BACKGROUND

1 . Cross-Reference to Related Application

[0001] This application claims the benefit of priority under 35 U.S.C. § 1 19 of Korean Application Serial No. 10-201 7-0092736 filed on J uly 21 , 2017, the content of which is relied upon and incorporated herein by reference in its entirety.

2. Field

[0002] One or more embodiments relate to a pressure mapping apparatus and a method of cleaning a glass substrate by using the same, and more particularly, to a pressure mapping apparatus and a method of cleaning a glass substrate by using the same, whereby an objective and quantitative test may be conducted without deviations between workers in a cleaning process.

3. Description of the Related Art

[0003] As consumer demand for glass substrates with high surface quality has increased and glass substrates having larger area are used more and more, the possibility of occurrence of particle defects during a process of manufacturing a glass substrate has increased.

[0004] Regarding a glass su bstrate manufacturing process, there is few equipment for an objective and quantitative test or evaluation of a cleaning process, and thus, reducing the occurrence of particle defects is difficult. Also, it is required to decrease non-uniformity in substrate quality which is caused by deviation between workers in the cleaning process.

SUMMARY

[0005] One or more embodiments include a pressure mapping apparatus, whereby an objective and quantitative test may be conducted without a deviation between workers in a cleaning process.

[0006] One or more embodiments include method of cleaning a glass substrate, whereby product defects such as particle defects may be considerably reduced. [0007] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

[0008] According to one or more embodiments, a pressure mapping apparatus includes: a supporting substrate; a plurality of pressure sensors arranged on the supporting substrate, each of the plurality of pressures sensors being configured to output a signal in response to pressure applied thereto; a waterproof pouch surrounding the supporting substrate; and an analyzer configured to receive the signal from each of the plurality of pressure sensors and output in real time a pressure map on the supporting substrate based on the received signal.

[0009] Each of the plurality of pressure sensors may include an upper conductor layer and a lower conductor layer, the lower conductor layer being separated from the upper conductor layer and disposed under the upper conductor layer, the upper conductor layer may include a first conductor part including a first electrode and a second conductor part including a second electrode, and the upper conductor layer may be deformed by the applied pressure to the corresponding one of the pressure sensors and may contact the lower conductor layer.

[0010] The pressure mapping apparatus may further include a plurality of lead lines connected to the first and second electrodes of each of the plurality of pressure sensors, the plurality of lead lines extending to a connector provided on one side of the supporting substrate, wherein the analyzer may be configured to receive the signal through the connector and a signal cable.

[0011] The first conductor part and the second conductor part may be deformed in proportion to the applied pressure to the corresponding one of the pressure sensors, and a contact area where each of the first conductor part and the second conductor part contacts the lower conductor layer may increase accordingly.

[0012] The first conductor part may include a plurality of first fingers arranged in parallel, and the second conductor part may include a plurality of second fingers arranged in parallel, wherein the plurality of fist fingers and the plurality of second fingers may be alternately arranged with respect to each other.

[0013] Each of the plurality of pressure sensors may further include a spacer under the first electrode and the second electrode, wherein the spacer may separate the upper conductor layer from the lower conductor layer. [0014] The supporting substrate may be a flexible substrate.

[0015] The plurality of pressure sensors may be arranged on the supporting substrate in a lattice form.

[0016] According to one or more embodiments, a method of cleaning a glass substrate including: positioning a pressure mapping apparatus under a plurality of friction cleaning parts; lowering each of the plurality of friction cleaning parts to a cleaning position; mapping pressures respectively applied by the plurality of friction cleaning parts to the glass substrate by using the pressure mapping apparatus; adjusting downward pressurization characteristics of the plurality of friction cleaning parts based on the mapped pressures; positioning a glass substrate under the plurality of friction cleaning parts; and cleaning the glass substrate by using the plurality of friction cleaning parts, wherein the pressure mapping apparatus includes: a supporting substrate; a plurality of pressure sensors arranged on the supporting substrate, each of the plurality of pressure sensors being configured to output a signal in response to pressure applied thereto; and an analysis apparatus configured to receive the signal from each of the plurality of pressure sensors to output a pressure map on the supporting substrate in real time based on the received signal.

[0017] The mapping of the pressures may include determining whether the pressures respectively applied from the plurality of friction cleaning parts are within a reference pressure value range or not.

[0018] The adjusting of the downward pressurization characteristics may include, for a friction cleaning part which applies a pressure outside the reference pressure value range, adjusting an installation height of the friction cleaning part.

[0019] Each of the plurality of friction cleaning parts may be lowered to the cleaning position via pneumatic or hydraulic pressure, and the adjusting of the downward pressurization characteristics may include adjusting a setting value of the pneumatic or hydraulic pressure applied to each of the plurality of friction cleaning parts for cleaning.

[0020] The glass substrate may move in a horizontal direction while the cleaning of the glass substrate is being performed.

[0021] The plurality of friction cleaning parts may include: a plurality of first friction cleaning parts arranged at certain intervals from one another in a first row corresponding to a lateral direction, which is vertical to a moving direction of the glass substrate; and a plurality of second friction cleaning parts arranged at certain intervals from one another in a second row corresponding to a lateral direction parallel to an arrangement direction of the plurality of first friction cleaning parts of the first row, and one second friction cleaning part of the second row may be disposed apart from a position between two adjacent first friction cleaning parts of the first row in the moving direction of the glass substrate.

[0022] The cleaning of the glass substrate may include supplying a cleansing solution onto the glass substrate.

BRIEF DESCRIPTION OF TH E DRAWINGS

[0023] These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0024] FIG. 1 is a conceptual diagram schematically illustrating a pressure mapping apparatus according to an embodiment;

[0025] FIG. 2A is a conceptual diagram illustrating a pressure sensor according to an embodiment;

[0026] FIG. 2B is a side cross-sectional view taken along line B-B' in FIG. 2A according to an embodiment;

[0027] FIGS. 3A and 3B are side cross-sectional views schematically illustrating deformation states of first and second fingers caused by pressure applied thereto according to an embodiment;

[0028] FIG. 4 is a schematic diagram illustrating a connection configuration between pressure sensors and a connector according to an embodiment;

[0029] FIG. 5 is an exemplary block diagram of an analysis apparatus according to an embodiment;

[0030] FIG. 6 is a pressure contour map showing a level of pressure with respect to an area and a position to which pressure is applied by a pressure mapping apparatus manufactured according to an embodiment;

[0031] FIG. 7 is a conceptual diagram illustrating a pressure sensor according to another embodiment; [0032] FIG. 8 is a side cross-sectional view illustrating a pressure sensor according to another embodiment;

[0033] FIGS. 9A to 9C are cross-sectional views for illustrating a method of manufacturing a pressure sensor according to an embodiment;

[0034] FIG. 10 is a flowchart of a method of cleaning a glass substrate according to an embodiment;

[0035] FIG. 1 1 is a flowchart illustrating in detail an operation of mapping pressures applied by a plurality of friction cleaning parts;

[0036] FIG. 12 is a schematic diagram illustrating a pressure mapping method wherein a plurality of pressure sensor units are disposed under a friction cleaning part;

[0037] FIG. 13 is a schematic diagram two-dimensionally illustrating a glass su bstrate cleaning process according to an embodiment;

[0038] FIGS. 14 and 15 are images showing results obtained by performing pressure mapping with respect to friction cleaning parts arranged in five rows at a cleaning position, by using a pressure mapping apparatus according to an embodiment;

[0039] FIGS. 16A and 16B are images showing a pressure contour map before and after adjusting a downward pressurization characteristic of each friction cleaning part by using a pressure mapping system according to an embodiment;

[0040] FIG. 17 is a graph showing the number of positions of particle defects with respect to a change of FIGS. 16A and 16B; and

[0041] FIGS. 18A and 18B are graphs showing changes in the number of positions of particle defects positions before and after adjusting a downward pressurization characteristic of each friction cleaning part by using a pressure mapping system according to an embodiment in another glass product manufacturing process.

DETAILED DESCRIPTION

[0042] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throug hout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of" when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0043] The inventive concept will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as being 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 concept of the inventive concept to those of ordinary skill in the art. Like reference numerals refer to like elements throughout. In the drawings, some elements are exaggerated, omitted, or schematically illustrated. In addition, the size of each element does not fully reflect the actual size. Embodiments of the inventive concept are not limited by a relative size or interval which is illustrated in the drawings.

[0044] Terms like a first and a second may be used to describe various elements, but the elements should not be limited by the terms. The terms may be used only as object for distinguishing an element from another element. For example, without departing from the spirit and scope of the inventive concept, a first element may be referred to as a second element, and similarly, the second element may be referred to as the first element.

[0045] The terms used in this application, only certain embodiments have been used to describe, is not intended to limit the present embodiments. In the following description, the technical terms are used only for explain a specific exemplary embodiment while not limiting the present embodiments. The terms of a singular form may include plural forms unless referred to the contrary. The meaning of "include," "comprise," "including," or "comprising," specifies a property, a region, a fixed number, a step, a process, an element and/or a component but does not exclude other properties, regions, fixed numbers, steps, processes, elements and/or components.

[0046] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0047] When a specific embodiment may be differently implemented, a specific process sequence may be performed differently from a described sequence. For example, two processes which are successively described may be substantially performed, or may be performed in a sequence opposite to a described sequence.

[0048] In the accompanying drawings, for example, modifications of an illustrated shape may be expected according to manufacturing tech nology and/or tolerance. Therefore, embodiments of the inventive concept should not be construed as being limited to a specific shape of a region illustrated in the drawing, and for example, should include a shape change caused in a manufacturing process. The term "and/or" used herein includes a combination of one or more and each of described elements. Also, the term "substrate" used herein may denote a stacked structure which includes a substrate itself or includes the substrate and a certain layer or film formed on a surface thereof. Also, a surface of a substrate used herein may denote an exposed surface of the substrate itself or an outer surface of a certain layer or film formed on the substrate.

[0049] FIG. 1 is a conceptual diagram schematically illustrating a pressure mapping apparatus 100 according to an embodiment.

[0050] Referring to FIG. 1 , the pressure mapping apparatus 100 may include a su pporting substrate 1 10, a plurality of pressure sensors 120 arranged on the su pporting substrate 1 10, a waterproof pouch 130 surrounding the supporting substrate 1 10, and an analyzer 140 which can receive signals from the plurality of pressure sensors 120 and output a pressure map on the supporting substrate 1 10 in real time.

[0051] According to an embodiment, the supporting substrate 1 10 may be an arbitrary substrate having flexibility. According to an embodiment, the supporting su bstrate 1 10 may be of a film type. For example, the supporting substrate 1 10 may include polyethyleneterephthalate (PET), polyethylenenaphthalate, polybutyleneterephthalate (PBT), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polycarbonate (PC), polyvinylchloride (PVC), polymethylmethacrylate (PMMA), norbornene resin, polyester, polystyrene (PS), and/or the like, but is not limited thereto. A thickness of the supporting su bstrate 1 10 may be about 50 /an to about 3 mm.

[0052] The plurality of pressure sensors 120 may be arranged at regular intervals or irregular intervals with respect to one another on the supporting substrate 1 10. The pressure sensors 120 may be configured to output an electrical signal in response to a pressure applied to an upper portion thereof. FIG. 2A is a conceptual diagram illustrating a pressure sensor 120 according to an embodiment. FIG. 2B is a side cross-sectional view taken along line B-B' in FIG. 2A.

[0053] Referring to FIGS. 2A and 2B, the pressu re sensor 120 may include an upper conductor layer 122 and a lower conductor layer 124.

[0054] The upper conductor layer 122 may include a first conductor part 122a and a second conductor part 122b. The first conductor part 122a may include a first electrode 122ae, and the second conductor part 122b may include a second electrode 122be.

[0055] The upper conductor layer 122 may include a metal material , and for example, may include copper (Cu), aluminum (Al), nickel (Ni), zinc (Zn), iron (Fe), gold (Au), silver (Ag), platinum (Pt), cobalt (Co), tungsten (W), titanium (Ti), tantalum (Ta), chromium (Cr), manganese (Mn), zirconium (Zr), or an alloy thereof, but is not limited thereto. In some embodiments, the upper conductor layer 122 may include a carbon- based material having conductivity like graphite, graphene, carbon nanotube (CNT), and fullerene.

[0056] The first conductor part 122a and the second conductor part 122b may be spaced apart from each other by a certain interval. In some embodiments, the first conductor part 122a may include a plurality of first fingers 122af arranged in parallel and a first con nection part 122ac connecting the plurality of first fingers 122af. In some embodiments, the second conductor part 122b may include a plurality of second fingers 122bf arranged in parallel and a second connection part 122bc connecting the plurality of second fingers 122bf.

[0057] The plurality of first fingers 122af and the plurality of second fingers 122bf, as illustrated in FIG. 2A, may be alternately arranged in parallel with respect to one another. [0058] The first fingers 122af and the first connection part 122ac may be deformed by pressure applied on an upper portion thereof and may contact the lower conductor layer 124. Also, the second fingers 122bf and the second connection part 122bc may be deformed by a pressure applied on an upper portion thereof and may contact the lower conductor layer 124. The deformation of the first and second fingers 122af and 122bf and the deformation of the first and second connection parts 122ac and 122bc may be proportional to the pressure applied on the upper portion thereof.

[0059] An upper insulation layer 128 may be provided on the upper conductor layer 122. The upper insulation layer 128 may act as a supporting substrate of the upper conductor 122 in a process of manufacturing the pressure sensor 120. Also, the upper insulation layer 128 may protect the upper conductor layer 122.

[0060] In some embodiments, an area where the first and second fingers 122af and 122bf and/or the first and second connection parts 122ac and 122bc contact the lower conductor layer 124 may vary with the pressure applied to the upper portion thereof. In detail, the area where the first and second fingers 122af and 122bf and/or the first and second connection parts 122ac and 122bc contact the lower conductor layer 124 may be proportional to the pressure applied to the upper portion thereof within a certain pressure range.

[0061] FIGS. 3A and 3B are side cross-sectional views schematically illustrating deformation states of the first and second fingers 122af and 122bf caused by pressure applied thereto.

[0062] Referring to FIG. 3A, the first and second fingers 122af and 122bf may be deformed by first pressure P1 and may physically contact the lower conductor layer 124. In this case, the second fingers 122bf may each have a contact area corresponding to a width W1 and may contact the lower conductor layer 124.

[0063] Referring to FIG. 3B, when second pressure P2 which is higher than the first pressure P1 is applied on the first and second fingers 122af and 122bf, the first and second fingers 122af and 122bf may be deformed more than FIG. 3A and may contact the lower contactor layer 124. As the second fingers 122bf are deformed more, the second fingers 122bf may each have a contact area corresponding to a width W2 greater than the width W1 and may contact the lower conductor layer 124. [0064] As the area where the first and second fingers 122af and 122bf and/or the first and second connection parts 122ac and 122bc contact the lower conductor layer 124 becomes wider, a current flowing via the lower conductor layer 124 may increase with a certain voltage applied between the first electrode 122ae and the second electrode 122be. Therefore, the current may be correlated with the applied pressure, and by measuring a value of the current, a level of the applied pressure may be obtained .

[0065] The lower conductor layer 124 may be spaced apart from the upper conductor layer 122 and may be disposed under the upper conductor layer 122. The lower conductor layer 124 may include a conductor such as metal or a carbon-based material. The metal or the carbon-based material used as a material of the lower conductor layer 124 is as described above on the upper conductor layer 122, and thus, no additional description is provided.

[0066] In FIG. 2B, the lower conductor layer 124 is illustrated as extending over a whole area of the supporting substrate 1 10, but is not limited thereto. In some embodiments, the lower conductor layer 124 may be restricted in a cell region including one pressure sensor 120. That is, lower conductor layers of two adjacent pressure sensors 120 may be electrically insulated from each other.

[0067] The upper conductor layer 122 and the lower conductor layer 124 may be electrically separated from each other by a spacer 126. When pressure is applied on an upper portion of the upper conductor layer 122, the spacer 126 may maintain a gap between the upper conductor layer 122 and the lower conductor layer 124, and thus, separation may be maintained at a position at which the spacer 126 is disposed, and the upper conductor layer 122 may be deformed at a position at which the spacer 126 is not disposed.

[0068] The spacer 126 may include an arbitrary electrical insulator, and for example, may include polymer resin, metal oxide having electrical insulating properties, metal nitride having electrical insulating properties, undoped silicon oxide, undoped silicon nitride, or a combination thereof.

[0069] Referring again to FIG. 1 , the waterproof pouch 130 may be configured to surround the supporting substrate 1 10 including a surface on which the plurality of pressure sensors 120 are provided. The waterproof pouch 130 may surround the su pporting substrate 1 10, and for example, may prevent a liquid component, such as water or chemicals used for cleaning, from directly contacting the pressure sensors 120.

[0070] The waterproof pouch 130 may include a flexible material . In some embodiments, the waterproof pouch 130 may include a material which is different from or the same as that of the supporting substrate 1 10. For example, the waterproof pouch 130 may include polyethyleneterephthalate (PET), polyethylenenaphthalate, polybutyleneterephthalate (PBT), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polycarbonate (PC), polyvinylchloride (PVC), polymethylmethacrylate (PMMA), norbornene resin, polyester, polystyrene (PS), and/or the like, but is not limited thereto.

[0071] The waterproof pouch 130 may expose a connector 150 for an electrical connection between the plurality of pressure sensors 120 and the below-described analyzer 140. The connector 150 may be electrically connected to the plurality of pressure sensors 120 through a lead line.

[0072] FIG. 4 is a schematic diagram illustrating a connection configuration between pressure sensors and a connector according to an embodiment.

[0073] Referring to FIG. 4, the plurality of pressure sensors 120 may be arranged according to a certai n rule. In FIG. 4, four pressure sensors 120 are illustrated as being arranged in one direction, but the number of the pressure sensors 120 may be greater or less than four. In some embodiments, the plurality of pressure sensors 120 may be arranged in a lattice form. However, the present embodiment is not limited thereto. First electrodes of a plurality of pressure sensors 120 arranged in one row may be connected to a first lead line 160a in common. Also, second electrodes of the plurality of pressure sensors 120 arranged in the one row may be connected to a second lead line 160b in common.

[0074] The first lead line 160a and the second lead line 160b may be electrically connected to a terminal of the connector 150. The connector 150 may include a plurality of connection terminals which are arranged at certain intervals from one another, or may be a connector which transmits or receives a signal to or from an external device according to a certain standard, for example, serial advanced technology attachment (SATA) standard, parallel advanced technology attachment (PATA) standard, or small computer system interface (SCSI) standard. Here, the SATA standard may include all SATA series standards such as SATA-2, SATA-3, and external SATA (e-SATA) as well as SATA-1 . The PATA standard may include all IDE series standards such as integrated drive electronics (IDE) and enhanced-I DE (E-IDE).

[0075] The analyzer apparatus 140 may receive an electrical signal from each of the plurality of pressure sensors 120. The electrical signal may be a value of a current

(hereinafter referred to as a current val ue) measured from each of the pressure sensors 120 and may be secondary data generated by processing data of current values respectively measured from the pressure sensors 120.

[0076] FIG. 5 is an exemplary block diagram of the analyzer apparatus 140.

[0077] Referring to FIG. 5, the analyzer apparatus 140 may include a controller 2010, an input/output (I/O) device 2020, memory 2030, and an interface 2040. These elements may be connected to each other through a bus 2050.

[0078] The controller 2010 may include at least one of a microprocessor, a digital signal processor, or a processing device similar thereto. The I/O device 2020 may include at least one of a keypad, a keyboard, and a display. The memory 2030 may be used to store a command executed by the controller 2010. For example, the memory 2030 may be used to store user data.

[0079] In some embodiments, the interface 2040 may be configured to be connected to the connector 150 (see FIG. 4).

[0080] When the analyzer 140 receives a signal (or data) through the connector 150 and the interface 2040, the analyzer apparatus 140 may process the signal to generate a pressure contour map as illustrated in FIG. 6. FIG. 6 is a pressure contour map showing a level of pressure with respect to an area and a position to which pressure is applied by a pressure mapping apparatus manufactured according to an embodiment. The pressure contour map may be output through the I/O device 2020 such as a display device.

[0081] The analyzer 140 may store a program and/or a routine for generating the pressure contour map. The program and/or the routine is/are commercially available, and thus, their detailed descriptions are omitted.

[0082] FIG. 7 is a conceptual diagram illustrating a pressure sensor 220 according to another embodiment.

[0083] Referring to FIG. 7, except that a first electrode 122ae and a second electrode 122be are connected to each other via a bypass line 122c, the pressure sensor 220 illustrated in FIG. 7 is the same as the pressure sensor 120 illustrated in FIG. 2A. Therefore, common details are not additionally described , and just different details will be described below.

[0084] Since the bypass line 122c is provided, a current may fundamentally flow between a first electrode 122ae and a second electrode 122be irrespective of whether pressure is applied to the pressure sensor 220 or not. When the first fingers 122af and the second fingers 122bf are deformed by the pressure applied to an upper portion of the pressure sensor 220, the first fingers 122af and the second fingers 122bf may contact the lower conductor layer 124 (see FIG. 2B) located thereunder. In this case, a path through which the current flows between the first electrode 122ae and the second electrode 122be may be additionally formed in addition to the bypass line 122c, and thus, the current flowing between the first electrode 122ae and the second electrode 122be may increase.

[0085] In the pressure sensor 220 of FIG. 7, by adding the bypass line 122c, a sensitivity of measurement of the value of the current flowing between the first electrode 122ae and the second electrode 122be may be adjusted .

[0086] FIG. 8 is a side cross-sectional view illustrating a pressure sensor 320 according to another embodiment.

[0087] Referring to FIG. 8, except that a protrusion 129 having a dome shape is further provided on the upper insulation layer 128, the pressure sensor 320 illustrated in FIG. 8 is the same as the pressure sensor 120 illustrated in FIG. 2B. Therefore, common details are not additionally described, and only different details will be described below.

[0088] When pressure is applied from the outside to the pressure sensor 320, a protrusion 129 may promote a plurality of fingers 122af and 122bf to be deformed even by relatively low pressure or side-direction pressure. In other words, when pressure is applied from the outside to the pressure sensor 320, the protrusion 129 may allow the pressure to concentrate on an area of the protrusion 129, and thus, despite relatively low pressure, the fingers 122af and 122bf may be deformed enough.

[0089] Moreover, the protrusion 129 may have a convex shape, and thus, a force or pressure acting in a side direction may be efficiently transferred to the fingers 122af and 122bf disposed under the protrusion 129. [0090] Therefore, a sensitivity of the pressure sensor 320 increases due to the protrusion 129.

[0091] FIGS. 9A to 9C are cross-sectional views illustrating a method of manufacturing a pressure sensor 120 according to an embodiment.

[0092] Referring to FIG. 9A, an upper conductor layer 122 may be formed on an upper insulation layer 128. Various methods may be used for forming a pattern of the upper conductor layer 122. For example, a conductive material layer may be formed on the upper insulation layer 128, and then, may be patterned by a photolithography process or the like. Alternatively, a sacrificial layer pattern may be formed on the upper insulation layer 128, and after the conductive material layer is conformally deposited by a chemical vapor deposition (CVD) process or the like, an undesired conductive material layer may be lifted off by removing the sacrificial layer pattern, thereby performing patterning.

[0093] In FIG. 9A, the upper conductive layer 122 is illustrated as being disposed on a lower surface of the upper insulation layer 128, but an upward direction and a downward direction may be reversed.

[0094] Referring to FIG. 9B, a spacer 126 may be formed at an appropriate position of the upper conductor layer 122. The spacer 126 may be formed by, for example, a printing process, a screen printing process, a doctor blade process, or the like, but is not limited thereto. If an inorganic material is used as the spacer 126, the spacer 126 may be formed by a physical vapor deposition (PVD) process, a CVD process, or the like.

[0095] Referring to FIG. 9C, a lower conductor layer 124 may be formed on a su pporting su bstrate 1 10 and may be coupled to a structure illustrated in FIG. 9B. The supporting substrate 1 10 and the lower conductor layer 124 have been described above in detail with reference to FIG. 1 , and thus, no additional descriptions will be provided. The lower conductor layer 124 may be formed on the su pporting substrate 1 10 through a coating process, a plating process, a vapor deposition process, or the like.

[0096] FIG. 10 is a flowchart sequentially illustrating a method of cleaning a glass substrate according to an embodiment.

[0097] A glass substrate may be cleaned by a plurality of friction cleaning parts which are arranged at certain intervals from one another in a lateral direction with respect to the glass substrate. The friction cleaning parts may be, for example, one or more brushes, woven fabrics, non-woven fabrics, felts, sponges, fabrics, etc. , but are not limited thereto.

[0098] In operations S1 10, S120, and S130, whether the plurality of friction cleaning parts are capable of pressing the glass substrate with an appropriate pressure may be first determined for cleaning the glass substrate. When it is determined that the plurality of friction cleaning parts cannot press the glass substrate with the appropriate pressure, a downward pressurization characteristic of each of the friction cleaning parts may be tuned in operation S140. Subsequently, the glass substrate may be disposed under the plurality of friction cleaning parts, and a cleaning process may be performed in operations S150 and S160. Hereinafter, each operation will be described .

[0099] First, a pressure mapping apparatus may be disposed under the plurality of friction cleaning parts in operation S1 10. Particularly, a pressure sensor unit of the pressure mapping apparatus may be disposed under the plurality of friction cleaning parts, and an analyzer may be connected to the pressure sensor unit through a cable after separation. For example, as illustrated in FIG. 12, if it is difficult for a plurality of friction cleaning parts 201 to be covered by one pressure sensor unit PSU because a total width where the plurality of friction cleaning parts 201 are disposed is large, a plu rality of pressure sensor units PSU may be simultaneously disposed under the plurality of friction cleaning parts 201 .

[00100] Subsequently, each of the plurality of friction cleaning parts may be lowered to a cleaning position, and pressure may be applied to the pressure sensor unit in operation S120. Since each of the plurality of friction cleaning parts is disposed at the cleaning position, a pressure applied to the pressure sensor unit may be substantially the same as a pressure applied to the glass substrate when cleaning the glass substrate. Since the pressure sensor unit is protected by the waterproof pouch 130 (see FIG. 1 ), the pressure sensor unit is safe from water or chemical materials.

[00101] Subsequently, by mapping pressures applied by the plurality of friction cleaning parts, whether a downward pressing characteristic is appropriate may be determined in operation S130. This operation will be described below in detail with reference to FIG. 1 1 . [00102] Referring to FIG. 1 1 , first, the above-described pressure mapping apparatus may calculate a position-based pressure val ue within each pressure mapping range in operation S131 . That is, a pressure at a position of each of a plurality of pressure sensors and/or pressure at a position between the pressure sensors may be calculated based on data received from each of the pressure sensors.

[00103] Optionally, a pressure applied by each of the friction cleaning parts may be calculated based on the calculated position-based pressure value in operation S133. That is, whether identification (ID) of a friction cleaning part is appropriate may be determined by recognizing a pressed boundary, and if the ID is appropriate, a pressure applied by the friction cleaning part may be obtained based on a pressure distribution of a corresponding boundary. In some embodiments, the pressure applied by the friction cleaning part may be determined by si mply averaging or weighted-averaging pressure values at points of the corresponding boundary.

[00104] Subsequently, whether the pressure applied by the friction cleaning part is within a reference pressure value range may be determined in operation S135. If the pressure applied by the friction cleaning part is within the reference pressure value range, an operation of cleaning the glass substrate (S150 of FIG. 10) may be immediately performed without an additional process. On the other hand, if the pressure applied by the friction cleaning part is not within the reference pressure value range, an operation of adjusting a downward pressing characteristic (S140 of FIG. 10) may be performed with respect to a friction cleaning part of which an applied pressure is outside the reference pressure value range.

[00105] Referring again to FIG. 10, in operation S140, the downward pressing characteristic may be adjusted with respect to each friction cleaning part of which an applied pressure is outside the reference pressure value range.

[00106] If the friction cleaning part is fixed to an actuator and is configured to sh uttle in a vertical-direction section, the adjusting may be performed by changing an installation position (for example, an installation height) of the friction cleaning part. On the other hand, if the friction cleaning part is fixed to the actuator but the downward pressing characteristic is determined based on pneumatic or hydraulic pressure applied by an external power source to the actuator or pneumatic or hydraulic pressure applied by the actuator to the friction cleaning part, the adjusting may be performed by adjusting a setting value of each actuator.

[00107] After the downward pressing characteristic of the friction cleaning part is adjusted, the glass substrate may be disposed under the plurality of friction cleaning parts in operation S150. Subsequently, the plurality of friction cleaning parts may clean the glass substrate in operation S160.

[00108] FIG. 13 is a schematic diagram two-dimensionally illustrating a glass su bstrate cleaning process according to an embodiment.

[00109] Referring to FIG. 13, a plurality of friction cleaning parts 201 may be arranged accord ing to a certain rule. For example, the plurality of friction cleaning parts 201 may be arranged in several rows, for example, a first row R1 , a second row R2, a third row R3, etc. The friction cleaning parts 201 of each of the first to third rows R1 to R3 may be arranged in an x direction, namely, a side direction. Also, a plurality of rows (for example, R1 , R2, R3, ...) may be arranged in the order of the first row R1 , the second row R2, the third row R3, ... in a y direction. In FIG 13, only three rows are illustrated, but fewer rows than three rows or four or more rows may be arranged in the y direction.

[00110] A glass substrate G may be configured to travel in the y direction for cleaning. Particularly, a plurality of friction cleaning parts 201 arranged in the x direction may be arranged at a certain interval from one another to configure one row. For example, in the first row R1 , the glass substrate G may not be cleaned in a portion corresponding to the interval between the friction cleaning parts 201 . Therefore, in a next row (for example, the second row R2), in order for the uncleaned portion of the glass substrate G to be cleaned, the friction cleaning parts of the second row R2 may be disposed in the y direction at an interval between two friction cleaning parts adjacent to the first row R1 .

[00111] When the glass substrate G passes through the rows where the friction cleaning parts 201 are arranged and travels in the y direction , the friction cleaning parts 201 may clean a surface of the glass substrate G while rotating. Simultaneously, foreign materials stuck on the glass substrate G are completely removed by spraying a cleansing solution including water and/or a chemical cleaner on the glass substrate G. [00112] FIG. 14 is an image showing a result obtained by performing pressure mapping with respect to friction cleaning parts arranged in five rows at a cleaning position, by using a pressure mapping apparatus according to an embodiment. As shown in FIG. 14, a number of friction cleaning parts of which a downward pressure is not sensed have been checked even at the cleaning position. In the related art, since a user recognizes heights of friction cleaning parts with the naked eye and evaluates whether an installation height is appropriate or not, it is difficult to check friction cleaning parts of which a downward pressure does not act on a glass substrate.

[00113] FIG. 15 is an image showing another result obtained by performing pressure mapping with respect to friction cleaning parts arranged in five rows at a cleaning position, by using a pressure mapping apparatus accord ing to an embodiment.

[00114] As shown in FIG. 15, with respect to a first row, it is determined that most of friction cleaning parts press and clean a glass substrate via an appropriate pressure. However, it is determined that a downward pressing characteristics of each of the friction cleaning parts disposed close to the right of the image degraded progressively closer to a second row, a third row, a fourth row, and a fifth row. Particularly, since a distribution of the friction cleaning parts having a bad pressing characteristic is not random but has follows a certain tendency, it is primarily estimated that a left-right balance of an equipment frame affecting heights of all friction cleaning parts is not appropriate.

[00115] As shown in FIGS. 14 and 15, since it is possible to check a pressing characteristic of each of all friction cleaning parts in real time, a cause of a product defect of a glass substrate may be more easily determined in a subsequent process.

[00116] FIGS. 16A and 16B are images showing a pressure contour map before and after adjusting a downward pressing characteristic of each of friction cleaning parts by using a pressure mapping system according to an embodiment.

[00117] Referring to FIG. 16A, it can be seen that a pressing characteristic of friction cleaning parts arranged in four rows is very bad. Particularly, it can be seen that downward pressi ng is hardly performed in a first row.

[00118] After a downward pressing characteristic of each friction cleaning part is adjusted based on the pressure contour map which has been checked, a pressure contour map is as shown in FIG. 16B. As shown in FIG. 16B, it can be seen that a downward pressing characteristic of each of a first row, a second row, and a fourth row is considerably improved.

[00119] FIG. 17 is a graph showing a number of particle defect positions with respect to the changes of FIGS. 16A and 16B. In FIG. 17, the abscissa axis indicates time, and the ordinate axis indicates the number of particle defect positions.

[00120] In FIG. 17, a pressing characteristic of each of friction cleaning parts has been adjusted at a time T. Before the adjusting (i.e., the left side with respect to the time T), the nu mber of particle defects is large and an average value thereof is 162. After the adjusting (i.e. , the right side with respect to time T), it is determined that the number of particle defects is reduced and an average value thereof is about 1 15.

[00121] As described above, it can be concluded that the number of particle defect positions is reduced because the number of friction cleaning parts contributing to removal of particles is increased by adjusting a pressing characteristic of a friction cleaning part which does not contribute to removal of the particles.

[00122] FIGS. 18A and 18B are graphs showing changes in the number of particle defect positions before and after adjusting a downward pressing characteristic of each of friction cleaning parts by using a pressure mapping system according to an embodiment in another glass product manufacturing process.

[00123] Referring to FIG. 1 8A, it is determined that the number of particle defects is considerably reduced with respect to a time T. That is, before the time T (i.e., before adjusting), it is determined that the number of particle defects is about 1 , 100, but after the time T (i.e., after the adjusting), it is determined that the number of particle defects is about 700.

[00124] Referring to FIG. 1 8B, it is determined that the number of particle defects is considerably reduced with respect to a time T. That is, before the time T (i.e., before adjusting), it is determined that the number of particle defects is about 751 , but after the time T (i.e., after the adjusting), it is determined that the number of particle defects is about 413.

[00125] By using the pressure mapping apparatus and method of cleaning a glass su bstrate according to the above embodiments, an objective and quantitative test may be performed without deviation between workers in a cleaning process, and thus, product defects s uch as particle defects are considerably reduced .

[00126] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation . Descriptions of features or aspects within each embodiment should typically be considered as available for other similar featu res or aspects in other embodiments.

[00127] While one or more embodiments have been described with reference to the figu res, it will be understood by those of ordi nary skill in the art that various ch anges in form and details may be made therein without departi ng from the spirit and scope of the disclosure as defined by the following claims.