TWI655511B - Exposure apparatus, exposure method, and method of manufacturing the same - Google Patents

Abstract

An exposure apparatus for performing scanning exposure of a substrate (P) while moving the substrate (P) and the reticle (M), having an illumination optical system (IL) configured to illuminate the reticle (M) with exposure light, and A projection optical system (PO) configured to project a pattern of a photomask (M) onto a substrate (O). The exposure apparatus includes: a measurement light source (13) configured to irradiate a mark with measurement light; A light receiver (15) for the projection image of the marker received by the optical system; and a control unit (51) configured to calculate position information of the marker based on the projection image received on the light receiver, and based on the The calculated position information controls a correction unit (42) configured to perform correction, wherein a marker is provided outside the light path of the exposure light illuminated on the photomask.

Description

Exposure equipment, exposure method and method of manufacturing device

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

In a lithography process for manufacturing a semiconductor device or the like, an exposure apparatus is used which transfers a pattern of an original onto an exposure area of a substrate via a projection optical system. As devices and the like become smaller, it is necessary to improve the line width uniformity of a pattern transferred by an exposure apparatus. Changes in the imaging performance of the projection optical system will reduce line width uniformity. A change in the imaging performance of the projection optical system may occur due to the vibration of an optical element included in the projection optical system. Japanese Patent Laid-Open No. 2010-283089 discloses an exposure apparatus that detects the vibration of each part including the projection optical system with a sensor and vibrates the optical element included in the projection optical system based on the detected vibration. To reduce the amount of change in line width. Japanese Patent Laid-Open No. 2001-185478 discloses an exposure apparatus which measures the The posture of the optical element is changed and the original or the substrate is moved based on the measurement result to correct the deviation of the transfer position caused by the posture change.

In order to improve the line width uniformity by the exposure apparatus of the above patent document, it is necessary to increase the number and types of sensors attached to the optical elements contained in the apparatus, but it is not a problem in terms of cost and the like realistic. In addition, because although any given exposure equipment does not directly obtain the amount of change in the line width of the pattern transferred to the exposed area, they may obtain it indirectly through calculations based on the amount of vibration detected, etc. An error occurred during the calculation.

For example, the present invention provides an exposure apparatus that is advantageous for improving line width uniformity.

The present invention is an exposure apparatus for performing scanning exposure of a substrate while moving the substrate and a photomask, the exposure apparatus having an illumination optical system configured to illuminate the photomask with exposure light, and configured to project a pattern of the photomask onto The projection optical system on the substrate, the exposure apparatus includes: a measurement light source configured to irradiate the marker with the measurement light; a light receiver configured to receive a projection image of the marker via the projection optical system; and a controller configured to The projection image received on the light receiver calculates the position information of the marker, and controls a correction unit configured to perform the correction based on the calculated position information, wherein the marker is set on an exposure illuminated on the photomask Outside of the light path of light.

With reference to the following description of the attached drawings from an exemplary embodiment, Further features of the invention will become apparent.

10‧‧‧ measuring light

11‧‧‧ Components

12‧‧‧ measurement mark

13‧‧‧Measuring light source

14‧‧‧Mirror

15‧‧‧Sensor (light receiver)

16‧‧‧Mirror

21‧‧‧ opening

23‧‧‧ opening

41‧‧‧ flat glass

42‧‧‧Driver (correction unit)

43‧‧‧Driver

51‧‧‧controller (control unit)

200‧‧‧short dash

202‧‧‧lighting area

301‧‧‧area

401‧‧‧area

500‧‧‧short dash

510‧‧‧Measurement light

511‧‧‧ abutment

512‧‧‧Measurement mark

513‧‧‧Measuring light source

514‧‧‧Mirror

515‧‧‧Sensor

516‧‧‧Mirror

701‧‧‧Measurement mark

EE‧‧‧Scanning exposure equipment

IL‧‧‧lighting system (lighting optical system)

M‧‧‧Original (Mask)

M1‧‧‧First Plane Mirror

M2‧‧‧The first concave mirror

M3‧‧‧ convex mirror

M4‧‧‧Second concave mirror

M5‧‧‧Second Plane Mirror

MST‧‧‧Original holder

P‧‧‧ substrate

PO‧‧‧ Projection Optical System

PST‧‧‧Board Holder

FIG. 1 is a schematic diagram showing a configuration of a scanning projection exposure apparatus according to a first embodiment.

FIG. 2 is a bird's-eye view of the vicinity of the original holder.

FIG. 3 is a cross-sectional view near the original holder.

FIG. 4 is a view near the substrate holder.

FIG. 5 is a view near the substrate holder.

FIG. 6 is a schematic diagram showing a configuration of a scanning projection exposure apparatus according to a second embodiment.

FIG. 7 is a bird's-eye view of the vicinity of the original holder.

FIG. 8 is a cross-sectional view of the vicinity of the original holder.

FIG. 9 is a view near the substrate holder.

Hereinafter, embodiments for implementing the present invention will be explained with reference to the drawings.

(First Embodiment)

FIG. 1 is a schematic diagram showing a configuration of a scanning exposure apparatus EE according to a first embodiment. The scanning exposure apparatus EE includes an illumination system IL for illuminating an original (mask) M, an original holder MST for holding the original M, a projection optical system PO including a flat glass 41, and a holding A substrate holder PST of the substrate P, a measurement light source 13, a sensor (light receiver) 15, a driver (correction unit) 42, and a controller (control unit) 51. In the figure, the XY plane is the surface along the surface of the original M and the substrate P, the Z axis is perpendicular to the XY plane, the Y axis is in the scanning direction of the original M and the substrate P, and the X axis is orthogonal to the Y axis Non-scanning direction.

The illumination system IL includes a light source (not shown) and an illumination optical system (not shown), and illuminates an illumination area on the original M with a substantially uniform illuminance. A mercury lamp is used, for example, as a light source (not shown), and a part of the output wavelength of the mercury lamp, for example, i-line, h-line, and g-line is used as exposure light. The illumination optical system (not shown) collects light emitted from the light source, so that a desired illumination distribution can be obtained on the original M. The original M is made of, for example, quartz glass, and is formed to have a pattern (for example, a circuit pattern) to be transferred onto the substrate W. The original holder MST and the substrate holder PST are moved synchronously by a driver (not shown), respectively, and the pattern of the original M is transferred onto the exposure area of the substrate P via the projection optical system PO (scanning 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, and a plate glass 41. The light path between the original M and the first plane mirror M1 and the light 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 surface of the second plane mirror M5 is 90 degrees. The first plane mirror M1 and the second plane mirror M5 are preferably integrated into a plane mirror, and the first concave mirror M2 and the second concave mirror M4 are also preferably integrated into a concave mirror.

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

FIG. 2 is a view of the original holder MST and the structures in the vicinity thereof viewed from the upper side (+ Z direction) of the device. The original holder MST holds the original M by supporting the edge of the original M. The lighting system IL illuminates the lighting area 202. The original holder MST includes a slit-like opening 21 extending in the Y-axis direction (scanning direction) in a portion through which the measurement light 10 passes. A measurement mark 12 is provided between the opening 21 and the lighting system IL. The measurement mark 12 is provided on a member 11 fixed to the body of the exposure apparatus EE. The measurement mark 12 is irradiated with the measurement light 10 emitted from the measurement light source 13.

FIG. 3 is a cross-sectional view taken along a short dashed line 200 of FIG. 2. 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 opening 21. The opening 21 extends in the Y-axis direction in the original holder MST, and during exposure by scanning the original holder MST in the Y direction, the measurement light 10 always passes through the original holder MST without being blocked. When the position through which the measurement light 10 passes is transparent, the opening 21 is not necessary. The mirror 14 is a flat mirror, and is placed outside the area 301 through which the exposure light passes (the outside of the light path) so as not to interfere Exposure light. Similarly, the measurement mark 12 (member 11) is placed outside the light path of the exposure light. The measurement light source 13 and the mirror 14 are respectively fixed to a structure to which the measurement mark 12 is fixed by a holding mechanism (not shown), that is, the member 11.

FIG. 4 is a view of a substrate holder PST and a structure in the vicinity thereof. The measurement light 10 emitted from the measurement light source 13 and passed through the opening 21, the measurement mark 12, and the projection optical system PO is deflected by the mirror 16 and is incident on the sensor 15. The detection surfaces of the sensor 15 and the measurement mark 12 are arranged at positions of optical conjugation, and an image of the measurement mark 12 is formed on the sensor 15 via the projection optical system PO. The mirror 16 is a plane mirror and is placed outside the area 401 through which the exposure light passes during the exposure. The sensor 15 and the mirror 16 are respectively fixed to the body of the exposure apparatus EE by a holding mechanism (not shown). Since the magnification of the projection optical system PO is -1, the image of the original M is inverted in the X direction after passing through the projection optical system PO. And therefore, the measurement light 10 according to the present embodiment advances in the -Z direction via the + X side with respect to the exposure light after passing through the projection optical system PO.

The controller 51 calculates position information of the measurement mark 12 based on the projection image of the measurement mark 12 and obtains a deviation (difference value) by comparing calculation results between predetermined position information (reference position). The predetermined position information is coordinates and the like of a position to which the sensor 15 is fixed. The controller 51 sends a control signal for performing control to the driver 42 so that the deviation is reduced. The driver 42 changes the angle (inclined in the Z-axis direction) with respect to the XY plane of the plate glass based on the control signal. Therefore, the light of the measuring light 10 The path is changed, and the position of the image of the measurement mark 12 detected by the sensor 15 is corrected.

A method for detecting a position change amount of the image of the measurement mark 12 without using the above reference position will be described below. FIG. 5 shows a configuration of a device further having a measurement mark 701 arranged between the mirror 16 and the sensor 15. The measurement marks 701 and the measurement marks 12 are arranged at positions of optical conjugation. The sensor 15 can measure the deviation of the position of the optical image 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.).

Since the image of the measurement mark 12 and the image of the original M (pattern) are formed via the projection optical system PO, the image of the measurement mark 12 is caused by the positional deviation of the optical element included in the projection optical system PO. The position deviation is the same as the position deviation of the image of the original M. Therefore, the positional deviation of the original M on the substrate P can be corrected by correcting the positional deviation of the measurement mark 12. Since the measurement light 10 is continuously incident on the sensor 15 while the original holder MST is being scanned, fluctuations in positional deviation (vibration of the optical image) during scanning exposure can be corrected in real time.

In addition to or as an alternative to tilting the plate glass 41, fluctuations in positional deviation can be corrected by controlling the positions of the substrate holder PST and / or the original holder MST. The components (member 11, sensor 15, etc.) related to the detection measurement mark 12 are integrated as disclosed above, so that the positional deviation factors (vibrations, etc.) in each component are related with. Therefore, if this effect is obtained, the present invention is not limited to the above embodiments.

As disclosed above, according to this embodiment, it is possible to provide an exposure apparatus that is advantageous for improving the uniformity of the line width.

(Second Embodiment)

In the first embodiment, the measurement mark is set at only one point between the illumination system IL and the original M. The second embodiment is characterized in that measurement marks are provided at a plurality of positions. FIG. 6 is a schematic diagram showing a configuration of a scanning projection exposure apparatus EE according to a second embodiment. The difference between the first embodiment and this embodiment is that this embodiment includes a measurement light source 513 that emits measurement light 510, a sensor 515 that detects the measurement light source 513, and a driver 43.

FIG. 7 is a view of the original holder MST and its surrounding structures viewed from the upper side (+ Z direction) of the device according to the present embodiment. The difference between the first embodiment and this embodiment is that this embodiment has a slit-like opening 23 on the original holder MST that extends parallel to the Y axis. The openings 23 and 21 are preferably provided symmetrically with respect to the YZ plane including the optical axis. Further, a measurement mark 512 provided on a base 511 fixed to the body of the exposure apparatus EE is positioned between the opening 23 and the illumination system IL. These additional elements are fixed by a holding mechanism (not shown) similar to the first embodiment.

FIG. 8 is a cross-sectional view taken along a short dashed line 500 of FIG. 7. The difference between the first embodiment and this embodiment is that this embodiment has There are a base 511, a measurement mark 512, a measurement light source 513, and a mirror 514. These elements are preferably arranged symmetrically with respect to the YZ plane and the member 11, the measurement mark 12, the measurement light source 13, and the mirror 14 with the original M interposed therebetween. 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 the holding mechanism in the first embodiment.

FIG. 9 is a view of a substrate holder PST and a structure in the vicinity thereof. The difference between the first embodiment and this embodiment is that this embodiment has a sensor 515 and a mirror 516. These elements are preferably arranged symmetrically with the sensor 15 and the mirror 16 with respect to the YZ plane. In the above configuration, the rotation component of the image of the measurement mark can be detected by detecting the positional deviation of the two measurement marks. The rotation component of the image of the measurement mark is detected as a difference in the positional deviation of the two measurement positions.

The difference (rotational component) in the positional deviation between the two measurement positions cannot be corrected by moving the plate glass 41. The controller 51 performs correction by controlling the driver 43 to rotate the mirror M1 and the mirror M5 about the Z axis. As described above, this embodiment provides the same effects as the first embodiment.

(Article manufacturing method)

The article manufacturing method according to the embodiment of the present invention is preferable in manufacturing an article such as a micro device (for example, a semiconductor device) or the like or an element having a micro structure. An article manufacturing method may include: forming a latent image pattern (for example, exposure processing) on an object using the above-mentioned exposure equipment A step; and a step of developing an object on which the latent image pattern has been formed in the previous step. In addition, the article manufacturing method may include other known steps (oxidation, film formation, gas deposition, doping, planarization, etching, resist peeling, cutting, bonding, packaging, etc.). Compared with the conventional device manufacturing method, the device manufacturing method of this embodiment has advantages in at least one of performance, quality, productivity, and production cost of the device.

Although the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The following patent application scope should be given the broadest interpretation so that it encompasses all such modifications as well as equivalent structures and functions.

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

Claims (11)

An exposure apparatus for performing scanning exposure of a substrate while moving the substrate and a photomask, the exposure apparatus having an illumination optical system configured to illuminate the photomask with exposure light, and a pattern configured to illuminate the photomask A projection optical system projected onto the substrate, the exposure device includes: a measurement light source configured to irradiate a mark with measurement light; and a light receiver configured to receive the mark via the projection optical system during the scanning exposure And a control unit configured to calculate position information of the marker based on the projection image received on the light receiver, and to control the position information configured to perform correction based on the calculated position information. A correction unit, wherein the mark is provided on a member fixed to the exposure apparatus and is provided outside a light path of the exposure light illuminated on the photomask, the member is configured not to be on the Move during scanning exposure. For example, the exposure apparatus of the first patent application range, wherein the area through which the measurement light passes is extended along the scanning direction of the substrate on an original holder configured to hold the photomask. For example, the exposure apparatus of the scope of patent application, wherein the measurement light source is fixed to the member. For example, the exposure apparatus of the scope of patent application includes: a second measurement light source configured to illuminate the second mark with the second measurement light; and a second receiver configured to receive the second measurement signal via the projection optical system. A second projected image of a marker, wherein the control unit is configured to control the correction unit based on the second projected image, wherein the second marker is disposed outside a light path of the exposure light and the measurement light . For example, the exposure apparatus of the fourth scope of the application, wherein the area through which the second measurement light passes is extended along the scanning direction of the substrate on the original holder configured to hold the photomask. For example, the exposure apparatus of the fourth scope of the patent application, wherein the second light receiver is fixed to a second member provided with the second mark. For example, the exposure apparatus of the scope of patent application, wherein the correction unit is configured to drive an optical member included in the projection optical system, an original holder configured to hold the photomask, and configured to hold A driver for at least one of the substrate holders of the substrate. For example, the exposure device of the first patent application range, wherein the correction unit performs the correction during the scanning exposure. For example, the exposure apparatus of the scope of patent application, wherein the correction is an operation for correcting a positional deviation of an image of the photomask in the substrate. An exposure method using an exposure apparatus for performing a scanning exposure of a substrate and a mask while moving the substrate, the exposure apparatus having an illumination optical system configured to illuminate the mask with exposure light, and configured to A pattern of a photomask is projected onto a projection optical system on the substrate, the exposure method includes: irradiating a mark with measurement light; receiving a projection image of the mark via the projection optical system during the scanning exposure; and based on a light receiver Calculating the position information of the marker on the received projection image; and performing correction based on the calculated position information, wherein the marker is set on a member fixed to the exposure device and is set on the illuminated Outside the light path of the exposure light on the reticle, the member is configured not to move during the scanning exposure. A method of manufacturing an article, the method comprising the steps of: exposing a substrate using an exposure method such as the item 10 of the scope of patent application; and developing the exposed substrate.