JP2600148Y2 - Photomask defect inspection equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask defect inspection apparatus for inspecting a pattern formed on a photomask used for exposing a photoresist applied to a semiconductor wafer in accordance with a desired pattern. Things.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, photomasks are widely used when optically forming a desired mask pattern using a photoresist. If the chip pattern formed on the photomask has a defect, the mask pattern cannot be accurately formed. Therefore, it is necessary to inspect the pattern for defects before using the photomask. Conventional photomask defect inspection equipment is, for example,
As disclosed in JP-A-37475, one flying spot scanner is provided, and its raster image is projected onto two adjacent chip patterns of a photomask via a lens. The light transmitted through these chip patterns is received by a light receiving device, and the output video signals are compared to inspect the pattern for defects. The photomask is placed on a stage that moves in the X and Y directions so that the entire surface of the photomask can be sequentially scanned.

[0003]

However, in the conventional photomask defect inspection apparatus, since the photomask is exposed to the atmosphere, foreign substances may fall on the surface of the photomask during or after inspection. If foreign matter falls on the photomask after it is confirmed that the photomask has no defect, the mask pattern cannot be formed accurately. On the other hand, even in an optical projection apparatus using a photomask, if a foreign substance falls on the photomask, accurate projection of a pattern cannot be performed, and a defect occurs in the semiconductor device. In order to prevent foreign matter from dropping on the photomask as described above, it has been proposed to cover the photomask with a pellicle which is a transparent optical thin film. In this case, it is necessary to separate the photomask and the pellicle by a predetermined distance in order to prevent foreign matter dropped on the pellicle from affecting pattern formation. For this reason, the pellicle is supported by a frame having a desired height.

The above-mentioned problem can be solved by mounting such a pellicle before inspecting the photomask for defects. However, since the bottom surface of the frame supporting the pellicle is adhered to the photomask surface, If it is determined that the photomask has a defect, the pellicle frame needs to be peeled from the photomask in order to repair the defect in the photomask. The pellicle peeled from the photomask in this manner cannot be reused and must be discarded. In addition, the photomask may be damaged when the frame supporting the pellicle is peeled off from the photomask. In this case, the photomask also needs to be discarded, which is wasteful in terms of effective use of resources. In addition, there is a disadvantage that the cost of the photomask is increased.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned inconvenience, and it is possible to prevent a defect from occurring on a photomask due to a foreign substance falling on a chip pattern during or after a defect inspection of the chip pattern. It is an object of the present invention to provide a photomask defect inspection apparatus which can repair a defect of a photomask without wasting a pellicle even when it is determined by inspection that there is a defect.

[0006]

According to the present invention, there is provided a photomask defect inspection apparatus for inspecting a defect of a pattern formed on a photomask, wherein a pellicle supported by a frame is placed above the photomask. A pellicle bonding means for holding the bottom of the frame and the surface of the photomask separated from each other, and after confirming that the photomask has no defects by inspection, bonding the pellicle frame on the photomask. The feature is that it is obtained.

[0007]

In the photomask defect inspection apparatus of the present invention, a pellicle having a frame is inspected for defects of the chip pattern of the photomask while the bottom of the frame and the photomask are kept at a constant interval. After confirming that there is no defect in the photomask, the pellicle frame is bonded onto the photomask, so that no foreign matter falls on the chip pattern of the photomask during or after inspection, and if there is a defect by inspection, If it is determined, the photomask and the pellicle supported by the frame can be separately removed from the apparatus, so that the photomask in which the defect is detected is subjected to processing such as cleaning to repair the defect. And the pellicle can be reused.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a state before the pellicle is attached to the photomask defect inspection apparatus of the present invention, and FIG. 2 shows a state when the pellicle is attached. The photomask defect inspection apparatus fixes an inspection objective lens 1 and a photomask 2 and uses X (not shown).
The photomask 2 includes a mask holder 3 mounted on a Y table and a pellicle bonding device 6 for bonding a pellicle 5 supported by a frame 4 provided with an adhesive on the bottom surface to the surface of the photomask 2. The pellicle bonding apparatus 6 includes a mounter 7 fixed to the mask holder 3 and a mounter 7
And a spring 10 provided between the mounter 7 and the frame holding portion 9 for pivotally biasing the frame holding portion away from the photomask. By pressing the frame holding portion 9 downward, the bonding surface of the frame 7 is
Is constituted by a pressing portion 11 adhered to the surface of the first member.

The operation of the photomask defect inspection apparatus will be described. First, the photomask 2 is fixed to the mask holder 3. Next, the frame 4 supporting the pellicle 5 is held by the frame holding unit 9. At this time, the gap between the bottom of the frame 4 to which the adhesive is applied and the surface of the photomask 2 is maintained at a distance of several hundred microns. In this state, the photomask 2 is inspected for defects. As a result of the inspection, when it is confirmed that the photomask 2 has no defect, the pressing portion 11 presses the frame holding portion 9 as shown in FIG. After the frame holding portion 9 is pressed, a state where the frame holding portion 9 is pressed by a stopper (not shown) is maintained. When the bonding is completed, the holding of the frame 4 by the frame holding unit 9 of the pellicle bonding apparatus 6 is released, and the photomask 2 to which the frame 4 supporting the pellicle 5 is bonded is removed from the mask holder 3. The photomask 2 provided with the pellicle 5 in this manner is used for forming a photoresist mask pattern.

When it is confirmed during the defect inspection that the photomask 2 has a defect, the frame 4 supporting the pellicle 5
The frame is removed from the pellicle bonding device 6 without bonding the photomask to the photomask, and then the photomask 2 is removed from the mask holder 3. Therefore, the photomask 2 can be subjected to processing such as cleaning to remove or repair defects. After performing such processing, a defect inspection is performed again, and if no defect is confirmed, the frame supporting the pellicle is bonded to the photomask as described above.

[0011]

As described above, according to the present invention, no foreign matter falls on the photomask 2 during or after the inspection, so that the foreign matter does not appear on the chip pattern during the inspection of the photomask 2 or after the inspection. Can be prevented from falling into the photomask 2 due to falling. That is,
Since the pellicle bonding apparatus 6 is integrated with the photomask defect inspection apparatus, there is no possibility that foreign matter will fall on the chip pattern during inspection or after transferring the photomask 2 to the pellicle bonding apparatus after the defect inspection.

Before or during the inspection, the frame supporting the pellicle is not adhered to the photomask, but is held in a state in which the gap between the bottom surface of the frame and the surface of the photomask is maintained at several hundred microns. After the inspection, after confirming that the photomask 2 has no defect, the frame for supporting the pellicle is bonded on the photomask.
If a defect is found in the photomask, remove the photomask and pellicle separately from the device, perform processing such as cleaning on the photomask, inspect again to confirm that there is no defect, and then remove the pellicle. The supporting frame can be glued to the photomask. Therefore, the pellicle is not wasted, and the running cost of the photomask can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a photomask defect inspection apparatus of the present invention before pellicle bonding.

FIG. 2 is a schematic configuration diagram of the photomask defect inspection apparatus of the present invention at the time of pellicle bonding.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inspection objective lens 2 photomask 3 mask holder 4 frame 5 pellicle 6 pellicle bonding device 7 mounter 8 shaft 9 frame holding unit 10 spring 11 pressing unit

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/84-21/91

Claims (1)

(57) [Scope of request for utility model registration] 1. A photomask defect inspection apparatus for inspecting a defect of a pattern formed on a photomask, wherein a pellicle supported on the frame is separated from a bottom surface of the frame and a surface of the photomask above the photomask. And a pellicle bonding means for bonding the pellicle frame on the photomask after confirming that the photomask has no defect by inspection.