JP3376045B2 - Scanning exposure apparatus and device manufacturing method using the scanning exposure apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning type exposure apparatus and a device manufacturing method using the scanning type exposure apparatus.
The present invention relates to a scanning type exposure apparatus for manufacturing devices such as semiconductor chips such as C and LSI, liquid crystal elements, magnetic heads, CCDs (imaging elements), and a method for manufacturing various devices using the scanning type exposure apparatus.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional scanning type exposure apparatus for manufacturing semiconductor devices. This apparatus illuminates a reticle 10 with slit-shaped exposure light 71, and a projection lens system 15 causes a circuit of the reticle 10 to illuminate. Pattern 70 on wafer 1
4, and the reticle 10 and the wafer 14 are scanned in the opposite directions to the exposure light 71 and the projection lens system 15 at the same speed ratio as the reduction magnification of the projection lens system 15 as shown in the figure. As a result, the pattern on the entire surface of the reticle 10 is transferred to the area 72 on the wafer 14.

[0003]

This exposure apparatus mainly uses a reticle 10 and a wafer 1 to ensure the uniformity of exposure.
Exposure of each of the Nos. 4 starts after reaching a constant speed.

This situation is shown in FIG. 7 using the reticle 10 side as an example.
Will be described below.

As can be seen from FIG. 7, in order to completely scan the pattern 70 with the slit-shaped exposure light 71, the pattern 70 is scanned by a distance obtained by adding the width L1 of the slit-shaped exposure light 71 to the width L of the pattern 70. Good.

However, in this exposure apparatus, the exposure is started after the scanning speed becomes constant.
It requires extra strokes 12 and 13 for acceleration and deceleration, and therefore spends extra time on the exposure.

[0007]

The object of the present invention is to
An object of the present invention is to provide a scanning type exposure apparatus that can shorten the time and a device manufacturing method using the scanning type exposure apparatus.

[0008]

[0009] the form status of the present invention, in the scanning type exposure apparatus that exposes the substrate with the pattern of the original plate by scanning the original sheet and the substrate to exposure light, said during acceleration and / or deceleration of the scan An exposure means for exposing the substrate, wherein the exposure means changes the scanning speed so that the exposure amount on the substrate during acceleration and / or deceleration is substantially constant . It is characterized by having an intensity modulating means for changing the intensity of the exposure light. It
In addition, a detector for detecting the intensity of the exposure light on the surface of the original plate
It is preferred to have steps.

[0010] In the form status of the scanning exposure apparatus of the present invention,
There is a form in which the intensity modulating unit includes a diaphragm unit having a variable aperture diameter, an interference filter having a variable tilt angle with respect to the exposure light, and an ND filter rotating plate having a transmittance changing in a rotating direction.

The device manufacturing method of the present invention exposes a wafer with a device pattern of an original plate by using the above-mentioned scanning type exposure apparatus.
Illuminating and developing the exposed wafer .

[0012]

1 is a schematic view of a scanning exposure apparatus for manufacturing a device according to an embodiment of the present invention. In FIG. 1, 1 is a mercury lamp lamp for generating exposure light, and 2 is a mercury lamp lamp 1. Ellipsoidal mirror for condensing the light of 3 is a condenser lens, 4 is an optical system for shaping the light condensed by the condenser lens 3 into a rectangle, and 5 is an ND filter whose transmittance continuously changes in the rotational direction. A rotating plate, 6 is a motor for rotating the ND filter rotating plate 5, and 7 is an optical path of 90 °.
A flat mirror for bending, 8 is a photo sensor for detecting the illuminance on the reticle surface, 9 is a condenser lens, 10 is a reticle, 11 is a reticle stage holding the reticle 10, and 12 is a direction in which the reticle stage 11 is shown. A linear motor for driving the scan on the reticle stage 11, a bar mirror fixed on the reticle stage 11, a laser interferometer for detecting the speed of the reticle stage 11 by shining a laser beam on the mirror 13, and a device pattern on the reticle 10. A projection lens system for reducing and projecting the image on the wafer 16, 16 is a wafer, 17 is a wafer chuck holding the wafer 16, 18 is a wafer stage holding the wafer chuck 17, and 19 is a wafer stage 18. A linear motor that drives the scan in the indicated direction,
Reference numeral 20 is a bar mirror fixed to the wafer stage 18, 21 is a laser interferometer for irradiating the mirror 20 with laser light to detect the speed of the wafer stage 18, and 30 is for controlling the reticle stage 11 and the wafer stage 18. A CPU, 31 is a ROM that stores the program code executed by the CPU 30, 32 is a RAM that the CPU 30 uses to write and read data, 3
3 is a memory for holding a scan speed command value of the reticle stage 11 from the CPU 30.
A to convert digital data from 3 to analog data
D converter, 35 is a driver for amplifying the analog value from the AD converter 34 to drive the linear motor 12, 36 is a memory for holding the scan speed command value of the wafer stage 18 from the CPU 30, and 37 is a memory 36. AD converter for converting the digital data of the above into analog data, 38 is a driver for amplifying the analog value from the AD converter 37 to drive the linear motor 19, 39 is a scan output from the laser interferometer 14 on the reticle stage 11 side. A counter for integrating and counting the pulse train proportional to the velocity to obtain position information, and 40 for integrating and counting the pulse train proportional to the scan velocity output from the laser interferometer 21 on the wafer stage 18 side to obtain the position information. Counter 41 detects the reticle surface illuminance A current-voltage converter for converting the photocurrent signal from the photosensor 8 into a voltage signal, 42 is an AD converter for converting the voltage output signal of the current-voltage converter 41 into digital data, and 44 is an ND filter rotating plate from the CPU 30. A memory for holding the position (angle) command value 5; 45, a DA converter for converting the position command value, which is digital data from the memory 44, into analog data; and 46, a position command, which is analog data from the DA converter 45. A driver for receiving the value and driving the ND filter rotating plate at that position, 47 is a memory for holding the input power command value from the CPU 30 to the mercury lamp lamp, and 48 is a digital data from the memory 47 for the mercury lamp lamp. DA converter for converting the input power command value into analog data, 49 is a DA converter It receives input power command value which is an analog data from the converter 48, a lighting device power supply for driving a mercury lamp 1.

In the exposure apparatus of the present embodiment, the position counters 39 and 40 cumulatively count the pulse signals from the laser interferometers 14 and 21 in which the positions of the reticle stage 11 and wafer stage 18 are proportional to the respective speeds. It can measure in real time. During scanning exposure, the CPU 30 is driven in the opposite directions at the same speed ratio as the magnification of the projection lens system 15 while maintaining the predetermined positional relationship between the reticle 10 and the wafer 16 by the program written in the ROM 31 in advance. .

Further, in the present exposure apparatus, the illuminance on the reticle surface during scanning exposure can be detected by the sensor 8, and the illuminance on the reticle surface is always maintained in a region where the scan speed of the reticle 10 and the wafer 16 is constant. The CPU 30 controls the input power to the mercury lamp 1 by controlling the input power command value to the lighting device power supply 49 by a program written in advance in the ROM 31 so that the value becomes constant.

A characteristic of the exposure apparatus is that it has an ND filter rotary plate 5 whose transmittance changes continuously in the rotation direction in the illumination system. To achieve the illuminance on the reticle surface proportional to the scan speed command values written in the memories 33 and 36 for holding the scan speed command values of the reticle stage 11 and the wafer stage 18. The position command value of the ND filter rotating plate 5 is written in the memory 44 from the CPU 30 and controlled in synchronization with the writing of the scan speed command value depending on the position of 18 into the memories 33 and 36. The position command value is converted into analog data by the DA converter 45 and input to the driver 46 that drives the ND filter rotating plate 5, and the driver 46 outputs N
The D filter rotating plate 5 is driven to a command position by a motor 6 which is rotatably supported, so that the exposure amount on the wafer 16 becomes substantially constant even during acceleration and / or deceleration during scanning.

In the exposure apparatus, first, before scanning exposure, ND
The filter rotation 5 is rotated so that the light transmittance is almost 100%, the sensor 8 detects the illuminance on the reticle surface, and the electric power supplied to the mercury lamp 1 is controlled so that the illuminance becomes a predetermined value.

Next, the relative position of the alignment mark on the reticle 10 and the alignment marks on a plurality of chips on the wafer 16 is subjected to the same scanning operation as in the scanning exposure, and an alignment mark detection system (not shown) is used. Detected at. By this operation, the positional relationship between the pattern of the reticle 10 and each chip on the wafer 16 is known, and how to control the relative positions of the reticle stage 11 and the wafer stage 18 during scanning exposure is determined.

After the above operation, the reticle stage 11 and the wafer stage 18 enter the scan scanning exposure operation while maintaining the relative positional relationship determined by the above operation. At this time, in the conventional exposure apparatus, the acceleration stroke 12 as shown in FIG. 7 is required, but in the scan type semiconductor exposure apparatus of the present invention, the scanning exposure is started immediately before the pattern 70 of the reticle 11. Immediately before starting the exposure, the ND filter rotation plate 5 is in a state of complete light shielding, and when the exposure covers the area of the pattern 70, the reticle 11 at that time is exposed.
The ND filter rotating plate 5 is controlled so that the reticle surface illuminance proportional to the side scanning speed is achieved. The reticle surface illuminance is constantly detected by the sensor 8 during the scanning exposure, particularly during the acceleration time and the deceleration time, and if the detected reticle surface illuminance does not match the target reticle surface illuminance, ND Further correction driving of the filter rotary plate 5 is performed. This reticle surface illuminance control is performed during deceleration as well as during acceleration, and scanning exposure for one chip is completed. Further, such an operation is performed for all the chips on the wafer 16, and the processing of one wafer is completed.

In this embodiment, in order to control the illuminance on the reticle surface, the ND filter rotating plate 5 is used as a means for modulating the intensity of the exposure light, but in addition to this, the ND filter rotating plate 5 is used for the optical axis as shown in FIG. An interference filter 70 whose transmittance is continuously variable by changing the angle and a diaphragm whose aperture size is continuously variable with respect to the optical axis as shown in FIG.
Further, it is also possible to implement a structure in which the mechanism for controlling the reticle surface illuminance also uses a shutter function for controlling the exposure amount.

Instead of the projection lens system 15, a projection optical system such as a projection mirror system may be used.

Next, an embodiment of a device manufacturing method using the above-described scanning type exposure apparatus will be described. FIG. 4 shows a manufacturing flow of a semiconductor device (semiconductor chip such as IC or LSI, liquid crystal panel, CCD or the like). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask manufacturing), a mask having the designed circuit pattern is manufactured. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the mask and the wafer prepared above. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip by using the wafer manufactured in step 4, such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like. including. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).

FIG. 5 shows a detailed flow of the wafer process. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. Step 1
In 5 (resist processing), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is printed and exposed on the wafer by the exposure apparatus described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist image are removed. In step 19 (resist stripping), the resist that is no longer needed after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, a highly integrated semiconductor device can be manufactured with high throughput.

[0024]

The exposure apparatus of the present invention has the following great effects.

1. The acceleration time and / or the deceleration time of the scanning operation can be effectively used for exposure, and the throughput can be improved.

2. It is possible to reduce or lose the run-up section and / or overrun section during scanning operation.
Wear.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing another example of intensity modulating means.

FIG. 3 is a schematic view showing another example of the intensity modulating means.

FIG. 4 is a diagram showing a manufacturing flow of a semiconductor device.

FIG. 5 is a diagram showing the wafer process of FIG. 4;

FIG. 6 is a diagram showing a conventional scanning type exposure apparatus.

FIG. 7 is an explanatory diagram showing a state of scanning exposure of the exposure apparatus of FIG.

[Explanation of symbols]

1 Mercury lamp 2 elliptical mirror 3 condenser lens 4 Optical element 5 ND filter rotating plate 6 motor 7 plane mirror 8 photo sensors 9 Condenser lens 10 reticle 11 Reticle stage 12 Linear motor 13 bar mirror 14 Laser interferometer 15 Projection lens system 16 wafers 17 Wafer chuck 18 Wafer stage 19 Linear motor 20 bar mirror 21 Laser interferometer

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/027 G03B 27/32 G03F 7/20 521

Claims (6)

(57) [Claims] 1. A scanning type exposure apparatus that exposes the substrate in a pattern of the original plate by scanning the original plate and the substrate with exposure light, the exposure exposing the substrate during acceleration and / or deceleration of the scanning. The exposure means has an intensity of the exposure light on the original plate surface according to a change in the scanning speed so that the exposure amount with respect to the substrate during the acceleration and / or the deceleration is substantially constant. A scanning exposure apparatus having an intensity modulating means for changing 2. The intensity of the exposure light on the surface of the original plate
2. A detection means for detecting
The scanning type exposure apparatus according to. Wherein said intensity modulating means, scanning exposure apparatus according to claim 1 or 2, characterized in that the opening diameter is provided with variable throttle means. Wherein said intensity modulating means, scanning exposure apparatus according to claim 1 or 2, characterized in that the inclination angle with respect to the exposure light comprises a variable interference filter. Wherein said intensity modulating means, scanning exposure apparatus according to claim 1 or 2, characterized in that it comprises an ND filter rotation plate transmittance in the rotational direction is changed. 6. A device manufacturing method including the steps of exposing a wafer with a device pattern of an original plate using the scanning exposure apparatus according to claim 1 and developing the exposed wafer. .