JPH11163081A - Cassette mounting stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the type of a substrate in a cassette appropriately while increasing the degree of freedom in the direction for carrying the cassette into a stage or carrying out the cassette therefrom. SOLUTION: An H bar receiver 151 for positioning an H bar 121 on the cassette mounting face is disposed on the base stage 15 of a cassette mounting stage 1 and a unit 16 for detecting the H bar 121 is provided. The H bar receiver 151 is provided with recesses 151a-151d for positioning waters of respective size through the H bar 121. The detection unit 16 comprises members 163a-163d being oscillated by respective H bars 121 when they are fitted in respective recesses 151a-151d of the H bar receiver 151, and a sensor for detecting each member 163a-163d upon oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for processing a substrate such as a photomask substrate for producing a semiconductor integrated circuit, a semiconductor wafer or a glass substrate for a liquid crystal display, or a method for measuring a film thickness formed on these substrates. The present invention relates to a cassette mounting stage applied to a film thickness measuring device that performs the measurement.

[0002]

2. Description of the Related Art As a film thickness measuring apparatus for measuring the thickness of a transparent thin film formed on a substrate such as a semiconductor wafer, the present applicant has proposed an apparatus disclosed in Japanese Patent Application Laid-Open No. 8-320389. And filed.

This apparatus measures the thickness of a thin film formed on a semiconductor wafer (hereinafter abbreviated as a wafer), and includes a cassette mounting section (cassette mounting stage) on which a wafer cassette is mounted and a transfer means. , A measurement head for measuring a film thickness, and a measurement stage for holding a wafer to be measured by the measurement head.

According to this apparatus, a wafer stored in a cassette is transferred to a measurement stage while being taken out by a loader, and is arranged at a predetermined measurement position immediately below a measurement head to measure a film thickness. . When the film thickness measurement is completed, the film is picked up from the measurement stage by the loader and stored in the cassette again.

[0005]

In the above apparatus, the thickness of a plurality of types of wafers having different diameters (sizes) is measured by a single apparatus. Therefore, in order to control a loader or the like according to the size, a conventional apparatus is used. The operator inputs the size of the wafer via the operation unit.

[0006] However, in this case, there is a concern that a wafer may be damaged or a measurement failure may occur due to an input error or forgetting of input by the operator. For this reason, recently, for example, a light irradiating unit and a light receiving unit are provided with a cassette interposed, and a plurality of light transmitting sensors for detecting the cassette by blocking the irradiation light are provided side by side on the cassette mounting unit. The cassette size is detected by checking the presence / absence of detection by each sensor, thereby automatically detecting the wafer size.

However, in the case of this configuration, it is necessary to erect an arm or the like and arrange the light irradiating portions side by side above the cassette mounting portion, so that the cassette and the arm at the time of loading and unloading the cassette, or In order to avoid interference with the irradiation unit, there is a problem in that restrictions are imposed on the direction of loading and unloading the cassette with respect to the cassette mounting unit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is an object of the present invention to appropriately determine the type of a substrate in a cassette and to increase the degree of freedom in the direction of loading and unloading the cassette with respect to a stage. To provide a placement stage.

[0009]

In order to solve the above-mentioned problems, a cassette mounting stage according to the present invention is arranged such that a cassette containing substrates is positioned so that a substrate stored in the cassette can be taken out by a robot. A cassette mounting stage for mounting, a positioning means for positioning the cassette via a shape characteristic portion formed on the cassette mounting surface, and a detection means for detecting the shape characteristic portion of the positioned cassette Is provided, and the positioning means is configured to position the shape characteristic portion at a different position for each type of the substrate stored in the cassette,
The detecting means is configured to detect each cassette positioned by the positioning means (claim 1).

According to this apparatus, since the type of the substrate stored in the cassette and the position of the geometric characteristic portion of the positioned cassette are in one-to-one correspondence, the cassette is mounted on the stage. And the type of the substrate can be determined based on the detection of the shape characteristic portion by the detection unit.

[0011] In this case, the shape characteristic portion may be a leg projecting from the cassette mounting surface, and the positioning means and the detecting means may be configured to position and detect the leg. Item 2).

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a film thickness measuring apparatus to which a cassette mounting stage according to the present invention is applied.
The film thickness measuring device shown in FIG. 1 is a device for measuring the film thickness of a thin film formed on a semiconductor wafer, a cassette mounting stage 1 for mounting a wafer cassette, and an indexer for moving a wafer into and out of the wafer cassette. A measuring unit 3 for measuring the thickness of the wafer; The film thickness measuring apparatus according to this embodiment has a layout configuration in which the cassette mounting stage 1 and the measuring unit 3 are arranged around the indexer unit 2 around the indexer unit 2.

In the illustrated example, two cassette mounting stages 1 are provided, and each stage 1 has wafer cassettes 11 and 12 containing a plurality of wafers in multiple stages.
Each of them is placed with its storage opening facing the indexer unit 2. The specific configuration of the cassette mounting stage 1 will be described later in detail.

The indexer unit 2 includes an indexer robot 21 as a means for transferring wafers, and a center adjusting device 22 for correcting (centering) the center position of the wafers taken out of the wafer cassettes 11 and 12 by the indexer robot 21. Are provided.

The indexer robot 21 is a horizontally articulated robot that can move up and down, and a thin plate-like hand 211 for holding a wafer is mounted at the end of the arm. A suction hole 212 is opened on the surface of the hand 211, and a negative pressure is supplied through the suction hole 212 so that the hand 211 sucks and holds the wafer.

The center adjusting device 22 corrects the position of the wafer with respect to the hand 211, and includes a pair of chucks 221 which can be separated from each other.
The wafers taken out of the chucks 22
1, the position of the wafer is mechanically corrected by clamping in the radial direction.

The measuring section 3 has a measuring stage 4 serving as a portion for holding a wafer to be measured, and a measuring head 5 arranged on the measuring stage 4 for measuring a film thickness.

The measurement stage 4 has a six-axis table 41 for movably holding a wafer, a pre-alignment sensor 47, and an auxiliary stage 48 for holding the wafer on standby.
Are provided.

The six-axis table 41 has a disk-shaped holding plate 411 for holding a wafer by suction, and holds the disk in a six-axis direction, that is, an X-axis, a Y-axis, a Z-axis, and around these axes (θY direction, θX direction). The holding plate 41 includes a supporting mechanism 412 that supports the holding plate 41 so as to be displaceable in the
The wafer is transferred to and from the auxiliary stage 48 while the wafer 1 is moved in each of the above directions.
In addition, the wafer is arranged at a predetermined measurement position of the pre-alignment sensor 47.

The pre-alignment sensor 47 has a light irradiation unit 471 and a light receiving unit 472 arranged vertically above and below a predetermined inspection space. The pre-alignment sensor 47 has a wafer edge in the inspection space. Is rotated, the pre-alignment, that is, the eccentricity of the center of the wafer with respect to the center of the holding plate 411 is detected.

The auxiliary stage 48 is disposed between the indexer unit 2 and the six-axis table 41. In the illustrated example, the auxiliary stage 48 is the same as the supply stage 481 in which a wafer before measurement is placed on standby. And a discharge-side stage 482 that waits for the wafer after measurement.
Each of the stages 481 and 482 is formed in a substantially U-shape having a cutout for interposing the holding plate 411 as shown in FIG. The delivery of the wafer is performed under the holding plate 41 below the notch of the supply side stage 481.
1, the supply side stage 481 and the holding plate 4
11 is moved up and down relatively. On the other hand, the transfer of the wafer from the six-axis table 41 to the discharge side stage 482 is performed based on the reverse operation.

In FIG. 1, reference numeral 31 denotes an operation unit provided at the front of the apparatus for inputting various data and commands to the film thickness measuring apparatus by an operator. A monitor (not shown) for displaying various messages, information, and the like to the worker is provided above the monitor.

FIGS. 2 to 5 show a specific configuration of the cassette mounting stage 1. FIG. As shown in this figure,
Various members for positioning the wafer cassette are provided on the base 15 of the cassette mounting stage 1 (a cassette mounting stage on the front side of the apparatus on which the wafer cassette 12 is mounted).
A detection unit 16 (detection means) for detecting the placed wafer cassette 12 is provided.

Here, the positioning of the wafer cassette 12 on the cassette mounting stage 1 is generally performed by using a leg which is protruded from the mounting surface of this type of wafer cassette 12, specifically, FIG.
As shown by the one-dot chain line in FIG.
In FIG. 2, the middle part of the pair of vertical bars 121a extending in the Y-axis direction is perpendicular to the wafer loading / unloading direction (X in FIG. 2).
This is performed through legs called H-bars (H-bars 121; legs) connected by horizontal bars 121b extending in the axial direction), and the H-bars 121 are positioned as various members for positioning. A pair of H bar receivers 151
(Positioning means), a pair of back supports 152, and a pair of side faces 153 are provided.

The H-bar receiver 151 positions the wafer cassette 12 in the Y-axis direction.
As shown in FIG. 3, a concave portion is formed, and the horizontal bar 121b is interposed in the concave portion to position the wafer cassette 12 in the Y-axis direction. A plurality of the concave portions are formed in accordance with the size of the wafer cassette 12, that is, the size of the wafer. In the illustrated example, four concave portions corresponding to the wafer cassettes 12 for 4 inches, 5 inches, 6 inches, and 8 inches are provided. Recesses 151a-
151d are sequentially formed from the indexer unit 2 side (the left side in FIGS. 2 and 3). That is, the wafer cassette 1
By fitting the two horizontal bars 121b into the corresponding recesses 151a to 151d of the H bar receivers 151, the wafer cassette 12 can be positioned at a predetermined position in the Y-axis direction for each size.

The back support 152 is provided on each of the vertical bars 121a.
At the rear end (rear end in the wafer loading / unloading direction). Each back support 152 has a vertical bar 121a.
Is formed on the rear end of the wafer cassette 1 in cooperation with the H-bar receiver 151.
2 is positioned in the Y-axis direction.

The side contact 153 is the wafer cassette 1
2 is positioned in the X-axis direction. As shown in FIG. 2, the vertical bars 12 are positioned from both outer sides (both outer sides of the wafer cassette).
The wafer cassette 12 is provided so as to abut the wafer cassette 1a.

The H-bar receiver 151 and the back support 1
Although not shown, the 52 and the side contact 153 are fixed by bolts or the like via long holes formed in the base 15, and are provided so as to be displaceable within the range of the long holes. That is, when the size of the wafer to be measured is different, the outer shape of the wafer cassette is different.
The mounting position of the bar receiver 151 and the like can be changed. For example, FIG. 2 shows a state in which the wafer cassette 12 for 8 inches is placed, but when the wafer cassette 12 containing smaller wafers is placed, 151, each back support 152 and each side surface 153 are arranged closer to each other in the X-axis direction, and the back support 152 is moved and fixed to an arrangement closer to the indexer unit 2.

The detection unit 16 is disposed below the base 15 as shown in FIGS. 4 and 5, and is swingable on a support shaft 162 in the Y-axis direction supported via a frame 161. Swinging members 163a to 163 supported side by side
d, and sensors 167a to 167d for detecting the swing members 163a to 163d, respectively.

Each of the swinging members 163a to 163d has a detecting piece 164 at one end (right side in FIG. 5) with the support shaft 162 interposed therebetween, and a cylindrical contact 165 at the other end. By the coil spring 166 inserted through the shaft 162, the opening 165a of the base 15
Are protruded upward (the state shown by the solid line in FIG. 5). Here, as shown in FIG. 2, the opening 15a is a long hole in the Y-axis direction formed between the H-bar receivers 151, and each of the swing members 163a to 163d has one hole.
65 are concave portions 151a-1 of each H bar receiver 151, respectively.
They are arranged so as to be respectively located on line segments connecting 51d. Thereby, each swing member 163a-163d
Correspond to the recesses 151a to 151d.

Each of the sensors 167a to 167d has a light irradiating portion and a light receiving portion across the swing path of the detecting piece 164 in each of the swinging members 163a to 163d.
4 and the rocking members 163a to 163a-16
When the swing members 163a to 163d are caused to swing against the urging force of the coil spring 166, as shown by a dashed line in FIG. 163d is detected.

That is, the wafer cassette 12 is placed on the base 15, and the horizontal bars 121b of the cassette 12 are fixed to the predetermined recesses 151a to 151 of the H bar receiver 151 as described above.
When intervening at 51d, the corresponding hit 165 becomes the horizontal bar 1
21b.
3d is oscillated and detected by the sensors 167a to 167d. At this time, the size of the wafer, the wafer cassette 12 containing the wafer, and the concave portions 151a to
The position of 151d and the swing members 163a to 163d are
As described above, the wafer cassette mounted on the cassette mounting stage 1 is detected by detecting the rocking members 163a to 163d by the sensors 167a to 167d because of the one-to-one correspondence as described above. The size of the wafer 12 is detected.

In FIG. 2, reference numeral 154 denotes a back surface provided between the base 15 and the wafer cassette 12, and the wafer cassette 12 supports the base 1 via the back surface 154.
5. 15 per back
4 can also be changed in position according to the size.

The configuration of the cassette mounting stage on the front side of the apparatus for mounting the wafer cassette 12 has been described above.
The cassette mounting stage on the side of the apparatus on which the wafer cassette 11 is mounted has basically the same configuration.

Next, the film thickness measuring operation by the above film thickness measuring apparatus will be described based on the timing chart of FIG. 6 showing the flow of the wafer.

In the film thickness measuring apparatus, for example, the wafer cassettes 11 and 12 are carried onto the cassette mounting stage 1 by a transfer means (not shown). At this time, the wafer cassettes 11 and 12 hold the H bar receiver 151 and the back
It is mounted on the cassette mounting stage 1 while being positioned by 52 and 153 per side. The wafer size is detected by the detection unit 16 by positioning the wafer cassettes 11 and 12 in this manner, and the subsequent measurement operation of each unit is controlled based on the detected size.

First, the wafer (first wafer) taken out of the wafer cassette 11 or 12 by the indexer robot 21 is centered by the center adjusting device 22 as shown by the solid line in FIG. The hexagonal table 481 is transferred from the supply side stage 481 to the holding plate 411 of the six-axis table 41. After the wafer is detected (pre-aligned) by the pre-alignment sensor 47, the wafer is placed at a predetermined measurement position immediately below the measurement head 5 and the film thickness is measured.

While the pre-alignment and the film thickness measurement of the first wafer are being performed, the indexer robot 21 moves the next wafer from the wafer cassette 11 or 12 as shown by the one-dot chain line in FIG. The second wafer is taken out, centered by the center adjustment device 22, and mounted on the supply stage 481.

When the measurement of the film thickness of the first wafer is completed,
The wafer is moved from the six-axis table 41 to the discharge-side stage 482.
The wafer cassette 1 is then picked up from the discharge side stage 482 by the indexer robot 21 and transferred to the wafer cassette 1.
1 or 12. Thus, all the steps of measuring the film thickness of the first wafer are completed.

When the first wafer is transferred to the discharge stage 482 as described above, the holding plate 411
Is moved to the supply side stage 481 side, and the waiting wafer is transferred from the supply side stage 481 to the six-axis table 41. Then, in the same manner as the first wafer, pre-alignment and film thickness measurement of the second wafer are sequentially performed, and during that, the next wafer is moved by the indexer robot 21 as shown by a broken line in the figure. The (third wafer) is taken out of the wafer cassette 11 or 12.

After that, similarly, the pre-alignment and the film thickness measurement of the wafer and the transfer of the wafer into and out of the wafer cassette 11 or 12 are performed in parallel, and the film thickness measurement of the wafer stored in each of the wafer cassettes 11 and 12 is performed. Will be performed.

As described above, in the above-described film thickness measuring apparatus, the H bar receiver 1 is mounted on the base 15 of the cassette mounting stage 1.
Various members for positioning such as 51 and the detection unit 16 are provided, and while the wafer cassettes 11 and 12 are positioned, the swing members 163 a to 163 a through the H bar 121 are weighted by their weights.
63d is mechanically oscillated so that the wafer size can be detected from the mounting surface side of the wafer cassette 12, so that the arm stands on the cassette mounting stage 1 as in a conventional apparatus of this type. There is no need to provide a size detection sensor (light irradiation unit). Therefore, there is no restriction imposed on the loading / unloading direction of the wafer cassette as in the related art, and the degree of freedom in the loading / unloading direction of the cassette to / from the cassette mounting stage 1 can be effectively increased.

Further, the above device has an advantage that the assemblability is improved as compared with the conventional device. That is, in the conventional apparatus, the light irradiating section and the light receiving section are arranged to face each other with the cassette interposed therebetween, but if they do not properly face each other, the cassette cannot be accurately detected. Therefore, it is necessary to attach the irradiation unit and the light receiving unit with high accuracy, and the assembly is complicated. However, according to the device of the above embodiment, the swinging members 163a to 163a-1
As long as the contact 165 of 63d can be pushed down, there is no problem even if the H bar receiver 151 and the swing members 163a to 163d are slightly shifted from the designed positions. Therefore, when assembling the members for detecting the cassette size, such as the detection unit 16, high precision is not required, and the assemblability of the apparatus is improved.

In the above embodiment, the wafer cassettes 11, 12
The wafer cassettes 11 and 12 are positioned on the basis of the H bar 121 formed on the mounting surface, and the swing members 163a to 163d are swung by the H bar 121, in other words, the H members are swung by the swing members 163a to 163d. Although the cassette size is detected by detecting the bar 121, it is needless to say that the positioning is performed based on the other shape characteristic portions of the wafer cassettes 11 and 12, and based on the detection of the shape characteristic portion. The cassette size may be detected.

In the embodiment (FIG. 2), the swing members 163a to 163d are arranged side by side in the Y-axis direction.
The contact 165 is pushed below the base 15 by the horizontal bar 121b of the bar 121, and the swing members 163a to 163d are pushed.
The rocking members 163a to 163d are arranged side by side on the X axis, and the vertical bar 121a
Alternatively, the swing members 163a to 163d may be configured to swing.

In the above-described embodiment, an example in which the cassette mounting stage according to the present invention is applied to a film thickness measuring device has been described. For example, the present invention can be applied to a device that needs to be placed in a state where the cassette is positioned so that a substrate can be taken out by a robot, such as a substrate processing apparatus that performs a predetermined process on the surface of the substrate while taking out the substrate from the cassette.

[0047]

As described above, the cassette mounting stage of the present invention has a positioning means for positioning a characteristic shape portion formed on the cassette mounting surface, and a detecting means for detecting the characteristic shape portion of the cassette. And the positioning unit is configured to position the shape characteristic portion at a different position for each type of substrate stored in the cassette, and each of the cassettes positioned by the positioning unit is detected. Since the detection means is configured, the type of the substrate stored in the cassette can be determined from the mounting side of the cassette with a simple configuration.

Therefore, unlike the conventional stage of this type, in which the light irradiating section is provided above the cassette mounting portion, there is no restriction on the cassette loading / unloading direction, and the cassette loading / unloading direction to the stage is not limited. The degree of freedom can be effectively increased. In this case, the above-mentioned positioning means and detecting means can be configured so that the shape characteristic portion is a leg projecting from the cassette mounting surface, and the leg is positioned and detected.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a film thickness measuring apparatus to which a cassette mounting stage according to the present invention is applied.

FIG. 2 is a schematic plan view showing a cassette mounting stage.

FIG. 3 is a cross-sectional view taken along line AA of FIG. 2, showing a positioning state of a wafer cassette by an H bar receiver.

FIG. 4 is a schematic plan view showing a detection unit.

FIG. 5 is a sectional view taken along the line BB of FIG. 4 showing the detection unit.

FIG. 6 is a timing chart illustrating a flow of a semiconductor wafer in the film thickness measuring apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mounting stage (cassette mounting means) 11, 12 Wafer cassette 121 H bar 121a Vertical bar 121b Horizontal bar 15 Base 15a Opening 151 H bar receiver 151a to 151d Concave 152 Back surface receiver 153 Side surface 154 Back surface detection unit 16 163a to 163d swing member 164 detection piece 165 contact 167 sensor 2 indexer section 3 measurement section 4 measurement stage 5 measurement head

Claims (2)

[Claims] 1. A cassette mounting stage for mounting a substrate storing a cassette in a positioned state so that a substrate stored in the cassette is taken out by a robot, wherein the cassette mounting stage is formed on a cassette mounting surface. Positioning means for positioning the cassette via the characteristic portion, and detecting means for detecting the geometric characteristic portion of the positioned cassette, wherein the positioning means is located at a different position for each type of substrate stored in the cassette. A cassette mounting stage configured to position the geometric characteristic portion, wherein the detecting means is provided to detect each cassette positioned by the positioning means. 2. The method according to claim 1, wherein the shape characteristic portion is a leg protruding from the cassette mounting surface, and the positioning means and the detecting means are configured to position and detect the leg. The cassette mounting stage according to claim 1, wherein: