JPH088329A - Carrier holding device and wafer detection method using the same - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a carrier holding device for holding a carrier in which a wafer conveyed in a semiconductor manufacturing process is held, and a wafer detection method for detecting the presence or absence of a wafer by the carrier holding device. To improve the throughput. [Structure] When a carrier 42 for accommodating a wafer 43 is mounted on a stage 35 and rear guides 37a, 37b and moved to a position of a holding table 32, a load characteristic in a condition of accommodating the wafer 43 in the carrier 42 is detected. It Then, the control unit 41 compares and collates the detected load characteristic pattern with the preset load characteristic pattern, and the wafer 43 for the corresponding load characteristic pattern is compared.
The storage position and the number of sheets are detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier holding device for holding a carrier in which a wafer transferred in a semiconductor manufacturing process is stored, and a wafer detecting method for detecting the presence or absence of a wafer.

In recent years, in the semiconductor manufacturing process, in order to reduce the manufacturing cost, it is required to improve the processing capacity (throughput) of a wafer per unit time. Therefore, it is necessary to shorten the wafer holding time in each processing unit.

[0003]

2. Description of the Related Art In recent years, when a wafer is processed in a semiconductor manufacturing process, a predetermined number of wafers are stored in a carrier, and the carrier is transferred to each semiconductor processing apparatus in units of the carrier. In the transported semiconductor processing apparatus or the like, the carrier is placed on the carrier stage, and the presence or absence of the wafer in the carrier and the wafer storage position are detected and confirmed.

Here, FIG. 9 shows a configuration diagram of a conventional carrier stage. In FIG. 9, the carrier stage 11
The rotary base 14 is rotatably connected by the shaft 13 at one end of the holding base 12, and the stage 15 is attached to the rotary base 14.

The shaft 13 constitutes a tilt mechanism which is rotated by a drive motor 16 via a timing belt 17 and the rotary base 14 and the stage 15 are rotated accordingly. Further, the stage 15 is provided with rear guides 18a and 18b (18b is not shown in the figure) at a position corresponding to the back of the carrier 15.

On the other hand, a predetermined number (for example, 25) of wafers 19 are horizontally accommodated in a carrier 20, and the carrier 20 is mounted on the stage 15. And a vertically movable transmissive beam sensor (21a, 21b, see FIG. 10C)
Thus, the presence / absence of the wafer is detected.

The carrier stage 11 is the stage 1
5 is placed on the holding table 12, the tilt-down state is set, and the carrier 2 is placed on the stage 15 as shown in FIG.
The state in which 0 is mounted is the tilt-up state.

Therefore, FIG. 10 shows an operation explanatory view of the tilt mechanism of FIG. FIG. 10A shows a state in which the shaft 13 is rotated by the drive motor 16 via the timing belt 17 and the rotation base 14 and the stage 15 are rotated and tilted up. The carrier 20 is mounted on the stage 15.

In FIG. 10B, when the carrier 20 is mounted on the stage 15, the drive motor 16 causes the shaft 1 to move.
3 is rotated in the opposite direction to rotate the turntable 14 and the stage 15 to a position on the holding table 12 and tilted down. In this state, the wafer 19 in the carrier 20 becomes horizontal.

Then, as shown in FIG. 10C, the transmissive beam sensors 21a and 21b are moved up and down step by step by pitch feed to detect the presence or absence of the wafer 19 in the carrier 20.

[0011]

However, after the stage 15 is tilted down as described above, the carrier 2 is
Since the presence / absence of the wafer 19 is detected for all stages within 0, it takes a long time after the carrier 20 is mounted on the carrier stage 11 until the detection of the presence / absence of the wafer 19 is completed. That is, there is a problem that the holding time of the wafer 19 before processing becomes long and the throughput decreases.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a carrier holding device and a wafer detection method for shortening the wafer detection time and improving the throughput.

[0013]

In order to solve the above-mentioned problems, according to a first aspect of the present invention, in a carrier holding device for mounting and holding a carrier, which accommodates a predetermined number of wafers in semiconductor manufacturing, on a carrier, Moving means for moving from a mounting position to be mounted on the mounting portion to a predetermined holding position, and detecting means for detecting a load characteristic when the wafer is stored in the carrier when the carrier is moved by the moving means, A predetermined number of load characteristic patterns for the storage state of the wafers in the carrier are set in advance, and control is performed to obtain the storage state of the wafers for the corresponding set load characteristics from the load characteristic patterns detected by the detection means. And means for configuring.

According to a second aspect of the present invention, the moving means is configured to move the mounting portion from the mounting position to the holding position by a rotating member that is rotated by a driving portion, and the detecting means is
The rotation detecting member is composed of a strain detecting unit that detects strain.

According to a third aspect of the present invention, the detecting means is composed of a predetermined number of piezoelectric members for detecting the pressure state of the carrier provided at a predetermined position of the mounting portion.

According to a fourth aspect of the present invention, the moving means is configured to move the mounting portion from the mounting position to the holding position by a rotating member that is rotated by a driving portion.
The configuration is such that the output value from the drive unit is detected.

According to a fifth aspect of the present invention, a carrier containing a predetermined number of wafers in semiconductor manufacturing is mounted on the mounting portion of the carrier holding device according to the first aspect, and is moved to a holding position by a moving means. A wafer detection method for detecting the presence / absence of a wafer, the step of detecting a load characteristic corresponding to a storage state of the wafer in the carrier by a detection unit included in the carrier holding device, and storing the wafer in the carrier in advance. A predetermined number of load characteristic patterns for the states are set, the step of comparing and collating the load characteristic patterns detected by the detecting means with the set predetermined number of load characteristics, and the wafer for the corresponding set load characteristics And a step of obtaining a stored state of.

According to a sixth aspect of the present invention, in the fifth aspect, the moving means causes the drive section to rotate the rotating member to move the mounting section, and the load characteristic detected by the detecting section is calculated as follows. It is detected by the strain of the moving member.

According to a seventh aspect of the present invention, the load characteristic detected by the detection means is detected based on the pressure state of the carrier on the mounting portion.

According to an eighth aspect of the present invention, in the fifth aspect, the moving means moves the mounting portion by rotating the rotating member by the drive portion, and the load characteristic detected by the detecting means is changed to the drive characteristic. It is detected from the output value from the department.

[0021]

As described above, in the inventions of claims 1 and 5, when the carrier is mounted on the mounting portion and moved to the holding position, the load characteristic in the state where the wafer is accommodated in the carrier is detected and preset. The wafer storage state for the load characteristic pattern corresponding to the selected load characteristic pattern is detected. As a result, it is not necessary to detect the presence or absence of the wafer when the carrier is positioned at the holding position for each wafer, and the wafer detection time can be shortened and the throughput can be improved.

In the inventions of claims 2 to 4 and 6 to 8, the load characteristics in the state where the wafer is stored in the carrier when the carrier is moved by the detecting means are determined by the distortion of the rotating member and the pressure applied to the carrier mounting portion. It is detected from the state or the output value of the drive unit. As a result, the wafer detection can be performed easily, the wafer detection time can be shortened, and the throughput can be improved.

[0023]

FIG. 1 shows a first embodiment of the present invention. FIG.
FIG. 1A is a side view and FIG. 1B is a back view.
A carrier stage 31A, which is a carrier holding device shown in FIGS. 1A and 1B, has a shaft 3 at one end of a holding table 32.
3 is provided, a rotation base 34 is attached to the shaft 33, and is rotated in the arrow direction. This shaft 3
Rear guides 37a and 37b are attached to the mounting plate 36 at 3 and one end. The stage 35, the mounting plate 36, and the rear guides 37a and 37b constitute a mounting portion.

The shaft 33 is rotated by a motor 38, which is a drive unit, via a timing belt 39.
The shaft 33, the turntable 34, the motor 38, and the timing belt 39 constitute a moving means. Then, a strain gauge 40, which is a strain detection unit as a detection unit, is attached to the shaft 33, and an electric signal corresponding to the strain is sent from the strain gauge 40 to a control unit 41 that is a control unit.

On the other hand, a predetermined number (for example, 25) of wafers 43 that can be stored in the carrier 42 are horizontally stored in a predetermined number in a predetermined portion.

The control section 41 is provided with a storage section in which data of load characteristics due to distortion of all combinations of the storage state (storage position, number of storages) of the wafer 43 in the carrier 42 is set and stored. (See below).

Here, FIG. 2 shows an operation explanatory diagram of the carrier stage shown in FIG. First, in FIG. 2A, the shaft 33 and the rotation base 34 are rotated in a direction away from the holding base 32 by driving the motor 38. This state is the tilt-up state, which is the carrier mounting position of the stage 35 and the rear guides 37a and 37b, which are the mounting portions.

Then, a carrier 42 containing a predetermined number of wafers 43 is carried and the stage 35 is moved in the direction of the arrow.
And mounted on the rear guides 37a and 37b.

Further, in FIG. 2B, when the motor 38 is rotated in the opposite direction, the stage 35 is rotated in a direction approaching the holding table 32 so that the wafer 43 becomes horizontal on the holding table 32. The carrier 42 is held. This state is the tilt-down state, which is the holding position of the carrier 42.

When the carrier 42 moves from the tilt-up state to the tilt-down state, the strain gauge 40
Distortion signals are sequentially input to the control unit 41 according to the position of the carrier 42. That is, the control unit 41
In, the displacement of the strain of the strain gauge 40 from the tilt-up state to the tilt-down state of the carrier 42 is input as the load characteristic.

Here, FIG. 3 shows an explanatory view of the load moment in the rotating direction of the shaft. FIG. 2 (A) described above.
As shown in, the stage 35, the rear guides 37a, 38b
When the carrier 42 is mounted in a tilted state, the carrier 42 applies a load in the rotation direction around the shaft 33, and the wafer 43 accommodated in the carrier 42 is loaded.
Different loads occur depending on the storage position and the number of stored sheets.

As shown in FIG. 3A, this is the moment obtained by multiplying the rotational direction component G ₁ of the center of gravity G _{0 at} the center of gravity of each wafer 43 by the distance between the center of gravity of the wafer 43 and the shaft 33. That is, the load moment applied in the rotation direction of the shaft 33 is proportional to the distance between the center of gravity of the wafer 43 and the shaft 33 as shown in FIG.

Therefore, it becomes possible to detect the housed state of the wafer 43 in the carrier 42 by reading the waveform of the load change generated when the carrier 42 is tilted down from the strain gauge 40.

Therefore, FIG. 4 shows an explanatory view of the load moment with respect to the wafer position, and FIG. 5 shows an explanatory view of the load moment of FIG. FIG. 4A shows the case where the wafer 43 is stored in the lower side of the carrier 42 on which the stage 35 is mounted in the tilted-up state, and FIG. 4B shows the same number of wafers in the upper side of the carrier 42. The case where 43 is stored is shown.

Further, FIG. 5A shows the shaft 33 (strain gauge 4 with respect to the tilt-down elapsed time in the case of FIG. 4A).
0) is a graph of the load moment in the rotating direction, and FIG. 5B is a graph of the load moment in the case of FIG. 4B.

As shown in FIGS. 5 (A) and 5 (B), even when the same number of wafers 43 are stored in the carrier 42, depending on the storage position, FIG. 4 (B) (FIG. 5 (B)) )
In this case, the load moment applied in the rotation direction of the shaft 33 is larger.

Therefore, the wafer 43 for the carrier 42 is
The waveform patterns of the load characteristics (graphs of load moments) of all combinations of the storage positions and the number of sheets are obtained in advance and stored in the storage unit of the control unit 41, and can be obtained by the strain signal from the strain gauge 40. The stored state of the wafer 43 can be detected by comparing and collating with the waveform pattern of the load characteristic.

Therefore, FIG. 6 shows an operation flowchart of the wafer detection by the controller. In FIG.
A carrier 42 accommodating a predetermined wafer 43 is mounted when the stage 35 is in the tilt-up state, and when the tilt-down is performed, a strain signal is input from the strain gauge 40 to the control unit 41 until the tilt-down is completed. The load moment (load characteristic) waveform pattern of is detected (step (S) 1).

The detected load characteristic waveform pattern is compared and collated with a predetermined number of load characteristic patterns stored in advance (S2). Then, the housed state of the wafer 43 with respect to the waveform pattern of the corresponding set load characteristic, that is, the housed position and the number of the wafer 43 in the carrier 42 are detected (S3).

As described above, it is not necessary to detect the presence / absence of a wafer by a sensor or the like after the stage 35 on which the carrier 42 is mounted is tilted down, the wafer detection time can be shortened, and the throughput in wafer processing is improved. Can be made.

Next, FIG. 7 shows a block diagram of a second embodiment of the present invention. The carrier stage 31B shown in FIG.
In place of the strain gauge 40 of the carrier stage 31A shown in FIG. 5, piezoelectric elements 44a to 44d, which are piezoelectric members as detection means, are provided on the stage 35 and the rear guide 37a (37b).
Is provided. Then, the output signals from the piezoelectric elements 44a to 44d are input to the control unit 41a.

When the carrier 42 is mounted on the stage 35 and the rear guides 37a and 37b and tilted down, the piezoelectric elements 44a to 44d generate electric signals in a pressure state according to external stress (load moment) by the carrier 42. Output to the control unit 41a. This change in external stress is obtained as a waveform pattern of load characteristics as shown in FIGS.

Therefore, similarly to the above, the control unit 41a previously obtains the waveform pattern of the load characteristic due to external stress by all combinations of the storage positions and the number of the wafers 43 in the carrier 42 and the storage unit of the control unit 41a. Will be stored in. Then, the housed state of the wafer 43 is detected by comparing and collating with the waveform pattern of the load characteristic obtained by the signal of the external stress sent from each of the piezoelectric elements 44a to 44d.

This also makes it possible to easily detect the wafer, shorten the wafer detection time, and improve the wafer processing throughput.

Next, FIG. 8 shows a block diagram of a third embodiment of the present invention. Carrier stage 31C shown in FIG.
Is the strain gauge 40 of the carrier stage 31A shown in FIG.
While the load characteristic is detected by the signal from, the detection means obtains the output current from the motor 38 and detects the change in the output value as the load characteristic.

That is, as shown in FIG. 8B, a part of the current supply line to the motor 38 is connected to the control section 41b.
Connect to.

This uses the characteristic that the drive current changes according to the load driven by the motor 38, and similarly to the above, the load due to the change in the output current value as shown in FIGS. 5A and 5B is used. The waveform pattern of the characteristic is obtained in advance by all combinations of the storage positions and the number of the wafers 43 in the carrier 42 and stored in the storage unit of the control unit 41b.

Then, the stored state of the wafer 43 is detected by comparing and collating the waveform pattern of the load characteristic obtained by the change of the output current value from the motor 39 with the stored waveform pattern.

This also makes it possible to easily detect a wafer, shorten the wafer detection time, and improve the throughput of wafer processing.

[0050]

As described above, according to the first and fifth aspects of the present invention, when the carrier is mounted on the mounting portion and moved to the holding position, the load characteristic in the state where the wafer is stored in the carrier is detected. By detecting the stored state of the wafer with respect to the load characteristic pattern corresponding to the preset load characteristic pattern, the presence or absence of the wafer when the carrier is positioned at the holding position is detected for each wafer. There is no need, and the wafer detection time can be shortened and throughput can be improved.

According to the inventions of claims 2 to 4 and 6 to 8, the load characteristics in the state where the wafer is accommodated in the carrier when the carrier is moved by the detecting means are changed to the distortion of the rotating member and the carrier mounting portion. By detecting from the pressure state or the output value of the drive unit, the wafer can be easily detected, the wafer detection time can be shortened, and the throughput can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is an operation explanatory view of the carrier stage of FIG.

FIG. 3 is an explanatory diagram of a load moment in a rotation direction of a shaft.

FIG. 4 is an explanatory diagram of a load moment with respect to a wafer position.

5 is a graph of the load moment of FIG.

FIG. 6 is an operation flowchart of wafer detection by the control unit.

FIG. 7 is a configuration diagram of a second embodiment of the present invention.

FIG. 8 is a configuration diagram of a third embodiment of the present invention.

FIG. 9 is a configuration diagram of a conventional carrier stage.

FIG. 10 is an operation explanatory view of the tilt mechanism of FIG.

[Explanation of symbols]

 31A-31C Carrier stage 32 Holding stand 33 Shaft 34 Rotating stand 35 Stage 37a, 37b Rear guide 38 Motor 39 Timing belt 40 Strain gauge 41, 41a, 41b Control part 42 Carrier 43 Wafer 44a-44d Piezoelectric element

Claims (8)

[Claims] 1. A predetermined number of wafers (4
A carrier holding device for mounting and holding a carrier (42) accommodating 3) on a mounting portion, wherein the carrier (42) is mounted on the mounting portion (35, 37a,
37b) moving means (33, 34, 38, 39) for moving the carrier (42) from the mounting position to a predetermined holding position, and when the carrier (42) is moved by the moving means (33, 34, 38, 39), Detecting means (40, 44a to 44d) for detecting load characteristics of the wafer (43) stored in the carrier (42), and load characteristics of the wafer (43) stored in the carrier (42) in advance. A predetermined number of patterns, and a control means for obtaining the housed state of the wafer (43) for the corresponding set load characteristic from the pattern of the load characteristic detected by the detection means (40, 44a to 44d). 41,4
1a, 41b), and a carrier holding device comprising: 2. The mounting means (35, 3)
7a, 37b) is moved from the mounting position to the holding position by a rotating member (33) which is rotated by a drive unit (38), and the detecting means detects a distortion of the rotating member (33). 2. The carrier holding device according to claim 1, wherein the carrier holding device comprises a strain detecting section (40) that operates. 3. The mounting means (35, 3)
7a, 37b) and the carrier (4
2) A predetermined number of piezoelectric members (44a-
The carrier holding device according to claim 1, wherein the carrier holding device is constituted by 44d). 4. The mounting means (35, 3)
7a, 37b) is moved from the mounting position to the holding position by a rotating member (33) which is rotated by a drive unit (38), and the detection means is configured to output the output value from the drive unit (38). The carrier holding device according to claim 1, wherein the carrier holding device is configured to detect. 5. A predetermined number of wafers (4
The carrier (42) accommodating 3) is a mounting part (35, 3) of the carrier holding device (31A-31C) according to claim 1.
7a, 37b) is mounted on the moving means (33, 34, 3)
8, 39) is a wafer detecting method of detecting the presence or absence of the wafer (43) in the carrier (42) by moving to a holding position by the detecting means (40) provided in the carrier holding device (31A to 31C). , 44a to 44d), the wafer (4
3) detecting the load characteristic corresponding to the storage state of the carrier (42), and a predetermined number of load characteristic patterns for the storage state of the wafer (43) in the carrier (42) are set in advance. A step of comparing and collating the load characteristic pattern detected by the detection means (40, 44a to 44d) with a predetermined number of set load characteristics; and the wafer (43) for the corresponding set load characteristics.
And a step of obtaining a storage state of the wafer. 6. The moving means includes the mounting portion (35, 37).
(a, 37b) is moved by rotating the rotating member (33) by the drive unit (38), and the load characteristic detected by the detecting means (40) is measured by the distortion of the rotating member (33). The wafer detection method according to claim 5, further comprising: 7. The load characteristic detected by the detection means (44a-44b) is detected from the pressure state of the carrier (42) on the mounting portion (35, 37a, 37b). Item 5. The wafer detection method according to item 5. 8. The moving means includes the mounting portion (35, 37).
(a, 37b) is moved by rotating the rotating member (33) by the drive unit (38), and the load characteristic detected by the detection means is detected from the output value from the drive unit (38). The wafer detection method according to claim 5, wherein: