aligning method as an exposure apparatus managing system which can perform high-throughput easily, and a device manufacturing method using the managing system.

[0008]

In order to solve the above problems, an exposure apparatus management system according to the present invention is a management system for managing an exposure apparatus that exposes a pattern of an original onto a substrate. Detecting means for detecting a deviation amount of the target from a predetermined position, obtaining a correction value for the position deviation on the stage, and storing the obtained correction value as a pre-alignment correction value peculiar to the apparatus, It is characterized in that the pre-alignment correction value is reflected in the alignment of the product sample.

According to the present invention, in the first step of pre-aligning the product sample, the target provided on the product sample is detected to detect the deviation amount of the target from the predetermined position, and the target on the stage is detected. It is preferable to further include means for obtaining a correction value for the positional deviation and storing the obtained correction value as a pre-alignment correction value specific to the product sample.

In order to solve the above problem, in the device manufacturing method of the present invention, it is possible to manufacture a device using any of the exposure apparatus management systems.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In a preferred embodiment of the present invention, means for measuring a device-specific PA correction value using a reference wafer, means for storing the correction value as a machine parameter of the device, and TVPA There are provided means for performing pre-alignment in the first step of measurement and managing the measured value on a wafer-by-wafer or lot-by-lot basis, and means for reflecting the measured value on the TVPA correction value for the subsequent steps.

According to the present embodiment, the reference wafer is used to eliminate the variation in the TVPA correction value of the device, and
By performing the pre-alignment in the first step of performing the A measurement, the position detection target provided on the wafer surface can be in the visual field range of the target detection microscope regardless of the position.

From these facts, in the present embodiment, even if the position detection target is printed at a position other than the position corresponding to the target provided on the reference wafer, it is possible to perform the alignment with high accuracy and it is high. It is possible to provide a semiconductor exposure apparatus management system in which throughput can be easily obtained.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a perspective view showing the outer appearance of a semiconductor exposure apparatus according to an embodiment of the present invention. As shown in the figure, this semiconductor exposure apparatus includes an EWS main body 106 having a CPU for controlling the apparatus main body, and an EWS display device 10 for displaying predetermined information in the apparatus.
2. The main body of the apparatus is provided with a monitor TV 105 for displaying image information obtained through the image pickup means, an operation panel 103 for performing a predetermined input to the apparatus, a console section including an EWS keyboard 104 and the like. Also, FIG.
In the figure, 107 is an ON-OFF switch, 108 is an emergency stop switch, 109 is various switches, a mouse and the like, 110 is a LAN communication cable, 111 is an exhaust duct for heat generated from the console function, and 112 is an exhaust device for the chamber.

The main body of the semiconductor exposure apparatus is installed inside the chamber 101. The EWS display 102 is E
L, plasma, liquid crystal, etc. are thin and flat type, and are housed in front of the chamber 101, and the LAN cable 1
It is connected to the EWS main body 106 by 10. Further, in this apparatus, the operation panel 103, the keyboard 104, the monitor TV 105, etc. are also installed on the front surface of the chamber 101, and the console operation similar to the conventional one can be performed from the front surface of the chamber 101.

FIG. 2 is a diagram showing the internal structure of the semiconductor exposure apparatus of FIG. 1, and FIG. 2 shows a stepper as the semiconductor exposure apparatus. In the figure, 202 is a reticle and 203 is a wafer. When the light flux emitted from the light source device 204 passes through the illumination optical system 205 and illuminates the reticle 202, the pattern on the reticle 202 can be transferred onto the photosensitive layer on the wafer 203 by the projection lens 206. The reticle 202 is supported by a reticle stage 207 for holding and moving the reticle 202. The wafer 203 is exposed while being vacuum-sucked by the wafer chuck 291. Wafer chuck 291
Can be moved in each axial direction by the wafer stage 209.

The reticle 20 is provided above the reticle 202.
Reticle optical system 281 for detecting the positional deviation amount of 2
Are placed. An off-axis microscope 282 is arranged adjacent to the projection lens 206 above the wafer stage 209. The off-axis microscope 282 mainly plays a role of detecting the relative position between the internal reference mark and the alignment mark on the wafer 203. Further, a reticle library 220 and a wafer carrier elevator 230, which are peripheral devices, are arranged adjacent to the stepper main body, and the reticle transport device 22 supplies necessary reticles and wafers.
1 and the wafer transfer device 231 transfers the wafer to the main body. When the reticle is transported to the reticle library 220 or the main body by the reticle transport device 221,
The reticle cassette barcode reader 222 reads the barcode on the reticle cassette.

The chamber 101 is mainly composed of an air conditioner 210 for controlling the temperature of the air, a filter box 213 for filtering fine foreign substances to form a uniform flow of clean air, and a booth 214 for shutting off the environment of the device from the outside. ing. In the chamber 101, the air whose temperature is adjusted by the cooler 215 and the reheat heater 216 in the conditioned air chamber 210 is supplied by the blower 217 into the booth 214 via the air filter g. The air supplied to the booth 214 is again returned from the return port ra to the air conditioner room 210.
And is circulated in the chamber 101. Normally, this chamber 101 is not strictly a complete circulation system,
Approximately 1 of the circulating air volume to maintain positive pressure inside the booth 214
The air outside the split booth 214 is introduced from the outside air introduction port oa provided in the air conditioner room 210 through the blower 217. In this way, the chamber 101 makes it possible to keep the ambient temperature in which the device is placed constant and keep the air clean. Further, the light source device 204 is provided with an intake port sa and an exhaust port ea in preparation for cooling of the ultra-high pressure mercury lamp and gas generation at the time of laser abnormality, and a part of the air in the booth 214 passes through the light source device 204, Air is forcibly exhausted to the factory equipment via a dedicated exhaust fan provided in the air conditioner room 210. Furthermore, a chemical adsorption filter cf for removing chemical substances in the air is provided by being connected to the outside air introduction port oa and the return port ra of the air conditioner chamber 210, respectively.

FIG. 3 is a block diagram showing an electric circuit configuration of the semiconductor exposure apparatus of FIG. In the figure, reference numeral 321 is a main body CPU incorporated in the EWS main body 106 of FIG. 1 which controls the entire apparatus, and comprises a central processing unit such as a microcomputer or a minicomputer. 322
Is a wafer stage drive device, 323 is an alignment detection system for the off-axis microscope 282 of FIG. 2, 324 is a reticle stage drive device, 325 is a light source device 204 of FIG.
An illumination system such as 326 is a shutter drive device, 327 is a focus detection system, and 328 is a Z drive device. They are,
It is controlled by the main body CPU 321. Reference numeral 329 denotes a transfer system such as the reticle transfer device 221 and the wafer transfer device 231 in FIG. Reference numeral 330 denotes a console unit having the display 102, the keyboard 104 and the like shown in FIG. 1, and is for giving various commands and parameters related to the operation of the exposure apparatus to the main body CPU 321. That is,
The console unit 330 is for exchanging information with the operator. 331 is a console CPU, and 332 is an external memory that stores parameters and the like.

FIG. 4 is a diagram showing a system configuration in a semiconductor factory according to an embodiment of the present invention. The stepper as the semiconductor exposure apparatus in FIG. 1 is connected by a LAN communication cable 406 in the semiconductor factory. Indicates that. In the figure, what is connected to the LAN cable 406 is
Host computer 401, first stepper 403,
Unit 2 404, Unit 3 405, and each stepper 40
The semiconductor exposure apparatus management system 402 collects information on the TVPA correction values measured at 3, 404 and 405.

Next, with reference to FIGS. 6 and 7, with respect to the operation of the semiconductor exposure apparatus of FIG. 1, an example of the function of measuring and storing the correction values specific to the apparatus and the product will be described. FIG. 6 is a device-specific TV according to an embodiment of the present invention.
It is a flow chart which shows PA correction value measurement operation. Here, the correction value measuring operation for one wafer (which is used as a reference wafer) containing a target for alignment will be described with reference to FIG.

First, in step S101, a reference wafer as a reference sample is transferred to the PA by the wafer transfer device 231.
Place on a stage (not shown). The reference wafer placed on the PA stage is pre-aligned in step S102. After the pre-alignment is completed, the reference wafer is transferred from the PA stage to the wafer stage 209 by a feed hand (not shown). Then, in step S103, the reference wafer is placed on the wafer stage 209.
In step S104, the reference wafer placed on the wafer stage 209 is measured by the target detection off-axis microscope 282 for the amount of displacement of the target provided on the reference wafer from the predetermined position. Then, in step S105, the reference wafer is collected from the wafer stage 209.

Then, in step S106, statistical and arithmetic processing is performed from the data of the measured positional deviation amount, and the correction amount (x, y, θ) in the X direction (x), the Y direction (y), and the rotation direction (θ). ) Is calculated. Furthermore, step S107
Then, the correction value peculiar to the apparatus is notified (transmitted) to the semiconductor exposure apparatus management system 402, and the correction value measurement operation is ended.
Here, the calculated correction value may be stored as a machine parameter of the apparatus itself.

FIG. 7 is a flow chart showing the TVPA correction value measuring operation peculiar to the product according to the embodiment of the present invention. Here, with reference to FIG. 7, a correction value measuring operation for a wafer (which will be referred to as a product wafer) containing a target for alignment used in the first step of performing TVPA measurement will be described.

First, in step S201, the product wafer as a product sample is transferred to the PA by the wafer transfer device 231.
Place on a stage (not shown). The product wafer placed on the PA stage is pre-aligned in step S202. After the pre-alignment is completed, the product wafer is transferred from the PA stage to the wafer stage 209 by a delivery hand (not shown). Then, in step S203, the product wafer is placed on the wafer stage 209.
In step S204, the variations among the devices are absorbed by reflecting the above-mentioned correction amount (x, y, θ) peculiar to the devices.

In step S205, the product wafer placed on the wafer stage 209 is measured by the target detection off-axis microscope 282 for the amount of displacement of the target provided on the product wafer from a predetermined position. Then, in step S206, the product wafer is collected from the wafer stage 209.

Then, in step S207, statistics / calculation processing is performed from the data of the measured positional deviation amount, and the X direction (s
The correction amounts (sx, sy, sθ) in the x direction, the Y direction (sy), and the rotation direction (sθ) are calculated. Further, in step S208, the correction value peculiar to the product is notified (transmitted) to the semiconductor exposure apparatus management system 402, and the correction value measurement operation is ended. Here, the method of storing and managing the calculated correction values may be wafer-based or lot-based. Further, this correction value may be stored and managed inside the device.

FIG. 5 is an explanatory diagram of a target for position detection printed on the wafer surface by the conventional exposure apparatus according to the embodiment of the present invention. In FIG. 5A, the target 502 for position detection provided on the wafer surface is within the range of the visual field 501 of the microscope for position detection. On the contrary,
In FIG. 5B, only the right side of the target 502 for position detection provided on the wafer surface is the field of view 50 of the microscope for position detection.
If the value is out of the range of 1, the right side is also included in the field of view 503 of the microscope for position detection by adding the product-specific TVPA correction value according to the present embodiment.

In this embodiment, the device-specific TVPA correction value and the product-specific TVPA correction value measured by each device are collected and explained by the semiconductor exposure apparatus management system 402. However, as another embodiment, the place where they are collected May be a host computer or a personal computer, or a semiconductor exposure apparatus (for example, stepper 1).

As described above, in the apparatus shown in FIG. 1, the reference wafer is used to eliminate variations in the TVPA correction value of the apparatus, and prealignment is performed in the first step of TVPA measurement, so that the wafer surface is corrected. Wherever the position detection target provided in the position is located, the position detection target comes into the visual field range of the microscope for target detection.

Therefore, in this embodiment, even if the position detection target is printed at a position other than the position corresponding to the target provided on the reference wafer, it is possible to perform the alignment with high accuracy and to achieve high throughput. Can be easily obtained.

[0032]

As described above, according to the present invention,
Detects the target provided on the reference sample, detects the amount of deviation of the target from a predetermined position, obtains a correction value for the positional deviation on the stage, and stores the obtained correction value as a pre-alignment correction value unique to the apparatus. Have the means to
Since the pre-alignment correction value is reflected in the alignment of the product sample, it is possible to absorb the variation between the exposure apparatuses, enable highly accurate alignment, and easily obtain high throughput.

Further, in the present invention, since the pre-alignment correction value peculiar to the product sample is obtained and stored, no matter what position the position detection target provided on the product sample exists, for example, it is highly accurate in the exposure apparatus. Positioning is possible and high throughput can be easily obtained.

Furthermore, it becomes possible to provide a device manufacturing method using this exposure apparatus management system.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a semiconductor exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an internal structure of the semiconductor exposure apparatus of FIG.

FIG. 3 is a block diagram showing an electric circuit configuration of the semiconductor exposure apparatus of FIG.

FIG. 4 is a system configuration diagram in a semiconductor factory according to an embodiment of the present invention.

5A and 5B are explanatory views of a target for position detection printed on a wafer surface by a conventional exposure apparatus according to an embodiment of the present invention, and FIG. 5A is a target 502 for position detection provided on the wafer surface. Is within the range of the field of view 501 of the microscope for position detection, (b) shows only the right side of the target 502 for position detection provided on the wafer surface is outside the range of the field of view 501 of the microscope for position detection. In this case, the right side is also included in the visual field 503 of the position detecting microscope by adding the product-specific TVPA correction value.

FIG. 6 is a device-specific TVP according to an embodiment of the present invention.
7 is a flowchart showing an A correction value measurement operation.

FIG. 7 is a product-specific TVP according to an embodiment of the present invention.
7 is a flowchart showing an A correction value measurement operation.

[Explanation of symbols]

101: temperature control chamber, 102: EWS display device, 103: operation panel, 104: EWS keyboard, 105: monitor TV, 106: EWS body, 10
7: ON-OFF switch, 108: Emergency stop switch, 109: Various switches, mouse, etc., 110: LAN
Communication cable, 111: exhaust duct, 112: exhaust device, 202: reticle, 203: wafer, 204: light source device, 205: illumination optical system, 206: projection lens, 20
7: Reticle stage, 209: Wafer stage, 21
0: air conditioner, 213: filter box, 214: booth, 215: cooler, 216: reheat heater, 217: blower, 220: reticle library, 221: reticle transport device, 222: reticle cassette barcode reader, 230: Wafer carrier elevator, 231: Wafer transfer device, 281: Reticle optical system, 282: Off-axis microscope, 291: Wafer chuck, g: Air filter, cf: Chemical adsorption filter, oa: Outside air inlet, r
a: return port, ea: exhaust port, sa: intake port, 32
1: Main body CPU, 322: Wafer stage drive device, 3
23: alignment detection system, 324: reticle stage drive device, 325: illumination system, 326: shutter drive device, 327: focus detection system, 328: Z drive device,
329: Transport system, 330: Console, 331: Console CPU, 332: External memory, 401: Host computer, 402: Semiconductor exposure apparatus management system, 40
3: Stepper No. 1 machine, 404: Stepper No. 2 machine, 40
5: Stepper No. 3, 406: LAN communication cable in semiconductor factory, 501: Field of view microscope for position detection, 50
2: Target for position detection, 503: Field of view of microscope for position detection with correction value added.

Continued front page    F term (reference) 2F065 AA20 AA31 BB02 BB27 CC20                       CC25 EE00 FF42 FF61 JJ03                       JJ09 PP12 PP13 PP24 QQ23                       QQ41 SS02 SS13                 5F031 CA02 CA05 CA07 CA11 DA01                       EA16 HA53 JA04 JA27 JA38                       JA49 JA51 KA05 MA27 NA02                       NA17                 5F046 BA04 FC08

Claims (3)

[Claims] 1. A management system for managing an exposure apparatus that exposes a pattern of an original onto a substrate, detects a target provided on a reference sample, detects a deviation amount of the target from a predetermined position, and detects the position on the stage. A means for obtaining a correction value relating to the deviation and storing the obtained correction value as a pre-alignment correction value peculiar to the apparatus,
An exposure apparatus management system, wherein the pre-alignment correction value is reflected in the alignment of a product sample. 2. In a first step of pre-aligning the product sample, a target provided on the product sample is detected to detect a deviation amount of the target from a predetermined position, and the positional deviation on the stage is detected. The exposure apparatus management system according to claim 1, further comprising means for obtaining a correction value and storing the obtained correction value as a pre-alignment correction value specific to a product sample. 3. A device manufacturing method, characterized in that a device is manufactured using the exposure apparatus management system according to claim 1.