JP3450584B2 - Semiconductor exposure equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used in a process of exposing and transferring a mask pattern such as a reticle onto a semiconductor substrate.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor memory manufacturing, circuits are becoming finer and finer, and the required circuit line width is 0.4 μm.
has reached m. In order to meet this requirement, it is necessary to improve the resolving power of an exposure apparatus that exposes and transfers a circuit pattern in a lithographic process. Regarding this, the resolution has been improved by increasing the numerical aperture of the projection lens, but the increase of the numerical aperture decreases the depth of focus. As a result, the depth of focus of the projection lens has become extremely short. It is unavoidable that the flatness required for the wafer becomes more severe in order to cope with this very short depth of focus. A minute foreign matter, such as a resist fragment, may be sandwiched between the wafer and the wafer chuck. When such a thing occurs, the wafer locally rises at that portion. Due to the local defocus that occurs, a chip defect is caused, which in turn lowers the yield in the exposure process. In order to remove such foreign matters from the wafer chuck, conventionally, the exposure process is stopped after a certain period of time or whenever a chip defect occurs, and the wafer chuck is moved to a position where it can be reached by an operator. Foreign substances were removed by hand using a grindstone or a dust-free cloth.

This manual removal of foreign matter takes 30 minutes to 1
It takes about time, which reduces the actual operating time of the device and lowers the throughput. Moreover, since the work is performed inside the air-conditioned exposure apparatus, there is a possibility that the temperature environment will be disturbed and that new dust will be carried in by the worker. Further, since this manual work is performed in a dense space of units that are precisely assembled, such as an XY stage, a projection lens, and a wafer observation microscope, workability is extremely poor and there is a risk of accidentally damaging peripheral units. is there.

For this reason, it has been proposed to provide the exposure apparatus with a cleaning function, for example, to remove foreign matter by repetitive movement between a cleaning plate for directly contacting the surface of a wafer chuck and polishing and an XY stage,
There is one that removes foreign matter by pressing a dust-free cloth and moving the XY stage.

[0005]

For example, in the case of a cleaning plate which polishes the surface of the wafer chuck using a grindstone, there is an inconvenience that the wafer chuck surface is abraded and the flatness is lowered by repeated cleaning. Further, if the cleaning plate is a flat plate, it is difficult to remove the foreign matter that is firmly attached. Therefore, there has been a demand for a cleaning unit that reliably removes foreign substances without damaging the wafer chuck. Further, since the drive mechanism of the cleaning member is above the XY stage, there is a possibility that new foreign matter may be attached due to secondary dust generation from the drive mechanism due to the cleaning operation. Since the drive mechanism of the cleaning member is above the XY stage, the flow of temperature-controlled clean air that maintains the stage space at a constant temperature and in an ultra-clean state has been hindered.

Further, there is a problem that the foreign matter removed from the wafer chuck by the cleaning means is peeled off from the cleaning member and scattered or redeposited.
Also, from the viewpoint of the throughput of the exposure apparatus, it is necessary to minimize the operation interruption due to the cleaning work,
For that purpose, it is important to minimize the movement area of the XY stage or the movement area of the cleaning member for cleaning.

An object of the present invention is to provide a semiconductor exposure apparatus which solves the above problems. Specifically, foreign matter can be efficiently removed from a wafer chuck without obstructing the flow of temperature controlled clean air. An object of the present invention is to provide a semiconductor exposure apparatus provided with cleaning means.

[0008]

To achieve the above object, according to an aspect of, the semi-conductor exposure apparatus of the present invention includes a wafer chuck for attracting a wafer on the XY stage, the foreign matter adhering to the wafer contact surface of the wafer chuck and a cleaning means for removing, the cleaning means comprises a cleaning plate, and a mechanism for driving the cleaning plate, the mechanism includes the said cleaning plate wafer
Rotating machine that rotates eccentrically to the wafer contact surface of the chuck
And the cleaning plate is the wafer chuck.
The plane that faces the wafer contact surface of the chuck is the wafer chuck.
Has a flat surface that is processed similarly to the flatness of
It has a child-like groove, and the pitch of the groove is the rotating machine.
It is smaller than the radius of rotation of the structure. This structure also scrapes off foreign matter that has firmly adhered to the wafer chuck.
Can be

[0009]Also, The present inventionHalf ofConductor exposure equipmentAt
IsThe mechanical unit includes the cleaning plate
Between the arrangement position of the parts and the wafer contact surface of the wafer chuck
It is preferable to further include a horizontal drive mechanism for reciprocating between the two..

Furthermore, <br/> in semiconductors exposure apparatus of the present invention are the same as the cleaning plate is a wafer chuck
Good material .

In each of the above constructions, the cleaning plate is preferably made of the same material as the wafer chuck.
This is to minimize the abrasion of the cleaning plate and the abrasion of the wafer chuck due to the sliding of the cleaning plate and the wafer chuck. The cleaning plate may be a flat plate having a plurality of elastic protrusions on the surface facing the wafer contact surface of the wafer chuck.

The mechanism section has a horizontal drive mechanism for reciprocating the cleaning plate between the arrangement position of the mechanism section and the wafer contact surface of the wafer chuck, and rotates the cleaning plate eccentrically with respect to the wafer contact surface of the wafer chuck. It is preferably composed of a rotating mechanism. When the flat plate having the plurality of edges is attached to the rotating mechanism and used as the cleaning plate, the plurality of edges are grid-like edges having a pitch smaller than the eccentric rotation. This is because the edge efficiently scrapes the foreign matter by the rotation.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The basic structure of the exposure apparatus of the present invention will be described with reference to FIG. In the figure, 1 is an illumination light source having an ultra-high pressure mercury lamp, 2 is a reticle on which a pattern to be transferred is drawn, 3 is a lens for reduction projection, and 4 is a wafer which is a substrate to be exposed. The wafer 4 is vacuum-sucked by the wafer chuck 5 mounted on the XY stage 6. XY stage 6
The XY stage 6 is moved to a desired position by stepping, and pattern exposure is performed there. In the XY stage space where the wafer 4 is exposed, in order to eliminate the occurrence of pattern defects caused by dust and the like, and to eliminate the error factor of the step amount of the XY stage due to the temperature change, cleanliness class 1 or less and 0. Environmental control by controlling the temperature of 05 ° C. is performed by the air flow from the ULPA filter 7.

Next, an embodiment of chuck cleaning which is a feature of the present invention will be described with reference to FIG. In the figure,
Reference numeral 8 is a cleaning plate for cleaning the wafer chuck 5, 9 is a supporting member for the cleaning plate 8, 10 is a linear guide for guiding the supporting member 9, and these are horizontal drive mechanisms together with a drive system (not shown). Make up the department. For chuck cleaning, the cleaning plate 8 is sent from a standby position outside the stage air-conditioned space to a position to be cleaned by a drive system of a mechanical unit according to a command from an exposure apparatus control unit or a command from an operator.
On the other hand, the XY stage 6 stands still and stands by at a predetermined cleaning position. The cleaning plate 8 is driven by a vertical drive mechanism (not shown) for the support member 9.
Are brought into contact with the wafer chuck 5 in an appropriate preload state. Further, the support member 9 has a rotation mechanism portion that rotates the cleaning plate 8 by a parallel ring mechanism. As a result, the cleaning plate 8 and the wafer chuck 5 perform relative movement due to eccentric rotation. Here, the rotational motion is used, but it may be a local repetitive motion, or a high-frequency vibration may be applied by the mechanical unit to move. The completion determination of the cleaning operation may be performed, for example, by monitoring the driving torque and determining the completion when the driving torque is equal to or less than the specified torque.

An example of the cleaning plate will be described with reference to FIG. FIG. 3A shows a surface used for cleaning the cleaning plate. As is apparent from the cross-sectional view of FIG. 3B, the lattice-like portion becomes a groove to form a recess with respect to the contact surface, whereby the edge 8-a is formed on the plane.
To form. The wafer chuck 5 is rotated by the rotating operation of the mechanical section.
Each of the points above will pass through each edge 8-a of the cleaning plate at least once. This edge scrapes off foreign matter such as resist fragments that are firmly attached. The flatness of the contact surface 8-b of the cleaning plate is processed with high precision like the flatness of the wafer chuck 5. Figure 1
According to the parallel link mechanism in the above embodiment, since the sliding distance of one rotation is short and the edge can pass a plurality of times, abrasion and flatness deterioration due to sliding between the cleaning plate and the wafer chuck are caused. Hard to cause.

Since the foreign matter removed from the wafer chuck by the cleaning operation is not scattered or redeposited, a groove or hole 8-c for sucking a negative pressure is formed in the cleaning plate.
Is provided so that foreign matter can be removed by suction.

In addition to the cleaning plate with a grid,
You may use the brush-shaped plate which embedded many resin protrusions, such as nylon, in the lower surface of the plate shown in FIG.

[0018]

According to the present invention, the wafer chuck of the exposure apparatus can be reliably cleaned in a short time, and the non-operation time of the semiconductor exposure apparatus can be shortened. Also, there is no fear that the presence of the cleaning means disturbs the temperature environment of the semiconductor exposure apparatus or introduces contamination.

[Brief description of drawings]

FIG. 1 is a plan view of a stage space of a semiconductor exposure apparatus.

FIG. 2 is an overall configuration diagram of a semiconductor exposure apparatus.

FIG. 3 is a sectional view (b) of a contact surface (a) of the cleaning plate and a broken portion of the cleaning plate.

FIG. 4 is a side view of a broken portion of the cleaning brush.

[Explanation of symbols]

1: Illumination system, 2: Reticle, 3: Reduction projection lens, 4:
Wafer, 5: Wafer chuck, 6: XY stage, 7:
Urpa filter, 8: Cleaning plate, 8a:
Edge, 8b: chuck contact surface, 8c: negative pressure suction hole,
9: Support member, 10: Linear guide, 11: Nylon brush.

Claims (3)

(57) [Claims] And 1. A wafer chuck for adsorbing the wafer on the XY stage, and a cleaning means for removing foreign matter adhering to the wafer contact surface of the wafer check, the chestnut <br/> Ningu means and cleaning plate , and a mechanism for driving the Cleaning <br/> Gupureto, the mechanism is the
Attach the cleaning plate to the wafer chuck.
A rotating mechanism for eccentric rotation relative Sawamen, the chestnut <br/> over training plate, like the flatness of the flat surface you face the wafer contact surfaces of the wafer chuck the wafer chuck
If it has a processed flat surface and the grid-like grooves are formed in the flat surface,
In both cases, the pitch of the groove is larger than the radius of rotation of the rotating mechanism.
A semiconductor exposure apparatus characterized by being small . Wherein said mechanism unit, obtain further Bei the horizontal driving mechanism for reciprocating between the cleaning plate and the arrangement position of the mechanism the wafer contact surface of the wafer chuck
The semiconductor exposure apparatus according to claim 1 , wherein: 3. The semiconductor exposure apparatus according to claim 1 , wherein the cleaning plate is made of the same material as the wafer chuck.