KR20170041145A - Exposure apparatus, exposure method, and method of manufacturing devices - Google Patents

Abstract

The present invention provides an exposure apparatus comprising an illumination optical system (IL) configured to illuminate a mask (M) with exposure light, and a projection optical system (PO) configured to project a pattern of the mask (M) onto a wafer (P) in order to move the wafer (P) and the mask (M) and thereby perform a scanning exposure on the wafer (P). The exposure apparatus further comprises: a measurement light source (13) configured to irradiate a mark with a measurement light; a light-receiving unit (15) having the projection optical system and configured to receive a projected image of the mark; and a control unit which based on the projected image received on the light-receiving unit, calculates location information about the mark, and controls a correction unit (42) to perform a correction based on the location information calculated, wherein the mark is disposed outside the light path of the exposure light irradiating the mark.

Description

TECHNICAL FIELD [0001] The present invention relates to an exposure apparatus, an exposure method,

The present invention relates to an exposure apparatus, an exposure method, and a device manufacturing method.

In a lithography process for manufacturing a semiconductor device or the like, an exposure apparatus for transferring a pattern of an original plate onto an exposure area of a substrate via a projection optical system is used. As a device or the like is miniaturized, it is required to improve the uniformity of the line width of the pattern transferred by the exposure apparatus. The line width uniformity can be lowered by a change in the imaging performance of the projection optical system. The change in the imaging performance of the projection optical system may occur due to the vibration of the optical element included in the projection optical system. Japanese Patent Application Laid-Open No. 2010-283089 discloses an exposure apparatus that detects a vibration of each part including a projection optical system by a sensor and vibrates the optical element included in the projection optical system based on the detected vibration to reduce the variation amount of the line width . Japanese Patent Application Laid-Open No. 2001-185478 discloses an exposure apparatus which corrects the deviation of the transfer position caused by the attitude change by measuring the attitude change of the optical element included in the projection optical system and moving the original plate or substrate based on the measurement result do.

In order to improve the uniformity of the line width by the exposure apparatus of the patent document, the number and types of sensors attached to the optical elements included in the apparatus should be increased, but this is not realistic from the viewpoint of cost and the like. Further, although any of the exposure apparatuses does not directly acquire the amount of change of the line width of the pattern transferred to the exposure area, it indirectly acquires by calculation based on the detected amount of vibration or the like, so that an error may occur in the calculation process.

The present invention provides an exposure apparatus advantageous from the viewpoint of, for example, line width uniformity.

The present invention is an exposure apparatus for performing a scan exposure of a substrate while moving a substrate and a mask, the exposure apparatus comprising an illumination optical system configured to illuminate a mask with exposure light and a projection optical system configured to project a pattern of the mask onto the substrate, A light receiving unit configured to receive a projected image of a mark via a projection optical system, and a light receiving unit configured to calculate positional information of the mark based on the received projection image on the light receiving unit, And a control unit configured to control a correction unit configured to perform correction based on the mark, wherein the mark is disposed outside the light path of the exposure light illuminated on the mark.

Additional features of the present invention will become apparent from the following detailed description of illustrative embodiments with reference to the accompanying drawings.

1 is a schematic view showing a configuration of an scanning projection exposure apparatus according to a first embodiment;
2 is a bird's-eye view of the vicinity of a disk holding portion;
3 is a cross-sectional view of the vicinity of a disk holding portion;
4 is a view of the vicinity of the substrate holding portion;
5 is a view of the vicinity of a substrate holding portion;
6 is a schematic view showing a configuration of an scanning projection exposure apparatus according to a second embodiment;
7 is a bird's-eye view of the vicinity of the disk holding portion;
8 is a cross-sectional view of the vicinity of a disk holding portion;
9 is a view of the vicinity of a substrate holding portion;

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings and the like.

(Embodiment 1)

1 is a schematic diagram showing the configuration of a scanning exposure apparatus (EE) according to the first embodiment. The scanning exposure apparatus EE includes an illumination system IL for illuminating an original plate (mask) M, a original plate holding member MST for holding a original plate M, a projection optical system PO including a flat glass 41, A substrate holding portion PST for holding the substrate P, a measuring light source 13, a sensor (light receiving portion) 15, a driving portion (correction unit) 42 and a control portion (control unit) . In the drawing, the XY plane is a plane along the surfaces of the original plate M and the substrate P, the Z axis is perpendicular to the XY plane, the Y axis is the scanning direction of the original plate M and the substrate P, In the non-scanning direction.

The illumination system IL includes a light source (not shown) and an illumination optical system (not shown), and illuminates the illumination area on the original plate M with almost uniform illumination. For example, a mercury lamp is used for a light source (not shown), and a part of the output wavelength of a mercury lamp such as i-line, h-line, and g-line is used as exposure light. An illumination optical system (not shown) condenses the light emitted from the light source so that a desired illumination distribution can be obtained on the original plate M. The original plate M is made of, for example, quartz glass, and a pattern (for example, a circuit pattern) to be transferred is formed on the substrate W. The pattern of the original plate M is transferred to the exposure area of the substrate P through the projection optical system PO by a driving unit (not shown), and the original plate holding unit MST and the substrate holding unit PST are moved in synchronism with each other by a driving unit (Scan exposure).

The projection optical system PO includes a first plane mirror M1, a first concave mirror M2, a convex mirror M3, a second concave mirror M4, a second plane mirror M5, . The optical path between the circular plate M and the first plane mirror M1 and the optical path between the second plane mirror M5 and the substrate P are parallel. The angle between the plane including the mirror surface of the first plane mirror M1 and the plane including the mirror plane of the second plane mirror M5 is 90 degrees. The first plane mirror M1 and the second plane mirror M5 are preferably integrated as one plane mirror and the first concave mirror M2 and the second concave mirror M4 are also integrated as one concave mirror .

The measurement light source 13 includes a light emitting device (such as an LED) and an illumination optical system, and emits the measurement light 10 in the -Z direction. The sensor 15 includes a light detecting element (not shown) such as a CMOS sensor and a light receiving optical system (not shown) and detects (receives) the measurement light 10 (a projected image of the measurement mark 12) . The control unit 51 calculates the positional deviation of the image based on the detection signal of the sensor 15, and controls the driving unit 42 to move the flat glass 41. Details will be described later.

Fig. 2 is a diagram showing the structure of the disk holding portion MST and its vicinity, viewed from the upper side (+ Z direction) of the apparatus. The disk holding portion (MST) holds the disk (M) by supporting the edge of the disk (M). The illumination system IL illuminates the illumination area 202. The disk holding portion MST includes a slit-shaped opening 21 extending in the Y-axis direction (scanning direction) at a portion through which the measurement light 10 passes. The measurement mark 12 is provided between the opening 21 and the illumination system IL. The measurement mark 12 is provided on the member 11 fixed to the main body of the exposure apparatus EE. The measurement mark 12 irradiates the measurement light 10 emitted from the measurement light source 13.

3 is a sectional view along the one-dot chain line 200 in Fig. The measurement light 10 emitted from the measurement light source 13 is deflected by the mirror 14 and passes through the measurement mark 12 and the aperture 21. [ The aperture 21 extends in the Y axis direction of the disk holding section MST and the measuring light 10 passes through the disk stage MST without being blocked at all times during the exposure by scanning the disk stage MST in the Y direction. do. When the position through which the measurement light 10 passes is transparent, the opening 21 is not required. The mirror 14 is a flat mirror and is disposed outside (outside the optical path) of the region 301 through which the exposure light passes so as not to interfere with the exposure. Similarly, the measurement mark 12 (member 11) is disposed outside the light path of exposure light. The measurement light source 13 and the mirror 14 are fixed to the structure, i.e., the member 11, to which the measurement mark 12 is fixed by a holding mechanism (not shown).

4 is a view showing the structure of the substrate holding portion (PST) and the vicinity thereof. The measurement light 10 emitted from the measurement light source 13 and passing through the aperture 21, the measurement mark 12 and the projection optical system PO is deflected by the mirror 16 and enters the sensor 15. [ The detection surface of the sensor 15 and the measurement mark 12 are arranged at optically conjugate positions and the image of the measurement mark 12 is formed on the sensor 15 through the projection optical system PO. The mirror 16 is a plane mirror and is disposed outside the region 401 through which the exposure light passes during exposure. The sensor 15 and the mirror 16 are fixed to the body of the exposure apparatus EE by a holding mechanism (not shown), respectively. Since the magnification of the projection optical system PO is -1, the image of the original plate M is reversed in the X direction after passing through the projection optical system PO. Therefore, the measurement light 10 according to the present embodiment passes through the + X side with respect to the exposure light and then proceeds in the -Z direction after passing through the projection optical system PO.

The control unit 51 calculates positional information on the measurement mark 12 based on the projection image of the measurement mark 12 and compares the calculation result with predetermined positional information (reference position) to obtain a deviation (difference) . The predetermined positional information is coordinates of the position where the sensor 15 is fixed thereto, and the like. The control section 51 transmits to the driving section 42 a control signal for performing control so as to reduce the deviation. The driving unit 42 changes the angle (slope with respect to the Z-axis direction) of the flat glass to the XY plane based on the control signal. Thereby, the optical path of the measurement light 10 is changed, and the position of the image of the measurement mark 12 detected by the sensor 15 is corrected.

A method of detecting the positional change amount of the image of the measurement mark 12 without using the reference position will be described later. 5 shows a configuration of an apparatus further comprising a measurement mark 701 arranged between the mirror 16 and the sensor 15. As shown in Fig. The measurement mark 701 and the measurement mark 12 are arranged at optically conjugate positions. The sensor 15 can measure the deviation of the optical image position by detecting the relative positional relationship between the image of the measurement mark 12 and the measurement mark 701. [ In this case, the sensor 15, the mirror 16, and the measurement mark 701 are preferably fixed to the same structure (the body of the exposure apparatus EE, etc.).

The positional deviation of the image of the measurement mark 12 and the positional deviation of the image of the original plate M which are generated by the positional deviation of the optical element included in the projection optical system PO are the same as the image of the measurement mark 12, (Pattern) is formed through the projection optical system PO. Therefore, by correcting the positional deviation of the measurement mark 12, the positional deviation of the original plate M on the substrate P can be corrected. The fluctuation of the positional deviation (oscillation of the optical image) during the scanning exposure can be corrected in real time because the light metering 10 enters the sensor 15 constantly while the disk holding portion MST is being scanned.

The variation of the positional deviation can be corrected by controlling the position of the substrate holding portion (PST) and / or the disk holding portion (MST) in addition to or in addition to the tilting of the flat glass (41). The reason why the respective elements (the member 11, the sensor 15, etc.) associated with the detection of the measurement mark 12 are integrated as described above is that the position deviation factors (vibration, etc.) are equal in each element. Therefore, when this effect is obtained, the present invention is not limited to the above embodiment.

As described above, according to this embodiment, an exposure apparatus which is advantageous for improving the line width uniformity can be provided.

(Second Embodiment)

In the first embodiment, the measurement mark is installed in only one place between the illumination system IL and the circular plate M. A feature of the second embodiment is that measurement marks are provided at a plurality of positions. 6 is a schematic diagram showing the configuration of the scanning exposure apparatus (EE) according to the second embodiment. The difference between the first embodiment and the present embodiment is that the present embodiment has a measuring light source 513 that emits measurement light 510, a sensor 513 that detects the measurement light source 513, and a drive unit 43 It is a point.

Fig. 7 is a diagram showing the structure of the disk holding member MST according to the present embodiment and the structure in the vicinity thereof, viewed from the upper side (+ Z-axis direction) of the apparatus. The difference between the first embodiment and this embodiment is that this embodiment has a slit-shaped opening 23 extending on the disk holding portion MST in parallel with the Y-axis. The opening 23 and the opening 21 are preferably provided symmetrically with respect to the YZ plane including the optical axis. A measurement mark 512 provided on the base 511 fixed to the main body of the exposure apparatus EE is positioned between the aperture 23 and the illumination system IL. These additional elements are fixed by a holding mechanism (not shown) similarly to the first embodiment.

8 is a sectional view along the one-dot chain line 500 in Fig. The difference between the first embodiment and the present embodiment is that the present embodiment includes the base 511, the measurement mark 512, the measurement light source 513, and the mirror 514. These elements are preferably provided symmetrically with respect to the YZ plane through the original plate M with respect to the member 11, the measurement mark 12, the measurement light source 13, and the mirror 14. The measurement light 510 emitted from the measurement light source 513 proceeds similarly to the measurement light of the first embodiment. These additional elements are fixed by a holding mechanism (not shown) similar to that of the first embodiment.

9 is a view showing the structure of the substrate holding portion (PST) and the vicinity thereof. The difference between the first embodiment and this embodiment is that the present embodiment includes the sensor 515 and the mirror 516. [ These elements are preferably provided symmetrically with the sensor 15 and the mirror 16 with respect to the YZ plane. In the above arrangement, the rotation component of the image of the measurement mark can be detected by detecting the positional deviation of the two measurement marks. The rotational component of the image of the measurement mark is detected as the difference of the positional deviation in the two measurement marks.

The difference (rotational component) of the positional deviation at the two measurement positions can not be corrected by moving the flat glass 41. The control unit 51 performs the correction by controlling the driving unit 43 to rotate the mirror Ml and the mirror M5 around the Z axis. As described above, this embodiment provides the same effect as the first embodiment.

(Article manufacturing method)

The article manufacturing method according to the embodiment of the present invention is preferable for manufacturing an article such as a micro device such as a semiconductor device, an element having a micro structure, or the like. The article manufacturing method includes a step (for example, an exposure step) of forming a latent image pattern on an object using the above-mentioned exposure apparatus, and a step of developing an object on which the latent image pattern is formed in the previous step. The article manufacturing method may also include other known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, and packaging, etc.). The device manufacturing method according to the present embodiment has an advantage over at least one of performance, quality, productivity, and device manufacturing cost as compared with the conventional device manufacturing method.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the embodiments of the invention are not limited to the disclosed exemplary embodiments. The scope of the following claims should be accorded the broadest interpretation so as to encompass all such modifications and equivalent structural examples and functional examples.

This application claims priority from Japanese Patent Application No. 2015-198420, filed October 6, 2015, the entirety of which is incorporated herein by reference.

Claims (9)

An exposure optical system configured to illuminate a mask with exposure light, and a projection optical system configured to project a pattern of the mask onto a substrate, the exposure apparatus performing scan exposure of the substrate while moving the substrate and the mask,
A measurement light source configured to irradiate the mark with measurement light,
A light receiving portion configured to receive a projected image of the mark via the projection optical system,
And a control unit configured to calculate a positional information of the mark based on the projection image received on the light receiving unit and to control a correction unit configured to perform correction based on the calculated positional information,
Wherein the mark is disposed outside the light path of the exposure light illuminated on the mask. The method according to claim 1,
And an area through which the measurement light passes extends in the scanning direction of the substrate on the disk holding member configured to hold the mask. The method according to claim 1,
Wherein the light receiving unit and the member provided with the mark are fixed to a common structure. The method according to claim 1,
A second measurement light source configured to irradiate the second mark with the second measurement light, and
And a second light receiving portion configured to receive a second projected image of the second mark via the projection optical system,
Wherein the control unit is configured to control the correction unit based on the second projection image,
And the second mark is disposed outside the light path of the exposure light and the measurement light. 5. The method of claim 4,
And an area through which the second measurement light passes extends in the scanning direction of the substrate on the disk holding member configured to hold the mask. 5. The method of claim 4,
Wherein the member provided with the mark, the light receiving unit, the second member provided with the second mark, and the second light receiving unit are fixed to a common structure. 7. The method according to any one of claims 1 to 6,
Wherein the correction unit is a drive unit configured to drive at least one of an optical member included in the projection optical system, a disk holding unit configured to hold the mask, and a substrate holding unit configured to hold the substrate. An exposure method for performing a scan exposure of a substrate while moving the substrate and a mask using a projection optical system configured to project a pattern of a mask irradiated with exposure light onto a substrate,
Receiving a projected image of a mark irradiated with light different from the exposure light during the scan exposure,
And calculating a positional information of the mark based on the projection image and controlling a correction unit configured to perform correction based on the calculated positional information. A method of manufacturing an article,
Performing scan exposure while moving the substrate and the mask using a projection optical system configured to project a pattern of the mask irradiated with exposure light onto the substrate, and
And developing the exposed substrate,
The scan exposure may include:
Receiving a projected image of a mark irradiated with light different from the exposure light via the projection optical system; and
And controlling a correction unit configured to calculate positional information of the mark based on the projection image and to perform correction based on the calculated positional information.

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