JPH1032164A - Scanning exposure apparatus and device manufacturing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning exposure apparatus using a step-and-scan method, which achieves high resolution by uniforming the illuminance distribution on a reticle surface, and a device using the same. Obtaining a manufacturing method for A pattern on a first object surface is illuminated with an illumination light beam having coherence anisotropy from an illumination system, and the pattern on the first object surface is placed on a movable stage by a projection optical system. In a scanning type exposure apparatus that performs projection exposure while relatively scanning the first object and the movable stage on an object surface at a speed ratio corresponding to the projection magnification of the projection optical system, and performing relative scanning, the illumination system includes the illumination system. The direction in which the coherence of the illumination light beam is low is set so as to substantially coincide with the scanning direction,
Vibrating means for vibrating the illumination light beam in a direction of high coherence;

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a scanning exposure apparatus and a device manufacturing method using the same, and relates to an IC, LS, and the like.
In the lithography process for manufacturing devices such as I, CCD, magnetic head, liquid crystal panel, etc., an appropriate amount of exposure is given to a wafer using an illumination light beam having anisotropy of coherence in a light beam cross section, and a highly integrated device. It is suitable when manufacturing.

[0002]

2. Description of the Related Art In recent years, the integration of semiconductor devices such as ICs and LSIs has been increasing at an ever-increasing rate, and as a result, an arc-shaped exposure area has been used as a projection exposure apparatus which is the center of fine processing technology for semiconductor wafers. A 1: 1 projection exposure apparatus (mirror projection aligner) that exposes a 1 × mirror optical system while scanning a mask and a photosensitive substrate while scanning a mask and a photosensitive substrate. A reduction projection exposure apparatus (stepper) for exposing a substrate by a step-and-repeat method has been proposed.

Recently, a chip pattern of one semiconductor element has been increasing in size, and a projection exposure apparatus is required to have a larger area for exposing a larger area pattern on a mask onto a photosensitive substrate.

In response to these demands, various types of step-and-scan type scanning projection exposure apparatuses (exposure apparatuses) capable of obtaining a high resolution and increasing the screen size have recently been proposed. In this scanning type exposure apparatus, a pattern on a reticle surface is illuminated by a slit light beam, and the pattern illuminated by the slit light beam is exposed and transferred onto a wafer by a scanning operation via a projection system (projection optical system). I have. In order to respond to the above-mentioned high resolution, a pulse laser such as an excimer laser is used in an exposure apparatus as a light source in the far ultraviolet region.

[0005]

Generally, in a scanning exposure apparatus, exposing the wafer surface with an appropriate exposure amount is a major factor for improving the projection resolution. When illuminating a circuit pattern such as a mask or a reticle with an illuminating light beam from a light source that emits a coherent light beam such as an excimer laser, interference fringes called speckle patterns are generated while passing through an illumination system, and the irradiated surface ( Irradiation unevenness occurs on the (mask).

In general, in a scanning exposure apparatus, the illuminance at each point in an exposure area is represented by an integrated exposure amount in a scanning direction in a slit illumination area. Therefore, even if illuminance unevenness exists in the scanning direction, the accumulated exposure amount at a point on the same line in the scanning direction becomes equal if there is no temporal variation in the illuminance distribution. That is, the illuminances at points on the same line in the scanning direction are all equal.

However, illuminance non-uniformity in the scanning orthogonal direction (non-scanning direction) results in direct exposure non-uniformity, which greatly affects printing performance. As a result, in the pattern transferred onto the wafer (substrate), there arises a problem that the image quality is different between the scanning direction of the substrate and the direction perpendicular thereto (non-scanning direction).

According to the present invention, a reticle surface (first object) is illuminated with an illumination light beam having coherence anisotropy, and a pattern of the reticle surface is scanned and projected on a wafer (second object) by a projection optical system. When the projection exposure is performed, the direction of anisotropy of the coherence of the illumination light beam and the scanning direction are appropriately set, and the illumination light beam is vibrated in a predetermined direction. It is an object of the present invention to provide a scanning exposure apparatus which has a high resolution and facilitates projection exposure to a large screen, and a method of manufacturing a device using the same.

[0009]

A scanning exposure apparatus according to the present invention illuminates a pattern on a first object surface with an illumination light beam having anisotropy of coherence from an illumination system. A pattern on one object plane is placed on a movable stage by a projection optical system, and the first object and the movable stage are synchronized on a second object plane at a speed ratio corresponding to the projection magnification of the projection optical system. In a scanning type exposure apparatus that performs projection exposure while scanning, the illumination system is set so that the direction of low coherence of the illumination light beam substantially coincides with the scanning direction, and vibrates the illumination light beam in the direction of high coherence. It is characterized by having a vibration means for causing the vibration.

[0010] In particular, (1-1-1) the illumination system has a uniforming means for uniformizing a cross-sectional light intensity distribution of the illumination light beam.

(1-1-2) The vibrating means vibrates the uniformizing means in a direction in which the coherence of the illumination light beam is high.

(1-1-3) The illumination light beam is pulse light,
The uniforming means is displaced by a predetermined amount every predetermined number of times of emission of the pulse light or every predetermined number of times of a trigger signal for emitting the pulse light.

(1-1-4) The vibrating means has a vibrating mirror provided in an optical path and a drive unit for vibrating the vibrating mirror.

(1-1-5) The illumination light beam has a slit shape through a slit opening, and the movable stage scans in a short direction of the slit opening. And so on.

(1-2) A pattern on the first object plane is illuminated with an illumination light beam having a coherence anisotropy of a slit shape through a slit opening from the illumination system, and the pattern on the first object plane is illuminated. The first object and the movable stage are synchronized on the second object surface placed on the movable stage by the projection optical system in the short direction of the slit opening at a speed ratio corresponding to the projection magnification of the projection optical system. In a scanning type exposure apparatus that performs projection exposure while relatively scanning, the illumination system is set such that the lower coherence of the illumination light beam substantially coincides with the scanning direction, and the cross-sectional light intensity distribution of the illumination light beam is adjusted. It is characterized by having a uniforming means for uniformizing and a vibrating means for vibrating the illumination light beam in a direction of high coherence.

The method for manufacturing a device according to the present invention is characterized in that
A wafer projected and exposed by using the scanning exposure apparatus of (1-1) or (1-2) is manufactured through a development processing step.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing a configuration of a scanning exposure apparatus according to a first embodiment of the present invention. The present embodiment is a light beam having coherence anisotropy emitted from a light source 1 such as a laser, and is provided with a reticle (first light) through an illumination optical system (illumination means).
The reticle 9 and the substrate 1 are illuminated on a substrate (second object) 11 on which a circuit pattern formed on the reticle is coated with a photoreceptor by a projection lens (projection optical system) 10.
1 shows a scanning type exposure apparatus that prints by reducing and projecting while relatively scanning 1 and is suitable for manufacturing devices such as semiconductor devices such as ICs and LSIs, imaging devices such as CCDs, and magnetic heads. It is.

In FIG. 1, reference numeral 1 denotes a light source (light source means) which is composed of an excimer laser or the like and emits a light beam having coherence anisotropy. Reference numeral 2 denotes a beam shaping optical system, which shapes a light beam from the light source 1 into a predetermined shape and enters the correction means 3. The correcting means 3 is a homogenizing means 4 having an optical integrator or the like for making the light intensity distribution of the light beam uniform.
And a vibrating means 20 for vibrating the uniformizing means in a direction in which the coherence of the light beam is high in a plane perpendicular to the light beam. Reference numeral 5 denotes a condenser lens (optical system), which guides a light beam from the correction unit 3 to a stop (masking blade) for adjusting an illumination area on the reticle 6 surface.

The luminous flux passing through the stop 6 illuminates a reticle 9 via an imaging lens 7 and a mirror 8. The stop 6 and the reticle 9 have an optically conjugate positional relationship, and the shape and size of the illumination area of the reticle 9 are defined by the shape of the opening of the stop 6.

In the present embodiment, the aperture of the stop 6 has a slit shape. The reticle (first object) 9 has a circuit pattern thereon and is held on a reticle stage 13. Reference numeral 10 denotes a projection lens (projection optical system), which transfers a circuit pattern of the reticle 9 to a semiconductor substrate (second object) 11
The projection is reduced above. The semiconductor substrate 11 is, for example, a wafer, a surface of which is coated with a resist as a photoreceptor, and is mounted on a wafer stage 14 which is three-dimensionally displaced.

Reference numeral 101 denotes a stage drive control system (scanning means)
The reticle stage 13 and the wafer stage 14 are controlled so as to be moved in the scanning direction SC in a direction opposite to each other at a constant speed exactly at a speed of the same ratio as the imaging magnification by the projection lens 10.

In this embodiment, scanning is performed by the scanning means 101 in the short side direction of the slit opening shape of the diaphragm 6.

FIG. 2 is an enlarged explanatory view of the vicinity of the light source 1 in FIG. In the present embodiment, in the light flux having coherence anisotropy emitted from the light source 1, the coherence is low in the V direction and high in the h direction. Therefore, the light source 1 is installed such that the V direction with low coherence coincides with the scanning direction SC on the reticle 9 surface.

Generally, when the light source 1 is disposed as described above without scanning the reticle 9 and the wafer 11 and the light beam is irradiated on the surface of the reticle 9, the coherence of the light beam varies depending on the direction. Bright and dark fringes extending in the scanning direction on the surface are likely to occur, and fringes extending in a direction perpendicular thereto (the non-scanning direction of the reticle) are unlikely to occur.

Therefore, in the present embodiment, with respect to the originally weak interference fringes extending in the non-scanning direction of the reticle, the luminous flux is slightly shifted little by little and overlapped during scanning exposure of the reticle to further average. As a result, sufficient uniformity is achieved for interference fringes extending in the non-scanning direction of the reticle.

On the other hand, with respect to strong interference fringes extending in the scanning direction of the reticle 9, the uniformizing means 4 is vibrated by the vibration means 20 in the direction of high coherence (non-scanning direction) in a plane perpendicular to the light beam. As a result, interference fringes are eliminated while maintaining uniformity and balance in the non-scanning direction on the reticle 9 surface. As a result, uniform illumination is obtained over the entire surface of the substrate 11 and high-resolution exposure transfer is enabled.

As described above, in this embodiment, each element is set so that the direction of low coherence (V direction) of the light beam from the light source 1 and the scanning direction on the reticle 9 surface coincide with each other. The exposure unevenness is reduced, and the exposure unevenness in the non-scanning direction is reduced by the vibration means.

FIG. 3 is a schematic view of a main part of a second embodiment of the present invention. This embodiment is the same as the first embodiment in FIG. 1 except that a part of the correction means 3 is different. Members having the same functions as in the first embodiment are given the same numbers.

In this embodiment, the beam emitted from the beam shaping optical system 2 passes through the correction means 3 including at least the fixed mirror 30, the movable mirror 31, and the movable part 32 thereof, and enters the equalizing means 4.

The movable mirror 31 and its movable portion 32 constitute a beam deflecting means, and deflect the beam incident on the equalizing means 4 so that the direction of high coherence becomes the non-scanning direction.

As in the case of the first embodiment, for the strong interference fringes extending in the scanning direction of the reticle 9, the deflecting means (31,
At 32), the beam is deflected and scanned in the direction of high coherence and is incident on the uniformizing means, so that interference fringes are eliminated in a good balance between the scanning direction on the reticle 9 and the direction perpendicular thereto. Thereby, uniform illumination is obtained over the entire surface of the substrate 11 and high-resolution exposure transfer is enabled. In the present embodiment, the correcting means 3 including the deflecting means (31, 32) is disposed before the equalizing means 4,
May be placed after the.

In the first and second embodiments, when the light beam having coherence anisotropy from the light source 1 is a pulse light, in the first embodiment, the position of the equalizing means is determined by the number of times of light emission of the pulse light. It is effective that the pulse light is changed by a predetermined amount every time or every certain number of times of the trigger signal for causing the light source to emit the pulse light. At this time, it is desirable that the number of times of emission of the pulsed light, the number of times of the trigger signal, the moving amount of the equalizing means, and the like be obtained in advance.

Similarly, in the second embodiment, it is also effective to change the state of the deflecting means by a predetermined amount each time the pulsed light is emitted or the trigger signal is emitted a certain number of times. At this time, it is desirable that the number of times of emission of the pulsed light, the number of times of the trigger signal, the moving amount of the equalizing means, and the like be obtained in advance.

Next, an embodiment of a method for manufacturing a semiconductor device using the above-described projection exposure apparatus will be described.

FIG. 4 is a flowchart of manufacturing a semiconductor device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD).

Step 1 (circuit design) in this embodiment
Now, the circuit design of the semiconductor device will be performed. Step 2
In (mask production), a mask on which a designed circuit pattern is formed is produced.

On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4
The (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.

The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing and bonding) and a packaging process (chip encapsulation). And the like.

In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 5 is a detailed flowchart of the wafer process in step 4 described above. First, in step 11 (oxidation), the surface of the wafer is oxidized. Step 12 (C
In VD), an insulating film is formed on the wafer surface.

In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

[0043]

As described above, according to the present invention, the reticle surface (first object) is illuminated with the illumination light beam having coherence anisotropy, and the pattern of the reticle surface is projected onto the wafer (second object) by the projection optical system. When the projection exposure is performed on the object using the scanning exposure method, the direction of the coherence anisotropy of the illumination light beam and the scanning direction are appropriately set, and the illumination light beam is vibrated in a predetermined direction, thereby simplifying the configuration. As a result, it is possible to achieve a scanning type exposure apparatus capable of reducing illuminance unevenness on the first object surface, having a high resolution and facilitating projection exposure to a large screen, and a device manufacturing method using the same.

In particular, by using a light source that emits a light beam having coherence anisotropy and making the direction of low coherence of the light beam on the reticle surface substantially coincide with the scanning direction of the reticle, the originally weak reticle can be used. The interference fringes extending in the non-scanning direction can be made uniform. For this reason, there is no particular need for a correction means for equalizing interference fringes extending in the non-scanning direction.

In order to equalize the interference fringes extending in the scanning direction of the reticle, the interference fringes are eliminated in a well-balanced manner in the scanning direction on the reticle and the direction perpendicular thereto by only the equalizing means or mirror provided in the optical path. I have.

According to the present invention, uniform illumination can be obtained and high-resolution exposure transfer can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a scanning exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between the light source of FIG. 1 and coherence of an illumination light beam.

FIG. 3 is a schematic view of a main part of a scanning exposure apparatus according to a second embodiment of the present invention.

FIG. 4 is a flowchart of a device manufacturing method according to the present invention.

FIG. 5 is a flowchart of a device manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Beam shaping optical system 3 Correction means 4 Uniformization means 5, 7 Optical system 6 Stop 8 Mirror 9 Reticle (first object) 10 Projection optical system 11 Substrate (wafer, second object) 13 Reticle stage 14 Wafer stage 20 Vibration means 30 Mirror 31 Movable mirror 32 Movable part 101 Scanning means

Claims (8)

[Claims] A pattern on a first object surface is illuminated with an illumination light beam having anisotropy of coherence from an illumination system, and the pattern on the first object surface is mounted on a movable stage by a projection optical system. In a scanning type exposure apparatus for projecting and exposing while relatively scanning the first object and the movable stage at a speed ratio corresponding to the projection magnification of the projection optical system on the two object planes, the illumination system is The direction in which the coherence of the illumination light beam is low is set so as to substantially coincide with the scanning direction,
A scanning exposure apparatus comprising: a vibrating means for vibrating the illumination light beam in a direction of high coherence. 2. The scanning type exposure apparatus according to claim 1, wherein said illumination system has a uniforming means for making a sectional light intensity distribution of said illumination light beam uniform. 3. The scanning exposure apparatus according to claim 2, wherein said vibrating means vibrates said uniformizing means in a direction in which said illumination light flux has high coherence. 4. The illumination light beam is a pulse light, and the equalizing means sets the equalizing means by a predetermined amount every predetermined number of times of emission of the pulse light or every predetermined number of times of a trigger signal for emitting the pulse light. 4. The scanning exposure apparatus according to claim 2, wherein the scanning exposure apparatus is displaced. 5. The scanning type exposure apparatus according to claim 3, wherein said vibrating means has a vibrating mirror provided in an optical path and a drive section for vibrating said vibrating mirror. 6. The apparatus according to claim 1, wherein the illumination light beam has a slit shape through a slit opening, and the movable stage scans in a short direction of the slit opening. 2. The scanning exposure apparatus according to claim 1. 7. A pattern on a first object plane is illuminated with an illumination light beam having slit-shaped coherence anisotropy through a slit opening from an illumination system, and the pattern on the first object plane is projected onto a projection optical system. The first object and the movable stage are relatively synchronized on the second object surface mounted on the movable stage in the short direction of the slit opening at a speed ratio corresponding to the projection magnification of the projection optical system. In a scanning exposure apparatus that performs projection exposure while scanning, the illumination system is set so that the lower coherence of the illumination light beam substantially coincides with the scanning direction, and makes the cross-sectional light intensity distribution of the illumination light beam uniform. A scanning exposure apparatus comprising: a uniformizing unit; and a vibrating unit that vibrates the illumination light beam in a direction of high coherence. 8. A device manufacturing method, comprising manufacturing a device using the scanning exposure apparatus according to claim 1. Description: