TW201714024A - Exposure apparatus, exposure method, and method of manufacturing devices - Google Patents

Abstract

An exposure apparatus, having an illumination optical system IL configured to illuminate a mask M with an exposure light and a projection optical system PO configured to project a pattern of the mask M onto a substrate P, for performing scanning exposure of the substrate P while moving the substrate P and the mask M, comprising: a measurement light source 13 configured to irradiate a mark with a measurement light; a light receiver 15 configured to receive a projection image of the mark via the projection optical system; and a control unit 51 configured to calculate position information for the mark based on the projection image received on the light receiver and to control a correction unit 42 configured to perform correcting based on calculated position information, wherein the mark is disposed outside of an optical path of the exposure light illuminated on the mask.

Description

Exposure apparatus, exposure method, and method of manufacturing the same

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

In the lithography process for manufacturing a semiconductor device or the like, an exposure apparatus that transfers a pattern of an original to an exposure area of a substrate via a projection optical system is used. As devices and the like become smaller and smaller, it is required to improve the line width uniformity of the pattern transferred by the exposure device. Variations in the imaging performance of the projection optics reduce linewidth uniformity. A change in imaging performance of the projection optical system may occur due to vibration of an optical element included in the projection optical system. Japanese Patent Publication No. 2010-283089 discloses an exposure apparatus that vibrates an optical element included in a projection optical system by detecting vibration of each part including the projection optical system with a sensor and detecting vibration based on the detected vibration. To reduce the amount of change in line width. Japanese Patent Publication No. 2001-185478 discloses an exposure apparatus which is included in a projection optical system by measurement The posture of the optical element changes 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 type of sensors attached to the optical elements included in the apparatus, but it is not in terms of cost or the like. realistic. Further, since although any given exposure apparatus does not directly obtain the amount of change in the line width of the pattern transferred onto the exposure area, they indirectly obtain it by calculation based on the detected amount of vibration or the like, and may 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 a substrate and a photomask having an illumination optical system configured to illuminate the photomask with exposure light, and configured to project a pattern of the photomask to a projection optical system on the substrate, the exposure apparatus comprising: a measurement light source configured to illuminate the mark with the measurement light; a light receiver configured to receive the projected image of the mark via the projection optical system; and a controller configured to be based on a projection image received on the optical receiver to calculate position information of the marker, and based on the calculated position information, to control a correction unit configured to perform correction, wherein the marker is set to be illuminated on the reticle The light path of the light outside.

From the following description with reference to the accompanying drawings, Further features of the present invention will become apparent.

10‧‧‧Measurement light

11‧‧‧ components

12‧‧‧Measurement mark

13‧‧‧Measurement light source

14‧‧‧Mirror

15‧‧‧Sensor (Optical Receiver)

16‧‧‧Mirror

21‧‧‧ openings

23‧‧‧ openings

41‧‧‧ flat glass

42‧‧‧Drive (correction unit)

43‧‧‧ drive

51‧‧‧Controller (Control Unit)

200‧‧‧short dashed line

202‧‧‧Lighting area

301‧‧‧Area

401‧‧‧Area

500‧‧‧short dashed line

510‧‧‧Measurement light

511‧‧‧Abutment

512‧‧‧Measurement mark

513‧‧‧Measurement 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‧‧‧ first concave mirror

M3‧‧‧ convex mirror

M4‧‧‧second concave mirror

M5‧‧‧ second plane mirror

MST‧‧ Original Holder

P‧‧‧Substrate

PO‧‧‧Projection Optical System

PST‧‧‧ substrate holder

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

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

Figure 3 is a cross-sectional view of the vicinity of the original holder.

4 is a view of the vicinity of a substrate holder.

Fig. 5 is a view of the vicinity of the substrate holder.

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

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

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

Figure 9 is a view of the vicinity of the substrate holder.

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

(First Embodiment)

FIG. 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 (mask) M, an original holder MST for holding the original M, a projection optical system PO including a flat glass 41, for 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 drawing, 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. 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 M with substantially uniform illumination. 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, an i-line, an h-line, and a g-line, is used as the exposure light. An illumination optical system (not shown) collects the light emitted from the light source such 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 synchronously moved by a driver (not shown), respectively, and the pattern of the original M is transferred to 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 containing the mirror surface of the first plane mirror M1 and the plane containing 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 one plane mirror, and the first concave mirror M2 and the second concave mirror M4 are preferably also integrated into one concave mirror.

The measuring light source 13 includes a light emitting device (LED or the like) and an illumination optical system, and emits the measuring light 10 in the -Z direction. The sensor 15 includes a light detecting element such as a CMOS sensor or the like (not shown) and a light receiving optical system (not shown), and detects (receives) the measuring light 10 (the projected image of the measuring 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 plate glass 41. Details are explained below.

Fig. 2 is a view showing the structure of the original holder MST and its vicinity viewed from the upper side (+Z direction) of the apparatus. The original holder MST holds the original M by supporting the edge of the original M. The illumination system IL illuminates the illumination 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 measuring light 10 passes. The measurement mark 12 is disposed between the opening 21 and the illumination system IL. The measurement mark 12 is disposed on the member 11 that is fixed to the body of the exposure apparatus EE. The measurement mark 12 is illuminated with the measurement light 10 emitted from the measurement light source 13.

3 is a cross-sectional view taken along the 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. In the case where the position at which the measuring light 10 passes is transparent, the opening 21 is not required. The mirror 14 is a plane mirror and is placed outside the region 301 through which the exposure light passes (outside of the light path) without interference Exposure light. Similarly, the measurement mark 12 (member 11) is placed outside the light path of the exposure light. The measuring light source 13 and the mirror 14 are respectively fixed to a structure to which the measuring mark 12 is fixed by a holding mechanism (not shown), that is, the member 11.

4 is a view of the structure of the substrate holder PST and its vicinity. The measurement light 10 emitted from the measurement light source 13 and passing through the opening 21, the measurement mark 12, and the projection optical system PO is deflected by the mirror 16 and incident on the sensor 15. The detecting surface of the sensor 15 and the measurement mark 12 is disposed at the position of the optical conjugate, and the 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 exposure light passes during 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 reversed in the X direction after passing through the projection optical system PO. And therefore, the measuring light 10 according to the present embodiment advances in the -Z direction with respect to the +X side of the exposure light after passing through the projection optical system PO.

The controller 51 calculates the position information of the measurement mark 12 based on the projected image of the measurement mark 12, and obtains the deviation (difference value) by comparing the calculation result between the predetermined position information (reference position). The predetermined position information is the coordinates of the position to which the sensor 15 is fixed, and the like. The controller 51 sends a control signal to the driver 42 to implement the control so that the deviation is reduced. The driver 42 changes the angle (inclination in the Z-axis direction) to the XY plane of the sheet glass based on the control signal. Therefore, measuring the light of the 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 the amount of change in the position 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 disposed between the mirror 16 and the sensor 15. The measurement mark 701 and the measurement mark 12 are arranged at the position of the optical conjugate. 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.).

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 caused by the positional deviation of the optical element contained in the projection optical system PO The positional deviation and the positional deviation of the image of the original M are the same. 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 when the original holder MST is scanned, fluctuations in the positional deviation (vibration of the optical image) during the scanning exposure can be corrected in real time.

In addition to or instead of tilting the plate glass 41, the fluctuation of the positional deviation can be corrected by controlling the position of the substrate holder PST and/or the original holder MST. The elements (member 11, sensor 15, etc.) associated with the detection measurement mark 12 are generally integrated as disclosed above such that positional deviation factors (vibration, etc.) in each element with. Therefore, if this effect is obtained, the present invention is not limited to the above embodiments.

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

(Second embodiment)

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

Fig. 7 is a view showing the structure of the original holder MST and its vicinity viewed from the upper side (+Z direction) of the apparatus according to the present embodiment. The difference between the first embodiment and the present embodiment is that the present embodiment has a slit-like opening 23 extending in parallel with the Y-axis on the original holder MST. The opening 23 and the opening 21 are preferably symmetrically arranged with respect to the YZ plane containing the optical axis. Further, a measurement mark 512 provided on the 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 retaining mechanism (not shown) similar to the first embodiment.

FIG. 8 is a cross-sectional view taken along the short dashed line 500 of FIG. The difference between the first embodiment and the embodiment is that the embodiment has There are a base 511, a measurement mark 512, a measurement light source 513, and a mirror 514. These elements are preferably symmetrically disposed 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 advances similarly to the measurement light of the first embodiment. These additional elements are held by a retaining mechanism (not shown) similar to the retaining mechanism of the first embodiment.

Fig. 9 is a view showing the structure of the substrate holder PST and its vicinity. The difference between the first embodiment and the present embodiment is that the present embodiment has the sensor 515 and the mirror 516. These elements are preferably symmetrically disposed with respect to the YZ plane and the sensor 15 and mirror 16. 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 the difference in positional deviation of the two measurement positions.

The difference (rotational component) of the positional deviation in 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 around the Z axis. As described above, the present 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 the manufacture of an article such as a micro device (for example, a semiconductor device) or the like, or a member having a microstructure. The article manufacturing method may include: forming a latent image pattern (for example, exposure processing) on the object using the exposure apparatus described above a step of developing the object on which the latent image pattern has been formed in the preceding step. Additionally, article manufacturing methods can include other known steps (oxidation, film formation, gas deposition, doping, planarization, etching, resist stripping, cutting, bonding, packaging, etc.). The device manufacturing method of the present embodiment has an advantage in at least one of performance, quality, productivity, and production cost of the device as compared with the conventional device manufacturing method.

While the invention has been described with reference to the preferred embodiments thereof, it is understood that the invention is not limited to the illustrative embodiments disclosed. The scope of the following claims is to be accorded the broadest understanding of the invention

The present application claims the benefit of Japanese Patent Application No. 2015-198420, filed on Oct. 6, 2015, the entire disclosure of which is hereby incorporated by reference.

10‧‧‧Measurement light

13‧‧‧Measurement light source

15‧‧‧Controller (Control Unit)

41‧‧‧ flat glass

42‧‧‧Drive (correction unit)

51‧‧‧Controller (Control Unit)

EE‧‧‧ scanning exposure equipment

IL‧‧‧Lighting System (Lighting Optical System)

M‧‧‧ original (mask)

M1‧‧‧ first plane mirror

M2‧‧‧ first concave mirror

M3‧‧‧ convex mirror

M4‧‧‧second concave mirror

M5‧‧‧ second plane mirror

MST‧‧ Original Holder

P‧‧‧Substrate

PO‧‧‧Projection Optical System

PST‧‧‧ substrate holder

Claims (9)

An exposure apparatus for performing scanning exposure of a substrate while moving a substrate and a reticle, the exposure apparatus having an illumination optical system configured to illuminate the reticle with exposure light, and a pattern configured to the reticle Projection optical system projected onto the substrate, the exposure apparatus comprising: a measurement light source configured to illuminate the mark with the measurement light; a light receiver configured to receive the projected image of the mark via the projection optical system; and control a unit configured to calculate position information of the mark based on the projected image received on the light receiver, and control a correction unit configured to perform correction based on the calculated position information, wherein the mark It is disposed outside the light path of the exposure light that is illuminated on the reticle. The exposure apparatus of claim 1, wherein the area through which the measurement light passes extends on the original holder configured to hold the reticle along the scanning direction of the substrate. The exposure apparatus of claim 1, wherein the member provided with the mark and the optical receiver are fixed to a common structure. The exposure apparatus of claim 1, comprising: 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 via the projection optical system a second projected image of the marker, wherein the control unit is configured to control based on the second projected image The correction unit is configured, wherein the second mark is disposed outside the exposure light and the light path of the measurement light. The exposure apparatus of claim 4, wherein the area through which the second measurement light passes extends on the original holder configured to hold the reticle along the scanning direction of the substrate. The exposure apparatus of claim 4, wherein the member provided with the mark, the light receiver, the second member provided with the second mark, and the second light receiver are fixed to the common structure . The exposure apparatus of claim 1, 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 be held A driver of at least one of the substrate holders of the substrate. An exposure method using a projection optical system to perform scanning exposure of a substrate while moving a substrate and a photomask, the projection optical system being configured to project a pattern of the photomask illuminated by exposure light onto the substrate, the exposure The method includes receiving a projected image of a mark illuminated by light different from the exposure light during the scanning exposure; calculating position information of the mark based on the projected image, and controlling based on the calculated position information control A correction unit that performs calibration. A method of manufacturing an article, the method comprising the steps of: exposing a substrate using an exposure method as in claim 8; The exposed substrate is developed.