JPH07115050A - Inspection method, scanning aligner wherein the inspection method is used and manufacture of device wherein the method is used - Google Patents

Abstract

PURPOSE:To provide a scanning aligner having a foreign matter inspection device whose constitution is not complicated. CONSTITUTION:In a device wherein a circuit pattern of a reticle 4 is projected onto a wafer 7 by scanning the reticle 4 mounted on a reticle stage 5 and the wafer 7 mounted on a wafer stage to exposure light from an illumination system 1 by moving the reticle stage 5 and the wafer stage, a foreign matter inspection device 3 is moved to an exposure position before scanning exposure and the foreign matter in a surface of the reticle 4 is detected while scanning the reticle 4 mounted on the reticle stage 5 by movement of the reticle stage 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method, a scanning type exposure apparatus using the inspection method, and a device manufacturing method using the inspection method. In particular, a pattern of a device such as an IC, an LSI, a magnetic head or a liquid crystal panel is formed. Method for inspecting surface state (defects, dust) of masks and wafers that have been formed, and scanning type exposure apparatus for manufacturing devices such as IC, LSI, magnetic head, liquid crystal panel, and the inspection method using the inspection method The present invention relates to a device manufacturing method for devices such as ICs, LSIs, magnetic heads, and liquid crystal panels.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor chips such as IC and LSI, an exposure apparatus projects a circuit pattern formed on an original plate such as a reticle or a photomask onto a wafer coated with a resist and transfers it. There is an exposure step to perform. In this exposure step, if foreign matter such as dust is present on the original plate such as a reticle or a photomask, the shadow (image) of the dust is transferred onto the wafer at the same time as the circuit pattern, and the yield of semiconductor chip production is reduced.

FIG. 7 shows a scanning type batch projection exposure apparatus used in the exposure process. 7A is a plan view showing the mask during exposure, FIG. 7B is a schematic view showing a 1 × imaging optical system of the exposure apparatus, and FIG. 7C is a view showing a wafer being exposed. The mask 300 is illuminated by ultraviolet rays from an illumination system (not shown), and the light flux emitted from the mask 300 is trapezoidal mirror 301,
After being sequentially reflected by the concave mirror 302 and the convex mirror 303, they are again reflected by the concave mirror 302, reflected by the trapezoidal mirror 301, and then incident on the wafer 304 to form an image of the pattern of the mask 300. The optical system of FIG. 7B is rotationally symmetric with respect to the optical axis OO ′, and forms an off-axis circular good image area (a slit area consisting of the image height of the radius H shown in the figure and its periphery). Using the mask 300 against the ultraviolet rays from the illumination system
And the wafer 304 are integrally scanned to transfer the entire pattern on the mask 30 onto the wafer 304.
As shown in FIG. 7A, the chip pattern 3 of the mask 300
If the foreign matter 310 is present in the wafer 11, the foreign matter image 3 is present in the chip area 321 of the wafer 304 as shown in FIG.
Transferred as 20, giving rise to defects.

The influence of such foreign matter on the original plate is far greater in the case of the step-and-repeat method than in the case of this collective exposure. In the case of the step-and-repeat method, the chip pattern on the reticle is projected and transferred onto a plurality of shot areas arranged on the wafer by the reduction projection lens system having high resolution, so that the image of one foreign matter on the reticle is transferred onto the wafer. Is transferred to the entire shot area, and the production yield of semiconductor chips is significantly reduced.

Therefore, in the exposure process, it is indispensable to detect the presence of foreign matter on the original plate such as the reticle or photomask by the foreign matter inspection device.

FIG. 8 is a schematic view showing an example of a foreign matter inspection apparatus. The laser beam emitted from the laser 81 passes through the pinhole 82, then passes through the beam expander 83 and the reflection mirror 84, and is converted into a parallel beam by the polygon mirror 8.
It is incident on 5. The polygon mirror 85 rotates in a plane orthogonal to the paper surface. The beam reflected by the polygon mirror 85 becomes a convergent beam by the scanning lens 86, and is split into two upper and lower beams by the action of the beam splitter 87, and each split beam passes through mirrors 88 and 89, and passes through the upper surface of the reticle 94 ( The light is focused on the blank surface) and the lower surface (pattern surface), and the upper and lower surfaces are scanned. The reticle 94 moves (scans) in the direction of arrow S in the paper in synchronization with the scanning of the beam.
To do. It should be noted that many reticles are equipped with a frame in which pellicle films 95 and 96, which are transparent thin films, are stretched to prevent dust. The two beams that scan the upper and lower surfaces of the reticle 94 form scanning lines on the upper pellicle 95 surface, the lower pellicle 96 surface, the blank surface, and the pattern surface. Therefore, the light receiving systems 90, 91, 92, 93 corresponding to the respective surfaces are arranged so as to receive the scattered light from the foreign matter on these scanning lines.

[0007]

FIG. 9 shows a possible arrangement relationship when the foreign substance inspection apparatus shown in FIG. 8 is mounted on a scanning type exposure apparatus. As shown in FIG. 9, the foreign matter inspection apparatus 1113 includes a reticle changer 1114 and an exposure stage E.E. P. Placed between. The scanning exposure apparatus refers to an apparatus that projects the pattern of the original plate onto the substrate by scanning the original plate and the substrate with respect to the exposure light,
Between the original plate and the substrate, for example, a catoptric optical system of the same size as in FIG.
A reduction catoptric system or a refraction optical system (lens system) and a reduction catadioptric system (catadioptric system) are supplied.

As is apparent from FIG. 9, when the foreign matter inspection apparatus is mounted on the scanning type exposure apparatus, a stage and a drive mechanism for moving the reticle and the mask are required for the exposure and the inspection, which complicates the structure. There will be a problem.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inspection method, a scanning type exposure apparatus using the inspection method and a device manufacturing method using the inspection method, which can solve the above problems. is there.

The inspection method of the present invention is a scanning type in which the pattern of the original plate is projected onto the substrate by moving the exposure stage and scanning the original plate and the substrate placed on the exposure stage against the exposure light. It is characterized in that the plate to be inspected is placed on the exposure stage of the exposure apparatus, and the state of the surface of the plate to be inspected is inspected by moving the exposure stage.

A scanning type exposure apparatus of the present invention is an apparatus for projecting a pattern of an original plate on the substrate by moving an exposure stage and scanning an original plate and a substrate placed on the exposure stage with respect to exposure light. In the above, there is provided a means for inspecting the surface condition of the inspection plate by moving the inspection plate placed on the exposure stage by the exposure stage.

The scanning exposure apparatus of the present invention has a form in which the exposure stage has a place for mounting the original plate and the substrate and a place for mounting the substrate to be inspected.

The device manufacturing method of the present invention comprises the step of projecting the pattern of the original plate onto the substrate by moving the exposure stage and scanning the original plate and the substrate placed on the exposure stage against the exposure light. In the method of manufacturing a device including, placing the original plate on the exposure stage,
The state of the surface of the original plate is inspected by moving the exposure stage.

In another device manufacturing method of the present invention, the pattern of the original plate is projected onto the substrate by moving the exposure stage and scanning the original plate and the substrate placed on the exposure stage against the exposure light. In a method of manufacturing a device including steps, an inspection plate is placed beside the original plate on the exposure stage, the exposure stage is moved to project the pattern of the original plate onto the substrate, and It is characterized by inspecting the surface condition of the inspection plate.

[0015]

FIG. 1 is a diagram showing a first embodiment of the present invention.
A scanning type exposure apparatus for manufacturing devices such as ICs, LSIs, magnetic heads, and liquid crystal panels is shown.

In FIG. 1, prior to scanning exposure, the reticle 4 set on the reticle stage 5 is aligned with the wafer 7 using the alignment scope 2. Thereafter, the reticle 4 is irradiated with deep ultraviolet rays by the illumination system 1, and the circuit pattern on the reticle 4 is reduced and imaged on the wafer 7 through the scanning projection exposure system 6. The shape of the illumination area on the reticle 4 by the far-ultraviolet rays is a slit or arc extending substantially in the X direction. The scanning projection exposure system 6 is a projection optical system (lens system) composed only of lenses, a projection optical system (mirror system) composed only of mirrors, and a projection optical system composed of lenses and mirrors. (Catadioptric system) etc. The reticle 4 and the wafer 7 are simultaneously scanned with circular ultraviolet rays in the directions of the arrows (Y direction) by moving the stages supporting them. At this time, the moving speeds of the reticle stage 5 and the wafer stage (not shown) are determined so that the speed ratio between them matches the projection magnification of the scanning projection exposure system 6.

The feature of this embodiment is that the reticle 4 is attached on the reticle 4 by using its scanning motion before exposure while being set on the reticle stage 7 which is an exposure stage for scanning the reticle 4 during exposure. The point is that a foreign matter inspection system for detecting foreign matter such as dust is provided.

Reference numeral 3 in the drawing denotes a foreign matter inspection system, and the foreign matter inspection system 3 of the present embodiment only exposes the exposure position EP when the reticle 4 is inspected.
The foreign matter inspection system 3 detects the foreign matter on the reticle 4 while scanning the reticle 4 with respect to (the inspection beam of) the foreign matter inspection system 3 by moving the reticle stage 7. The foreign matter inspection system 3 is moved to a position other than the exposure position as shown by 3'in the figure except for the inspection. As the foreign matter inspection system 3, the device shown in FIG. 8 is used.

FIG. 2 is a diagram showing a second embodiment of the present invention. FIG. 2 also shows a scanning type exposure apparatus for manufacturing devices such as ICs, LSIs, magnetic heads and liquid crystal panels. In FIG. 2, the same members as those in FIG. 1 are designated by the same reference numerals as those in FIG. . The difference between this embodiment and the first embodiment is that the foreign matter inspection system 3
Is provided at a distant position IP beside the exposure position EP, and the inspection is performed at this position IP. When the scan stroke of the reticle stage 5 is sufficiently long, the exposure position E is set while the reticle 4 is set on the reticle stage 5.
After moving from P to the inspection position IP, the inspection is performed there. After the inspection, the reticle 4 and the stage 7 are directly exposed to the exposure position E. It is sent to P and scanning exposure is performed. The advantage of this embodiment is that the foreign substance inspection system 3 can be separated from the alignment scope 2 and the scanning projection exposure system 6. As a result, the degree of spatial freedom is increased, and the foreign matter inspection system can be made larger, and the reticle size can be increased and the optical system diameter required for improving the detection sensitivity can be coped with.

FIG. 3A shows a third embodiment of the present invention. FIG. 3A also shows a scanning type exposure apparatus for manufacturing devices such as ICs, LSIs, magnetic heads and liquid crystal panels. In FIG. 3, the same members as those in FIG. is doing.

One of the features of this embodiment is that the reticle 4 for exposure and the reticle 11 for inspection are mounted on the reticle stage 10.
And are set side by side at the same time, and the inspection is performed during the exposure operation. In this embodiment, the scanning for the exposure and the inspection is in the Y direction, and the reticle replacement after the exposure is also performed by moving the stage 10 in the Y direction. With such a configuration, the moving direction of the stage 10 is limited to one direction, and the precision of the stage is improved.

Another feature of the present embodiment is that the amount of exposure light, the amount of inspection light, and the moving speed of the stage 10 are related.

In FIG. 3A, 15 is a stage controller, 16 is an inspection light source, 17 is an inspection light intensity controller, 18 is an exposure light intensity controller, 19 is an exposure light source, and 20 is the entire scanning exposure apparatus. Is the controller of.
The light quantity controllers 17 and 18 are associated with the corresponding light sources 16 and 19.
It has a function to monitor the amount of light and adjust it. In order to perform the exposure and the inspection in the same scan of the same stage as in the present embodiment, each of the amount of the exposure light and the amount of the inspection light is an appropriate integrated amount with respect to the scanning speed of the stage 10. Must be set. Therefore, the controller 20 obtains the outputs of the two light amount controllers 17 and 18 and calculates the condition of the same scan speed. As a result, the light amounts of the light sources 16 and 19 are set, and
A command is sent to the stage controller 15 to determine the scan speed. For example, in order to increase the exposure throughput, the amount of exposure light is increased and the scan speed is also increased. Accordingly, in order to maintain the predetermined detection sensitivity,
The amount of inspection light is increased. In the semiconductor process, such control is effective because it is necessary to change the integrated exposure amount between processes due to the sensitivity of the resist and the like.

FIG. 3B is a plan view of a reticle stage showing a modification of the embodiment shown in FIG. 3A. This embodiment is different from the embodiment of FIG. 3A in that the stage movement for reticle exchange is performed in the X direction. Scanning for exposure and inspection is performed in the Y direction as in the embodiment of FIG.

The advantage of this embodiment is that the scan stroke (Y direction) for exposure and inspection which requires high precision can be shortened.

In each of the above embodiments, the foreign matter inspection system 3 and the alignment scope 2 are separately provided. However, if the size can be sufficiently reduced, the inspection system may be built in the alignment system, or the alignment system may have a foreign matter inspection function. It is also within the scope of the present invention to have

In each of the above embodiments, the foreign matter inspection system 3 is shown in FIG.
Although the device shown in FIG. 4 is used, a device for detecting foreign matter from a video signal obtained by imaging the surface of a reticle with a TV camera and a device as shown in FIG. 4 are also applied as the foreign matter inspection system 3.

FIG. 4 is a schematic view showing an example of the foreign matter inspection device. While the apparatus of FIG. 8 scans the beam on the substrate surface by rotating the polygon mirror 85 and inspects it, the apparatus of FIG. 8 analyzes the divergent beam from the semiconductor laser 53 with the collimator lens 54. Parallel beam 5 by
After setting to 6, the light is made incident on the substrate surface 51 substantially in parallel, and the substrate surface 5
A linear illumination area (scanning line) 59 extending in the X direction is formed on the surface 1. Then, the blank surface 61, which is the outermost surface other than the pattern surface, and the lower pellicle surface (not shown) are inspected. The scattered light from the foreign matter 60 is focused on the CCD array sensor 58 by the SELFOC lens array 57 and forms an image of the foreign matter. The substrate is scanned in the Y direction in synchronization with the timing of taking in the CCD sensor. Alternatively, a method of directly capturing an image and performing signal processing may be used.

In the embodiment described above, the following effects are obtained because the reticle scanning mechanism such as the reticle stage is used to inspect the reticle for foreign matter.

1. By using a reticle stage for scanning exposure that is configured with high accuracy, it is possible to cope with higher sensitivity of the foreign matter inspection apparatus.

2. Since the reticle does not need to be transferred to the scanning hand unique to the inspection system as in the case where a foreign matter inspection device is provided between the reticle changer and the exposure position, the device becomes compact and the risk of dust generation is greatly reduced. The inspection time can be shortened as a whole.

3. Since the reticle can be inspected at or near the final exposure position, there is no risk of dust generation due to movement of the reticle to the exposure position after inspection.

4. For the reasons 1 to 3 above, the reticle can be prevented from being contaminated, so that the defects of the wafer are not generated, and the yield of the semiconductor chip manufacturing can be greatly improved.

Next, one embodiment of a device manufacturing method using the scanning type exposure apparatus of FIGS.

FIG. 5 shows a manufacturing flow of semiconductor devices (semiconductor chips such as IC and LSI, liquid crystal panels and CCDs). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask manufacturing), a mask (reticle 304) on which the designed circuit pattern is formed is manufactured. On the other hand, in step 3 (wafer manufacturing), a wafer (wafer 306) 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 chip using the wafer created in step 4,
An assembly step including (dicing, Bonde _b ring), packaging step (chip encapsulation). 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. 6 shows a detailed flow of the wafer process. In step 11 (oxidation), the wafer (wafer 30
6) Oxidize the surface. 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. In step 15 (resist processing), a resist (photosensitive material) is applied to the wafer. In step 16 (exposure), a foreign matter inspection is performed by the projection exposure apparatus, and the wafer is exposed with an image of the circuit pattern of the mask (reticle 304) having no problem of foreign matter. In step 17 (development), the exposed wafer is developed. Step 18
In (etching), parts other than the developed resist are scraped off. In step 19 (resist stripping), the resist that is no longer needed after etching is removed. By repeating these steps, a circuit pattern is formed on the wafer.

The use of the manufacturing method of this embodiment makes it possible to manufacture highly integrated devices with high yield.

[0038]

As described above, according to the present invention, the foreign matter inspection apparatus can be incorporated in the scanning type exposure apparatus without making the structure of the scanning type exposure apparatus too complicated.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3A is a diagram showing a third embodiment of the present invention.
(B) is a figure which shows the modification of the apparatus of (A).

FIG. 4 is a diagram showing an example of a foreign matter inspection device used in the present invention.

FIG. 5 is a diagram showing a manufacturing flow of a semiconductor device.

FIG. 6 is a diagram showing the wafer process of FIG. 5;

FIG. 7 is a diagram showing a scanning type collective projection exposure apparatus.

FIG. 8 is a diagram showing an example of a foreign matter inspection device.

FIG. 9 is an explanatory diagram showing an arrangement when a foreign matter inspection device is mounted on the scanning exposure apparatus.

[Explanation of symbols]

 3 foreign matter inspection device 4 reticle 5 reticle stage 6 scanning exposure optical system 7 wafer EP exposure position IP inspection position

Claims (5)

[Claims] 1. The exposure of a scanning type exposure apparatus for projecting the pattern of the original plate onto the substrate by moving the exposure stage to scan the original plate and the substrate placed on the exposure stage against the exposure light. An inspection method comprising placing a plate to be inspected on a stage and moving the exposure stage to inspect a surface state of the plate to be inspected. 2. An apparatus for projecting a pattern of the original plate onto the substrate by moving the exposure stage to scan the original plate and the substrate placed on the exposure stage with respect to the exposure light. 2. A scanning type exposure apparatus, comprising means for moving the plate to be inspected placed on the plate by the exposure stage to inspect the state of the surface of the plate to be inspected. 3. The scanning type exposure apparatus according to claim 2, wherein the exposure stage has a place for placing the original plate and the substrate and a place for placing the inspection target substrate. 4. A method for manufacturing a device, which comprises the step of moving an exposure stage to scan an original plate and a substrate placed on the exposure stage with respect to exposure light to project the pattern of the original plate onto the substrate. 2. The device manufacturing method according to claim 1, wherein the original plate is placed on the exposure stage, and the state of the surface of the original plate is inspected by moving the exposure stage. 5. A method of manufacturing a device, comprising the step of projecting a pattern of the original plate onto the substrate by moving the exposure stage and scanning the original plate and the substrate placed on the exposure stage with respect to exposure light. In, the inspection plate is placed beside the original plate on the exposure stage, the exposure stage is moved to project the pattern of the original plate onto the substrate, and at the same time the state of the surface of the inspection plate is checked. A device manufacturing method characterized by inspecting.