JPH02177315A - Exposure - Google Patents

Abstract

PURPOSE:To lessen characteristic change of each member at initial stage of exposure as far as possible so as to enable proper exposure by retreating a substance to be exposed to a position other than the exposure position before exposure so as to irradiate only the member in an exposure light path with pulse light when the substance to be exposed is irradiated with the pulse light from a light source. CONSTITUTION:When an exposure device is in start-waiting conditions and a device and a sequence controller 17 are in idling conditions, if a start command is issued from an input device 8, a wafer 11 is carried in onto a wafer chuck 20 on an theta, Z-stage 13 based on a carrying-in command from the controller 17. Next, a stage controller 16 is operated so as to drive X- and Y-stage 14 and 15 to retreat the wafer 11 to a position different from the exposure position right below a projecting lens 10, and an illumination photometer 19 on the stage is positioned at the exposure position. Thereafter, the controller 17 issues an oscillation command to an excimer laser 1 so as to make each member, such as an optical member on the light path, a detector 5, etc., start warming-up. When this finishes, the wafer 11 is returned to a shot position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exposure method using an exposure apparatus that uses a light source that emits pulsed light as an exposure light source.

[Prior Art] Conventionally, many exposure apparatuses using optical lithography have been used that use continuous light such as G-line or I-line as an exposure light source. On the other hand, in recent years, with the miniaturization of semiconductor devices, g-line and
Lasers that generate light with a shorter wavelength than that of a line, such as excimer lasers, have been used in exposure equipment. One of the characteristics of this type of short wavelength laser is that it often oscillates in a pulsed manner. It is one.

FIG. 2 is a block diagram of a conventional exposure apparatus using an excimer laser as a light source, and FIG. 3 is a flowchart for explaining its operation.

In FIG. 2, 1 is an excimer laser which is an exposure light source. The luminous flux emitted from the excimer laser 1 is
The beam passes through a beam shaping optical system 2, is totally reflected by a total reflection mirror 3, and reaches a half mirror 4. A part of the light beam is reflected by this half mirror 4 and detected by a detector 5 for integrating the exposure amount in exposure control. On the other hand, the light beam that has passed through the half mirror 4 is totally reflected by the total reflection mirror 7, and the illumination optical system 8
The reticle 9, which is the original of the circuit element, is illuminated through the light.

The circuit pattern drawn on the reticle 9 is then transferred onto the wafer 11 via the projection lens 10.

6 is an exposure control unit, 17 is a sequence controller, 18
is an input device. Further, 12 is a wafer transport system, 13 is a θZ stage, 14 is an X stage, 15 is a Y stage,
16 is a stage control section.

Next, the operation of the apparatus shown in FIG. 2 will be explained with reference to the flowchart shown in FIG. First, while waiting for the start of step S31, the sequence controller 17 is in an idling state. When a start command is input from this input device 18, this is determined in step S32, and the process proceeds to step 333.

In step 333, the sequence controller 17 outputs an oscillation command to the excimer laser 1 to increase the ohm of each member such as the optical member and the detector 5 on the optical path.

After the warm-up is completed, in step S34, the sequence controller 17 outputs a wafer loading command to the wafer transport system 12, whereby the wafer 11 is transferred from the wafer transport system 12 onto the θZ stage 13. Next, in step S35, a "first shot feed command" is further output to the stage control section 16, and the X stage 14 and Y stage I5 are driven to move the first shot area of the wafer 11 to the printing position below the projection lens 10. Next, in step 336, the sequence controller 17 outputs an oscillation command to the excimer laser 1 to start exposure.

In step S37, it is determined whether or not the exposure of all shots of the wafer 11 has been completed, and if all shots have not been completed yet, the process moves to the next shot in step S338, and then
Return to step S36. After the step-and-repeat operation is performed in this way, and the exposure of all shots is completed in step S37, the wafer transport system 12 is moved in step S39.
The wafer 11 is carried out. And step S4
If there is a wafer to be processed at 0, the process returns to step S33 and the operations after the ohm-up are repeated. If all wafers have been processed, the process returns to step 531 and waits for the start again.

[Problems to be Solved by the Invention] By the way, the ohm-up operation shown in step S33 in FIG. Based on the knowledge that the characteristics of each component change, we minimize the effects of changes in the characteristics of each component during the initial stage of exposure by irradiating each component with exposure light and warming it up before actually exposing it. It is in. and,
At this time, in order to avoid erroneous irradiation of the exposure light and its scattered light onto the wafer, a laser light source is oscillated and the optical members are irradiated with exposure light to increase the ohm before the wafer is transferred to the XY stage. are doing.

However, in this method, between the ohm-up and the actual exposure, there are (1) time for loading the wafer onto the XY stage, and (2) time for moving the wafer to the XYX stage 14 from the wafer loading position to the first shot position. . Therefore, at these intervals, the optical system and other characteristics begin to return to the state before the ohm-up, resulting in the drawback that the ohm-up effect is not fully reflected.

In view of the above-mentioned problems with the conventional type, the present invention suppresses the reduction in the effect of warm-up due to the interval between warm-up and actual exposure in order to reduce the influence of changes in the characteristics of each member at the initial stage of exposure. It is an object of the present invention to provide an exposure method in which the effect of warm-up is sufficiently reflected, and the time during warm-up is effectively utilized.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an exposure method in which a target object such as a wafer is exposed in advance using pulsed light emitted from a light source that emits pulsed light as exposure light. The exposed object (
Alternatively, move the XY stage (on which the object to be exposed is placed) to a position other than the exposure position such that the illuminance meter installed on the stage to measure the illuminance of the exposure light is at the exposure position, and then operate the exposure light source, A so-called warm-up is performed by irradiating pulsed light onto components in the exposure optical path, such as the illumination system, the exposure amount integration detector, and the surrounding projection system. By measuring this, it is reflected in the illuminance of the exposure light during actual exposure and in the correction of illuminance unevenness.

This shortens the interval between warm-up and actual exposure, and the effect of warm-up is fully reflected. Also, warm-up time can be used effectively. Therefore, it is possible to reduce the effects of changes in the characteristics of each member during the initial stage of exposure, to achieve proper exposure, and to improve throughput.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a flowchart for explaining an exposure method according to an embodiment of the present invention, and is an operation flow in a so-called 1st mask mode in a semiconductor exposure apparatus.

The exposure method according to this embodiment described here is one in which the present invention is applied to the exposure apparatus having the configuration shown in FIGS. 2 and 4.

Note that FIG. 4 is a schematic diagram of the XY-θ stage in the exposure apparatus configuration shown in FIG. 2.

Items with the same numbers as in Figure 2 indicate the same items, 2
0 is a wafer chuck, and 19 is an illuminometer provided integrally with the stage.

In FIG. 1, first in step S1, the exposure apparatus is in a start waiting state, and the exposure apparatus and sequence controller are in a waiting state. 7 is in the idle link state. When a start command is manually input from the input device 18, this is detected in step S2 and the process proceeds to step S3.In step S3, the sequence controller 17 outputs a wafer loading command to the wafer transport system 12, and the wafer 11 is The wafer is loaded onto the wafer chuck 20 on the stage 13.

Next, in step S4, the sequence controller 17 outputs a stage evacuation command to the stage control section 16. In response to this, the stage control unit 16 controls the X stage 14.
Then, the Y stage 15 is driven, and the wafer 11 is placed at a position different from the exposure position directly under the projection lens 10 and where the wafer 11 is not irradiated with the exposure light and its scattered light, and the illuminometer 19 on the stage move it to a position where it is at the exposure position. By the way, here is the illumination meter! 9 is provided at a position on the stage such that when it is at the exposure position, the wafer on the same stage is in a position where the wafer is not irradiated with the exposure light and its scattered light. It is assumed that this retreat position has been input in advance using the input device 18 or the like.

Next, in step S5, the sequence controller 17 outputs an oscillation command to the excimer laser 1, and starts warming up each member such as the optical member and the detector 5 on the optical path. Then, in step S6, the illuminance at the exposure position is measured.

This illuminance measurement is performed using an illuminance meter 19 to measure one or more points at the exposure position, and the measured values are stored by the sequence controller 17 and reflected in the illuminance during actual exposure and correction of illuminance unevenness. By the way, tsuohmua”
The case where the output of the laser 1 at the time of sharpening is different from that at the time of exposure is also considered and reflected in the correction. When the warm-up is finished,
The sequence controller 17 outputs an oscillation stop command to the excimer laser 1 to stop oscillation. Then, in step S6, a first shot feed command is further output to the stage control section 16, and the X stage 14 and Y stage 15 are
The wafer 11, which had been evacuated to the evacuated position, is moved to the first
Move to shot position.

Next, in step S7, the sequence controller 17 outputs an oscillation command to the excimer laser 1 to start exposure.

In step S8, it is determined whether or not exposure of all shots of the wafer 11 has been completed. If all shots have not been completed yet, the process moves to the next shot in step S9, and then returns to step S7. The step-and-repeat operation is performed in this way, and when the exposure of all the shots is completed in step S8, the wafer 11 is carried out by the wafer transport system 12 in step 310. If there are any queries to be processed in step 511, the process returns to step S3 and repeats the operations after loading the wafer, and if all the processes have been completed, the process returns to step S1 to wait for the start again.

〔Effect of the invention〕

As explained above, according to the present invention, the object to be exposed, such as a square, is carried onto the XY stage in advance, and the object to be exposed, such as a square, is evacuated to the stage before actual wafer exposure, and the illumination system, projection system, and exposure amount are Since we are planning to warm up the detector and surrounding parts for integration,
It has the advantage of shortening the interval between warm-up and actual exposure and fully bringing out the warm-up effect, and also because the illumination meter on the stage is used to measure the illuminance when the XY stage is evacuated. There is no need to measure illuminance, which has the advantage of improving throughput. Therefore, the influence of changes in the characteristics of each member during the initial stage of exposure can be minimized, and appropriate exposure with high throughput can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a flowchart for explaining an exposure method according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional exposure apparatus using an excimer laser as a light source, and FIG. 3 is a conventional exposure method. A flowchart for explaining the operation of the apparatus, FIG. 4 shows the X-
It is a schematic diagram of a Y-theta stage. 1: Excimer laser, 2: Beam shaping optical system, 3.7: Total reflection mirror 4: Half mirror 5: Detector, 6: Exposure control unit, 8: Illumination optical system, 9 Reticle, 10: Projection lens, 11: Wafer , 12: Wafer transport system, 16: Stage control section, 17: Sequence controller, 18: Input device.

Claims (3)

[Claims] (1) In an exposure method in which pulsed light emitted from a light source that emits light in a pulsed manner is used as exposure light, the object to be exposed is moved to a position other than the exposure position before the object is exposed, and then the exposure light source is turned off. An exposure method characterized by operating the light source and irradiating a member in an exposure optical path with pulsed light. (2) A position other than the exposure position to which the object to be exposed is to be moved is outside the irradiation range of the exposure light and its scattered light.
Exposure method described in. (3) The exposure method according to claim 1 or 2, wherein a position other than the exposure position to which the object to be exposed is to be moved can be specified arbitrarily from the outside.