JP2004228216A - Aligner, exposure control method, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner, an exposure control method, and a semiconductor device, which set an appropriate exposure condition for a high dimension accuracy at exposure, while a high production efficiency is maintained. <P>SOLUTION: In a constant temperature chamber 10, a lighting system 11 and a reticle stage 13 that holds a reticle 12 as a photo mask are deployed, and further, a projection optical system 14, an alignment optical system 15, a wafer stage mechanism 16, and a stage position measuring system 17 are deployed. An optical sensor 18 for detecting intensity of the exposure light that has at least passed through a reference mark MK for a specified inspection in the reticle 12 is deployed at a prescribed part of the wafer stage mechanism 16. A calculation control part 19 acquires the data required for setting exposure condition according to the detection result of the optical sensor 18, and reflects it on setting of the exposure condition. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to semiconductor device manufacturing, and more particularly, to an exposure apparatus, an exposure control method, and a semiconductor device in a manufacturing line that repeatedly and sequentially exposes a pattern of an integrated circuit on a semiconductor substrate.
[0002]
[Prior art]
Circuit patterns required for LSI manufacture are sequentially exposed on a semiconductor substrate by a plurality of reticle patterns. For example, a reduction projection exposure apparatus (not shown) in which a predetermined reticle is set repeatedly projects and exposes a pattern while sequentially shifting a region to be projected on a semiconductor substrate. Thus, a predetermined number of integrated circuit chip areas are obtained in the semiconductor substrate.
[0003]
In the exposure using a fine device, exposure conditions (exposure amount (illuminance × time), focus / offset amount) are strictly set so that a desired resist pattern can be obtained.
In particular, it is difficult to control the dimension of a critical pattern of a fine pattern such as a gate pattern or a contact pattern due to variations in mask dimensions, variations in accuracy of an exposure apparatus, and the like. In general, as a countermeasure, a method of feeding back exposure conditions to a main body lot by setting conditions for inspecting various fluctuations on a preceding wafer or a test wafer is adopted.
[0004]
[Problems to be solved by the invention]
The above-described conventional exposure condition setting requires a considerable amount of time and may affect the operation efficiency (throughput) of the exposure apparatus.
The present invention has been made in view of the above circumstances, and has an exposure apparatus, an exposure control method, and a semiconductor device capable of setting appropriate exposure conditions so as to obtain high dimensional accuracy during exposure while maintaining high production efficiency. It is intended to provide.
[0005]
[Means for Solving the Problems]
An exposure apparatus according to the present invention includes a projection optical system that irradiates exposure light and projects a pattern image of a photomask onto a photosensitive coating layer on a substrate, and the photosensitive optical system in a plane perpendicular to an optical axis of the projection optical system. A stage mechanism for moving a substrate provided with a coating layer, a stage position measuring system for measuring a movement amount of the stage mechanism, and a light for detecting at least the intensity of exposure light provided at a predetermined portion of the stage mechanism A sensor, and an arithmetic control unit that acquires data necessary for setting the exposure condition in accordance with the detection result obtained from the optical sensor and reflects the data on the setting of the exposure condition.
[0006]
According to the exposure apparatus of the present invention, an optical sensor is provided at a predetermined portion of the stage mechanism, and the exposure condition is set in advance by the arithmetic and control unit without loading a wafer in accordance with a detection result obtained from the optical sensor. . Thereby, the exposure condition is optimized in a short time, which contributes to the improvement of the production efficiency.
In the exposure apparatus according to the present invention, the optical sensor acquires data based on an optical profile related to a minimum dimension of a design rule.
[0007]
An exposure control method according to the present invention includes a projection optical system that irradiates exposure light and projects a pattern image of a photomask onto a photosensitive coating layer on a substrate, and the photosensitive optical system in a plane perpendicular to an optical axis of the projection optical system. A stage mechanism for moving the substrate provided with the conductive coating layer, a stage position measuring system for measuring the amount of movement in the stage mechanism, and at least an exposure light provided at a predetermined portion of the stage mechanism for detecting the intensity of exposure light. An optical sensor, and an arithmetic control unit that acquires data necessary for exposure condition setting in accordance with a detection result obtained from the optical sensor and reflects the data on the exposure condition setting, and the exposure light is applied to a predetermined region of the photomask. A subsequent exposure condition is optimized via the arithmetic and control unit according to a light intensity profile which is irradiated and received by the optical sensor.
[0008]
According to the exposure control method of the present invention, the light intensity profile obtained by the optical sensor changes by affecting the exposure amount and the focus. By using information obtained from the light intensity profile via the arithmetic and control unit, exposure conditions are set in advance without loading a wafer. Thereby, the exposure condition is optimized in a short time, which contributes to the improvement of the production efficiency.
[0009]
In the exposure control method according to the present invention, a reference mark for inspection including substantially the same size as a critical pattern to be transferred onto the substrate is provided in a predetermined region of the photomask to which the exposure light is applied. It is characterized by that. This contributes to inspecting the accuracy and preventing defects.
[0010]
In the above-described exposure control method according to the present invention, the optical sensor has a function for controlling an alignment position in the stage mechanism. That is, the stage position measurement system is set as a recognition target.
[0011]
A semiconductor device according to the present invention is formed using the above-described exposure apparatus or exposure control method. This contributes to the reduction of defects related to exposure and the improvement of production efficiency.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic view showing a main configuration of an exposure apparatus according to an embodiment of the present invention. An illumination system 11 is provided in the constant temperature chamber 10, and a reticle stage 13 for holding and positioning a reticle 12 as a photomask is provided. Further, the projection optical system 14 projects the pattern image of the reticle 12 onto the photosensitive coating layer on the semiconductor substrate Waf upon irradiation with the exposure light. Further, the alignment optical system 15 is used for obtaining the accuracy of the alignment processing of the reticle 12 and the overlay processing of the exposure area.
[0013]
A wafer stage mechanism 16 for holding the semiconductor substrate Waf is further provided in the constant temperature chamber 10. The stage position measurement system 17 measures the amount of movement of the wafer stage mechanism 16. At a predetermined portion of the wafer stage mechanism 16, an optical sensor 18 for detecting at least the intensity of the exposure light is provided. The optical sensors 18 are provided, for example, at the four corners on the wafer stage mechanism 16, but depending on the performance of the wafer stage mechanism 16, only one optical sensor 18 may be required. Further, the arithmetic and control unit 19 acquires data necessary for setting the exposure condition according to the detection result obtained from the optical sensor 18 and reflects the data on the exposure condition setting. The display unit 20 is installed in a place where an operator can operate, and can perform various input / output operations such as a recipe including exposure conditions and various monitors.
[0014]
According to the above embodiment, the optical sensor 18 is provided at a predetermined portion of the wafer stage mechanism 16, and according to the detection result obtained from the optical sensor 18, the exposure control is not set in advance by the arithmetic and control unit 19 without loading the wafer. obtain. That is, the optical sensor 18 detects the exposure light that has actually passed through the reticle 12, and the arithmetic control unit 19 analyzes the light. Thereby, the exposure condition is optimized in a short time, which contributes to the improvement of the production efficiency. The exposure control method will be described below.
[0015]
In a predetermined area of the reticle 12, an inspection reference mark MK for irradiating exposure light is arranged. The reference mark MK includes substantially the same size as a critical pattern (minimum size pattern) to be transferred onto the semiconductor substrate Waf. Thereby, the subsequent exposure conditions are optimized via the arithmetic and control unit 19 according to the light intensity profile received by the optical sensor 18.
[0016]
FIG. 2 is a configuration example of the reference mark MK on the reticle 12, and FIGS. 3A and 3B are characteristic diagrams of an image received by the optical sensor 18 and an optical profile thereof.
In FIG. 2, a mask M1 having a gate size to be actually exposed is arranged at predetermined intervals in a reference mark MK. For example, for the width dimension Xa and the arrangement interval Yb of the mask M1, the minimum design rule related to the product is adopted.
In FIG. 3A, the optical sensor 18 can be regarded as a contrast for detecting the intensity of exposure light with respect to the reference mark MK on the surface. Thus, an optical profile as shown in FIG. 3B is obtained. The optical sensor 18 can also have an alignment function by capturing the reference mark MK. Further, a light-shielding band (not shown) for alignment may be provided on the surface of the optical sensor 18 to obtain an appropriate optical profile. Simulation is performed by the arithmetic and control unit 19 based on the optical profile acquired by the optical sensor 18 to calculate an optimal exposure amount (illuminance × time) and a focus / offset amount. This is reflected in the 16 leveling controls.
[0017]
According to such an exposure control method, the light intensity profile obtained by the optical sensor 18 changes depending on the exposure amount and the focus. By using the information obtained from the light intensity profile via the arithmetic and control unit 19, exposure conditions are set in advance without loading a preceding wafer or an inspection wafer. Thereby, the exposure condition is optimized in a short time, which contributes to the improvement of the production efficiency.
[0018]
In addition, the reference mark MK on the reticle 12 includes substantially the same dimensions as the critical pattern, thereby inspecting the precision of the fine patterning and contributing to preventing defects. Note that the optical sensor 18 may have a function for controlling the alignment position in the stage mechanism 16. That is, the stage position measurement system 17 is a position recognition target. It can be a non-contact pre-alignment function.
[0019]
In the semiconductor device formed by using the exposure apparatus and the exposure control method according to the above-described embodiment, even if a fine pattern is required, defects related to exposure are significantly reduced. Further, when improving or changing the exposure conditions, time loss is small, the exposure can be performed relatively freely, and the production efficiency is improved.
[0020]
As described above, according to the present invention, an optical sensor is provided at a predetermined portion of the stage mechanism, and the exposure condition is set in advance by the arithmetic and control unit without loading a wafer according to the detection result obtained from the optical sensor. You. Thereby, the exposure condition is optimized in a short time, which contributes to the improvement of the production efficiency. As a result, it is possible to provide an exposure apparatus, an exposure control method, and a semiconductor device capable of setting appropriate exposure conditions so as to obtain high dimensional accuracy during exposure while maintaining high production efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a main configuration of an exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a plan view showing a configuration example of a reference mark on the reticle in FIG. 1;
FIG. 3 is a characteristic diagram of an image and an optical profile received by an optical sensor.
[Explanation of symbols]
Reference Signs List 10 constant temperature chamber, 11 illumination system, 12 reticle, 13 reticle stage, 14 projection optical system, 15 alignment optical system, 16 wafer stage mechanism, 17 stage position measurement system, 18 optical sensor, 19 ... Arithmetic control unit, 20. Display unit, Waf. Semiconductor substrate.

Claims (7)

A projection optical system for projecting a pattern image of a photomask onto a photosensitive coating layer on a substrate, which is irradiated with exposure light,
A stage mechanism for moving the substrate provided with the photosensitive coating layer in a plane perpendicular to the optical axis of the projection optical system,
A stage position measuring system for measuring a movement amount in the stage mechanism,
An optical sensor provided at a predetermined portion of the stage mechanism for detecting at least the intensity of the exposure light,
An arithmetic control unit that acquires data necessary for exposure condition setting according to the detection result obtained from the optical sensor and reflects the data on the exposure condition setting,
An exposure apparatus comprising: The exposure apparatus according to claim 1, wherein the optical sensor acquires data based on an optical profile related to a minimum dimension of a design rule. A projection optical system for projecting a pattern image of a photomask onto a photosensitive coating layer on a substrate, which is irradiated with exposure light,
A stage mechanism for moving the substrate provided with the photosensitive coating layer in a plane perpendicular to the optical axis of the projection optical system,
A stage position measuring system for measuring a movement amount in the stage mechanism,
An optical sensor provided at a predetermined portion of the stage mechanism for detecting at least the intensity of the exposure light,
An arithmetic control unit that acquires data necessary for exposure condition setting according to the detection result obtained from the optical sensor and reflects the data on the exposure condition setting,
With
An exposure control method, wherein a predetermined area of the photomask is irradiated with exposure light, and subsequent exposure conditions are optimized via the arithmetic and control unit according to a light intensity profile received by the optical sensor. 4. The exposure according to claim 3, wherein a reference mark for inspection including substantially the same size as a critical pattern to be transferred onto the substrate is arranged in a predetermined area of the photomask to which the exposure light is applied. Control method. 5. The exposure control method according to claim 3, wherein the optical sensor has a function for controlling an alignment position in the stage mechanism. A semiconductor device formed by using the exposure apparatus according to claim 1. A semiconductor device formed by using the exposure control method according to claim 3.

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