JPH0334218B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a pre-alignment device for sample processing, and is used for pre-alignment before positioning a sample and a mask, for example in the process of optically producing integrated circuits. It is suitable for performing step-by-step work.

(Prior Art) In this step, a sample or wafer made of single crystal silicon or the like is exposed to light to form a circuit of a desired pattern. In order to correctly set the wafer in the exposure processing section, pre-alignment (rough positioning on the exposure stage) is performed during the transport process, and the process generally consists of transport → centering → transport →
The order is OF issue → completion. Here, OF means an orientation flat, that is, a reference side that is flattened for positioning. Conventionally, in order to perform pre-alignment in the order of each process, dedicated mechanisms were required for each process. However, in conventional semiconductor manufacturing equipment, each mechanical part is lined up in series, which requires a large area as a whole.
This goes against the reality that clean rooms equipped with this type of equipment are very expensive per unit area.

Furthermore, wafers are not of one type, but are divided into various shapes, and circular ones are used in 2, 3, and 4 inch sizes, but the mechanism for making adjustments to accommodate size differences is not conventional. It is almost never seen on the device. Therefore, the conventional equipment is a special purpose machine. However, it is not always the case that a large number of circuits are formed using the entire surface of a wafer; there are cases in which only a very small number of circuits are manufactured, or there is a need for high-mix, low-volume production in which wafers of different sizes are used interchangeably. There is also. In such a case, the conventional device results in a large amount of waste.

(Technical Problem) The present invention has been made in view of the above-mentioned drawbacks and problems, and its object is to solve several problems in order to keep the price per unit area occupied by the device low. The goal is to ensure that work can be done in parallel, with no waste, and with high efficiency.

It is also an object of the present invention to provide a pre-alignment device suitable for high-mix, low-volume production in which samples of different sizes are used.

(Technical Means) In order to solve the above problems, the present invention provides a guide rail that supports one side of the sample and a guide rail that supports one side of the sample along a path for transporting the sample, which is made of a thin piece and has a reference side on the outer periphery, to the processing section. A guide belt is installed that transports the sample by traveling along the transport path while supporting the other side, and the processing section locks the sample around the outer circumference of the sample and rotates the sample at the locking position. A pin for bringing the reference side into contact with the reference surface is provided so as to be retractable from the conveyance path, and a sensor is provided for detecting when the reference side properly contacts the reference surface and for stopping the running of the guide belt. The method is such that it is provided on the reference plane.

In addition, there is a size adjustment mechanism that equally expands and contracts the gap between the guide rail and guide belt based on the sample center in the processing section, and a size adjustment mechanism that works in conjunction with the adjustment mechanism to stop the sample at a fixed position in the processing section. By providing an interlocking mechanism that changes the position of the pin that locks on the edge, it is possible to accommodate samples of different sizes very easily.

(Function) In the apparatus of the present invention configured as described above, the sample having the reference side, the wafer W having the OF part according to the embodiment, is pre-aligned by the transport mechanism 10 while being randomly oriented with respect to the OF part. It is sent to the section A, reaches the same section A, is stopped by a pin 21 protruding on the conveyance path, and is rotated at that position by the guide belt 14. Due to the rotation, the OF part of the wafer W comes into line contact with the reference surface 25, and the sample is thus positioned. Therefore
When the OF part makes a line contact with the reference surface 25, it is detected by the sensor 25c, and the transport mechanism 10 is stopped by the detection signal, the positioning state is maintained, and the OF part is advanced to the next process, and then returned and carried out by the transport mechanism. That will happen. In the case of the embodiment in which the exposure process proceeds after positioning, the wafer W is accurately raised by the Z-axis stage 38, so that no displacement occurs in the wafer W due to transfer.

(Example) This will be explained below with reference to the drawings.

1 to 3 show the entire exposure processing section of a semiconductor manufacturing apparatus, in which a prealignment apparatus A of the present invention is installed approximately in the center of a base 1, and a wafer W as a sample is placed in a first It is taken out from the carrier (storage cassette) 2 on the left side of the figure and transported to the right.
After exposure, it is stored in carrier 3 on the right side.

Carriers 2 ₁ to 2 ₃ and 3 1 to _{3 3} of different sizes are prepared depending on the wafer size, and the stages of lifting mechanisms 4 and 5 installed on the left and right sides of the front of the base 1 are used to automatically supply wafers. It is fitted into the shaped carrier receivers 6a and 7a and installed vertically. Inside the carrier, a large number of wafer storage sections 8 are formed by a large number of partitions in the width direction, and a notch 9 into which the transport mechanism 10 is inserted is formed in the end face (FIG. 5). The elevating mechanisms 4 and 5 are for elevating and lowering elevating tables 6 and 7 provided with carrier receivers.The loading side lowers to take out the wafers in the carrier from bottom to top, and the unloading side lowers the lower compartment. It is set to go up in order to fill it from 8, and when viewed from the front of each figure, the left side is the carry-in side and the right side is the carry-in side.

The transport mechanism 10 takes out a wafer W, which is a sample, from the carry-in carrier, and transports it in a horizontal state to insert it into the carry-out carrier through the exposure processing section 30. The guide rail 13 and the guide belt 14 in the present invention also serve as a part of the guide rail 13 and the guide belt 14, and the conveyance mechanism 10 is
As shown in Fig. 5, a carry-in belt 11 consists of two parallel belts whose tips protrude into the carry-in carrier, and a carry-in belt 11 consists of two parallel belts whose tips protrude into the carry-out carrier. It is comprised of a guide rail 13 that connects the carry-out belt 12 and both belts 11 and 12 and supports one side of the wafer W, and a guide belt 14 that supports the other side of the wafer W.

Both the carry-in and carry-out belts 11 and 12 consist of a pair of belts running in parallel at a narrow interval so that the smallest wafer can be stably taken out and carried from the carrier, and the tips of each pair of belts protrude into the carriers 2 and 3, respectively.

On the other hand, the guide rail 13 and the guide belt 1
Reference numeral 4 supports a wafer W, which is a sample, on both sides farthest apart from each other, and the spacing thereof can be adjusted according to the wafer size by a size adjustment mechanism 20, which will be described later. The guide rail 13 has a horizontal rail surface 13a that bears the load on one side of the wafer, and a vertical guide surface 13 that defines the position of the wafer edge on the outside of that surface.
b, and the guide belt 14 is formed of a suitable frictional material that bears the load on the other side of the wafer. 14a shows a stopper along the guide belt. Loading and unloading belts 11, 12
The guide belt 14 and the guide belt 14 can be made of the same material. The guide rail 13 and the guide belt 14 are movably mounted on a plurality of rails 17 and 18 arranged orthogonally to the direction of the conveyance path via support members 15 and 16 provided on the outside of each guide rail 13 and guide belt 14, respectively. ,
In addition, each of the support members 15 and 16 is threadedly engaged with a rotating shaft 19 having a tambuckle-type screw, so that the distance between the supporting members 15 and 16 can be changed by operating the rotating shaft. These support member 15 to rotating shaft 19 constitute the main part of the size adjustment mechanism 20.

A pre-alignment position P is set approximately at the center of the transport path, and a pin 21 for stopping and pre-aligning the wafer W, which is a sample being transported, is located between the guide rail 13 and the guide belt 14. It is provided near the guide belt 14. In other words, the pin 21 protrudes into the transport path at a position where it locks onto the edge of the wafer W so that the wafer W is set at the center of the pre-alignment position P, and the pin 21 protrudes into the transport path in order to pass the exposed wafer. An interlocking mechanism 2 is air-driven so as to move downward, and is also interlocked with the operation of the adjustment mechanism 20 so that centering can always be performed even if the wafer size changes.
Change the position by 2. 23 is a guide groove fixed to the support member 15 side in order to define the movement path of the pin 21, and 24 is an interlocking member attached to the member 29 to which the adjustment mechanism 20 is attached, and has a pin engagement groove 24a. .

In the vicinity of the guide rail at the pre-alignment position P, a reference surface 25 is provided on which the OF portion of the wafer W, which is the sample, or the reference side is applied. The stopper portion 25a is provided with a reflective sensor 25c that turns on when pre-alignment is completed. Therefore, the OF part of the wafer W is on the surface 25.
Pre-alignment is completed when the line contacts. A nozzle 26 is provided on the opposite side of the reference surface 25, and this sprays an inert gas such as nitrogen gas onto the other side of the wafer to increase the contact resistance with the belt when using a light wafer. It also has the advantage of removing or preventing adhesion. 27 is the air supply tube,
28 indicates a deflection plate that directs the airflow downward.

The exposure processing section 30 is provided directly above the pre-alignment position P, and a calibrator 33 that aligns the mask 31 and the wafer W in parallel is provided on the lower surface of the mounting plate 32 on which the mask 31 is set so as to be movable forward and backward. It is being 34 is the calibrator 33
The slide rail 35 indicates the driving cable mechanism of the calibrator 33 (FIG. 3). A sample stage 36 on which the wafer W is placed is arranged directly below the exposure section 30, and the sample stage 36 is connected to the θ-axis 37 and the Z-axis stage 3.
8. The Y-axis stage 39 and the X-axis stage 40 are installed on the base 1 so as to be movable in XYZ-axis directions perpendicular to each other and to obtain a desired inclination angle θ. 41 is the spherical surface of the lower surface of the sample stage 36; 42
is a spherical bearing on the θ-axis side, and is provided on the θ-axis 37.

45 in each figure is a lamp house of the exposure processing section 30;
46 and 47 have an observation microscope and a CCD camera 48. 49 ₁ ... indicates a motor that is a driving source for each part. In this embodiment, the case where the sample is a circular wafer W is explained and illustrated. However, since the present invention corrects the rotation of the sample for positioning, the sample does not need to be circular as long as it has reference sides. Further, the sample itself is not limited to a wafer.

In the above configuration, first, the carry-in carrier 2 containing a large number of wafers W as samples and the empty carry-out carrier 3 are set in their respective lifting mechanisms. At this time, when the size of the wafer is set on the operating section of the apparatus, the guide rail 13 and guide belt 14 are moved by the motor drive and are automatically adjusted to the appropriate spacing, and are properly positioned by interlocking the pins 21. Ru.

The wafers W are pulled out one by one from under the unexposed carrier 2 by the carry-in belt 11, and when transferred to the guide rail 13 and guide belt 14, are pulled by one guide belt 14 and rotated toward the pre-alignment position. While being transported. Note that depending on the shape of the sample, it may rotate only a few degrees or less. In the illustrated case, one edge of the wafer W is perpendicular to the guide surface 13b of the guide rail 13,
Move while rotating.

When the wafer W reaches the pre-alignment part P,
It is configured so that it continues to rotate even when its edge touches the pin 21 protruding onto the conveyance path, and when the OF portion, which is the reference side, comes into line contact with the reference surface 25, the rotation is stopped due to the contact resistance. That is, reference plane 2
The contact piece 25b of No. 5 helps point contact rotation of the wafer, but the stopper 25a is used for stopping.
Friction contributes to stability. Pre-alignment is completed by stopping the rotation, so the reference side is placed on the reference surface 25.
The sensor 25c is activated by the line contact of the OF part.
When the motor is turned on, the CPU of the control unit immediately stops the motor operation of the transport mechanism 10 upon receiving the signal. Next, the wafer W is moved to the mask 31 by the Z-axis stage 38.
There, processing for pattern exposure is performed.

After the exposure, the wafer W is again lowered into the transport mechanism 10 and sent out toward the unloading carrier 3, but at this time the pins 21 are in the lowered position and do not interfere with the wafer. The unloading carrier 3 is loaded with wafers in order from the top, and the elevating mechanism 5 performs positioning for this purpose and gradually ascends.

(Effects) According to the present invention, in the process of transporting a sample such as a wafer, the transport action is used to place the sample at a predetermined pre-alignment position (centering), and while rotating, the OF surface is Pre-alignment is performed by applying the reference side to the reference surface (OF removal), and when this is detected, the guide belt stops running, so it is possible to carry in, center, OF, and carry out as before. Compared to the case where each mechanism is independently arranged in series and samples are transferred between each mechanism, the area occupied is significantly smaller, and the area utilization efficiency in the clean room can be significantly improved.

In particular, according to the present invention, a pre-alignment device is set in the process of transporting the sample, the sample is locked to the pin at the position, and after rotation by the guide belt, the reference side of the sample is aligned properly with the reference surface on the guide rail. Upon contact, the guide belt will stop running immediately.
Since it is maintained in a normal positioning state and does not shift, it is possible to perform work with high precision and efficiency.

Further, the distance between the guide belt and the guide rail can be adjusted, and in conjunction with this, the pin that holds the sample at a predetermined position can be appropriately positioned, so it is possible to use samples of different sizes.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view of a semiconductor manufacturing apparatus illustrated for the embodiment;
Fig. 2 is a right side view, Fig. 3 is a plan view, Fig. 4 is a plan view of the prealignment device according to the present invention, Fig. 5 is a front view thereof, Fig. 6 is an enlarged plan view of the main part, Figure 7 is a cross-sectional view of the size adjustment mechanism, Figure 8 is a cross-sectional view of the nozzle section that injects gas onto the sample, and Figure 9 is a cross-sectional explanatory diagram showing the relationship between the θ axis, wafer, mask, etc. in the exposure state. , FIG. 10 is a front view of the size adjustment mechanism, and FIG. 11 is a right side view of the same.

Claims (1)

[Claims] 1. A guide rail that supports one side of the sample and a guide rail that supports the other side of the sample along the path for transporting the sample, which is made of a thin piece and has a reference side on the outer periphery, to the processing section; A guide belt that transports the sample by traveling along the guide rail is installed, and the processing section locks the sample around the outer periphery, causing the sample to rotate at the locking position and applying the reference side to a reference surface near the guide rail. a pin is provided so as to be retractable from the conveyance path, and detects when the reference side properly contacts the reference surface;
A pre-alignment device for sample processing, further comprising a sensor provided on the reference surface for stopping the running of the guide belt. 2. In order to process samples of different sizes, there is a size adjustment mechanism that equally expands and contracts the distance between the guide rail and guide belt based on the center of each size sample in the processing section, and a size adjustment mechanism that works in conjunction with the adjustment mechanism to 2. The pre-alignment device for sample processing according to claim 1, further comprising an interlocking mechanism for changing the position of a pin that is engaged with an edge of the sample in order to stop the pre-alignment device at a fixed position in the processing section.