JP3008591B2 - Exposure apparatus and circuit manufacturing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and a circuit manufacturing method using the same, and more particularly, to a circuit pattern formed on a reticle surface on a wafer surface as a projection surface by a projection optical system (projection lens system). This is suitable when manufacturing devices such as semiconductor elements using illuminance distribution measuring means (illuminance detector) for measuring illuminance and illuminance distribution in the projection plane when projecting and exposing at a predetermined magnification.

[0002]

2. Description of the Related Art In recent semiconductor manufacturing technology, the resolution pattern line width is reduced to, for example, 1 .mu.m or less in accordance with the high integration of electronic circuits. Requested.

Generally, when projecting a circuit pattern on a reticle surface onto a wafer surface (projection surface) via a projection optical system, the resolution line width of the circuit pattern depends on the wavelength used and the N.D. of the projection optical system. Along with A, etc., the quality of the uniformity of the illuminance distribution on the projection surface has a great influence.

For this reason, in many conventional exposure apparatuses, an illuminometer is arranged on an XY stage surface on which a wafer is mounted, and an illuminance distribution on a projection surface is measured by various methods.

For example, (a) an illuminance meter is mounted on a part of an XY stage on which a wafer is placed, and if necessary, the illuminance meter on the XY stage is moved to a projection plane to perform measurement repeatedly. To measure the illuminance distribution. (B) A method of measuring an illuminance distribution in a projection plane by mounting an illuminance meter each time a part of the XY stage surface is measured, and repeatedly measuring the illuminance while moving the XY stage. Etc. are used.

[0006]

Among the methods for measuring the illuminance distribution on the projection plane, the method (a) has an illuminance meter on the XY stage surface, so that the number of wires to the XY stage increases and the detector increases. There is a problem in that heat is generated from the power supply, the amplifier, and the like, making it difficult to move with high precision.

Further, the driving force and the exciting force of the XY stage increase, the vibration of the entire apparatus increases, the alignment accuracy decreases, and, for example, the throughput of waiting for the vibration of the exposure apparatus to converge decreases. There was a point.

On the other hand, in the above method (b), the wafer chuck must be removed and the illuminance meter must be mounted on the XY stage surface each time the measurement is performed, so that the throughput decreases and the wafer chuck is repeatedly attached and detached. There has been a problem that the parallelism between the wafer chuck and the projection surface of the projection optical system changes, and the resolving power decreases.

According to the present invention, a projection optical system is provided by providing a condensing system on a part of an XY stage in an exposure apparatus and providing a two-dimensional imaging means such as a CCD on the optical axis of a projection optical system below the XY stage. It is an object of the present invention to provide an exposure apparatus capable of measuring illuminance and illuminance distribution within a relatively large area in a projection plane by a system quickly, for example, once, and with high accuracy, and a circuit manufacturing method using the same. .

[0010]

According to a first aspect of the present invention, there is provided an exposure apparatus for exposing a second object placed on a stage through a pattern of a first object. A light condensing system is provided on the stage, and light is incident on the illuminance detector via the light condensing system. The projection surface corresponding to the second object surface and the illuminance detector It is characterized by having a conjugate relationship via an optical system. An exposure apparatus according to claim 2 is an exposure apparatus that projects a pattern of a first object onto a second object placed on a movable stage via a projection optical system, wherein the pattern of the projection optical system is separated from the movable stage. An illuminance detector is provided on an extension of the optical axis, a condensing system is provided on the movable stage, and in a state where the condensing system is positioned on the optical axis, from the projection optical system via the condensing system. Is incident on the illuminance detector. The invention of claim 3 is claim 2
In the invention, the projection surface corresponding to the second object surface and the illuminance detector have a conjugate relationship via the light-collecting system. The invention of Claim 4 is Claim 1 or 3
In the invention, the illuminance distribution of the projection plane is measured based on the output of the illuminance detector. According to a fifth aspect of the present invention, in the fourth aspect, the illuminance detector includes a sensor in which light receiving elements are two-dimensionally arranged. According to a sixth aspect of the present invention, in the fourth or fifth aspect, the illuminance detector includes an image sensor such as a CCD. According to a seventh aspect of the present invention, in the first or second aspect, the stage is movable in different X and Y directions.

The circuit manufacturing method according to the invention of claim 8 is the first aspect of the invention.
7. A step of projecting a circuit pattern of a mask onto a substrate using the exposure apparatus according to any one of the above items 1 to 7.

[0012]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an illumination system. Lighting system 1
Is a light source 1 composed of an ultra-high pressure mercury lamp or excimer laser, etc.
a and an illumination optical system 1b for uniformly illuminating a reticle 5, which is a projection object, on which a light beam from the light source 1a is placed on the surface to be irradiated.

Reference numeral 2 denotes a lamp lighting means, which drives and controls the light source 1a of the illumination system 1. Reference numeral 3 denotes a shutter means for controlling the amount of light from the illumination system 1 incident on the reticle 5 surface.

Reference numeral 8 denotes a projection lens system (projection optical system) which projects a circuit pattern on the reticle 5 in a reduced size onto the wafer 9.

Reference numeral 4 denotes a Z stage on which a wafer 9 is mounted. The wafer 9 is placed on a plane (x, y) orthogonal to the optical axis direction (Z direction) of the projection lens system 8 and the optical axis of the projection lens system 8.
The tilt within the plane is adjusted for driving.

Reference numeral 10 denotes an XY stage, and a Z stage 4
, And drive adjustment is performed in the x and y directions on the x and y planes. Motors 11 and 12 drive the XY stage 10 in the x and y directions, respectively.

Reference numeral 6 denotes a light condensing system, which is provided on a part of the X, Y stage 10. Reference numeral 7 denotes an image pickup means (illuminance detector), which is disposed below the XY stage 10 on the optical axis extension of the projection lens system 8. The imaging means 7 comprises a two-dimensional sensor such as a CCD.

The condensing system 6 is configured such that the projection surface of the projection lens system 8 (corresponding to the surface of the wafer 9) and the light receiving surface of the image pickup means 7 have a substantially conjugate relationship.

Reference numeral 13 denotes a control unit comprising a microcomputer, which processes an output signal from the imaging unit 7 and
The motors 11 and 12 are driven to control the drive so that the XY stage 10 comes to a predetermined position.

In this embodiment, when measuring the illuminance and the illuminance distribution on the projection surface (wafer 9 surface) of the projection lens system 8, the XY stage 10 is first moved by the motors 11 and 12 so that the optical axis of the condenser system 6 is measured. Is set so as to substantially coincide with the optical axis of the projection lens system 8.

Next, the shutter unit 3 is opened to irradiate a light beam from the illumination system 1 onto the projection surface on which the reticle 5 is located. At this time, the reticle 5 has been retracted outside the optical path.

The projection lens system 8 irradiates a light beam from the surface to be projected onto the projection surface where the wafer 9 is located. The light beam from the projection surface of the projection lens system 8 is made incident on the image pickup means 7 by the condensing system 6. At this time, the condensing system 6 is configured such that the divergent light beam from the projection surface of the projection lens system 8 forms an image on the surface of the imaging means 7.

The two-dimensional illuminance distribution on the projection plane is measured at a time using the output signal from the imaging means 7.

Next, when the measurement is completed, the shutter means 3
Closes the shutter.

FIG. 2 is a block diagram showing measurement control when measuring the illuminance distribution on the projection surface of the projection lens system 8 in this embodiment.

In this embodiment, before measuring the illuminance distribution on the projection surface, the sensitivity unevenness in the combination of the light collecting system 6 and the image pickup means 7 is measured and corrected in advance.

For this reason, the condensing system 6 and the imaging means 7 are provided in the exposure apparatus.
Before mounting the lens, the focusing system 6 and the imaging means 7 are
Are set under the same conditions as when measuring the illuminance distribution, and the light converging system 6 irradiates the imaging means 7 with reference light having a uniform illuminance distribution.

At this time, an output signal obtained from each pixel of the image pickup means 7 is stored in the non-luminous memory 22.

Next, the condensing system 6 and the image pickup means 7 are mounted on the exposure apparatus, and the illuminance distribution on the projection plane is actually measured by the method described above.

First, the microcomputer 21 uses X
The motor 24 is driven via the Y stage circuit 23 to move the XY stage 10 so that the optical axis of the light focusing system 6 coincides with the optical axis of the projection lens system 8.

Next, the shutter means 3 is opened by the shutter control circuit 25. As a result, the light beam from the projection target surface passes through the projection optical system 8 and the light collection system 6 and enters the imaging unit 7.

At this time, the output signal from each pixel obtained from the image pickup means 7 is corrected by the video signal processing circuit 26 with the value stored in the non-luminous memory 22.

Next, the digital signal A / D converted by the video signal processing circuit 26 is transferred to the frame memory circuit 27.

The microcomputer 21 calls the converted signal value MCP of each pixel from the frame memory circuit 27. Further, it is extracted as data CENT of a pixel corresponding to the center position of the projection plane (wafer plane) from the data of the frame memory circuit 27.

Thus, the illuminance I _P at the position of the projection plane corresponding to the pixel is calculated from the value MCP obtained from each pixel.

[0037]

(Equation 1) It is calculated from the formula. Then, the microcomputer 21 calculates the illuminance at each position on the projection plane, that is, at each pixel obtained by the equation (1).
Calculates the illuminance distribution of the projection plane.

[0038]

According to the present invention, it is possible to achieve an exposure apparatus capable of accurately measuring illuminance and illuminance distribution in a projection plane by a projection optical system, and a circuit manufacturing method using the same.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

FIG. 2 is a block diagram when measuring the illuminance distribution on the projection plane in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination system 2 Lamp lighting means 3 Shutter means 4 Z stage 5 Reticle 6 Condensing system 7 Imaging means 8 Projection lens system 9 Wafer 10 XY stage 11, 12 Motor 13 Control means

Claims (8)

(57) [Claims] 1. An exposure apparatus for exposing a second object placed on a stage via a pattern of a first object, comprising: an illuminance detector provided separately from the stage; Light is incident on the illuminance detector via a light condensing system, and a projection plane corresponding to the second object plane and a
Exposure apparatus whose serial illuminance detector and said conjugate relationship near isosamples through the condensing system. 2. An exposure apparatus for projecting a pattern of a first object onto a second object placed on a movable stage via a projection optical system, wherein the pattern is separated from the movable stage and extends on an extension of an optical axis of the projection optical system. Provided in the movable stage, a light-collecting system is provided on the movable stage, and in a state where the light-collecting system is positioned on the optical axis, the light from the projection optical system is transmitted through the light-collecting system to the illuminance. An exposure apparatus, wherein the light is incident on a detector. 3. The exposure apparatus according to claim 2 , wherein a projection plane corresponding to the second object plane and the illuminance detector have a conjugate relationship via the light-collecting system. 4. The method of claim 1, wherein the measuring the illuminance distribution of the projection surface based on the output of the irradiance detector also
Is the exposure device of 3. 5. An exposure apparatus according to claim 4, wherein said illuminance detector includes a sensor in which light receiving elements are arranged two-dimensionally. 6. The exposure apparatus according to claim 4, wherein the illuminance detector includes an image sensor such as a CCD. 7. The stage has different X and Y directions.
3. The device according to claim 1, wherein the movable member is movable in a direction.
Exposure equipment. 8. A circuit manufacturing method characterized by including the step of projecting a circuit pattern of a mask onto a substrate using any of the exposure apparatus of claims 1-7.