JP4058482B2 - Substrate holding device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a substrate holding apparatus that holds a substrate, and more particularly to a device that holds a substrate by vacuum suction.
[0002]
[Prior art]
Conventionally, when a substrate such as a silicon wafer, a liquid crystal panel substrate, a color filter substrate, or a TFT substrate is mounted on a chuck table in a semiconductor manufacturing apparatus, a measuring apparatus, an inspection apparatus, etc., the surface of the chuck table by vacuum suction using a vacuum chuck A substrate holding device for holding a substrate has been proposed.
[0003]
As an example of such a conventional substrate holding device, for example, a substrate holding device described in JP-A-10-218364 is cited. FIG. 8 shows a configuration example of the substrate holding device. The substrate holding apparatus includes a wafer holding stage 10, a base 11, a wafer holding unit 12, and a rotating shaft 16. The wafer holding stage 10 includes a disk-shaped base 11 and a wafer holding part 12 protruding upward from the periphery of the base 11, and the peripheral part of the wafer 1 is attracted to the wafer holding part 12. Is retained. More specifically, the wafer holding unit 12 is formed so as to extend along the entire periphery of the base 11, and the wafer holding unit 12 is formed with a suction groove 13 for sucking the wafer. ing. A suction path 14 is formed in the base 11 so as to extend in the radial direction of the base 11 and to communicate with both ends of the suction groove 13. The base 11 is provided with an unillustrated opening passage 15 (not shown) for communicating the space S between the wafer 1 and the base 11 surrounded by the wafer holder 12 with the outside air. It is formed so as to penetrate through.
[0004]
A rotation shaft 16 extending perpendicularly to the base 11 is provided on the lower surface of the base 11 in the wafer holding stage 10. The rotation shaft 16 extends along the axial direction and has one end thereof. An air passage 17 communicating with the suction passage 14 and having the other end opened to the outer peripheral surface of the rotary shaft 16 is formed. An appropriate suction device (not shown) is connected to the other end of the air passage 17. Yes. A motor 30 is provided at the lower end of the rotating shaft 16.
[0005]
In the wafer holding stage 10 described above, when the suction device is operated in a state where the wafer 1 is placed on the wafer holding unit 12, the suction groove 13 via the air passage 17 and the suction passage 14 of the rotating shaft 16. A negative pressure is applied to the wafer 1, and the wafer 1 is held by the peripheral portion of the wafer 1 being attracted to the wafer holder 12 by the suction force of the negative pressure. Here, the magnitude of the negative pressure applied to the suction groove 13 is, for example, 500 mmHg (260 mmHg as an absolute pressure). In the above, when a negative pressure is applied to the suction groove 13, the space between the wafer 1 and the base 11 is interposed through a slight gap between the back surface of the wafer 1 and the upper surface of the wafer holding unit 12. Although the air existing in S is sucked, this space S communicates with the outside air by an unillustrated opening passage 15 formed in the base 11, so that the space S between the wafer 1 and the base 11. Is reliably prevented from becoming a reduced pressure state.
[0006]
[Problems to be solved by the invention]
However, the conventional substrate holding apparatus having such a configuration only holds the outer edge portion of the wafer 1 and does not have a configuration for supporting the inner portion of the wafer holding portion 13 of the base 11 of the wafer 1. There is a problem that it is impossible to prevent the inner portion from being bent downward due to its own weight.
[0007]
The present invention has been made in consideration of the above points, and an object of the present invention is to provide a substrate holding device that can hold a substrate without being bent and further reduce the wafer back surface contact area.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a substrate holding apparatus according to the present invention includes a first bank portion that supports an outer edge portion of a substrate (for example, the bank portion 21 in the present embodiment), and the first bank portion. A second bank part (for example, bank part 22 in the present embodiment) provided on the inner side and formed lower by 10 to 20 μm than the first bank part, and the first bank part and the second bank part A vacuum suction means (for example, the vacuum pump 4 in the present embodiment) for vacuum-sucking the substrate via a vacuum path (for example, the vacuum path 25 in the present embodiment) provided between the sections, and the second bank And a pressurizing means (for example, the pressurizing pump 6 in the present embodiment) that pressurizes the inner region of the unit. With such a configuration, when the substrate is placed, the space surrounded by the lower surface of the substrate, the first bank portion, and the second bank portion is reduced by a vacuum pump via a vacuum path. It is possible to securely hold the substrate, and by pressurizing the space inside the second bank portion by the pressure pump through the air flow path, the substrate can be bent downward due to the decompressed state of the space or its own weight. Can be prevented. Further, since the upper surface of the second bank portion does not contact the wafer, the contact area with the wafer can be reduced and contamination of the wafer back surface can be more effectively suppressed.
[0009]
You may further provide the partition plate which divides the space between the said 1st bank part and the said 2nd bank part. The vacuum suction means vacuum-sucks the substrate by reducing the pressure between the first bank portion and the second bank portion partitioned by the partition plate. With this configuration, when a substrate with a notch or orientation flat is placed, even if a leak occurs from a part of the space corresponding to the notch, the remaining partition The substrate can be held by the formed space.
[0010]
Further, a rotating means for rotating a substrate having a notch or an orientation flat at the outer edge, an irradiating means for irradiating a laser beam to the substrate rotated by the rotating means, and reflection of the laser beam irradiated by the irradiating means Detection means for detecting the rotation angle or substrate position of the substrate by receiving light and detecting the position of the notch of the substrate or the outer periphery of the wafer may be provided. With such a configuration, it is possible to confirm the rotation angle of the wafer and whether or not the substrate is accurately placed on the chuck.
[0011]
The substrate described above may be a wafer. With such a configuration, the substrate holding apparatus according to the present invention can be used for a wafer.
[0012]
The substrate described above may be a liquid crystal panel substrate. With such a configuration, the substrate holding device according to the present invention can be used for a liquid crystal panel substrate.
[0013]
The substrate described above may be a color filter substrate. Such a configuration can also be used for a color filter substrate.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration of a substrate holding apparatus according to the present embodiment. As shown in FIG. 1, the substrate holding device includes a chuck 2, a chuck base 3, a vacuum pump 4, a pressure regulator 5, and a pressure pump 6.
[0015]
The chuck 2 is a plate-shaped member made of, for example, silicon, and as shown in FIG. 1, a ring-shaped first bank portion 21 that supports the wafer 1 is provided on the upper surface, and a bank portion is provided inside the bank portion 21. A second bank portion 22 that is formed to be lower by about 10 μm than 21 is provided. The wafer 1 is placed on the upper surface of the bank portion 21. A vacuum path 25 is provided between the bank portions 21 and 22. The vacuum path 25 communicates with the chuck base 3 and is further connected to the vacuum pump 4. By reducing the space between the bank portion 21 and the bank portion 22 via the vacuum path 25 by the vacuum pump 4, the wafer 1 can be held on the upper surface of the bank portion 21 by vacuum suction. In addition, vacuum adsorption means adsorption | suction by decompressing a certain sealed space below to external pressure. Further, the chuck 2 is provided with an air flow path 26 at a portion inside the bank portion 22. The air flow path 26 is connected to the pressurizing pump 6 through the pressure regulator 5. It is possible to pressurize the inside of the space 23 by sending gas into the space 23 surrounded by the wafer 1, the bank portion 22 and the upper surface of the chuck 2 through the air flow path 26 and the pressure regulator 5 by the pressurizing pump 6. By pressurizing the inside of the space 23, it is possible to prevent the wafer 1 from being bent downward due to the reduced pressure state or the own weight of the space 23.
[0016]
FIG. 2 is an enlarged cross-sectional view of the main part A in FIG. As shown in FIG. 2, the bank portion 22 is formed to be, for example, about 10 μm lower than the bank portion 21, so that a gap is formed between the lower surface of the wafer 1 and the upper surface of the bank portion 22.
[0017]
FIG. 3 shows a plan view of the wafer 1. As shown in FIG. 3, the wafer 1 is supported with its outer edge in contact with the upper surface of the bank portion 21, and has a portion constituting a gap with the bank portion 22 inside thereof.
[0018]
Although the surface of the chuck table 3 is mirror-finished so as to reflect a beam output from a beam output device 21 described later, the chuck table 3 may be a scattering object.
[0019]
The vacuum pump 4 has a function of depressurizing the space 24 surrounded by the bank portions 21 and 22 and the lower surface of the wafer 1 by taking in air through the vacuum path 25.
[0020]
The pressure regulator 5 has a function of controlling the pressure of the gas applied from the pressurization pump 6 through the airflow path 26. The pressurizing pump 6 is configured by, for example, a motor or the like, and can pressurize the space 23 by sending a gas such as outside air through the airflow path 26.
[0021]
Here, the wafer 1 is accurately placed on the chuck 2 as follows, for example.
[0022]
First, the substrate holding apparatus in the present embodiment is provided with an LD (laser diode) 31, a condenser lens 32, a reflecting means 33, and a PD (photodiode) 34. In addition, as shown in FIG. 5, the wafer 1 is provided with a notch 13 which is a notched portion at the outer edge portion. The notch 13 has a width and length of about 1 mm, for example. The chuck table 3 is provided with a rotation mechanism (not shown).
[0023]
The LD 31 has a function of outputting a laser beam for detecting the position of the wafer 1. The condensing lens 32 can concentrate the laser beam output from the LD 31 on one point on the wafer 1. The reflection means 33 can guide the laser beam reflected from the upper surface of the wafer 1 or the chuck table 3 in one direction.
[0024]
The PD 34 has a function of detecting a reflected signal of the laser beam guided by the reflecting means 33. The LD 31, the condenser lens 32, the reflecting means 33, and the PD 34 are installed at two places on the inspection optical axis above the wafer 1 and on the notch detection optical axis as shown in FIG.
[0025]
When the wafer 1 is placed on the chuck 2, each LD 31 provided on the inspection optical axis and the notch detection optical axis outputs a laser beam. Further, a rotation mechanism (not shown) provided on the chuck table 3 operates to rotate the chuck table 3, the chuck 2, and the wafer 1 together, whereby the outer edge portion of the wafer 1 is scanned by the laser beam. Then, the PD 34 on the inspection optical axis detects a reflection signal of a laser beam scanned on the upper surface of the wafer 1. The PD 34 on the notch detection optical axis is gradually lowered by the edge portion of the wafer 1 as shown in FIG. 6 by the laser beam scanned on the notch 13 portion, and further gradually rises by reflecting the upper surface of the chuck base 3. The reflected signal is detected. The PD 34 on the notch detection optical axis detects the position of the notch 13 based on the data path of the reflected signal, thereby detecting the position of the wafer 1 and confirming that it is accurately placed on the chuck 2.
[0026]
Next, the effect produced when the board | substrate holding | maintenance apparatus concerning this Embodiment has the above structures is demonstrated. First, when the wafer 1 is placed on the chuck 2, the space 24 surrounded by the lower surface of the wafer 1, the inner peripheral surface of the bank portion 21, the outer peripheral surface of the bank portion 22, and the outer edge portion of the upper surface of the chuck 2 is sealed. Therefore, the wafer 1 can be reliably held on the upper surface of the chuck 2 by operating the vacuum pump 4 and depressurizing the space 24 via the vacuum path 25.
[0027]
At this time, the air present in the space 23 is taken into the vacuum pump 4 through a gap formed by the lower surface of the wafer 1 and the upper surface of the bank portion 22. By pressurizing via the regulator 5 and the airflow path 26, the space 23 can be prevented from being depressurized. For this reason, it is possible to prevent the wafer 1 from being bent downward due to the decompressed state of the space 23. Further, the pressure state of the space 23 is adjusted by the pressure regulator 5 and the pressure pump 6, and the wafer 1 is pushed up from below by applying pressure equal to or higher than the atmospheric pressure, so that the bank 22 of the wafer 1 is pushed up. It is possible to prevent the inner portion from bending downward due to the reduced pressure or the dead weight of the space 23. Therefore, it is possible to hold the wafer 1 without the surface being bent. Further, since only the outer edge portion of the wafer 1 is supported by the bank portion 21, for example, when the wafer 1 is placed on the entire upper surface area of the chuck 2, dust and dust on the upper surface of the chuck 2 are not in contact with the wafer 1. There is no problem of contamination of the wafer 1 due to being pinched. In particular, since the wafer 1 and the chuck 2 are in contact with only the bank portion 21 and are not in contact with the inner bank portion 22, the contact area is smaller and the occurrence of contamination can be suppressed.
[0028]
Since the gap between the lower surface of the wafer 1 and the upper surface of the bank portion 22 is configured to be about 10 μm and is narrow, only a small amount of air flows into the space 24 from this gap, and the reduced pressure state of the space 24 changes abruptly. Thus, the holding of the wafer 1 is not released. The wafer 1 is continuously held by vacuum suction by the vacuum pump 4.
[0029]
According to the substrate holding apparatus in the present embodiment as described above, the wafer 1 can be reliably held on the upper surface of the bank portion 21 by reducing the pressure of the space 24 by the vacuum pump 4. Further, by pressurizing the space 23 with the pressurizing pump 6, it is possible to prevent a portion inside the bank portion 22 of the wafer 1 from being bent downward due to a reduced pressure state or its own weight of the space 23, so that the surface is not bent. It is possible to hold the wafer 1. Further, since the gap between the lower surface of the wafer 1 and the upper surface of the bank portion 22 is narrow and the amount of air flowing out is small, it is possible to hold the wafer 1 continuously and reliably even when the space 23 is pressurized. .
[0030]
Other embodiments.
In the substrate holding apparatus in the above-described embodiment, the space 23 is divided into a plurality of spaces by a partition plate connected to the bank portions 21 and 22, as shown in FIG. A vacuum path 25 and a vacuum pump 4 may be provided for each of a plurality of spaces to perform vacuum suction. Further, vacuum suction may be performed by the vacuum pump 4 in a space selected from these divided spaces. In this case, there is a leak from the notch or the orientation flat part, and even if the suction pressure in a part of the divided space is reduced, the remaining part can be vacuum-sucked, so only the outermost part of the wafer contacts. Can be a design.
[0031]
In order to prevent only the deflection of the wafer 1 due to its own weight, the vacuum pump 4 may not be held by vacuum suction of the wafer 1 but only the space 23 may be pressurized by the pressure pump 6. .
[0032]
The air flow path 26, the pressure regulator 5, and the pressure pump 6 can be provided at any location inside the bank portion 22 as long as the space 23 of the wafer 1 can be prevented from being bent due to the reduced pressure state or its own weight. It is also possible to provide a plurality.
[0033]
Further, if the space 24 of the wafer 1 can be in a reduced pressure state, the vacuum path 25 and the vacuum pump 4 can be provided at any location between the bank portions 21 and 22. It is also possible to provide a plurality.
[0034]
The wafer 1 can also be a polycrystalline silicon, a glass wafer, a SiC wafer, a compound wafer (for example, GaAs, GaP, etc.), a glass substrate of a liquid crystal display device, or the like.
[0035]
A plurality of vacuum paths 23 and air flow paths 25 may be provided.
[0036]
The substrate holding device in the above-described embodiment is not limited to the wafer 1 and can be used for a liquid crystal panel substrate, a color filter, and the like. When used for a liquid crystal panel substrate, for example, a portion below the liquid crystal panel substrate of the chuck 2 is formed of a transparent member such as a plate glass, thereby allowing the entire surface to be illuminated.
[0037]
The pressure regulator 5 may include a filter for removing dust, dust and the like in the airflow.
[0038]
【The invention's effect】
As described above, the substrate holding device of the present invention can hold a substrate without the surface being bent.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a substrate holding device in an embodiment of the invention.
FIG. 2 is an enlarged cross-sectional view showing a main part A of the substrate holding device in the embodiment of the invention.
FIG. 3 is a diagram showing a wafer 1 of a substrate holding device in an embodiment of the invention.
FIG. 4 is a configuration diagram showing a configuration for detecting a notch 13 of a substrate holding device in an embodiment of the invention.
FIG. 5 is a diagram showing an inspection optical axis and a notch detection optical axis of the substrate holding device in the embodiment of the invention.
FIG. 6 is a diagram showing a data path of a reflected signal of a laser beam in the substrate holding device in the embodiment of the invention.
FIG. 7 is a configuration diagram showing a chuck 2 according to another embodiment.
FIG. 8 is a configuration diagram showing a conventional substrate holding apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wafer 2 Chuck 3 Chuck base 4 Vacuum pump 5 Pressure regulator 6 Pressure pump 10 Wafer holding stage 11 Base 12 Wafer holding part 13 Suction groove 14 Suction path 15 Opening path 16 Rotating shaft 17 Air path 21 Bank part 22 Bank portion 23, 24 Space 25 Vacuum path 26 Airflow path 30 Motor 31 LD 32 Condensing lens 33 Reflecting means 34 PD

Claims (6)

A first bank for supporting the outer edge of the substrate;
A second bank portion provided inside the first bank portion and formed lower by 10 to 20 μm than the first bank portion;
A vacuum suction means for vacuum-sucking the substrate by decompressing the space between the first bank portion and the second bank portion;
A substrate holding apparatus comprising pressurizing means for pressurizing a region inside the second bank portion.   A partition plate for partitioning a space between the first bank portion and the second bank portion;
  2. The substrate holding according to claim 1, wherein the vacuum suction unit decompresses each of the spaces between the first bank portion and the second bank portion partitioned by the partition plate to vacuum-suck the substrate. apparatus. A rotating means for rotating a substrate having a notch or an orientation flat at the outer edge;
Irradiating means for irradiating the substrate rotated by the rotating means with a laser beam;
2. A detection unit that receives reflected light of the laser beam irradiated by the irradiation unit and detects a rotation angle of the substrate or a substrate position by detecting a position of the notch of the substrate or the outer periphery of the wafer. 3. The substrate holding device according to 2.   The substrate holding apparatus according to claim 1, wherein the substrate is a wafer.   The substrate holding apparatus according to claim 1, wherein the substrate is a liquid crystal panel substrate.   The substrate holding apparatus according to claim 1, wherein the substrate is a color filter substrate.

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