JPH05114539A - Wafer processing method and equipment - Google Patents

Abstract

PURPOSE:To obtain wafer processing technique capable of realizing precision improvement of a pattern which is transferred on resist, by measuring exposure characteristics of a wafer and resist without decreasing throughput in the wafer processing step. CONSTITUTION:An optical fiber 1 casting exposure light 1a is arranged so as to face a wafer chuck 10 retaining a wafer 7. The reflected light or the scattered light 1b by a beam splitter 2 arranged on the optical path of the exposure light 1a is detected by a filter 3, a photodiode 4, an A/D converter 5, etc. An information processing equipment 6 calculates exposure characteristics data 9a, which are, if necessary, outputted to an external aligner to correct exposure conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer processing technique, and more particularly to a technique effective when applied to an exposure process of a wafer after resist coating.

[0002]

2. Description of the Related Art For example, in a well-known wafer exposure process in a semiconductor device manufacturing process, it is important to use appropriate exposure conditions for a resist applied to a wafer from the viewpoint of improving dimensional accuracy of a transfer pattern. Becomes

Conventionally, as a method for obtaining such an appropriate exposure condition, for example, the exposure process is actually performed in each exposure process, and the dimension of the obtained transfer pattern is measured to judge the suitability of the exposure condition. The method of doing was adopted.

Regarding the wafer processing technology such as wafer exposure, for example, Industrial Research Institute Co., Ltd., issued November 18, 1986, "Electronic Materials", November 1986, p.
95-P100, etc.

[0005]

However, in the conventional method of determining the exposure conditions as described above, the change in the reflectance of the wafer surface also affects the measurement result, so that it must always be performed in each process. At the same time, automation is difficult, and the inclusion of such a complicated work in the actual process causes a problem such as a reduction in the number of wafers processed (throughput) per unit time.

An object of the present invention is to provide a wafer processing technique capable of measuring the exposure characteristics of a wafer and a resist without lowering the throughput in the wafer processing step and improving the accuracy of a pattern transferred to the resist. To provide.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0008]

Among the inventions disclosed in the present application, a typical one will be briefly described as follows.
It is as follows.

That is, the wafer processing method of the present invention is a wafer processing method in which the peripheral portion of a wafer coated with a resist is irradiated with the first exposure light so that the resist in the peripheral portion is selectively exposed. In the first exposure light, the reflected light or the scattered light is detected, or the exposure characteristics of the wafer and the resist are measured by the inspection light different from the first exposure light.

Further, in the wafer processing method of the present invention, in the wafer processing method according to claim 1, a desired pattern is transferred onto the wafer by irradiating the wafer with the measurement result of the exposure characteristics of the wafer and the resist. The data is transmitted to the exposure device that performs the exposure process, and the exposure device corrects the exposure condition for the wafer based on the measurement result.

Further, the wafer processing apparatus of the present invention includes a first optical system for selectively irradiating the peripheral portion of the wafer coated with the resist with the first exposure light, and the first exposure from the wafer. A second optical system for detecting reflected light or scattered light of the light, and a signal processing means for converting information of the reflected light or the scattered light detected by the second optical system into an electric signal and processing the electric signal. In addition, the resist in the peripheral portion of the wafer is selectively exposed to light, and the operation of measuring the exposure characteristics of the wafer and the resist is performed based on the information of the reflected light or the scattered light.

Further, the wafer processing apparatus of the present invention comprises a first optical system for selectively irradiating the peripheral portion of the wafer coated with the resist with the first exposure light, and an inspection light for an arbitrary region of the wafer. And a third optical system for measuring the exposure characteristics of the wafer and the resist by irradiating.

The wafer processing apparatus of the present invention is the wafer processing apparatus according to claim 3 or 4, wherein the measurement result of the exposure characteristics of the wafer and the resist applied to the wafer is transferred to the resist in the central portion of the wafer. The exposure light is transmitted to an exposure device that transfers a desired pattern, and the exposure condition in the exposure device is corrected based on the measurement result.

Further, in the wafer processing apparatus of the present invention, the wafer processing apparatus according to claim 3, 4 or 5 applies a second exposure light to the coating section for coating the resist on the wafer and the resist coated on the wafer. It is designed to be incorporated into a part of a wafer integrated processing system including an exposure device that irradiates a wafer with a desired pattern and a developing unit that performs a developing process after the exposure.

[0015]

In general, after the exposure process, for example, in the ion implantation or plasma etching process, since the wafer is placed in a vacuum atmosphere, a fixing method such as vacuum suction cannot be adopted, and the peripheral portion of the wafer is desired to be cured. It is essential to fix with tools. At this time, if the unexposed resist remains attached to the peripheral portion of the wafer, it will be a cause of foreign matter generation.

Therefore, in addition to the exposure of a normal pattern, after the resist application, a peripheral exposure operation is performed in which the resist in the peripheral portion of the wafer is selectively exposed and the resist in the peripheral area is removed by development. Is required.

The wafer processing technique of the present invention utilizes the peripheral exposure operation of this wafer and uses the first peripheral exposure process.
When irradiating the exposure light of, the reflected light or scattered light is detected, or the inspection light is used to measure the overall exposure characteristics including the photosensitive characteristics of the resist and the reflection characteristics of the wafer. Without adding complicated steps such as pattern exposure to measure dimensions
That is, the exposure characteristics of the actual wafer can be accurately grasped without lowering the throughput.

Further, the measurement result is given to an exposure apparatus that irradiates the wafer with a second exposure light to transfer a desired pattern, and various exposure conditions in the exposure apparatus are corrected, so that various results are obtained. It is possible to improve the accuracy of the transfer pattern in the actual exposure process using a different wafer or resist.

Recently, there have been diversified resist consistent processing systems for consistently performing a series of resist processing from coating of resist on a wafer to development, and if the wafer processing technology of the present invention is applied to the system, it will be drastically increased. It can be expected to improve productivity.

[0020]

First Embodiment A wafer processing method and apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a wafer processing apparatus A which is an embodiment of the present invention.
[Fig. 4] is a diagram showing an example of its action.

The wafer processing apparatus A of this embodiment is composed of the wafer 7
The wafer chuck 10 is mounted on the wafer chuck 10. The back surface of the wafer 7 is fixed to the wafer chuck 10 by a method such as vacuum suction with the coating surface of the resist 7a facing upward. The wafer chuck 10 can be rotated and moved horizontally relative to the optical fiber 1 described later.

Above the periphery of the wafer chuck 10,
An optical fiber 1 (first optical system) that emits the exposure light 1a (first exposure light) downward is arranged, and by appropriately moving the wafer chuck 10 with respect to the optical fiber 1, the wafer chuck A peripheral exposure operation is possible in which the peripheral portion of the wafer 7 mounted on the wafer 10 is irradiated with the exposure light 1a and the resist 7a in the peripheral portion is selectively exposed.

In this case, a beam splitter 2 (second optical system) is provided on the optical path of the exposure light 1a from the optical fiber 1 to the peripheral portion of the wafer 7. The beam splitter 2 transmits the exposure light 1a emitted from the optical fiber 1 and irradiates the wafer 7 with the exposure light 1a, and the reflected light or the scattered light 1b generated when the wafer 7 is irradiated with the exposure light 1a is exposed. The light 1a is reflected to the side of the optical path and separated.

On the optical path of the reflected or scattered light 1b separated by the beam splitter 2, a filter 3 (second
Optical system), a detection light switching unit 11 (a second optical system selects reflected light or scattered light), and a photodiode 4 (second optical system). The filter 3 has a function of selectively transmitting a desired wavelength component in the reflected light or the scattered light 1b, and the photodiode 4 is sensitive to the wavelength component, and electrically detects the light amount of the wavelength component. The operation of converting to signal 9 is performed.

The photodiode 4 is an A / D converter 5
Is connected to an information processing device (CPU) 6 (signal processing means) via a digital signal, and the detection signal 9 is input to the information processing device 6 after being digitized. Is calculated.

Further, the exposure device 8 is connected to the information processing device 6 as necessary, and the exposure characteristic information 9a is transmitted. Although not particularly shown, the exposure device 8 includes a light source that generates second exposure light, a predetermined reticle that transmits the second exposure light into a desired pattern, a reduction projection optical system, and the wafer 7. A positioning mechanism for placing and positioning the wafer 7 is provided, and an operation of irradiating the central portion of the wafer 7 with the second exposure light in a desired pattern to expose the resist 7a in the central portion to the desired pattern. I do.

An example of the operation of the wafer processing method and apparatus of this embodiment will be described below.

First, the wafer 7 coated with the resist 7a through the resist coating step (not shown) in the previous stage is placed and fixed on the wafer chuck 10 with the coating surface facing upward.

Thereafter, while moving the wafer chuck 10 relative to the optical fiber 1, the optical fiber 1
The resist 7a in the peripheral portion of the wafer 7 is selectively exposed to light by irradiating the exposure light 1a from the above.

At this time, the reflected light or scattered light 1b generated from the irradiation portion of the exposure light 1a on the wafer 7 is guided to the filter 3 by the beam splitter 2 and a predetermined wavelength component is selected by the filter 3 to detect the detection light. It is incident on the photodiode 4 via the switching unit 11, the incident light amount is converted into a detection signal 9, which is further digitized by the A / D converter 5 and then input to the information processing device 6.

Here, the detection signal 9 of the reflected light or the scattered light 1b changes with the irradiation time of the exposure light 1a, for example, as illustrated in the diagram of FIG.
For example, based on various information such as the level of the detection signal 9 after a specific irradiation time and the amount of change per unit time, the exposure characteristic information 9a such as the optimum exposure time of the wafer 7 and the resist 7a is calculated, Output to the exposure device 8.

Based on the information input from the information processing unit 6 of the wafer processing apparatus A, the exposure apparatus 8 applies a desired pattern by the second exposure light (not shown) to the wafer 7 coming from the wafer processing apparatus A. The optimum control of the exposure conditions such as the exposure time during the exposure is performed.

As a result, the reflectance of the individual wafers 7 and the resist 7a at the central portion of the wafer 7 are
A pattern having a desired dimension is accurately formed without being affected by variations in the photosensitive characteristics of a.

As described above, according to the wafer processing method and the wafer processing apparatus A of this embodiment, in the peripheral exposure process of the wafer 7 which is usually required, the operation of detecting the exposure characteristic information 9a of the resist 7a in the wafer 7 is performed. Since it is incorporated, it is not necessary to add a complicated work process such as actual measurement of a pattern by actual exposure and development for measuring the exposure characteristic information 9a and the like, and a decrease in throughput can be prevented. At the same time, by providing the exposure characteristic information 9a to the exposure device 8, it is possible to realize highly accurate pattern transfer by optimizing the exposure conditions in the exposure device 8.

[0036]

[Embodiment 2] FIG. 3 is an explanatory diagram showing a wafer processing method and a wafer processing apparatus A according to another embodiment of the present invention.

In the case of the second embodiment, the wafer processing apparatus A is incorporated in the integrated resist processing system illustrated in FIG.

The integrated resist processing system of this embodiment is
A loader 21 that receives an uncoated wafer 7 from the outside, a coating unit 2 that coats the wafer 7 with a resist 7a
2. Soft bake unit 23 for stabilizing applied resist 7a, exposure device 8a, exposed resist 7a
Post-exposure bake section 25 for performing the stabilization processing of the film, and developing section 2 for developing the transfer pattern with a predetermined chemical solution
6, hard bake part 27 for curing pattern resist 7a after development, resist 7a having a desired pattern
Is composed of an unloader 28 for discharging the wafer 7 formed as a mask to the subsequent steps.

In this case, the wafer processing apparatus A (peripheral exposure section) is provided between the soft bake section 23 and the exposure apparatus 8a.

Further, between the exposure device 8a, the wafer processing device A in the front stage, and the post-exposure bake unit 25 in the rear stage,
The interface unit 24 is interposed, and the exposure device 8
The difference between a and the processing time per wafer 7 in each of the front and rear portions is absorbed, and a large number of wafers 7 are transferred without delay.

In the wafer processing apparatus A, the peripheral exposure of the wafer 7 coated with the resist 7a coming from the former soft bake unit 23 is performed, and at the same time, the first embodiment described above is performed.
The exposure characteristic information 9a is collected and input to the exposure apparatus 8a by the method illustrated in FIG. At this time, if necessary, the exposure characteristic information 9a includes the individual wafers 7
Identification information such as a wafer number for identifying is added, and the exposure apparatus 8a stores the identification information and the exposure characteristic information 9a in association with each other.

As a result, in the exposure apparatus 8a, a transfer operation of a desired pattern can be immediately executed under the optimum exposure condition based on the exposure characteristic information 9a for each wafer 7 that will arrive later. it can.

As described above, in the case of the second embodiment, in the consistent resist processing system, the throughput can be increased by improving the accuracy of the exposure pattern and improving the system operating rate.

[0044]

[Embodiment 3] FIG. 4 is an explanatory view showing still another embodiment of the present invention.

In the case of this embodiment, the wafer chuck 1
Along with the optical fiber 1 that selectively exposes the resist 7a on the peripheral portion of the wafer 7 held at 0 to the exposure light 1a, the inspection light 3 is applied to an arbitrary region of the wafer 7.
The inspection optical system 30 (third optical system) for irradiating 0a to detect the exposure characteristic information 9a in the resist 7a of the wafer 7 is arranged.

Then, the exposure characteristic information 9a is collected simultaneously with the peripheral exposure of the wafer 7. As a result, as in the case of Embodiments 1 and 2, prior to the exposure step of transferring the desired pattern onto the wafer 7, the number of complicated steps such as experimental exposure / development and pattern measurement is not actually increased. The exposure characteristic information 9a of the wafer 7 can be collected, and the accuracy of the transfer pattern can be improved by providing the exposure characteristic information 9a to the exposure process.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

[0048]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, according to the wafer processing method of the present invention, the exposure characteristics of the wafer and the resist are measured without lowering the throughput in the wafer processing step,
The effect that the accuracy of the pattern transferred to the resist can be improved can be obtained.

According to the wafer processing apparatus of the present invention,
The exposure characteristics of the wafer and the resist can be measured without lowering the throughput in the wafer processing step, and the accuracy of the pattern transferred to the resist can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a configuration of a wafer processing method and apparatus which is an embodiment of the present invention.

FIG. 2 is a diagram showing an example of the operation.

FIG. 3 is a block diagram showing an example of a case where a wafer processing apparatus is incorporated in a consistent resist processing system.

FIG. 4 is an explanatory view showing a wafer processing method and apparatus which is still another embodiment of the present invention.

[Explanation of symbols]

 1 optical fiber (first optical system) 1a exposure light (first exposure light) 1b reflected or scattered light 2 beam splitter (second optical system) 3 filter (second optical system) 4 photodiode (second) Optical system) 5 A / D converter 6 information processing device (CPU) 7 wafer 7a resist 8 exposure device 8a exposure device 9 detection signal 9a exposure characteristic information 10 wafer chuck 11 detection light switching unit (second optical system) 21 loader 22 coating section 23 soft bake section 24 interface section 25 post-exposure bake section 26 developing section 27 hard bake section 28 unloader 30 inspection optical system (third optical system) 30a inspection light A wafer processing apparatus

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Arao 2-3-3 Fujibashi, Ome City, Tokyo 2 Hitachi Hitachi Electronics Co., Ltd. Hitachi Co., Ltd. Musashi Factory (72) Inventor Masahiro Ishiuchi 3-3 Fujibashi, Ome City, Tokyo 2 Inside Hitachi Tokyo Electronics Co., Ltd.

Claims (6)

[Claims] 1. A wafer processing method of irradiating a peripheral portion of a wafer coated with a resist with a first exposure light to selectively expose the resist of the peripheral portion to the resist, wherein 2. The wafer processing method, wherein the exposure characteristics of the wafer and the resist are measured by detecting reflected light or scattered light of the exposure light or by inspection light different from the first exposure light. 2. The measurement result of the exposure characteristics of the wafer and the resist is transmitted to an exposure device that performs an exposure process of transferring a desired pattern onto the wafer by irradiation of a second exposure light, and the exposure device comprises: Based on the measurement result,
2. The wafer processing method according to claim 1, wherein exposure conditions for the wafer are corrected. 3. A first optical system for selectively irradiating a peripheral portion of a resist-coated wafer with first exposure light, and reflected light or scattering of the first exposure light from the wafer. The wafer peripheral part is provided with a second optical system for detecting light, and a signal processing means for converting information of the reflected light or the scattered light detected by the second optical system into an electric signal and processing the signal. 2. The wafer processing apparatus, which selectively exposes the resist, and measures the exposure characteristics of the wafer and the resist based on the information of the reflected light or the scattered light. 4. A first optical system for selectively irradiating a peripheral portion of a wafer coated with a resist with a first exposure light, and an inspection light for irradiating an arbitrary region of the wafer, And a third optical system for measuring the exposure characteristics of the resist. 5. An exposure device for irradiating the resist in the central portion of the wafer with a second exposure light to transfer a desired pattern on the measurement result of the exposure characteristics of the wafer and the resist applied to the wafer. 5. The wafer processing apparatus according to claim 3, wherein the wafer processing apparatus transmits the information and corrects the exposure condition in the exposure apparatus based on the measurement result. 6. The wafer processing apparatus applies an application unit that applies the resist to the wafer, and an exposure apparatus that applies a second exposure light to the resist applied to the wafer to expose a desired pattern. And a resist integrated processing system including a developing section for carrying out a developing process after exposure, and the like.
4. The wafer processing apparatus according to 4 or 5.