JPH02103948A - Wafer loader - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy of a wafer with a simple structure by supporting a rotating arm with a spring, and determining the position by using a positioning means for a wafer chuck provided on an X-Y stage. CONSTITUTION:A position setting means 14 lifts and lowers a positioning pin 16 which is provided at the specified positions of a prealignment table 6 and an X-Y stage 7 through a plunger 17. The position is set so that a wafer chuck 9 comes to the adequate position of the table 6 and the X-Y stage 7 when the pin 16 is made to protrude and its tip is coupled into a hole part 18 of the wafer chuck 9 of a rotating arm 13. At this time, a spring means 15 absorbs the vibration of the rotating arm 13. The means 15 is expanded and contracted. The chuck 9 is made to follow the determined position of the pin 16. Therefore, the chuck 9 is not affected by the backlash and the vibration of the arm, and a wafer 1 can be received and delivered.

Description

[Detailed Description of the Invention] [Summary] Regarding the mechanism of a wafer rotor in a semiconductor exposure apparatus, the purpose of this invention is to improve the accuracy of wafer positioning with a simple structure, and to provide a first stage for roughly positioning the wafer. The wafer rotor is equipped with a rotary arm that uses a wafer chuck at the tip to adsorb and transfer the wafer to a second stage that precisely positions the wafer, and the wafer chuck is positioned between the first and second stages. and a spring means for supporting the wafer chuck in an extendable and swingable manner on the rotary arm.

[Industrial application field]

The present invention relates to a wafer rotor mechanism in a semiconductor exposure apparatus (hereinafter referred to as a stepper).

In recent years, as semiconductors have become highly integrated, submicron precision has become necessary for aligning the exposure optical system and the wafer, and position detectors for detecting the position of the wafer in the exposure optical system have also become more precise.

For this reason, the measurable range of the position detector has become smaller, and the requirements for positioning at a stage before introducing the wafer position error into the measurement range of the position detector have become stricter.

[Conventional technology]

As shown in the perspective view of FIG. 3, when exposing a wafer using a stepper, first the first elevator 2 is driven to move the wafers in the first wafer magazine 3 to a position where the wafer transfer robot 4 can extract them.

Then, the wafer transfer robot 4 extracts the wafer and moves the wafer transfer robot rail 5 to the first stage (
The wafer 1 is mounted on a pre-alignment table (hereinafter referred to as a pre-alignment table) 6.

Next, the pre-alignment table 6 performs rough positioning before mounting the wafer 1 on the XY stage 7 for exposure.

When the positioning is completed, the rotating arm 8 shown in the side view of the same figure and FIG.
(hereinafter referred to as the XY stage) 7.

The XY stage 7 on which the wafer 1 is mounted is moved below the exposure optical system 10 shown in FIG. 3, and after precisely positioning the wafer 1, exposure is performed.

After the exposure, the wafer 1 is again transported from the XY stage 7 to the wafer transfer robot 4 by the rotating arm 8.
The second wafer magazine 11 is moved by the wafer transfer robot 4.
The wafer is then moved to a predetermined position by the second elevator 12, and the exposure of one wafer is completed.

In such a series of exposure operations, it is particularly necessary to align the exposure optical system 10 and the wafer l on the XY stage 7 with high precision.

For this alignment, the exposure optical system 10 is equipped with a position detector (not shown) that detects displacement using, for example, laser interference fringes.

It is difficult for such a position detector to detect a large position error, and the pre-alignment table 6 is used to bring the position error of the wafer 1 into the measurement range of this position detector.

[Problem to be solved by the invention]

As mentioned above, the positioning of the wafer in the previous stage is performed by the pre-alignment table, but the positioning error of the pre-alignment table itself is caused by the looseness of the rotating arm and the positioning error when transferring from the pre-alignment table to the XY stage. becomes a problem.

In general, the rotary arm needs to have a configuration that allows for as simple a movement as possible and is less prone to errors.

Although the rotating arm shown in FIG. 4 only rotates and moves slightly up and down, the effects of bearing play, arm vibration, etc. still appear.

This has caused a problem in that it is difficult to accurately position and mount the wafer on the XY stage.

An object of the present invention is to improve wafer positioning accuracy with a simple structure.

[Means to solve the problem]

In order to achieve the above object, in the present invention, as shown in FIG.
6 and the second stage (XY stage) 7 with rotating arm 1
Position setting means 1 for positioning the wafer chuck 9 of No. 3
4, and a spring means 15 for supporting the wafer chuck 9 in an extendable and swingable manner on the rotating arm 13.

[Effect]

The wafer chuck is positioned at an appropriate position on the pre-alignment table and the XY stage by the position setting means without being affected by rattling or vibration of the rotating arm.

〔Example〕

FIGS. 1 and 2 show an embodiment of the present invention.

Identical parts are designated by the same reference numerals throughout the figures.

In the present invention, as shown in the side view of FIG.
Position setting means 1 for positioning the wafer chuck 9 of No. 3
4, and a spring means 15 for supporting the wafer chuck 9 in an extendable and swingable manner on the rotating arm 13.

That is, the position setting means 14 uses the pre-alignment table 6
and a positioning pin 16 provided at a predetermined position on the XY stage 7, which is projected downward by a plunger 17.

When the positioning pin 16 protrudes and its tip fits into the hole 18 of the wafer chuck 9 of the rotating arm 13, the wafer chuck 9
It is set to be located at an appropriate position on the stage 7.

The tip of the positioning pin 16 is chamfered to guide the hole 18 of the wafer chuck 9 to the position of the positioning pin 16 and to facilitate insertion.

On the other hand, a spring means 15 that supports the wafer chuck 9 on the rotary arm 13 in an extendable and swingable manner is connected to the arm 1 as shown in the figure.
3 is divided into two parts, and an elastic member such as urethane rubber is interposed between the parts.

By doing so, the spring means 15 can rotate the rotating arm 13.
The wafer chuck 9 absorbs the vibration of the positioning pin 16, and expands and contracts when positioning the wafer chuck 9 using the positioning pin 16.
to follow the positioning.

The plan views of FIGS. 2(a) and 2(b) show a position setting means based on the abutting method, in which a pin 19 is provided protruding from the pre-alignment table 6 and the XY stage 7 as shown in FIG. 2(a). By abutting the side portion 20a of the rotary arm 20 (as shown in FIG.

With such a configuration, the wafer chuck 9 is not affected by rattling or vibration of the rotary arm, and is positioned at an appropriate position on the pre-alignment table 6 and the XY stage 7 to secure the wafer 1.
The delivery can be carried out.

〔Effect of the invention〕

By using the wafer rotor of the present invention, errors caused by wafer handling can be reduced without providing a complicated mechanism for increasing positioning accuracy.

In addition, in steppers, etc., it is possible to transfer high-precision wafers without placing the wafer rotor, pre-alignment table, etc. on the vibration isolation table of the stage, which has great economic and industrial effects. play.

[Brief explanation of the drawing]

Fig. 1 is a side view of the wafer rotor of the present invention, Fig. 2(a)
, (bl is a plan view showing another position setting means of the wafer rotor of the present invention, FIG. 3 is a perspective view showing the configuration of a stepper, and FIG. 4 is a side view showing a conventional wafer rotor. In the figures, l is the wafer, 6 is the first stage 7 is the second stage 8, 13, 20 is the rotary a, 9 is the wafer chuck 1, 15 is the spring means, 17 is the plunger, 19 is the pin, (pre-alignment table), (XY 14 is a position setting means, 16 is a positioning pin, 18 is a hole, and 20a is a side part.

Claims (1)

[Claims] A first stage (1) for roughly positioning the wafer (1);
6), the second stage (1) performs precise positioning of the wafer (1).
7) a wafer rotor comprising a rotary arm (13) for sucking and transferring a wafer with a wafer chuck (9) at its tip, the first stage (6) and the second stage (7);
a position setting means (14) for positioning the wafer chuck (9); and a spring means (15) for supporting the wafer chuck (9) in an extendable and swingable manner on the rotating arm (13). A wafer rotor characterized by: