JPH10173030A - Substrate carrier and exposure apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an obliquely entered wafer among wafers in a wafer carrier. SOLUTION: A wafer carrier 21 houses stacked wafers 10 in rack plates each supporting both ends of the wafer, and is mounted on a lift table 23 which is moved up and down to take out the wafer 10 at a take-out position by hand only when this wafer is detect by both photoelectric sensors 25a, 25b. When only one sensor 25a indicates with its output signal that the wafer exists, it is a wafer 11 obliquely entered into a rack plate offset by one stage. The table 23 is moved by one pitch to the next rack plate during detecting by both sensors 25a, 25b. If only one sensor 25a generates an output signal indicating the wafer exists, it is a wafer 12 obliquely entered by two stages.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a substrate transfer apparatus for transferring a substrate such as a wafer in an exposure apparatus for manufacturing semiconductors, and an exposure apparatus using the same.

[0002]

2. Description of the Related Art In an exposure apparatus for manufacturing semiconductors, a plurality of wafers are generally accommodated in a wafer carrier and transported to a predetermined standby position, and the wafer is automatically taken out of the wafer carrier in each exposure cycle. A substrate transfer device for supplying a wafer stage or the like is mounted.

FIG. 8 shows a conventional example, which includes a wafer stage 110 provided in a clean room, a wafer standby station 120 for holding a wafer carrier 121 for storing a plurality of wafers, and a wafer standby station 120. And a wafer transfer unit 130 for taking out wafers one by one from the wafer carrier 121 and transferring the wafers to the wafer stage 110.

The wafer stage 110 includes a wafer chuck 111 having a suction surface 111a for sucking a wafer, a Z stage (not shown) for moving the wafer chuck 111 in a direction (Z-axis direction) perpendicular to the suction surface 111a,
An X stage 112 for moving the wafer chuck 111 in the horizontal direction (X-axis direction) in the figure, and moving the wafer stage 111 in the vertical direction (Y
The X stage 112 and the Y stage 113 are moved in the X axis direction and the Y axis direction by rotating known ball screws 112a and 113a, respectively.

The wafer carrier 121 holds the wafers horizontally on a plurality of shelves therein and vertically holds the wafers. Each wafer is successively held by the hand 131 of the wafer transfer unit 130.
1 and transferred to the wafer stage 110. The wafer transfer unit 130 includes a Y stage 132 for moving the hand 131 in the Y-axis direction, an X stage 133 for moving the hand 131 in the X-axis direction, and a hand 13
Has a Z stage 134 for reciprocating the wafer 1 between the wafer carrier 121 and the wafer stage 110 in the Z-axis direction, takes out the wafer from the wafer carrier 121 and transfers it to the wafer stage 110, and transfers the exposed wafer to the wafer stage 110. Received from the wafer carrier 121
It is configured to automatically carry out the work of storing again.

[0006] On the front surface of the wafer stage 110, a mask stage, an alignment optical system, a shutter and the like (not shown) are provided. The wafer held on the wafer stage 110 is exposed to exposure light emitted through a mask on the mask stage, and the pattern of the mask is transferred to the wafer.

The wafer chuck 111 has its suction surface 111
The wafer is sucked and held by the vacuum suction force generated in the suction groove provided in a. Similarly, the hand 131 sucks the wafer on its surface by the vacuum suction force, and the wafer is transferred by alternately controlling the vacuum suction force of the hand 131 and the vacuum suction force of the wafer chuck 111 by a vacuum suction force control device. It is.

As shown in FIG. 7, the wafer standby station 120 includes a lift 123 supported by a support 122 so as to be vertically movable, and a lift motor 124 for vertically moving the lift 123 intermittently by one pitch. By raising or lowering the lifting table 123 intermittently by one pitch in this manner, the wafers 1 stacked in the wafer carrier 121 are
00 is moved one by one to a wafer take-out position set at substantially the same height as the hand 131.

A wafer detecting device 125 for detecting whether or not the wafer 100 at the wafer unloading position is accommodated in the wafer carrier 121 in an appropriate horizontal state is provided immediately below the elevating table 123. After confirming that the wafer 100 moved to the wafer take-out position by the motor 124 is housed in the wafer carrier 121 in an appropriate horizontal state, the hand 131 is driven to take out the wafer 100 by driving. If it is determined from the output of the wafer detection device 125 that the wafer 100 is inclinedly accommodated in the shelf in the wafer carrier 121 or is absent, the scheduled hand 1
The drive of the elevator 31 is stopped, the elevator motor 124 is driven again, and the wafer at the next shelf in the wafer carrier 121 is moved to the wafer removal position.

When the wafer 100 is accommodated in the wafer carrier 121, the wafer 1
00 may be accommodated at an angle, or a wafer may be missing in a part of the wafer carrier 121. Therefore, the hand 131 is driven after confirming that the wafer 100 at the wafer take-out position is housed in an appropriate horizontal state. This avoids troubles such as a wafer stored in an inclined state interfering with the hand 131 and damaging a driving unit and the like of the hand 131.

The wafer detecting device 125 has a capacitance sensor 125a for detecting whether or not the wafer 100 is present at the wafer take-out position, and detects the reflected light on the back surface of the wafer 100 to keep the wafer 100 in a horizontal state. An optical sensor 125b for measuring distance is provided to determine whether or not the driving of the hand 131 is started only when the outputs of both the capacitance sensor 125a and the optical sensor 125b are equal to or greater than a predetermined value.

[0012]

However, according to the above-mentioned prior art, it is impossible to accurately detect the presence or absence of a wafer in a wafer carrier and the state of the wafer. In other words, it is unavoidable to make a mistake in the determination, for example, that the oblique insertion state is erroneously detected as the absence of a wafer. Since this is configured to detect whether or not the wafer is horizontal by an optical sensor that measures the reflected light on the back surface of the wafer,
This is because an error occurs in the output of the optical sensor when the reflectivity of the wafer is different.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has been made in consideration of the above-mentioned problems. An object of the present invention is to provide an exposure apparatus using the same.

[0014]

In order to achieve the above object, a substrate transfer apparatus according to the present invention comprises: means for accommodating a plurality of substrates on a plurality of shelves having a predetermined pitch; Driving means for intermittently moving at a pitch of
Each time the accommodating means moves at the predetermined pitch, a pair of sensors for detecting the presence or absence of the substrate on the shelf at a first measurement point, and the accommodating means removes the substrate from the accommodating means based on both outputs. A hand for taking out, wherein the pair of sensors, in addition to the first measurement point, the accommodation means moves the predetermined pitch. It is characterized in that it is configured to detect the presence or absence, respectively.

[0015]

Only when a pair of sensors generate an output signal indicating that there is a substrate at the first measurement point, it is determined that the substrate is properly stored in the shelf of the storage means and the hand is driven. . If the hand is driven and the substrate is taken out after confirming the state of the substrate in the accommodating means in this way, the supply of the substrate to the wafer stage or the like of the exposure apparatus can be performed extremely smoothly as scheduled. There is no trouble such as the hand being damaged by interference with the board in an obliquely inserted state. When one output signal of the pair of sensors has a substrate and the other has no substrate, one side of the substrate in the storage means is in a so-called one-step oblique insertion state supported by a shelf shifted by one step. Judge.

When one side of the substrate in the storage means is in a so-called two-step oblique state in which one side of the substrate is supported by a shelf shifted by two steps, both sensors generate output signals without the substrate, and the substrate is output. Cannot be distinguished from absence (missing).
Then, the second movement of the accommodation means while moving the predetermined pitch is performed.
The presence or absence of a substrate is detected at the measurement point (1), and when the output signal of one of the sensors indicates that the substrate is present, it is determined that two stages are inserted obliquely.

Since all the states of the substrates in the storage means can be accurately determined, the supply of the substrates to the wafer stage and the like can be performed extremely smoothly, and the throughput of the exposure apparatus can be greatly improved.

[0018]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a substrate transfer apparatus according to one embodiment. This means that a wafer standby station 20 disposed in a clean room together with a wafer stage or the like as a substrate holding means, and a hand 31 for transporting and transferring the wafer 10 as a substrate between the wafer stage and the wafer standby station 20. Have.

The wafer waiting station 20 holds a wafer carrier 21, which is a storage means for storing the wafers 10 stacked vertically on a plurality of shelves in a vertically stacked state, on a lifting table 23 supported by a support 22. , The lift 23
It is moved up and down intermittently by a lift motor 24 as a driving means.

The hand 31 is configured to reciprocate horizontally with respect to the elevating table 23 by a driving unit (not shown), to take out the wafer 10 in the carrier 21 at a predetermined position, and to transfer it to the wafer stage.

When the wafer 10 is taken out by the hand 31, the state of the wafer 10 in the wafer carrier 21 is detected by the wafer detecting device 25, and the wafer 10 is properly accommodated in a shelf in the wafer carrier 21. After confirming that it is done. The wafer detection device 25 includes a pair of sensors, photoelectric sensors 25a and 25b, which are disposed at a predetermined height on the support 22. Each photoelectric sensor 25
a and 25b receive light beams L ₁ and L ₂ emitted horizontally from the light sources 251a and 251b.
When the wafer 10 reaches a predetermined height, that is, a take-out position by the hand 31 due to the intermittent vertical movement of the wafer 3, if the wafer 10 is stored horizontally in the shelves 21 a and 21 b (see FIG. 2), Kakutanadan 21a, in the vicinity of 21b, the light beams L _1, L each of ₂ is blocked by the wafer 10 by both photoelectric sensors 25a, 25b are configured to generate an output signal of there wafer.

As shown in a wafer 11 in FIG.
When one end 11a of the wafer 11 is in one shelf 21a in the wafer carrier 21 and the other end 11b is supported by a shelf shifted by one stage from the other shelf 21b, that is, both ends of the wafer 11 are only one stage. offset when in the state of one stage oblique insertion, only one of the photoelectric sensors 25a to one of the light beams L ₁ only wafer 11 obstructs generates a signal there wafer, the other light beam L ₂ is a wafer 11 and thus produces a signal without a wafer.

The operation of taking out the wafers 10 in the wafer carrier 21 one by one by the hand 31 is performed as follows. By driving the elevator motor 24, the shelf 10 in the wafer carrier 21 is intermittently moved up and down at a pitch equal to the vertical interval (pitch) of the shelf, and the wafers 10 in each shelf are sequentially moved to the take-out position by the hand 31. Hand 3
Before driving 1, the presence or absence of the wafer 10 is detected by the wafer detection device 25. If the output signals of both the photoelectric sensors 25a and 25b of the wafer detecting device 25 are both absent, the wafer 10 on the shelf is missing, and one of the output signals of the photoelectric sensors 25a and 25b is the presence of the wafer. When there is no wafer on the other side, it is determined that one stage is inserted obliquely as shown by the wafer 11, and in any case, the driving of the hand 31 is not started, and the elevator 23 is moved by one pitch to The operation shifts to the work of taking out the wafer 10 from the shelf. Only when both the photoelectric sensors 25a and 25b generate an output signal indicating that a wafer is present, it is determined that the wafer 10 is properly accommodated in the shelf of the wafer carrier 21 and the hand 31 is driven to take out the wafer 10. Perform

Thereafter, the wafer 10 is transported to the wafer station by the hand 31 and is exposed by exposure light generated from a light source as exposure means (not shown).

However, as described above, the lifting table 23 is sent one pitch at a time, and the wafers 10 on the shelf of the wafer carrier 21 are moved.
Measurement point for detecting the presence or absence of data (first measurement point)
Is only provided, when both ends are in a two-step oblique insertion state, as in the case of the wafer 12 shown in FIG. 1B, the output signals of both photoelectric sensors 25a and 25b are both absent. Therefore, there is an inconvenience that it cannot be distinguished from the case where the wafer 10 is missing on the shelf of the wafer carrier 21. Even if the elevating table 23 is further lowered by one pitch, the output signals of the photoelectric sensors 25a and 25b are both without a wafer as shown by the broken line,
Has the same effect as missing.

Therefore, a step is provided in which the elevator 23 is stopped at the second measurement point in the course of feeding the elevator 23 by one pitch and the presence / absence of a wafer is detected by the photoelectric sensors 25a and 25b. That is, as shown in FIG. 3, if the elevator 23 is stopped at the second measurement point in the middle of sending one pitch, the wafer 12 obliquely inserted in two steps blocks only _one light beam L1 as shown by the broken line. State
Therefore, the output signal of one of the two photoelectric sensors 25a and 25b has a wafer and the other has no wafer.

For example, the elevator motor 24 is controlled so that the elevator 23 moves up and down intermittently at a pitch equal to half the pitch of the shelf of the wafer carrier 21, and each time the elevator 23 stops, both motors are controlled. The output signals of the photoelectric sensors 25a and 25b are obtained. If an output signal indicating that there is a wafer is obtained from the photoelectric sensors 25a and 25b when each shelf of the wafer carrier 21 is located at the wafer take-out position, the hand 31 is driven to take out the wafer. At this position, if the output signal of one of the two photoelectric sensors 25a and 25b indicates that there is a wafer, it is determined that the wafer 11 is in a state of being inserted one step diagonally. Also, the output signals of both photoelectric sensors 25a and 25b are both without a wafer, and immediately before that,
If the output signals of the two photoelectric sensors 25a and 25b when there is no wafer are present, it is determined that the wafer is missing. When one of the two photoelectric sensors 25a and 25b generates an output signal indicating that there is a wafer, it can be determined that the state shown in FIG.

It is not always necessary to set the detection position for detecting the wafer 12 in the two-stage diagonally inserted state to half the pitch of the shelf of the wafer carrier 21. As shown in FIG. 4, in the case of, for example, a 6-inch wafer, the pitch P ₀ of the shelf of the wafer carrier 21 is usually 4.76 mm, and the beam diameters of the light beams L ₁ and L ₂ for detecting the presence or absence of the wafer. That is, the detection range D of the photoelectric sensors 25a and 25b
Is set to a width of 0.5 mm above and below the shelf. Therefore,
P from the pitch P ₀ of the shelves of the wafer carrier 21 by subtracting the photoelectric sensors 25a, a detection range D of 25b ₁ = P ₀ -
In the range of D = 3.76 mm, the height at which the two-step oblique insertion is most easily detected may be set as the second measurement point, and the wafer carrier 21 may be stopped here.

Even in the case of the smallest diameter wafer, since the pitch of the shelf of the wafer carrier is 2.28 mm, the second measurement point for detecting the two-step oblique insertion can be set within a range of 1.25 mm. Therefore, it is easy to provide a second measurement point in the middle of moving the wafer carrier up and down by one pitch of the shelf so as not to interfere with the first measurement point at the wafer take-out position.

According to this embodiment, it is possible to accurately detect the state of the wafers in the wafer carrier stored in the shelf. Therefore, the wafer can be taken out extremely smoothly without causing troubles such as the hand interfering with the wafer or the like in an obliquely inserted state. As a result, the supply of the wafer to the wafer stage can be smoothly performed as planned, and the throughput of the exposure apparatus can be greatly improved.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 5 shows a micro device (a semiconductor chip such as an IC or an LSI, a liquid crystal panel, a CC)
D, thin-film magnetic head, micromachine, etc.). In step 1 (circuit design), the circuit of the semiconductor device is designed. Step 2 is a process for making a mask on the basis of the circuit pattern design. On the other hand, in step 3 (wafer manufacturing), a wafer 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 prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 6 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device, which has been conventionally difficult to manufacture.

[0034]

Since the present invention is configured as described above, it has the following effects.

The state of accommodating a wafer or the like in a wafer carrier or the like can be accurately determined, and the supply of a wafer or the like to a wafer station or the like can be performed extremely smoothly as scheduled.

As a result, the throughput of the exposure apparatus can be improved, and the cost of semiconductor devices can be greatly reduced.

[Brief description of the drawings]

FIG. 1 shows a substrate transfer device according to one embodiment;
(A) is a perspective view of the same, and (b) is a view for explaining a housed state of a wafer.

FIG. 2 is a view for explaining a relative position between a wafer and a wafer detection device of the device of FIG. 1;

FIG. 3 is a diagram illustrating a process of detecting a state where a wafer is inserted two-step obliquely;

FIG. 4 is a diagram illustrating a detection range of a photoelectric sensor and a lifting pitch of a lifting platform.

FIG. 5 is a flowchart showing a semiconductor device manufacturing process.

FIG. 6 is a flowchart showing a wafer process.

FIG. 7 is a perspective view showing a conventional example.

FIG. 8 is an elevational view showing the entire exposure apparatus.

[Explanation of symbols]

 10, 11, 12 Wafer 20 Wafer Standby Station 21 Wafer Carrier 23 Elevator 24 Elevator Motor 25 Wafer Detector 25a, 25b Photoelectric Sensor 31 Hand

Claims (2)

[Claims] An accommodating means for accommodating a plurality of substrates on a plurality of shelves having a predetermined pitch; a driving means for intermittently moving the substrates at the predetermined pitch; A pair of sensors for respectively detecting the presence or absence of the board on the shelf at a first measurement point each time it moves, and a hand for taking out the board from the storage unit based on the output of both; The sensor is
In addition to the first measurement point, the accommodation unit is configured to detect the presence or absence of the substrate between the shelf steps at a second measurement point on the way of moving the predetermined pitch. A substrate transfer device characterized by the above-mentioned. 2. An exposure apparatus comprising: substrate holding means for holding a substrate transferred by the substrate transfer device according to claim 1; and exposure means for exposing the substrate.