WO2007018350A1

WO2007018350A1 - Apparatus for sensing substrate

Info

Publication number: WO2007018350A1
Application number: PCT/KR2006/002337
Authority: WO
Inventors: Joung-Shin Kim
Original assignee: Joung-Shin Kim
Priority date: 2005-08-08
Filing date: 2006-06-19
Publication date: 2007-02-15
Also published as: TW200706477A; KR100658520B1; CN101258437A; JP2009503885A; KR20060069417A; TWI302140B

Abstract

Provided is a substrate detection apparatus. The substrate detection apparatus includes: a sensor support frame disposed adjacent to a vertically elongated cassette in which a plurality of substrates are stacked; and a plurality of ultrasonic sensors installed at one surface of the sensor support frame, emitting ultrasonic waves in parallel to the substrates, and detecting the ultrasonic waves reflected by the substrates to detect the presence of each substrate. Therefore, since an operation for detecting whether substrates such as glass substrates or wafers are positioned in a cassette can be simplified, the detection process can be sped up.

Description

APPARATUS FOR SENSING SUBSTRATE

Technical Field

[1] The present invention relates to an apparatus for sensing a substrate, and more particularly, to an apparatus for sensing a substrate capable of detecting presence of a glass substrate or a wafer using an ultrasonic sensor. Background Art

[2] Generally, a liquid crystal display has a liquid crystal material, which is an intermediate material between solid and liquid, injected between two thin glass substrates. Arrangement of liquid crystal molecules is varied using a voltage difference to form light and darkness, thereby forming an image.

[3] In the manufacturing process of the liquid crystal display, a plurality of glass substrates are stacked in a cassette to be conveyed to an apparatus for performing a predetermined process using a glass substrate conveyance device. In order to accurately and rapidly convey the glass substrates, a glass substrate detection device should determine whether the glass substrates are stacked in the cassette at predetermined positions.

[4] FIG. 1 illustrates an example of a conventional glass substrate detection apparatus.

[5] As shown in FIG. 1, a cassette 10 is formed to have a hexahedron shape in which both sides are open opposite to each other, and a plurality of glass substrate support stages 11 are installed at front and rear surfaces of the cassette 10 at heights corresponding to each other. The glass substrate support stages 11 support a periphery of a lower surface of a glass substrate G so that the glass substrate G is horizontally stacked in the cassette 10.

[6] In addition, a glass substrate detection device 20 is installed adjacent to one surface

(a left side surface in FIG. 1) of both open sides of the cassette 10. The glass substrate detection device 20 functions to detect whether there are glass substrates G stacked in the cassette, and includes a sensor support frame 21 and a plurality of infrared sensors 23 installed at one surface of the sensor support frame 21.

[7] The sensor support frame 21 has a vertically elongated rectangular parallelepiped shape, and a height corresponding to that of the cassette 10. In addition, the sensor support frame 21 is disposed adjacent to the open surface of the cassette at its one side having the infrared sensor 23, which is installed movably toward the cassette 10 by a moving means (not shown).

[8] Meanwhile, the plurality of infrared sensors 23 are installed at one surface of the sensor support frame 21, between the glass substrate support stages 11 at pre- determined intervals. That is, the infrared sensors 23 are disposed under the glass substrates G, respectively, as the sensor support frame 21 moves toward the cassette 10. Then, the infrared sensor 23 emits infrared light to a lower surface of the glass substrate G and detects infrared light reflected by the glass substrate G to detect the presence of the glass substrate G.

[9] Hereinafter, a process of detecting a glass substrate G using a conventional glass substrate detection device 20 will be described in detail.

[10] First, the cassette 10 on which the glass substrate G is stacked is moved to be adjacent to the glass substrate detection device 20 at its open surface. In this state, the sensor support frame 21 is moved to the cassette 10 such that the infrared sensor 23 is disposed under the glass substrate G.

[11] Then, the infrared sensor 23 emits infrared light to a lower surface of the glass substrate G to detect the infrared light reflected by the glass substrate G and thereby detect the presence of the glass substrate G. Here, the infrared sensor 23 emits the infrared light perpendicular to the glass substrate G.

[12] For example, when the glass substrate G corresponding to any one of the infrared sensors 23 is not stacked in the cassette 10, the infrared light emitted from the infrared sensor 23 is reflected by the glass substrate G corresponding to the infrared sensor 23 positioned one level above and then detected. Here, it takes slightly more time for the infrared sensor 23 whose glass substrate G is absent to detect light reflected from the glass substrate G one level above.

[13] However, the conventional glass substrate detection device 20 has the following problems.

[14] As described above, the cassette 10 moves to be adjacent to the sensor support frame 21, and then the sensor support frame 21 moves to the cassette 10. That is, since the cassette 10 and the sensor support frame 21 both move toward each other, the overall operation for detecting the glass substrate G is overly complicated.

[15] In addition, movement of the sensor support frame 21 causes the infrared sensor 23 to be inserted between the glass substrates G through the open surface of the cassette 10 and thus disposed under the glass substrate G. In this process, the infrared sensor 23 may collide with one side of the cassette 10 or the glass substrate G causing damage. Disclosure of Invention Technical Problem

[16] In order to solve the foregoing and/or other problems, the present invention provides an apparatus for detecting a substrate capable of more simple operation.

[17] The present invention also provides an apparatus for detecting a substrate capable of minimizing damage of a product. [18] The present invention also provides an apparatus for detecting a substrate capable of more simple operation and minimizing damage of a product.

Technical Solution [19] One aspect of the invention provides an apparatus for detecting a substrate including: a sensor support frame disposed adjacent to a vertically elongated cassette in which a plurality of substrates are stacked; and a plurality of ultrasonic sensors installed at one surface of the sensor support frame, emitting ultrasonic waves in parallel to the substrates, and detecting the ultrasonic waves reflected by the substrates to detect the presence of each substrate. [20] In another embodiment, each ultrasonic sensor may be disposed in the same level as a corresponding substrate. [21] In still another embodiment, the substrate detection apparatus may further include a pair of fixing brackets for fixing the sensor support frame at a predetermined position. [22] In yet another embodiment, the ultrasonic sensors may be vertically disposed at one surface of the sensor support frame in a longitudinal direction at predetermined intervals. Here, the substrates may be wafers. [23] Another aspect of the invention provides an apparatus for detecting a glass substrate including: a sensor support frame disposed adjacent to a vertically elongated cassette in which a plurality of glass substrates are stacked; and a plurality of ultrasonic sensors installed at one surface of the sensor support frame, emitting ultrasonic waves in parallel to the glass substrates, and detecting the ultrasonic waves reflected by the glass substrates to detect existence of each glass substrate. [24] In another embodiment, each ultrasonic sensor may be disposed in the same level as corresponding glass substrate. [25] In still another embodiment, the glass substrate detection apparatus may further include a pair of fixing brackets for fixing the sensor support frame at a predetermined position.

Advantageous Effects

[26] As can be seen from the foregoing, a substrate detection apparatus in accordance with the present invention may have the following advantages.

[27] First, a cassette in which a substrate such as a glass substrate or a wafer is stacked is disposed adjacent to the substrate detection apparatus fixed at a predetermined position, and ultrasonic waves having a predetermined frequency are emitted to the cassette, thereby enabling detection of whether the substrate is stacked in the cassette. Therefore, since an operation for detecting the substrate can be simplified, the detection of the substrate can be performed quickly. Since it is possible to rapidly detect the presence of the substrate using the substrate detection apparatus, detection process efficiency can be increased.

[28] Second, the substrate detection apparatus in accordance with the present invention includes an ultrasonic sensor for detecting the presence of a substrate such as a glass substrate or a wafer, the sensor disposed adjacent to one surface of the periphery of the substrate rather than between substrates. Therefore, it is possible to prevent damage of the substrate during the process of detecting the presence of the substrate. In addition, since there is no need to use a separate moving device such as is used in the conventional substrate detection apparatus, overall manufacturing cost can be reduced Brief Description of the Drawings

[29] The above and other aspects and advantages of the present invention will become more apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which:

[30] FIG. 1 is a cross-sectional view of an example of a conventional glass substrate detection apparatus;

[31] FIG. 2 is an exploded perspective view of a substrate detection apparatus in accordance with an exemplary embodiment of the present invention;

[32] FIG. 3 is a cross-sectional view of a first embodiment of the substrate detection apparatus shown in FIG. 2;

[33] FIG. 4 is a perspective view of a second embodiment of the substrate detection apparatus shown in FIG. 2; and

[34] FIG. 5 is a perspective view of a third embodiment of the substrate detection apparatus shown in FIG. 2.

[35] * Description of Major Symbols in the above Figures

[36] 30: substrate detection apparatus

[37] 31 : sensor support frame

[38] 33: ultrasonic sensor

[39] 35: fixing bracket

Best Mode for Carrying Out the Invention

[40] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification and drawings.

[41] FIG. 2 is an exploded perspective view of an apparatus for detecting a substrate in accordance with an exemplary embodiment of the present invention.

[42] As shown in FIG. 2, a substrate detection apparatus 30 in accordance with the present invention includes a sensor support frame 31, ultrasonic sensors 35 installed at the sensor support frame 31 to detect a substrate, and a control unit 37 installed in the sensor support frame 31 and entirely controlling the substrate detection apparatus 30. The substrate detection apparatus functions to rapidly detect a plurality of substrates stacked in a cassette, and so on. The substrates may be glass substrates for liquid crystal displays, or wafers for manufacturing semiconductor devices. Ultimately, the substrate detection apparatus 30 may be used as a glass substrate detection apparatus or a wafer detection apparatus.

[43] More specifically, the sensor support frame 31 is formed to have a rectangular parallelepiped shape, which is elongated in a longitudinal direction, i.e., vertically. In addition, the sensor support frame 31 has a hollow structure for accommodating the control unit 37 therein. Meanwhile, the sensor support frame 31 may be fixed at a predetermined position by separate fixing brackets 33. In an embodiment, the fixing brackets 33 may be fastened to upper and lower ends of the sensor support frame 31, respectively. Therefore, the sensor support frame 31 may be fixed at a predetermined position or predetermined equipment by the fixing brackets 33. For example, the sensor support frame 31 may be fixed at a predetermined position or predetermined equipment by the fixing brackets 33 vertically. In addition, the sensor support frame 31 may have a plurality of fastening holes 32 at its side surfaces. In this case, the sensor support frame 31 may be fastened to a predetermined position or predetermined equipment through the medium of the plurality of fastening holes 32, and the fixing brackets may be omitted.

[44] The ultrasonic sensors 35 are installed at one surface of the sensor support frame 31 to detect a substrate stacked in a cassette. In an embodiment, the ultrasonic sensors 35 may be installed at one surface of the sensor support frame 31 in a longitudinal direction. In addition, the ultrasonic sensors 35 may be installed such that one sensor detects one substrate. Therefore, ultrasonic sensors 35 numbering the same as the maximum number of substrates stacked in the cassette may be installed at the sensor support frame 31 to detect the substrates stacked in the cassette at the same time. The number of ultrasonic sensors 35 installed at one surface of the sensor support frame 31 may vary depending on the size of the cassette or equipment.

[45] In addition, the plurality of ultrasonic sensors 35 installed at the sensor support frame 31 may be disposed in the same manner as the substrates stacked in the cassette such that the sensors correspond one-to-one with the substrates stacked in the cassette. For example, when the substrates are stacked in the cassette in the longitudinal direction, i.e., vertically, the plurality of ultrasonic sensors 35 may also be disposed vertically along the length of the sensor support frame 31. In this case, the sensor support frame 31 may be fixed vertically at a predetermined position or predetermined equipment by the fixing brackets 33 and the fastening holes 32. In addition, when the substrates are stacked in the cassette horizontally, i.e., in a lateral direction, the plurality of ultrasonic sensors 35 may be disposed horizontally. In this case, the sensor support frame 31 may be fixed horizontally at a predetermined position or predetermined equipment by the fixing brackets 33 or the fastening holes 32.

[46] Further, the ultrasonic sensor 35 emits ultrasonic waves to the substrate stacked in the cassette, and detects the ultrasonic waves reflected by the substrate, thereby detecting the presence of the substrate. In an embodiment, when the ultrasonic sensor emits ultrasonic waves to a predetermined position where the substrate is supposed to be positioned, and the ultrasonic waves are reflected by the substrate and detected by the ultrasonic sensor 35, the presence of the substrate at the predetermined position is detected on the basis on a detected value. However, when the ultrasonic waves do not return within a predetermined time to be detected, the absence of the substrate at the predetermined position is detected. In this process, the ultrasonic sensor 35 is disposed on the same level, i.e., in the same plane, as the substrate, and spaced apart from one surface (referred to as a sidewall) of the periphery of the substrate by a predetermined distance. Therefore, the ultrasonic sensor 35 emits ultrasonic waves to one surface of the periphery of the substrate in parallel to the substrate to detect the substrate. The ultrasonic waves emitted from the ultrasonic sensor 35 may have a frequency of hundreds of kHz, for example, 400 ~ 800 kHz, such that the ultrasonic sensor 35 can detect its corresponding thin substrate only, without interference from other substrates.

[47] Meanwhile, the control unit 37 is electrically connected to the plurality of ultrasonic sensors 35 to entirely control the substrate detection apparatus 30. Specifically, the ultrasonic sensor 35 functions to emit a predetermined frequency of ultrasonic waves to the substrate stacked in the cassette and detects the ultrasonic waves reflected by the substrate to detect the presence of the substrate. And, the control unit 37 is connected to the ultrasonic sensor 35 to detect the presence of the substrate, display the detection value to the exterior, or transmit the detection value to another device. In addition, the control unit 37 may selectively drive the plurality of ultrasonic sensors 35 on the basis of the predetermined value or a predetermined signal input from the exterior. In this case, the substrate detection apparatus 30 may be linked to another external apparatus.

[48] A reference numeral S designates a fastening hole for fixing the fixing brackets 33 to a predetermined position or predetermined equipment.

[49] Various embodiments of the substrate detection apparatus in accordance with the present invention will be described below in detail.

[50] FIG. 3 is a cross-sectional view of a first embodiment the apparatus for detecting a substrate shown in FIG. 2.

[51] As shown in FIG. 3, the substrate detection apparatus 30 in accordance with the present invention may be used to detect a glass substrate G used in a liquid crystal display. That is, the substrate detection apparatus 30 in accordance with the present invention may be used as a glass substrate detection apparatus. In this case, an ultrasonic sensor 35 installed in the substrate detection apparatus 30 emits ultrasonic waves having a frequency of about 400 kHz corresponding to a thin glass substrate G, to the glass substrate G to detect the glass substrate G.

[52] First, a cassette 10 is prepared to stack a plurality of glass substrates G to detect the glass substrates G using the substrate detection apparatus 30 of the present invention. At this time, the plurality of glass substrates G are supported by glass substrate support stages 11 installed in the cassette 10 to be horizontally stacked in the cassette 10.

[53] Then, the cassette 10 on which the glass substrates G are stacked is moved to a position adjacent to the substrate detection apparatus 30 fixed at a predetermined position. At this time, an open surface of the cassette 10 is directed to the ultrasonic sensor 35 of the substrate detection apparatus 30, and the ultrasonic sensor 35 is spaced apart from one surface of the periphery of the glass substrate G by a predetermined distance.

[54] Next, when the cassette 10 is disposed adjacent to the substrate detection apparatus

30, the ultrasonic sensor 35 is driven under the control of the control unit 37 to emit ultrasonic waves having a frequency of about 400 kHz to one surface of the periphery of the glass substrate G. When the ultrasonic waves emitted from the ultrasonic sensor 35 are incident on one surface of the periphery of the glass substrate G and reflected to the ultrasonic sensor 35, the ultrasonic sensor 35 detects the reflected ultrasonic waves to detect that the glass substrate G is stacked at the predetermined position in the cassette 10. However, when the glass substrate G is not stacked on a glass substrate support stage 11 of the glass substrate support stages 11 installed at the cassette 10, the ultrasonic waves emitted from the ultrasonic sensor 35 corresponding to the glass substrate G continue to propagate without reflection. Therefore, the ultrasonic waves are not detected by the ultrasonic sensor 35, and it is detected that the glass substrate G is not positioned on the glass substrate support stage l l's in the cassette 10.

[55] Meanwhile, when the ultrasonic waves are not detected by the ultrasonic sensor 35 thus determining absences of the glass substrate G, the control unit 37 connected to the ultrasonic sensor 35 displays the detection value to the exterior, or transmits the detection value to another apparatus. Then, a user or a glass substrate supply device recognizes that the glass substrate G is not stacked on the glass substrate support stage 11 through the displayed value or the transmitted value, and additionally stacks the glass substrate G on the glass substrate support stage 11'. [56] When the cassette 10 is full of glass substrates G, the detection procedure is complete and the cassette 10 is loaded into an apparatus for performing another process.

[57] Meanwhile, FIGS. 4 and 5 show other examples of the substrate detection apparatus in accordance with the present invention.

[58] FIG. 4 is a perspective view of a second embodiment of the apparatus for detecting a substrate shown in FIG. 2, and FIG. 5 is a perspective view of a third embodiment of the apparatus for detecting a substrate shown in FIG. 2.

[59] As shown in FIGS. 4 and 5, the substrate detection apparatus 30 in accordance with the present invention may be used to detect a wafer W used for manufacturing a semiconductor device. That is, the substrate detection apparatus 30 in accordance with the present invention may be used as a wafer detection apparatus. In this case, an ultrasonic sensor 35 installed in the substrate detection apparatus 30 emits ultrasonic waves having a frequency of about 800 kHz corresponding to a thin wafer W, to the wafer W to detect the wafer W. In addition, the substrate detection apparatus 30 in accordance with the present invention is disposed in front of a cassette 40, in which the wafer W is stacked, as show in FIG. 4, to detect the wafer W stacked in the cassette 40 in a forward direction (A direction of FIG. 4). Alternatively, the substrate detection apparatus 30 may be disposed at the back of a cassette 40, in which the wafer W is stacked, as show in FIG. 5, to detect the wafer W stacked in the cassette 40 in a backward direction (B direction of FIG. 5).

[60] First, a cassette 40 is prepared to stack a plurality of wafers W to detect the wafers

W using the substrate detection apparatus 30 of the present invention. The plurality of wafers W are supported by wafer support stages 41 installed in the cassette 40 to be horizontally stacked in the cassette 40.

[61] Then, the cassette 40 on which the wafers W are stacked is moved to a position adjacent to the substrate detection apparatus 30 fixed at a predetermined position. At this time, an open surface of the cassette 40 is directed to the ultrasonic sensor 35 of the substrate detection apparatus 30, and the ultrasonic sensor 35 is spaced apart from one surface of the periphery of the wafer W by a predetermined distance.

[62] Next, when the cassette 40 is disposed adjacent to the substrate detection apparatus

30, the ultrasonic sensor 35 is driven under the control of the control unit 37 to emit ultrasonic waves having a frequency of about 800 kHz to one surface of the periphery of the wafer W. Therefore, when the ultrasonic waves emitted from the ultrasonic sensor 35 are incident on one surface of the periphery of the wafer W to be reflected to the ultrasonic sensor 35, the ultrasonic sensor 35 detects the reflected ultrasonic waves to detect that the wafer W is stacked at the predetermined position of the cassette 40. However, when the wafer W is not stacked on a wafer support stage 41 of the wafer support stages 41 installed at the cassette 40, the ultrasonic waves emitted from the ultrasonic sensor 35 corresponding to the wafer W continue to propagate without reflection. Therefore, the ultrasonic waves are not detected by the ultrasonic sensor 35, and it is determined that the wafer W is not positioned on the wafer support stage 41' in the cassette 40.

[63] Meanwhile, when the ultrasonic waves are not detected by the ultrasonic sensor 35 to determine absence of the wafer W, the control unit 37 connected to the ultrasonic sensor 35 displays the detection value to the exterior, or transmits the detection value to another apparatus. Then, a user or a wafer supply device recognizes that the wafer W is not stacked on the wafer support stage 41 through the displayed value or the transmitted value, and additionally stacks the wafer W on the wafer support stage 41'.

[64] When the cassette 40 is full of wafers W, the detection process is complete and the cassette 40 is loaded into an apparatus for performing another process.

[65] While this invention has been described with reference to exemplary embodiments thereof, it will be clear to those of ordinary skill in the art that various modifications can be made to the described embodiments within the spirit and the scope of the invention set forth in the appended claims.

Claims

[1] An apparatus for detecting a substrate comprising: a sensor support frame disposed adjacent to a vertically elongated cassette in which a plurality of substrates are stacked; and a plurality of ultrasonic sensors installed at one surface of the sensor support frame, emitting ultrasonic waves in parallel to the substrates, and detecting the ultrasonic waves reflected by the substrates to detect the presence of each substrate.

[2] The apparatus according to claim 1, wherein each ultrasonic sensor is disposed in the same level as a corresponding substrate.

[3] The apparatus according to claim 1, further comprising a pair of fixing brackets for fixing the sensor support frame at a predetermined position.

[4] The apparatus according to claim 1, wherein the ultrasonic sensors are vertically disposed on one surface of the sensor support frame in a longitudinal direction at predetermined intervals.

[5] The apparatus according to claim 1, wherein the substrate is a wafer.

[6] An apparatus for detecting a glass substrate comprising: a sensor support frame disposed adjacent to a vertically elongated cassette in which a plurality of glass substrates are stacked; and a plurality of ultrasonic sensors installed at one surface of the sensor support frame, emitting ultrasonic waves in parallel to the glass substrates, and detecting the ultrasonic waves reflected by the glass substrates to detect the presence of each glass substrate. [7] The apparatus according to claim 6, wherein each ultrasonic sensor is disposed in the same level as a corresponding glass substrate. [8] The apparatus according to claim 6, further comprising a pair of fixing brackets for fixing the sensor support frame at a predetermined position.