WO2007142439A1

WO2007142439A1 - Method of transferring substrate using vacuum absorption

Info

Publication number: WO2007142439A1
Application number: PCT/KR2007/002692
Authority: WO
Inventors: Joung Sik Kim; Gi Chung Kwon; Chang Sil Yang
Original assignee: Jusung Engineering Co., Ltd
Priority date: 2006-06-08
Filing date: 2007-06-04
Publication date: 2007-12-13

Abstract

A method of transferring a substrate disposed on a plurality of substrates as an uppermost substrate using a transfer apparatus including first and second picker groups includes: a first step of absorbing and lifting a first side of the substrate by the first picker group; a second step of absorbing and lifting a second side of the substrate by the second picker group; and a third step of moving up and transferring the substrate by the first and second picker groups.

Description

METHOD OF TRANSFERRING SUBSTRATE USING VACUUM

ABSORPTION

Technical Field

[I] The present invention relates to a method of transferring a substrate, and more particularly, to a method of transferring a substrate in a system where a large number of substrates are treated.

[2]

Background Art [3] In a solar cell that may be a PN (positive-negative) junction diode, minor carriers excited due to a solar energy are diffused through a PN junction surface and an electromotive force is generated by a voltage difference at both ends of the PN junction diode. [4] A process of forming a thin film for P (positive) or N (negative) type semiconductor layer, an anti-reflective layer and an electrode and a process of etching the thin film to form a pattern for improving an energy conversion efficiency are required for forming the solar cell. [5] The processes are performed in a process chamber having an optimum condition for the corresponding process. [6] In the process of fabricating a solar cell, several tens or several hundreds of substrates are loaded on a movable means such as a tray in the process chamber to improve productivity. [7] As a result, a transfer apparatus loading the substrate on the tray or picking up and carrying out the substrate from the tray is provided outside the process chamber. [8] FIG. 1 is a schematic perspective view showing a transfer apparatus according to the related art. [9] In FIG. 1, the transfer apparatus 100 includes a transfer frame 110 and a transfer module 120. The transfer frame 110 is disposed over the tray 200 and the tray 200 relatively moves to the transfer frame 100. In addition, the transfer module 120 is combined to and moves relatively to the transfer frame 110. [10] The transfer module 120 picks up a substrate S stored in a substrate container, which is referred to as a magazine or a cassette, and loads the substrate S on the tray 200.

[I I] A picker 122 formed at a bottom portion of the transfer module 120 picks up the substrate S using a vacuum absorption for transferring. Although one picker 122 picks up one substrate S in FIG. 1, a plurality of pickers may pick up one substrate in another embodiment. [12] Specifically, a large sized substrate having a width of about 150mm and a length of about 150mm is used for a solar cell and four pickers are used to stably pick up the large substrate without a danger of breaking the substrate.

[13] FIG. 2 is a schematic perspective view showing first to fourth pickers of a transfer apparatus according to the related art.

[14] In FIG. 2, the first, second, third and fourth pickers 122a, 122b, 122c and 122d contact a substrate S and are made vacuous at the same time to absorb the substrate S. In addition, the first, second, third and fourth pickers 122a, 122b, 122c and 122d move up to lift the substrate S.

[15] The substrates for a solar cell are stored in contact with one another in the substrate container. When an uppermost substrate is picked up, a lower substrate contacting the uppermost substrate may be picked up together due to undesired force such as an electrostatic force or the uppermost substrate may be broken due to absorption between the uppermost and lower substrates contacting each other.

[16] FIG. 3 is a schematic side view showing a method of picking up a substrate in a transfer apparatus according to the related art.

[17] In FIG. 3, an air is horizontally jetted toward a side of substrates S to separate the substrates S and to prevent the break of the substrates S. Since a gap is generated due to the air jet, only the uppermost substrate S is stably picked up.

[18]

Disclosure of Invention

Technical Problem

[19] However, as the thickness of the substrate S is reduced to about 150mm, the substrate may be broken during the pick-up process even when the air is jetted.

[20] An uppermost substrate and a lower substrate are not completely separated from and partially contact each other even when the air is jetted. Accordingly, although weakened, a resisting force such as an electrostatic force that interferes with the lift of the uppermost substrate S exists.

[21] When the substrate S has a relatively large thickness, the weakened resisting force may be easily overcome. However, as the thickness of the substrate S is reduced, the resisting force becomes a cause of break of the substrate S.

[22] When the plurality of pickers absorb and pick up the substrate S at the same time, an upward force is applied to a top surface of the substrate S by the plurality of pickers and a downward force is applied to a bottom surface of the substrate S by the resisting force such as an electrostatic force. As a result, a steep pressure gradient is generated between the top and bottom surfaces of the substrate S and the substrate S may be broken due to the steep pressure gradient. Technical Solution

[24] Accordingly, embodiments of the invention is directed to a method of transferring a substrate using a vacuum absorption that substantially obviate one or more of the problems due to limitations and disadvantages of the related art are described.

[25] An object of the embodiments of the invention is to provide a method of transferring a substrate using a vacuum absorption without a break of the substrate even when the substrate is relatively thin.

[26] To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, a method of transferring a substrate disposed on a plurality of substrates as an uppermost substrate using a transfer apparatus including first and second picker groups includes: a first step of absorbing and lifting a first side of the substrate by the first picker group; a second step of absorbing and lifting a second side of the substrate by the second picker group; and a third step of moving up and transferring the substrate by the first and second picker groups.

[27] The method of transferring a substrate further includes a fourth step of jetting an air toward a side of the plurality of substrates.

[28] The fourth step is performed at the same time with at least one of the first and second steps.

[29] In addition, each of the first and second picker groups includes at least one picker that can be made vacuous individually, and the first and second sides of the substrate is lifted by about lmm to about 10mm in the first and second steps, respectively.

[30] The first and second sides are opposite sides of the substrate.

[31] In the first step, the first and second picker groups move down to contact the substrate and then move up in a state such that the first picker group is made vacuous to absorb the substrate and the second picker group is not made vacuous, and in the second step, the first picker group stays at the same height and the second picker group moves down to contact the substrate and then moves up in a state such that the second picker group is made vacuous to absorb the substrate.

[32] Further, in the first step, a non-reactive gas is supplied to the second picker group contacting the substrate.

[33] Moreover, in the first step, the first picker group moves down to contact the substrate and then move up in a state such that the first picker group is made vacuous to absorb the substrate, and the second picker group is separated from the substrate, and in the second step, the first picker group stays at the same height and the second picker group moves down to contact the substrate and then moves up in a state such that the second picker group is made vacuous to absorb the substrate. [34] In the first step, the second picker group moves down while the first picker group is lifted. [35]

Advantageous Effects

[36] In a method of transferring a substrate using a vacuum absorption according to the present invention, since one side portion of an uppermost substrate is lifted first, the uppermost substrate is picked up with completely separated from a lower substrate. As a result, a pressure gradient is relieved and a break of the uppermost substrate that is relatively thin is prevented while the uppermost substrate is transferred.

[37]

Brief Description of the Drawings

[38] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of embodiments of the invention. In the drawings:

[39] FIG. 1 is a schematic perspective view showing a transfer apparatus according to the related art;

[40] FIG. 2 is a schematic perspective view showing first to fourth pickers of a transfer apparatus according to the related art;

[41] FIG. 3 is a schematic side view showing a method of picking up a substrate in a transfer apparatus according to the related art;

[42] FIGs. 4 to 7 are schematic views illustrating a method of transferring a substrate according to a first embodiment of the present invention; and

[43] FIGs. 8 to 11 are schematic views illustrating a method of transferring a substrate according to a second embodiment of the present invention.

[44]

Best Mode for Carrying Out the Invention

[45] Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.

[46] FIGs. 4 to 7 are schematic views illustrating a method of transferring a substrate according to a first embodiment of the present invention.

[47] In FIGs. 4 to 7, a transfer apparatus includes first, second, third and fourth pickers

222a, 222b, 222c and 222d, which can be made vacuous at the same time or individually. For illustration, a substrate container such as a magazine or a cassette where a plurality of substrates are stored is omitted and only the plurality of substrates are shown in FIGs. 4 to 7. [48] In the first embodiment of the present invention, the first, second, third and fourth pickers 222a, 222b, 222c and 222d do not simultaneously absorb a first substrate Sl that is an uppermost substrate of the plurality of substrates in the substrate container. Instead, a first picker group including the first and second pickers 222a and 222b and a second picker group including the third and fourth pickers 222c and 222d are individually made vacuous with a time difference. The first and second picker groups correspond to one side and the other side of the first substrate Sl, respectively.

[49] Table 1 shows sequence of operation of the first, second, third and fourth pickers 222a, 222b, 222c and 222d. [50] Table 1 [Table 1] [Table ]

[51] In Table 1, the injector jets an air to separate the first and second substrates Sl and S2. In addition, "ON" of a selected picker represents a state such that the selected picker is made vacuous to absorb a substrate.

[52] At the first step as shown in FIG. 4, the first, second, third and fourth pickers 222a, 222b, 222c and 222d move down and contact a top surface of the first substrate Sl that is an uppermost substrate of a plurality of substrates stored in a substrate container (not shown). Next, a vacuum absorption of the first and second pickers 222a and 222b of the first picker group is turned on. Accordingly, the first and second pickers 222a and 222b are made vacuous to absorb a first side of the first substrate Sl. A vacuum absorption of a second picker group including the third and fourth pickers 222c and 222d is turned off. In addition, a non-reactive gas such as nitrogen (N ) may be supplied to the second picker group. The injector (not shown) may not be operated at the first step such that the air is not applied to the side of the first substrate Sl.

[53] At the second step as shown in FIG. 5, the first and second pickers 222a and 222b move up with the vacuum absorption turned on so that the first side of the first substrate Sl can be lifted. For example, the first side of the first substrate Sl may be lifted by about lmm to about 10mm. The third and fourth pickers 222c and 222d may move up at the same time with the first and second pickers 222a and 222b. Al- ternatively, the third and fourth pickers 222c and 222d may stay at the previous position without rising.

[54] Before or after the first and second pickers 222a and 222b are made vacuous, the injector may be turned on and instantaneously jets the air to separate the plurality of substrates, especially the first substrate Sl and a second substrate S2 that is a next uppermost substrate contacting the first substrate Sl. Alternatively, while the first and second pickers 222a and 222b absorb and lift the first substrate Sl, the injector may be turned on and continuously jets the air with various intensities.

[55] At the third step as shown in FIG. 6, the third and fourth pickers 222c and 222d move down to contact the top surface of the first substrate S 1 and the vacuum absorption of the third and fourth pickers 222c and 222d is turned on. Accordingly, the third and fourth pickers 222c and 222d are made vacuous to absorb a second side opposite to the first side of the first substrate Sl.

[56] Before or after the third and fourth pickers 222c and 222d are made vacuous, the injector may be turned on and instantaneously jets the air to separate the plurality of substrates, especially first substrate Sl and the second substrate S2. Alternatively, while the third and fourth pickers 222c and 222d absorb and lift the first substrate Sl, the injector may be turned on and continuously jets the air with various intensities.

[57] At the fourth step as shown in FIG. 7, the third and fourth pickers 222c and 222d move up such that the first, second, third and fourth pickers 222a, 222b, 222c and 222d are disposed at the same height. For example, the second side of the first substrate Sl may be lifted by about lmm to about 10mm.

[58] The injector may be turned on and continuously jets the air with various intensities while the third and fourth pickers 222c and 222d absorb and lift the first substrate Sl.

[59] At the fifth step, the first, second, third and fourth pickers 222a, 222b, 222c and 222d may further move up and the first substrate S 1 may be transferred.

[60] In the first embodiment of the present invention, one side of a substrate is first lifted and air is jetted to separate the substrate from a lower substrate sufficiently and then the substrate moves up. Accordingly, a resistive force such as an electrostatic force due to the contact of two adjacent substrates is reduced and the pressure gradient of the substrate is weakened. As a result, the substrate having a relatively small thickness of about 100mm to about 200mm may be stably transferred using a vacuum absorption.

[61]

Mode for the Invention

[62] FIGs. 8 to 11 are schematic views illustrating a method of transferring a substrate according to a second embodiment of the present invention.

[63] In FIGs. 8 to 11, a transfer apparatus includes first, second, third and fourth pickers 322a, 322b, 322c and 322d, which can be made vacuous at the same time or individually. For illustration, a substrate container such as a magazine or a cassette where a plurality of substrates are stored is omitted and only the plurality of substrates are shown in FIGs. 8 to 11.

[64] In the second embodiment of the present invention, the first, second, third and fourth pickers 322a, 322b, 322c and 322d do not simultaneously absorb a first substrate Sl that is an uppermost substrate of the plurality of substrates in the substrate container. Instead, a first picker group including the first and second pickers 322a and 322b and a second picker group including the third and fourth pickers 322c and 322d are individually made vacuous with a time difference. The first and second picker groups correspond to one side and the other side of the first substrate Sl, respectively.

[65] At the first step as shown in FIG. 8, the first and second pickers 322a and 322b of the first picker group move down and contact a top surface of the first substrate Sl that is an uppermost substrate of a plurality of substrates stored in the substrate container. The third and fourth pickers 322c and 322d of the second picker group do not move down and stay at a higher position at the first step. Next, a vacuum absorption of the first and second pickers 222a and 222b of the first picker group is turned on, while a vacuum absorption of the third and fourth pickers 322c and 322d of the second picker group is turned off. Accordingly, the first and second pickers 322a and 322b are made vacuous to absorb a first side of the first substrate Sl. In addition, a non-reactive gas such as nitrogen (N ) may be supplied to the third and fourth pickers 322c and 322d.

[66] At the first step, the injector (not shown) may not be operated such that the air is not applied to the side of the first substrate Sl. Further, the third and fourth pickers 322c and 322d do not contact and are spaced apart from the top surface of the first substrate Sl.

[67] At the second step as shown in FIG. 9, the first and second pickers 322a and 322b move up with the vacuum absorption turned on so that the first side of the first substrate Sl can be lifted. For example, the first side of the first substrate Sl may be lifted by about lmm to about 10mm.

[68] Before or after the first and second pickers 322a and 322b are made vacuous, the injector may be turned on and instantaneously jets the air to separate the plurality of substrates, especially the first substrate Sl and a second substrate S2 that is a next uppermost substrate contacting the first substrate Sl. Alternately, while the first and second pickers 322a and 322b absorb and lift the first substrate Sl, the injector may be turned on and continuously jets the air with various intensities.

[69] At the third step as shown in FIG. 10, the third and fourth pickers 322c and 322d move down to contact the top surface of the first substrate S 1 and the vacuum absorption of the third and fourth pickers 322c and 322d is turned on. Accordingly, the third and fourth pickers 322c and 322d are made vacuous to absorb a second side opposite to the first side of the first substrate Sl.

[70] In addition, the process of moving up the first and second pickers 322a and 322b may be performed at the same time with the process of moving down the third and fourth pickers 322c and 322d.

[71] Before or after the third and fourth pickers 322c and 322d are made vacuous, the injector may be turned on and instantaneously jets the air to separate the plurality of substrates, especially the first substrate Sl and the second substrate S2. Alternatively, while the third and fourth pickers 322c and 322d absorb and lift the first substrate Sl, the injector may be turned on and continuously jets the air with various intensities.

[72] At the fourth step as shown in FIG. 11, after the injector stops jetting air, the third and fourth pickers 322c and 322d move up such that the first, second, third and fourth pickers 222a, 222b, 222c and 222d are disposed at the same height. For example, the second side of the first substrate Sl may be lifted by about lmm to about 10mm.

[73] The injector may be turned on and continuously jets the air with various intensities while the third and fourth pickers 322c and 322d absorb and lift the first substrate Sl.

[74] At the fifth step, the first, second, third and fourth pickers 322a, 322b, 322c and 322d may further move up and the first substrate S 1 may be transferred.

[75] In the second embodiment of the present invention, one side of a substrate is first lifted and air is jetted to sufficiently separate the substrate from a lower substrate and then the substrate moves up. Accordingly, a resistive force such as an electrostatic force due to the contact of two adjacent substrates is reduced and the pressure gradient of the substrate is weakened. As a result, the substrate having a relatively small thickness of about 100mm to about 200mm may be stably transferred using a vacuum absorption.

[76] Although the transfer apparatus includes first to fourth pickers in the first and second embodiment of the present invention, the number of pickers may not be limited to four.

[77]

Industrial Applicability

[78] In the present invention, since one side of an uppermost substrate is first lifted, the uppermost substrate safely moves up with completely separated from a next uppermost substrate.

[79] As a result, a pressure gradient applied to the uppermost substrate is weakened and the uppermost substrate may be stably transferred using a vacuum absorption even when the uppermost substrate has a relatively small thickness.

Claims

[1] A method of transferring a substrate disposed on a plurality of substrates as an uppermost substrate using a transfer apparatus including first and second picker groups, comprising: a first step of absorbing and lifting a first side of the substrate by the first picker group; a second step of absorbing and lifting a second side of the substrate by the second picker group; and a third step of moving up and transferring the substrate by the first and second picker groups.

[2] The method according to claim 1, further comprising a fourth step of jetting an air toward a side of the plurality of substrates.

[3] The method according to claim 2, wherein the fourth step is performed at the same time with at least one of the first and second steps.

[4] The method according to claim 1, wherein each of the first and second picker groups includes at least one picker that can be made vacuous individually.

[5] The method according to claim 1, wherein the first and second sides of the substrate is lifted by about lmm to about 10mm in the first and second steps, respectively.

[6] The method according to claim 1, wherein the first and second sides are opposite sides of the substrate.

[7] The method according to claim 1, wherein in the first step, the first and second picker groups move down to contact the substrate and then move up in a state such that the first picker group is made vacuous to absorb the substrate and the second picker group is not made vacuous, and in the second step, the first picker group stays at the same height and the second picker group moves down to contact the substrate and then moves up in a state such that the second picker group is made vacuous to absorb the substrate.

[8] The method according to claim 7, wherein in the first step, a non-reactive gas is supplied to the second picker group contacting the substrate.

[9] The method according to claim 1, wherein in the first step, the first picker group moves down to contact the substrate and then move up in a state such that the first picker group is made vacuous to absorb the substrate, and the second picker group is separated from the substrate, and in the second step, the first picker group stays at the same height and the second picker group moves down to contact the substrate and then moves up in a state such that the second picker group is made vacuous to absorb the substrate. [10] The method according to claim 1, wherein in the first step, the second picker group moves down while the first picker group is lifted.