JPH09246170A - Aligner and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly integrate elements by dividing one exposure area into a plurality of sub-areas, exposing it, moving a masking blade on the partly superposed areas during exposure, and exposing in a shorter period of time in the case of exposing it by dividing one element into a plurality of areas. SOLUTION: One area to be exposed is divided into four sub-areas and exposed. Thus, a masking blade is moved to an exposure starting position. When the area A is exposed, a YU blade 203 is moved to the position 10mm from the center of the exposure in a positive direction, a YD blade 204 is moved to the position 8mm in a negative direction, an XL blade 201 is moved to the position 10mm in the negative direction and an XR blade 202 is moved to the position 8mm in the positive direction. In the area A, the YD and XR blades are moved, and the moving amounts of the YD and XR blades are respectively -4/100 and 4/100mm. The positions of the YD and XR blades are respectively -12 and 12mm at the time of finishing the exposure. The parts superposed with the other areas are respectively 4mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called division exposure type exposure apparatus that divides one exposure area into a plurality of sub-areas for exposure, and more particularly to an exposure apparatus suitable as a semiconductor element manufacturing apparatus.

[0002]

2. Description of the Related Art Semiconductor elements are becoming finer and more highly integrated.

[0003]

However, these semiconductor elements are required to have more functions than can be dealt with by miniaturization. A semiconductor device having such many functions cannot be manufactured as one device. Therefore, a desired function is realized by dividing the semiconductor element into a plurality of semiconductor elements and combining them on a substrate of an electronic circuit, but there are problems such as increase in size, cost, and deterioration in reliability. there were.

In order to solve this problem, there has been proposed a method of highly integrating a semiconductor element by dividing one semiconductor element into a plurality of areas and exposing the same. As one of the means, a method of moving a masking blade during exposure is proposed in JP-A-6-349711.

According to this method, the integrated value of the exposure amount is measured, and the masking blade is moved based on the value so that the seams of the patterns of adjacent areas which are divided into a plurality of areas and exposed are singular points (exposure amount is Too few,
It is a method to prevent too many points).
However, in this method, since a movement command is issued to the masking blade after measuring the integrated exposure amount, there is a time lag,
There is a problem that the masking blade position is displaced from a required position, and in some cases, it takes an extra time to expose one area.

The present invention has been made in view of the above-mentioned problems, and when one element, for example, a semiconductor element is divided into a plurality of areas and exposed, the element is manufactured by exposing in a shorter time, and the element is increased. It is in integration.

[0007]

In order to achieve the above object, the exposure apparatus of the present invention comprises means for exposing one exposure area by dividing it into a plurality of sub-areas and adjacent sub-areas of the divided sub-areas. An exposure apparatus having means for setting so that they partially overlap and means for moving a masking blade in an area where they partially overlap during exposure, and when pulsed light is used as a light source, the masking blade is based on the number of exposure pulses. It is characterized by having means for changing the position of 1 during exposure of one sub-area. Further, when continuous light is used as the light source, the exposure shutter is opened and closed a plurality of times in one exposure, and a means for changing the position of the masking blade during the exposure of one sub area based on the number of times of opening and closing is provided. And

In the exposure method of the present invention, pulsed light is used as the light source, one exposure area on the object to be exposed is divided into a plurality of sub-areas, and each sub-area is exposed with a plurality of pulsed light. In the exposure method, the step of setting each sub-area so that adjacent sub-areas partially overlap each other, and the masking blade is set at a position where the sub-area to be exposed on the exposed object is separated from the other part. And a step of exposing the position of the masking blade for partitioning the adjacent sub-areas while sequentially moving the positions of the masking blades for dividing the adjacent sub-areas based on the number of the pulsed lights in the overlapping portion of these adjacent sub-areas. Characterize. When using continuous light and shutter means as the light source, the shutter means is opened and closed a plurality of times when exposing each sub-area, the light source is pseudo-pulsed, and the masking blade is opened and closed by the shutter means. That is, they are sequentially moved based on the number of pulsed lights.

[0009]

With the above-described structure, when exposing one element, for example, a semiconductor element in a plurality of areas, the masking blade can be moved without time lag, and the exposure can be performed in a shorter time. It is possible to make a semiconductor device with a large pattern size. That is, a semiconductor element having many functions can be manufactured as one element, and a highly functional semiconductor element with low cost and high reliability can be realized.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a semiconductor exposure apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 is an excimer laser light source which emits pulsed laser light in which, for example, KrF or ArF is enclosed. Reference numeral 2 denotes an illumination system that shapes the laser light emitted from the excimer laser light source into a desired beam shape and emits the light with uniform orientation characteristics of the light beam. A beam shaping optical system, an optical integrator such as a fly-eye lens, a collimator lens, and a mirror. Etc.

M is a mask or reticle (hereinafter simply referred to as a mask) in which an integrated circuit pattern is formed on the exit optical path of the illumination system 2, 3 is a projection optical system, and W is a wafer. The formed integrated circuit pattern is projected and exposed on the wafer W through the projection optical system 3 in an area determined by the masking blade 9.

Illumination system 2 includes a mirror 4 and a sensor 5.
A part of the luminous flux emitted by the mirror 4 is made incident on the photoelectric conversion surface of the sensor 5 by the mirror 4. Reference numeral 6 is a light amount integrating circuit for integrating the light amount of the pulsed light incident on the sensor 5. 7 is CP
U, each time the excimer laser 1 emits light, a one-pulse signal is input from the light amount integrating circuit 6. The CPU 7 issues a control command such as a light emission timing to the excimer laser 1 via the laser control unit 8. Further, the masking blade control unit 10 moves the masking blade 9 according to a control command such as a position command of the CPU 7 and controls so that an illumination area matching the command value is exposed.

Next, a method of division exposure in this structure will be described with reference to FIGS. 2, 3, 4, and 5. FIG. 2 shows the upper, lower, left and right blades of the masking blade.
201 is an XL blade, 202 is an XR blade, 203
Is a YU blade, 204 is a YD blade, and 205
Is an illumination area through which illumination light passes between each blade. The light passing through the illumination area 205 passes through a masking imaging lens, a mirror, and a condenser lens (not shown),
The area on the mask M that is four times as large as the illumination area 205 is illuminated. The light applied to the mask M passes through the projection system 3 and the mask M
The upper pattern is reduced to 1/5 and imaged on the wafer W.
That is, the illumination area 205 of the masking blade 9 is 0.8 times the area on the wafer W. In the following, the positions and sizes of the masking blade 9 and the mask M are values converted into the positions and sizes on the wafer W, and the positions and movement directions of the respective blades will be described on the wafer W direction.

FIG. 3 shows one area to be exposed (40 mm × 40
(mm) is divided into four areas (sub areas) for exposure, and shows one area on the wafer W. 30
2 is an area (sub-area) A to be exposed first, 303 is an area (sub-area) B to be exposed for the second time, and 304 is 3
An area (subarea) C to be exposed for the fourth time and an area (subarea) D to be exposed for the fourth time 305. Wafer W
In order to move the sub-area to be exposed under the projection optical system 3, a chuck (not shown) for mounting and fixing the wafer W, and a stage for moving the chuck are used. Also, for each sub-area, a mask changer (not shown) is used to replace the mask M with a pattern to be printed on it.

FIG. 5 shows a sequence for exposing one divided area (sub-area). Step 50
The exposure amount per pulse and the required number of pulses are calculated from the target exposure amount designated by 1. In this embodiment, 100 pulses are required (N = 100). Step 50
At 2, the masking blade is moved to the exposure start position. When the area A of this embodiment is exposed, the YU blade is located 10 mm in the plus direction from the exposure center, the YD blade is located 8 mm in the minus direction, the XL blade is located 10 mm in the minus direction, and the XR blade is Move to the position of 8 mm in the plus direction. In step 503, the blade that moves during exposure and the amount of movement per pulse are calculated. In the area A of this embodiment, the YD and XR blades are moved, and the movement amounts are −4/100 mm for YD and 4/100 mm for XR. YD is -1 at the position at the end of exposure
2 mm and XR is 12 mm. The portions overlapping with other areas are 4 mm each.

In step 504, one pulse exposure is performed with the exposure amount calculated in step 501. In step 505, it is checked whether or not the number of pulses calculated in step 501 has been exposed, and when the number of calculated pulses reaches N, this sequence is ended. At this time, the illumination area 205 in which the blade is always open is exposed with the target exposure amount.

If the number of pulses (N = 100) calculated in step 501 has not been reached in step 505, the amount of movement per pulse of the moving blade calculated in step 503 is moved in step 506.
In this way, until the target exposure amount is reached, step 504
By repeating the 1-pulse exposure, the exposure amount determination in step 505, and the blade movement operation in step 506, the divided 1 area can be exposed. This sequence is repeated in each area.

Reference numeral 306 in FIG. 3 is a line drawn to the same Y position (parallel to the X axis), and FIG. 4 shows a graph of the exposure amount on this line. 401 is a target exposure amount. Between 307 and 308, area A is exposed with the blade always open. Between 309 and 310, area B is exposed with the blade always open. Between 308 and 309, both areas A and B are areas exposed while moving the blade, and areas A and B are areas where the pattern of the mask M is the same and the areas of the same pattern are overlapped and exposed. An alignment mechanism for the mask M (not shown) is used to exactly overlap the patterns. Then, no matter what part is seen between 308 and 309, the sum of the exposure amounts in areas A and B is 3
The target exposure amount 401 is set in the same manner as between 07 and 308 and between 309 and 310. The same applies to areas C and D, A and C, and B and D. Further, the same thing is performed in the two-dimensional XY even in the portion between the areas A, B, C and D, and the target exposure amount 401 is exposed at any point.

According to this embodiment, it is possible to expose an area having a size equal to or larger than the exposure area of the exposure apparatus evenly, without exposing the area to a singular point.
It becomes possible to manufacture a semiconductor element having a large pattern size with a fine pattern.

[0020]

Other Embodiments Although pulsed light is used as the light source in the above embodiments, the present invention can be similarly applied to the case where continuous light such as i-line is used. That is, the exposure shutter is opened and closed a plurality of times in one exposure, and based on the number of times of opening and closing,
The position of the masking blade may be changed during the 1-area exposure.

Further, in the above embodiment, each blade was moved to the outside while the masking blade widened the exposure area during the exposure, but each blade may be moved to the inside so as to sandwich the exposure area.

Further, in the case of dividing the exposure into more parts and exposing the area where the four blades are moved, the facing blades are moved in the same direction so that the area of the exposure area does not change. May be.

Further, in the above example, the blade is gradually moved by software to issue a light emission command to the laser. However, the amount of movement of the blade necessary for exposure is commanded at once by software, It is also possible to issue a light emission command to the laser by hardware every time the blade moves by a predetermined amount while measuring the position of the blade using an encoder or the like.

In the above embodiment, a mask is prepared for each area to be divided and exposed. However, when exposing a slightly wider area than the exposure area that can be exposed, one mask is used and the exposure area is changed. Therefore, there is also a method of changing the exposed area on the mask by moving the mask when moving the wafer.

In the above embodiment, an example is shown in which the pattern is baked on a wafer on which the pattern has not been baked yet. However, in the present invention, the pattern is already baked, and in order to form the next layer, it is overbaked. The same can be applied to the case.

[0026]

As described above, means for exposing one area into a plurality of sub-areas for exposure, means for setting adjacent areas of the divided areas so as to partially overlap each other, and a part during exposure. By having a means for moving the masking blade in the overlapping area, it is possible to perform exposure without forming a singular point at the joint, and it is possible to form a large element with a fine pattern. For example, in a semiconductor element, many functions can be incorporated in one semiconductor element, and low cost, high reliability, and high function can be realized.

[Brief description of drawings]

FIG. 1 is a schematic view of a reduction projection type exposure apparatus, that is, a so-called stepper according to an embodiment of the present invention.

FIG. 2 is a view showing a blade of a masking blade of the apparatus shown in FIG.

FIG. 3 is a diagram showing areas exposed by the present invention.

FIG. 4 is a graph showing the relationship between the X position and the exposure amount at the same Y position in FIG.

FIG. 5 is a flowchart for exposing one divided area of FIG.

[Explanation of symbols]

1: excimer laser, 2: illumination system, 3: projection optical system,
4: mirror, 5: photo sensor, 6: light quantity integrating circuit,
7: CPU, 8: Laser control unit, 9: Masking blade, 10: Masking blade control unit, M: Mask,
W: Wafer.

Claims (4)

[Claims] 1. An exposure apparatus which divides one exposure area on an object to be exposed into a plurality of sub-areas for exposure, and means for setting each sub-area so that adjacent sub-areas partially overlap each other; A masking blade that divides the portion to be exposed on the exposure body from other portions, a means for using pulsed light as a light source, means for exposing the portion divided by the masking blade with a plurality of pulsed light, and during exposure, An exposure apparatus comprising: means for moving a position of a masking blade for partitioning the adjacent sub-areas based on the number of exposure pulses within an overlapping portion of the adjacent sub-areas. 2. An exposure apparatus which divides one exposure area on an object to be exposed into a plurality of sub-areas for exposure, and means for setting each sub-area so that adjacent sub-areas partially overlap each other; A masking blade that separates a part to be exposed from the other part on the exposure body and continuous light and a shutter means are used as a light source, and the shutter means is opened and closed a plurality of times to expose the part separated by the masking blade. Means and means for moving the position of the masking blade that divides the adjacent sub-areas within the overlapping portion of these sub-areas based on the number of times of opening and closing of the shutter means during exposure. Exposure equipment. 3. An exposure method in which pulsed light is used as a light source, one exposure area on an object to be exposed is divided into a plurality of sub-areas, and each sub-area is exposed by a plurality of pulsed lights. A step of setting each sub-area so that a part of the sub-areas overlap each other; a step of setting a masking blade at a position that separates the sub-area to be exposed from the other part on the object to be exposed; And a step of exposing while sequentially moving positions of masking blades for partitioning the areas based on the number of the pulsed lights in an overlapping portion of these adjacent sub-areas. 4. An exposure method in which one exposure area on an object to be exposed is divided into a plurality of sub-areas for exposure, and a step of setting each sub-area so that adjacent sub-areas partially overlap each other, A step of setting a masking blade at a position where the sub-area to be exposed on the exposure body is separated from other parts, and continuous light and shutter means are used as a light source, and the shutter means is opened and closed a plurality of times for each sub-area. However, the step of exposing by sequentially moving the position of the masking blade that divides the adjacent sub-areas within the overlapping portion of these adjacent sub-areas based on the number of times the shutter means is opened and closed. A characteristic exposure method.