Display device manufacturing apparatus and display device manufacturing method

Abstract

A display device manufacturing apparatus and a display device manufacturing method are disclosed. In one embodiment, a display device manufacturing apparatus includes: a vacuum chamber; a negative pressure forming portion that provides a negative pressure to the vacuum chamber; an electrostatic chuck disposed in the vacuum chamber; an electrostatic chuck moving portion that moves the electrostatic chuck in a first direction; a gas injection portion that injects an inert gas into an inside of the vacuum chamber; and a laser engraver that irradiates laser light into the inside of the vacuum chamber.

Description

Technical Field

[0001] This invention relates to a display device manufacturing apparatus and a display device manufacturing method. Background Technology

[0002] Currently on the market are various types of display devices that display images, including smartphones, tablet PCs, digital cameras, laptops, navigators, and smart TVs.

[0003] Such a display device can be equipped with optical elements such as cameras and infrared sensors, and an optical hole is formed that physically penetrates a part of the display device in order to receive the light from the optical elements. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a display device manufacturing apparatus that can easily remove residual charge from an electrostatic chuck and a substrate mounted thereon, and a display device manufacturing method using the same.

[0005] The problems of this invention are not limited to those mentioned above, and those skilled in the art will clearly understand from the following description other technical problems not mentioned.

[0006] In one embodiment for solving the aforementioned problem, the display device manufacturing apparatus includes: a vacuum chamber; a negative pressure forming unit for providing negative pressure to the vacuum chamber; an electrostatic chuck disposed within the vacuum chamber; an electrostatic chuck moving unit for moving the electrostatic chuck along a first direction; and a gas injection unit for injecting inert gas into the vacuum chamber.

[0007] It can be that the gas jetting section sprays gas toward at least one of the side of the electrostatic chuck extending along the first direction and the side extending along a second direction intersecting the first direction.

[0008] Alternatively, the gas injection section may be disposed on the inner wall of the vacuum chamber.

[0009] Alternatively, the gas jet can be disposed on the electrostatic chuck and move as the electrostatic chuck moves.

[0010] Alternatively, a target substrate may be disposed on one side of the electrostatic chuck, and the gas jet section may jet gas toward the boundary between the side of the electrostatic chuck and the side of the target substrate.

[0011] Alternatively, the electrostatic chuck may further include: a pressure rod that presses the target substrate downwards to separate at least a portion of the target substrate from the bottom of the electrostatic chuck; and a gas jet that jets gas between the electrostatic chuck and the target substrate.

[0012] Alternatively, the display device manufacturing apparatus may further include: a gas supply unit for supplying gas to the gas injection unit; and a first gas supply path connecting the gas injection unit and the gas supply unit.

[0013] Alternatively, the display device manufacturing apparatus may further include two or more control valves configured in the first gas supply path.

[0014] Alternatively, the display device manufacturing apparatus may further include a laser etching machine for irradiating the interior of the vacuum chamber with a laser.

[0015] Alternatively, the laser etching machine may be positioned below the vacuum chamber and irradiate the laser downwards towards the electrostatic chuck.

[0016] Alternatively, the laser etching machine may irradiate the laser at an angle to the underside of the electrostatic chuck.

[0017] Alternatively, the laser etching machine may irradiate the laser vertically downwards onto the electrostatic chuck.

[0018] Alternatively, the laser etching machine may be positioned above the vacuum chamber and pass through the electrostatic chuck to irradiate the laser.

[0019] Alternatively, the electrostatic chuck may include a laser through-hole, wherein the laser of the laser etching machine penetrates the laser through-hole.

[0020] Alternatively, the display device manufacturing apparatus may further include: a movable glass, configured within the vacuum chamber to overlap with the laser etching machine in the height direction; and a glass moving part, which moves the movable glass along the first direction.

[0021] Alternatively, a target substrate may be adsorbed on the underside of the electrostatic chuck. The target substrate includes a glass substrate and an active element layer formed on the glass substrate, including a light-emitting element and a thin-film transistor driving the light-emitting element. The laser etching machine forms a through-hole penetrating the active element layer by removing the light-emitting element and the thin-film transistor.

[0022] The pressure inside the vacuum chamber can be between 100 nPa and 100 mPa.

[0023] Alternatively, the display device manufacturing apparatus may further include: a power supply device that provides electrostatic charge to the electrostatic chuck in a conducting state and stops providing electrostatic charge to the electrostatic chuck in a disconnected state, wherein the power supply device is conducting during a first time period before the inert gas is injected and disconnected during a second time period after the inert gas is injected.

[0024] Alternatively, the electrostatic chuck may include: a plurality of gas nozzles disposed below the electrostatic chuck; and an internal flow path communicating with the plurality of gas nozzles.

[0025] In one embodiment for solving the aforementioned problem, the method for manufacturing a display device includes: a step of adsorbing a target substrate onto the underside of an electrostatic chuck disposed in a vacuum chamber; a step of forming a hole by irradiating at least one layer of the target substrate including a light-emitting element with a laser; a step of spraying nitrogen gas onto the electrostatic chuck and the target substrate; and a step of releasing the adsorption of the target substrate from the electrostatic chuck.

[0026] The step of spraying nitrogen gas may include: forming a gap between the electrostatic chuck and the target substrate; and spraying nitrogen gas into the gap between the electrostatic chuck and the target substrate.

[0027] The step of spraying nitrogen gas may include spraying nitrogen gas at the boundary between the electrostatic chuck and the target substrate while the electrostatic chuck and the target substrate are in close contact.

[0028] The nitrogen injection step and the step of removing the adsorption from the target substrate can be performed simultaneously.

[0029] Alternatively, the step of forming the hole may include: irradiating the substrate with a laser at an angle below the electrostatic chuck.

[0030] Alternatively, the step of forming the hole may include irradiating the target substrate with a laser in a manner that penetrates the electrostatic chuck.

[0031] (Invention Effects)

[0032] By means of a display device manufacturing apparatus according to one embodiment and a display device manufacturing method thereunder, a substrate adsorbed on an electrostatic chuck can be easily separated.

[0033] The effects of the embodiments are not limited to those illustrated above, and many more effects are included in this specification. Attached Figure Description

[0034] Figure 1 This is a top view of a display device relating to a display device manufacturing apparatus according to an embodiment.

[0035] Figure 2 It is along Figure 1 The cross-sectional view taken from I-I'.

[0036] Figure 3 This is a perspective view of a display device manufacturing apparatus according to an embodiment.

[0037] Figure 4 It is along Figure 3 The cross-sectional view taken from A-A'.

[0038] Figure 5 It is along Figure 3 The cross-sectional view taken from B-B'.

[0039] Figure 6 This is a cross-sectional view of a display device manufacturing apparatus according to another embodiment.

[0040] Figure 7 This is a cross-sectional view of a display device manufacturing apparatus according to yet another embodiment.

[0041] Figure 8 This is a cross-sectional view of a display device manufacturing apparatus according to yet another embodiment.

[0042] Figure 9 This is a flowchart of a method for manufacturing a display device according to one embodiment.

[0043] Figure 10 This is a diagram illustrating the steps of adsorbing a substrate onto an electrostatic chuck.

[0044] Figure 11 This is a diagram illustrating the steps involved in performing a laser etching process.

[0045] Figure 12 as well as Figure 13 This diagram illustrates the steps of removing residual charge on the electrostatic chuck and the substrate by spraying gas.

[0046] Figure 14 This diagram illustrates the steps of detaching the substrate from the electrostatic chuck.

[0047] (Explanation of reference numerals in the attached diagram)

[0048] 1: Display device

[0049] 10: Display device manufacturing equipment

[0050] 100: Vacuum chamber

[0051] 200: Lifting pin

[0052] 300: Lifting Pin Moving Part

[0053] 400: Electrostatic chuck

[0054] 500: Electrostatic chuck moving part

[0055] 600: Laser Etching Machine

[0056] 700: Moving Glass

[0057] 810: Gas injection section Detailed Implementation

[0058] If referring to the attached appendix Figure 1 The advantages and features of the invention, as well as the methods of implementing them, will become clear from the detailed embodiments described below. However, the invention is not limited to the embodiments disclosed below and will be implemented in various forms that differ from each other. These embodiments are provided only to make the disclosure of the invention complete and to fully inform those skilled in the art of the invention of the scope of the invention. The invention is defined only by the scope of the claims.

[0059] The term "on" to refer to elements or layers includes all cases where an element is directly on another element or is intermediated with another layer or element. Throughout this specification, the same reference numerals refer to the same constituent elements. The shapes, dimensions, ratios, angles, numbers, etc., disclosed in the drawings used to illustrate embodiments are exemplary, and therefore the invention is not limited to the illustrated items.

[0060] Although terms like "first," "second," etc., are used to describe various constituent elements, these constituent elements are not limited by these terms. These terms are used only to distinguish one constituent element from others. Therefore, the first constituent element mentioned below can also be a second constituent element within the technical concept of this invention.

[0061] The following describes specific embodiments with reference to the accompanying drawings.

[0062] Figure 1 This is a top view of a display device relating to a display device manufacturing apparatus according to an embodiment. Figure 2 It is along Figure 1 The cross-sectional view taken from I-I'.

[0063] Reference Figure 1 as well as Figure 2 The display device 1 displays dynamic or static images. The main screen can be displayed facing the DR3 (e.g., a front-emitting display device), but is not limited to this.

[0064] Display device 1 can refer to all electronic devices that provide a display screen. For example, in addition to portable electronic devices such as mobile phones, smartphones, tablet PCs (Personal Computers), electronic watches, smartwatches, smartwatch phones, mobile communication terminals, electronic notebooks, e-books, PMPs (Portable Multimedia Players), navigators, game consoles, digital cameras, etc., which provide a display screen, televisions, laptops, monitors, billboards, Internet of Things devices, etc., can also be included in display device 1.

[0065] Display device 1 includes an active area AAR and an active area NAR. The active area AAR may include a display area for displaying a screen, and the active area NAR may include a non-display area for not displaying a screen. When display device 1 has touch functionality, the active area AAR may include a touch area for sensing touch input. That is, the active area AAR may be an area for sensing display and / or touch input.

[0066] An active region AAR can include multiple pixels PX. The multiple pixels PX can be arranged along the matrix direction. The shape of each pixel PX can be rectangular, square, or rhomboid in the top view (i.e., when viewed from a top view).

[0067] The passive area (NAR) is configured around the active area (AAR). The passive area (NAR) may surround at least a portion of the active area (AAR). The passive area (NAR) may be a border area. Signal wiring or drive circuitry for applying signals to the active area (AAR) (display area or touch area) may be configured in the passive area (NAR).

[0068] The display device 1 may include a display panel DP, a touch component TSP, a polarizing component POL, a window component 20, and a cover plate CPL.

[0069] Display panels (DP) can include, for example, organic light-emitting diode (OLED) display panels, micro LED display panels, nano LED display panels, quantum dot OLED display panels, liquid crystal display panels, plasma display panels, field emission display panels, electrophoretic display panels, and electrowetting display panels. The following example illustrates the application of OLED display panels, but it is not limited to this; if the same technical concept can be applied, it can also be applied to other display panels.

[0070] The display panel DP may include a first substrate SUB1, a second substrate SUB2, an active element layer ATL, an anti-reflective component AR, and a sealing component SL.

[0071] The first substrate SUB1 can support the active device layer ATL located above it. The first substrate SUB1 is generally transparent, and therefore can have high light transmittance. The first substrate SUB1 is not limited to this, but may contain inorganic materials such as glass and / or quartz. The inorganic materials are not limited to this, but may include, for example, silicon oxide (SiO2). However, it is not limited to this, the first substrate SUB1 can be a transparent plate or a transparent film.

[0072] The second substrate SUB2 can be positioned opposite and spaced apart from the first substrate SUB1. The second substrate SUB2 can protect the active component layer (ATL) from external moisture and air. The second substrate SUB2 is generally transparent, thus allowing for high light transmittance. While not limited to this, the second substrate SUB2 can contain inorganic materials such as glass and / or quartz. The inorganic materials are not limited to these, but can include, for example, silicon oxide (SiO2). However, it is not limited to this; the second substrate SUB2 can be a transparent plate or a transparent film.

[0073] The active element layer (ATL) can be disposed between the first substrate SUB1 and the second substrate SUB2. The active element layer (ATL) can be disposed on top of (or on one side of) the first substrate SUB1. The active element layer (ATL) can include a light-emitting element and a thin-film transistor driving it. Although not limited thereto, the active element layer (ATL) can be spaced apart from the upper second substrate SUB2.

[0074] An anti-reflective component AR can be disposed between the first substrate SUB1 and the second substrate SUB2. The anti-reflective component AR can be disposed on the underside (or the other side) of the second substrate SUB2. The anti-reflective component AR can be disposed within the aperture region HLA. The anti-reflective component AR can also be disposed within the active region AAR and / or the non-active region NAR. The anti-reflective component AR can reduce the amount of light reflected at the interface of the second substrate SUB2, thereby increasing the amount of light transmitted through the second substrate SUB2.

[0075] A sealing member SL can be disposed between the first substrate SUB1 and the second substrate SUB2. The sealing member SL can be disposed in the non-active region NAR of the display device 1 and configured to surround the active region AAR. The sealing member SL allows the first substrate SUB1 and the second substrate SUB2 to bond together, and can seal the active element layer ATL together with the first substrate SUB1 and the second substrate SUB2. In one embodiment, the sealing member SL can be formed by including a glass binder (Frit), but is not limited thereto.

[0076] An active element layer (ATL) and an anti-reflective element (AR) can be disposed within the internal region of the display panel DP, defined by the first substrate SUB1, the second substrate SUB2, and the sealing member SL. Within this internal region, a spacer space (EMT) can be provided between the active element layer (ATL) and the anti-reflective element (AR). The spacer space (EMT) can be in a vacuum state or filled with a gas, etc. While the gas is not limited to these, it can include, for example, an inert gas or ordinary atmosphere. However, the material that can fill the spacer space (EMT) is not limited to the gas; it can also be filled with a filler, etc. The spacer space (EMT) can overlap with the first through-hole HLE_TH1, which will be described later.

[0077] On the display panel DP, a touch component TSP for sensing touch input, a polarizing component POL for polarizing transmitted light to reduce external light, and a window component 20 for covering and protecting the display panel DP can be stacked sequentially. The window component 20 can be attached to the top (or one side) of the polarizing component POL by means of a transparent bonding layer OCR containing optically clear adhesive (OCA) or optically clear resin (OCR).

[0078] The window component 20 may include a window substrate 21 and a printed layer 22.

[0079] The window substrate 21 can be formed of a transparent material. The window substrate 21 can be formed by including, for example, glass or plastic.

[0080] A printed layer 22 can be disposed on the window substrate 21. The printed layer 22 can be disposed in the non-active area (NAR) of the frame portion of the window substrate 21. The printed layer 22 can also be disposed in the hole area (HLA). The printed layer 22 can be a light-shielding layer or an aesthetically pleasing decorative layer.

[0081] The cover plate CPL can be disposed on the other side of the first substrate SUB1. The cover plate CPL may include a heat dissipation layer, a buffer layer, etc. The cover plate CPL may not be disposed in an area that overlaps with at least one of the optical aperture HLE_OP and the through aperture HLE_TH.

[0082] The display device 1 may also include an optical element OPS and an overlapping aperture region HLA.

[0083] The optical element OPS can be configured to overlap with the aperture region HLA on the opposite side of the display panel DP. The optical element OPS includes a light receiver, which can be located within the optical aperture HLE_OP. Examples of optical elements OPS include cameras, lenses (condenser lenses or light-guiding lenses, etc.), infrared sensors, iris recognition sensors, illuminance sensors, and other optical sensors.

[0084] The aperture region HLA can be configured within the active region AAR. That is, the aperture region HLA can be configured as follows: Figure 1 As shown, it is surrounded by an active area AAR. The aperture area HLA can be arranged adjacent to one side of the display device 1 on the plane, but is not limited to this. The aperture area HLA itself can be a non-active area NAR that does not form a display and / or touch area. In a top view, the aperture area HLA can be circular, elliptical, dumbbell-shaped, rectangular with a raised short side, etc., but is not limited to this, and can be rectangular, square or other different polygons and other deformations.

[0085] The pore region HLA may include at least one pore HLE.

[0086] A hole HLE can include a physically penetrating through hole HLE_TH. The through hole HLE_TH can have an elliptical shape on a plane, but is not limited to this.

[0087] The through-hole HLE_TH may include a first through-hole HLE_TH1 that physically penetrates the active element layer ATL of the display panel DP, a second through-hole HLE_TH2 that physically penetrates the touch component TSP, and a third through-hole HLE_TH3 that physically penetrates the polarizing component POL. By removing the aforementioned components from the through-hole HLE_TH, the light transmittance in the corresponding area can be improved.

[0088] The first through-hole HLE_TH1, the second through-hole HLE_TH2, and the third through-hole HLE_TH3 can be configured such that at least a portion of them overlap in the thickness direction. This ensures that external light enters the optical path of the optical element OPS.

[0089] The aperture region HLA may also include an optical window, namely the optical aperture HLE_OP. The optical aperture HLE_OP may overlap with the through aperture HLE_TH and be defined by the pattern of the printed layer 22.

[0090] At least one via HLE can be formed by a laser etching process. For example, the first through-hole HLE_TH1 can be formed by laser etching in a high-vacuum chamber to remove a portion of the area corresponding to the hole region HLA of the active element layer ATL on the first substrate SUB1. The laser etching process can be performed as follows: Figures 3 to 14 The display device manufacturing apparatus and the display device manufacturing method using the apparatus are executed.

[0091] Figure 3 This is a perspective view of a display device manufacturing apparatus according to an embodiment. Figure 4 It is along Figure 3 The cross-sectional view taken from A-A'. Figure 5 It is along Figure 3 The cross-sectional view taken from B-B'.

[0092] Hereinafter, the first direction DR1, the second direction DR2, and the third direction DR3 intersect each other in different directions. For example, the first direction DR1 may be the length direction, the second direction DR2 the width direction, and the third direction DR3 the height direction (thickness direction). The first direction DR1, the second direction DR2, and the third direction DR3 may include two or more directions. For example, the third direction DR3 may include an upper direction facing the upper side of the drawing and a lower direction facing the lower side of the drawing. Furthermore, the side of the component positioned facing the upper side of the drawing may be referred to as the upper side, and the side opposite to the upper side may be referred to as the lower side. However, these directions are exemplary, and the following embodiments are not limited to those mentioned above.

[0093] Hereinafter, the target substrate T may include a base substrate GS and at least one layer EL on the base substrate GS, and the display device manufacturing apparatus 10 may be an apparatus for forming holes in the at least one layer EL. In one embodiment, the base substrate GS may be a glass substrate, and the at least one layer EL may be a layer including a light-emitting element, but is not limited thereto. In some embodiments, the base substrate GS of the target substrate T may be... Figures 1 to 3 The first substrate SUB1 has at least one layer EL, which is an active element layer ATL including a light-emitting element and a thin-film transistor driving it. The display device manufacturing apparatus 10 forms a first through-hole HLE_TH1. In some embodiments, the display device manufacturing apparatus 10 may form Figures 1 to 3 The second through-hole HLE_TH2 and / or the third through-hole HLE_TH3. In some embodiments, the display device manufacturing apparatus 10 may also form the second through-hole HLE_TH2 and / or the third through-hole HLE_TH3 sequentially or simultaneously. Figures 1 to 3 Two or more of the following: the first through hole HLE_TH1, the second through hole HLE_TH2, and the third through hole HLE_TH3.

[0094] Reference Figures 3 to 5 The display device manufacturing apparatus 10 may include a vacuum chamber 100, a negative pressure forming part 120, a lifting pin 200, a lifting pin moving part 300, an electrostatic chuck 400, an electrostatic chuck moving part 500, a laser etching machine 600, a gas jetting part 810, a gas supply flow path 820, and a gas supply part 840.

[0095] Vacuum chamber 100 can form an internal space sealed relative to the outside. Vacuum chamber 100 provides space for chucking / de-chucking of the target substrate T and laser etching processes. The internal pressure of vacuum chamber 100 can be lower than atmospheric pressure. The internal pressure of vacuum chamber 100 can be near-vacuum. The interior of vacuum chamber 100 can be a high vacuum state. For example, the internal pressure of vacuum chamber 100 can be maintained at approximately 100 nPa to 100 mPa. As another example, the internal pressure of vacuum chamber 100 can be maintained at approximately 0.01 mPa to 1 mPa. The internal pressure of vacuum chamber 100 can be maintained by a negative pressure forming part 120, such as a vacuum pump. Figure 3 The illustration shows a rectangular vacuum chamber 100, but the shape of the vacuum chamber 100 is not limited to this. In one embodiment, a gate 110 for accessing the target substrate T may be provided on one side of the vacuum chamber 100. In some embodiments, the display device manufacturing apparatus 10 may further include at least one sensor. The at least one sensor may be disposed within the vacuum chamber 100. For example, the display device manufacturing apparatus 10 may also include a pressure sensor for measuring the pressure inside the vacuum chamber 100 and / or a gas sensor for detecting the presence and / or concentration of the carrier gas described later.

[0096] The vacuum chamber 100 can be divided into a processing area PA for laser etching of the target substrate T and a non-processing area NPA for adsorption and desorption of the target substrate T. Specifically, the processing area PA refers to a portion of the internal space of the vacuum chamber 100 located above the laser etching machine 600, and the non-processing area NPA refers to another portion of the internal space of the vacuum chamber 100 located above the plurality of lifting pins 200. Alternatively, the processing area PA may be an area overlapping with the laser etching machine 600 in the height direction, and the non-processing area NPA may be an area overlapping with the plurality of lifting pins 200 in the height direction. In one embodiment, the processing area PA and the non-processing area NPA can be arranged along a first direction DR1 of movement of the electrostatic chuck 400.

[0097] Multiple lifting pins 200 may be positioned below the movement path of the electrostatic chuck 400 and move up and down via lifting pin moving parts 300. The multiple lifting pins 200 may be positioned in the non-processing area NPA. When the electrostatic chuck 400 is above the multiple lifting pins 200, the multiple lifting pins 200 can lift the target substrate T so that the target substrate T is in close contact with the underside of the electrostatic chuck 400, allowing the target substrate T to be adsorbed onto the electrostatic chuck 400. Furthermore, after processing of the target substrate T is completed, the lifting pins 200 rise towards the target substrate T to be in close contact with the underside of the target substrate T located above the lifting pins 200, thereby safely releasing the adsorption of the target substrate T. In one embodiment, the multiple lifting pins 200 may be configured to penetrate the lower part of the vacuum chamber 100, but are not limited thereto. In some embodiments, the multiple lifting pins 200 may also be replaced by a plate, worktable, and / or frame capable of loading the target substrate T and moving up and down.

[0098] An electrostatic chuck 400 can be disposed within a vacuum chamber 100 and uses electrostatic force to adhere the substrate T to its lower surface. The electrostatic chuck 400 can be positioned above multiple lifting pins 200 and / or a laser etching machine 600. The electrostatic chuck 400 can be moved along a first direction DR1 via an electrostatic chuck moving part 500, for example, a moving stage. The first direction DR1 can be horizontal. Specifically, as... Figure 4 As shown, the electrostatic chuck 400 can reciprocate from the processing area PA to the non-processing area NPA and vice versa. Specifically, the electrostatic chuck 400 can reciprocate between a position above the plurality of lifting pins 200 and a position above the laser etching machine 600. That is, the movement path of the electrostatic chuck 400 can be located above the plurality of lifting pins 200 and the laser etching machine 600, and depending on the process sequence, the electrostatic chuck 400 can be moved to a position above either the plurality of lifting pins 200 or the laser etching machine 600.

[0099] The electrostatic chuck 400 may include a lower electrode portion 410, a main body portion 420 disposed on and below the lower electrode portion 410, and a plurality of pressure rods 430 passing through the main body portion 420 and the lower electrode portion 410 along a third direction DR3.

[0100] Charges for adsorbing the target substrate T can be induced in the lower electrode portion 410. In some embodiments, the lower electrode portion 410 includes a plurality of electrodes, at least one dielectric layer, and at least one insulating layer. When a voltage is applied to the plurality of electrodes, charges are induced under the lower electrode portion 410 and in the target substrate T, allowing the target substrate T to adhere to the electrostatic chuck 400. In some embodiments, the display device manufacturing apparatus 10 may further include a power supply device electrically connected to the lower electrode portion 410 of the electrostatic chuck 400. In some embodiments, the power supply device may be mounted on the main body portion 420 and controlled by the control unit 900 described later. In some embodiments, when the power supply device is turned on, a voltage is applied to the electrodes of the lower electrode portion 410, generating electrostatic charges in the lower electrode portion 410; when the power supply device is turned off, the voltage application to the electrodes of the lower electrode portion 410 is stopped.

[0101] Multiple pressure bars 430 can be configured to be vertically movable and / or retractable. When the adsorption on the target substrate T is released, the multiple pressure bars 430 can slightly separate at least a portion of the target substrate T from the electrostatic chuck 400, allowing gas ejected through the gas jet section 810 to flow into the gap between the target substrate T and the electrostatic chuck 400. The laser etching machine 600 can irradiate a laser toward the target substrate T to process grooves or patterns of desired depth on the target substrate T. The laser etching machine 600 can be disposed in the processing area PA. The laser etching machine 600 can be disposed outside the vacuum chamber 100. In one embodiment, the laser etching machine 600 can be disposed below the vacuum chamber 100, overlapping the processing area PA in the height direction. When the electrostatic chuck 400 is located in the processing area PA, the laser etching machine 600 can irradiate a laser toward the target substrate T adsorbed below the electrostatic chuck 400 to form a through-hole in at least one layer EL of the target substrate T.

[0102] The laser etching machine 600 can irradiate the laser LB at a predetermined angle θ between the laser LB and the underside of the target substrate T and / or the underside of the electrostatic chuck 400. In one embodiment, the laser etching machine 600 can irradiate the laser LB at an angle towards the underside of the target substrate T and / or the underside of the electrostatic chuck 400. In this case, the predetermined angle θ can be greater than 45° and less than 90°. This minimizes interference between particles generated during etching and falling freely and the laser LB. In some embodiments, the laser etching machine 600 can irradiate the laser LB perpendicularly towards the underside of the target substrate T and / or the underside of the electrostatic chuck 400.

[0103] The gas jetting unit 810 can jet gas onto the target substrate T and / or the electrostatic chuck 400 to remove the charge generated on the surfaces of the electrostatic chuck 400 and the target substrate T. The gas can be supplied from the gas supply unit 840 connected via the gas supply flow path 820. In one embodiment, the gas jetting unit 810 is disposed in the non-processing area NPA, but is not limited thereto. In some embodiments, the gas jetting unit 810 can be disposed either in the processing area PA or along the movement path of the electrostatic chuck 400 across the processing area PA and the non-processing area NPA.

[0104] Under atmospheric pressure or in conditions that are not high vacuum, a medium exists that can remove the charge generated on the surface of the electrostatic chuck 400 and the target substrate T, thereby facilitating the removal of the target substrate T from the electrostatic chuck. Conversely, in near-vacuum conditions, such as high vacuum conditions, the medium is absent, making it difficult to remove the target substrate T from the electrostatic chuck 400. In contrast, according to one embodiment, the display device manufacturing apparatus 10, after processing the target substrate T, sprays a carrier gas carrying charge and holes onto the electrostatic chuck 400 and / or the target substrate T to remove residual charge on the target substrate T and / or the electrostatic chuck 400, thereby facilitating the removal of the target substrate T from the electrostatic chuck. The carrier gas may contain an inert gas. In one embodiment, the carrier gas may be nitrogen. In some embodiments, the carrier gas may also be helium or argon. Hereinafter, the carrier gas will be simply referred to as a gas.

[0105] The gas jetting section 810 can be disposed in the non-processing area NPA. The gas jetting section 810 can jet gas along at least one of the first direction DR1, the second direction DR2, and the third direction DR3. The gas jetting section 810 can jet gas in a direction intersecting the movement direction of the electrostatic chuck 400. The gas jetting section 810 can jet gas toward the side of the electrostatic chuck 400. In one embodiment, the electrostatic chuck 400 may move along the first direction DR1, and the gas jetting section 810 may jet gas toward the two sides of the electrostatic chuck 400 extending along the second direction DR2. In one embodiment, multiple gas jetting sections 810 can be disposed on the two inner sidewalls of the vacuum chamber 100 opposite to the two sides of the electrostatic chuck 400 extending along the second direction DR2. The multiple gas jetting sections 810 disposed on one inner sidewall of the vacuum chamber 100 can be arranged along the first direction DR1. The gas jetting section 810 can be configured to face the side of the electrostatic chuck 400 and / or the target substrate T. The gas jet section 810 may be located at the same height as the side of the electrostatic chuck 400 and / or the target substrate T. In one embodiment, the gas jet section 810 may be located at the height of the boundary between the lower electrode section 410 and the target substrate T. When the electrostatic chuck 400 is located in the non-processing area NPA, the electrostatic chuck 400 may be disposed among a plurality of gas jet sections 810. In some embodiments, the gas jet section 810 may be disposed on the electrostatic chuck 400 and move together with the electrostatic chuck 400 as it moves.

[0106] At least one control valve 830 may be configured on the gas supply flow path 820. In one embodiment, a first control valve 830_1 and a second control valve 830_2 for regulating the gas flow rate may be configured on the gas supply flow path 820. The first control valve 830_1 and the second control valve 830_2 may be opened or closed individually to finely adjust the amount of gas injected from the gas injection unit 810, such that the gas stored in the gas supply flow path 820 between the first control valve 830_1 and the second control valve 830_2 is supplied to the gas injection unit 810. For example, the first control valve 830_1 may be opened and the second control valve 830_2 closed, allowing a certain amount of gas to flow between the first control valve 830_1 and the second control valve 830_2. Then, the first control valve 830_1 may be closed and the second control valve 830_2 may be opened or closed to supply an appropriate amount of gas to the gas injection unit 810. The first control valve 830_1 and the second control valve 830_2 can be controlled by the control unit 900 (described later) to supply only a small amount of gas so that the pressure in the vacuum chamber 100 is maintained at a high vacuum state, for example, from about 0.01 mPa to 1 mPa and / or varied within a range of about 1 mPa. In some embodiments, the control valve 830 can also be replaced by a mass flow controller (MFC).

[0107] The display device manufacturing apparatus 10 may also include a movable glass 700 and a glass moving part 710 disposed in the processing area PA.

[0108] When the electrostatic chuck 400 is located in the processing area PA, the movable glass 700 can be positioned below the electrostatic chuck 400. That is, the height of the movable glass 700 can be lower than the height of the electrostatic chuck 400. During laser etching, the laser from the laser etching machine 600 can penetrate the movable glass 700 and irradiate the target substrate T. Particles that fall due to laser etching can accumulate on the movable glass 700. When a certain amount of particles accumulates, the movable glass 700 can be moved along at least one direction, such as the first direction DR1, by the glass moving part 710. This prevents interference between the accumulated particles and the laser.

[0109] The display device manufacturing apparatus 10 may also include a control unit 900 for controlling the operation of the display device manufacturing apparatus 10.

[0110] The control unit 900 can control at least one of the following: negative pressure forming unit 120, lifting pin moving unit 300, electrostatic chuck 400, electrostatic chuck moving unit 500, laser etching machine 600, gas jetting unit 810, and control valve 830.

[0111] The control unit 900 can control the negative pressure forming unit 120 and the control valve 830 to maintain the pressure inside the vacuum chamber 100 within a preset pressure range. The preset pressure range can be the pressure at which particles generated by laser etching can fall freely. The pressure can be, for example, between approximately 0.01 mPa and 1 mPa.

[0112] The control unit 900 can perform adsorption and desorption of the target substrate T based on the internal pressure of the vacuum chamber 100. In one embodiment, the control unit 900 can perform adsorption and desorption of the target substrate T within a preset pressure range. In some embodiments, the control unit 900 can control the power supply and the lifting pin moving part 300 so that when the internal pressure of the vacuum chamber 100 is within a first pressure range, the target substrate T is adsorbed onto the electrostatic chuck 400, and when the internal pressure of the vacuum chamber 100 is within a second pressure range, the adsorption of the target substrate T from the electrostatic chuck 400 is released. The first pressure range can be about 0.01 mPa or less. The second pressure range can be about greater than 0.01 mPa and less than 1 mPa.

[0113] The control unit 900 can perform adsorption and / or desorption of the target substrate T based on whether or not gas is injected. Specifically, the control unit 900 can perform adsorption and desorption of the target substrate T based on the presence and / or concentration of the carrier gas within the vacuum chamber 100. In one embodiment, the control unit 900 can control a power supply to generate and / or dissipate the electrostatic charge on the electrostatic chuck 400 based on the injection time of the inert gas. Specifically, the control unit 900 can control the power supply to be on during a first time period before gas injection and off during a second time period after gas injection. In some embodiments, the control unit 900 can control the power supply to be on or off during gas injection. In some embodiments, the control unit 900 can control the power supply to be on during a first time period before gas injection and on during a second time period after gas injection.

[0114] The detailed operation of the display device manufacturing apparatus 10a is as follows: Figures 9 to 14 The explanation is provided below.

[0115] Figure 6 This is a cross-sectional view of a display device manufacturing apparatus according to another embodiment.

[0116] Figure 6 The embodiment is similar to the aspect of configuring the gas nozzle GH below the electrostatic chuck 400a. Figure 4 The implementation methods differ.

[0117] Reference Figure 6 The electrostatic chuck 400a may also include a gas nozzle GH and an internal flow path 440 connected thereto.

[0118] The gas nozzle GH can be disposed below the electrostatic chuck 400a. Specifically, the gas nozzle GH can be disposed below the lower electrode portion 410 of the electrostatic chuck 400a. This allows gas to be sprayed onto the surface of the target substrate T, which is in close contact with the electrostatic chuck 400a. An internal flow path 440 can be formed inside the electrostatic chuck 400a, with one end connected to the gas nozzle GH and the other end connected to the gas supply flow path 820. Gas can be sprayed from the gas nozzle GH when the electrostatic chuck 400a is located in the non-processing area NPA and / or the processing area PA. In one embodiment, gas can be sprayed from the gas nozzle GH when the electrostatic chuck 400a is released from its grip. In some embodiments, gas can be sprayed from the gas nozzle GH when the electrostatic chuck 400a moves from the processing area PA to the non-processing area NPA or from the non-processing area NPA to the processing area PA.

[0119] The gas supply path 820 may include a first gas supply path 820a_1 connected at one end to the gas injection section 810 and a second gas supply path 820a_2 connected at one end to the internal flow path 440. In one embodiment, the second gas supply path 820a_2 branches off from the first gas supply path 820a_1, but is not limited thereto. In some embodiments, the display device manufacturing apparatus 10a may include a plurality of gas supply sections 840, and the first gas supply path 820a_1 and the second gas supply path 820a_2 may be separated from each other and connected to the plurality of gas supply sections 840 respectively to individually supply different amounts or types of gas to each other. In some embodiments, the display device manufacturing apparatus 10a may also include at least one control valve for controlling the flow rate of the gas supplied through the second gas supply path 820a_2.

[0120] Figure 6 The embodiment is similar to, except that the gas nozzle GH is arranged below the electrostatic chuck 400a. Figure 4 The embodiments are substantially the same or similar, therefore repeated descriptions are omitted below.

[0121] Figure 7 This is a cross-sectional view of a display device manufacturing apparatus according to yet another embodiment.

[0122] Figure 7 The embodiment is located on the upper side of the chamber of the laser etching machine 600b. Figure 4 The implementation methods differ.

[0123] Reference Figure 7 The electrostatic chuck 400b may include a main body 420, a lower electrode 410, and a laser through hole 450 that passes through the main body 420 and the lower electrode 410.

[0124] The laser through-hole 450 can be formed such that the main body portion 420 and the lower electrode portion 410 pass through along a third direction DR3. In one embodiment, the third direction DR3 can be perpendicular to the target substrate T. Thus, it can be configured such that one side opening of the laser through-hole 450 faces the top surface of the substrate GS of the target substrate T, and the other side opening of the laser through-hole 450 faces the laser etching machine 600b.

[0125] The laser etching machine 600b can be located outside the chamber and configured to overlap the processing area PA in the height direction on the upper side of the chamber. When the electrostatic chuck 400b is located in the processing area PA, the laser etching machine 600b can irradiate a laser downward through the laser through-hole 450. In this case, the substrate GS of the target substrate T can be formed of a light-transmitting material such as glass, allowing the laser to pass through. The transmitted laser can etch at least one layer EL on the underside of the substrate GS to form the through-hole.

[0126] The laser etching machine 600b can irradiate a laser at a predetermined angle θ' onto the top surface of the target substrate T, the bottom surface of the target substrate T, and / or the bottom surface of the electrostatic chuck 400b. In one embodiment, the predetermined angle θ' can be a near-vertical angle. For example, the predetermined angle θ' can be approximately 85° to 95°. Figure 4 Unlike other embodiments, the laser irradiation path does not overlap with the falling path of particles generated by etching, and the laser irradiates the target substrate T almost perpendicularly, thus enabling correct etching to be performed.

[0127] Figure 8 This is a cross-sectional view of a display device manufacturing apparatus according to yet another embodiment.

[0128] Figure 8 The embodiment further includes a first gas injection section 810c_1 and a second gas injection section 810c_2 in the gas injection section 810c, which is similar to... Figure 4 The implementation methods differ.

[0129] Reference Figure 8 The gas injection section 810c may further include a first gas injection section 810c_1 that injects gas along the second direction DR2 and a second gas injection section 810c_2 that injects gas along the first direction DR1.

[0130] First gas injection section 810c_1 and Figures 4 to 6 The gas injection unit 810 illustrated herein is substantially the same or similar, therefore repeated descriptions are omitted below.

[0131] The second gas jet section 810c_2 can be disposed on the electrostatic chuck 400. For example, the second gas jet section 810c_2 can be configured to be suspended on the electrostatic chuck 400 by a connecting member connecting the second gas jet section 810c_2 and the electrostatic chuck 400. When the electrostatic chuck 400 moves, the second gas jet section 810c_2 can move together with the electrostatic chuck 400 along a first direction DR1. The second gas jet section 810c_2 can be configured to face the side of the target substrate T and / or the electrostatic chuck 400. In one embodiment, the second gas jet section 810c_2 can be configured as a side of the side of the target substrate T and / or the electrostatic chuck 400 that extends along a second direction DR2. In some embodiments, the second gas jet section 810c_2 can be configured as a side of the side of the target substrate T and / or the electrostatic chuck 400 that extends along the first direction DR1, or configured to surround all four sides of the target substrate T and / or the electrostatic chuck 400. The second gas jet 810c_2 can be located at the height of the boundary between the lower electrode portion 410 and the target substrate T. The second gas jet 810c_2 can be located at the same height as the first gas jet 810c_1, or at a different height. When the electrostatic chuck 400 is located in the non-processing area NPA, the target substrate T and / or the four sides of the electrostatic chuck 400 can be configured to be surrounded by the first gas jet 810c_1 and the second gas jet 810c_2. Thus, gas can be jetted onto the target substrate T and all four sides of the lower electrode portion 410 of the electrostatic chuck 400. In some embodiments, the second gas jet 810c_2 can jet gas when the electrostatic chuck 400 is located in the processing area PA and / or when the electrostatic chuck 400 moves. In some embodiments, the second gas jet 810c_2 can also be configured on the inner side of the internal space forming the vacuum chamber 100. In some embodiments, only the second gas jet 810c_2 may be configured within the vacuum chamber 100.

[0132] The gas supply flow path 820c may further include a third gas supply flow path 820c_1 supplying gas to the first gas injection unit 810c_1 and a fourth gas supply flow path 820c_2 supplying gas to the second gas injection unit 810c_2. A first control valve 830_1 and a second control valve 830_2 for controlling the gas flow rate may be configured in the third gas supply flow path 820c_1. In one embodiment, the fourth gas supply flow path 820c_2 branches off from the third gas supply flow path 820c_1, but is not limited thereto. In some embodiments, the display device manufacturing apparatus 10c may include a plurality of gas supply units 840, with the third gas supply flow path 820c_1 and the fourth gas supply flow path 820c_2 being separate from each other and respectively connected to the plurality of gas supply units 840 to individually supply different amounts or types of gas to each other. In some embodiments, the display device manufacturing apparatus 10c may further include at least one control valve for controlling the flow rate of the gas supplied through the fourth gas supply flow path 820c_2.

[0133] Figure 9 This is a flowchart of a method for manufacturing a display device according to one embodiment. Figure 10 This is a diagram illustrating the steps of adsorbing a substrate onto an electrostatic chuck. Figure 11 This is a diagram illustrating the steps involved in performing a laser etching process. Figure 12 as well as Figure 13 This diagram illustrates the steps of removing residual charge on the electrostatic chuck and the substrate by spraying gas. Figure 14 This diagram illustrates the steps of detaching the substrate from the electrostatic chuck.

[0134] The following display device manufacturing method can be achieved through Figures 4 to 8 The display device manufacturing apparatus 10, 10a, 10b, and 10c are operated.

[0135] Reference Figure 9 The method for manufacturing a display device may include: a step of adsorbing a target substrate T onto the underside of an electrostatic chuck 400 disposed in a vacuum chamber 100 (S101); a step of forming a hole by irradiating at least one layer EL of the target substrate T, including a light-emitting element, with a laser (S102); a step of spraying nitrogen gas onto the electrostatic chuck 400 and the target substrate T (S103); and a step of releasing the adsorption of the target substrate T from the electrostatic chuck 400 (S104).

[0136] The nitrogen injection step may include: forming a gap between the electrostatic chuck 400 and the target substrate T; and injecting nitrogen into the gap between the electrostatic chuck 400 and the target substrate T.

[0137] The nitrogen injection step can be performed simultaneously with the step of removing the adsorption from the target substrate T.

[0138] The process of forming a hole may include irradiating a laser at an angle onto the substrate T below an electrostatic chuck 400.

[0139] The step of forming a hole may include irradiating the target substrate T with a laser in a manner that penetrates the electrostatic chuck 400.

[0140] The gas injection step may include injecting gas in a direction that intersects the movement direction of the electrostatic chuck 400.

[0141] The method for manufacturing a display device is not limited to the example described above; at least one of the steps may be omitted, or it may be referred to... Figures 1 to 8 It also includes at least one other step.

[0142] The following is for reference Figures 10 to 14 Detailed explanation of the manufacturing method of the display device.

[0143] Reference Figure 10 The object substrate T can be transported through the door 110 to the non-processing area NPA inside the vacuum chamber 100. The interior of the vacuum chamber 100 can be in a high vacuum state. The transported object substrate T can be lifted by multiple lifting pins 200 arranged in the non-processing area NPA and brought into close contact with the lower electrode portion 410 of the electrostatic chuck 400.

[0144] When the target substrate T is sufficiently close to the electrostatic chuck 400 or when the target substrate T is in close contact with the electrostatic chuck 400, a voltage is applied to the lower electrode portion 410 and the target substrate T can be adsorbed onto the underside of the lower electrode portion 410.

[0145] In some embodiments, before adsorbing the target substrate T, gas can be ejected from the gas injection section 810 to remove the charge from the electrostatic chuck 400. Afterward, the target substrate T can be adsorbed onto the electrostatic chuck 400. In some embodiments, the gas injection can be adjusted based on the pressure within the vacuum chamber 100, the presence or absence of gas, and / or the gas concentration sensed by at least one sensor disposed within the vacuum chamber 100.

[0146] Reference Figure 11 After the electrostatic chuck 400 adsorbs the target substrate T, the electrostatic chuck 400 can move from the non-processing area NPA to the processing area PA where the laser etching machine 600 is located.

[0147] After the electrostatic chuck 400 moves, the laser etching machine 600 can irradiate the target substrate T with laser LB to etch the target substrate T. In one embodiment, the laser etching machine 600 can etch the layer EL of the target substrate T, which includes the light-emitting element, to form a through-hole. To minimize interference caused by the falling of particles generated during etching, the laser can be irradiated onto the target substrate T at an angle.

[0148] During laser irradiation, the vacuum chamber 100 maintains a high vacuum state, allowing particles generated by laser etching to freely fall towards the movable glass 700 located below the target substrate T. When a certain amount of particles accumulates on the movable glass 700, the movable glass 700 can move. For example, the movable glass 700 can move a predetermined distance at preset time intervals. The predetermined distance can be greater than the width of the laser and / or the width of the laser-irradiated area of ​​the target substrate T.

[0149] Reference Figure 12 as well as Figure 13 After laser etching, the electrostatic chuck 400 can move from the processing area PA to the non-processing area NPA.

[0150] After the electrostatic chuck 400 moves, multiple lifting pins 200 can rise to support the object substrate T attached below the electrostatic chuck 400. Then, gas is injected from the first gas injection section 810 toward the object substrate T and / or the electrostatic chuck 400, removing the charge generated on the object substrate T and the electrostatic chuck 400. The gas can be nitrogen, but is not limited to this. The amount of gas injected from the first gas injection section 810 can be adjusted by the first control valve 830_1 and the second control valve 830_2, and the internal pressure of the vacuum chamber 100 can be maintained in a high vacuum state, for example, about 0.01 mPa to 1 mPa. In some embodiments, the gas injection can be adjusted based on the pressure inside the vacuum chamber 100, the presence or absence of gas, and / or the concentration of gas sensed by at least one sensor disposed within the vacuum chamber 100. For example, gas injection can be stopped when the pressure inside the vacuum chamber 100 is greater than a preset pressure, and gas injection can be performed when the pressure inside the vacuum chamber 100 is less than the preset pressure. The preset pressure can be from approximately 0.01 MPa to 1 MPa. For example... Figure 13 As shown, during gas injection, the target substrate T is pressurized downwards by the pressure rod 430, and at least a portion of it is separated from the underside of the lower electrode. At this time, the gas injected from the first gas injection section 810 can flow into the gap between the underside of the lower electrode and the topside of the target substrate T.

[0151] Reference Figure 14After the charge generated on the target substrate T and the electrostatic chuck 400 is fully removed, the multiple lifting pins 200 descend and can be released from the electrostatic chuck 400 from the target substrate T.

[0152] Although embodiments of the invention have been described above with reference to the accompanying drawings, those skilled in the art will understand that it can be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood to be illustrative rather than limiting in all respects.

Claims

1. A display device manufacturing apparatus, wherein, include: Vacuum chamber; The negative pressure forming section provides negative pressure to the vacuum chamber; An electrostatic chuck is disposed within the vacuum chamber; The electrostatic chuck moving part moves the electrostatic chuck along a first direction; The gas injection unit injects inert gas that carries charge and cavitation into the vacuum chamber. as well as The power supply device provides electrostatic charge to the electrostatic chuck in the on state and stops providing electrostatic charge to the electrostatic chuck in the off state. The power supply is turned on during a first period before the inert gas is injected and turned off during a second period after the inert gas is injected.

2. The display device manufacturing apparatus according to claim 1, wherein, The gas jetting section sprays gas toward at least one of the sides of the electrostatic chuck extending along the first direction and the sides extending along a second direction intersecting the first direction.

3. The display device manufacturing apparatus according to claim 1, wherein, The gas injection section is disposed on the inner wall of the vacuum chamber.

4. The display device manufacturing apparatus according to claim 1, wherein, The gas jet is disposed on the electrostatic chuck and moves as the electrostatic chuck moves.

5. The display device manufacturing apparatus according to claim 2, wherein, A target substrate is disposed on one side of the electrostatic chuck, and the gas jetting section jets gas toward the boundary between the side of the electrostatic chuck and the side of the target substrate.

6. The display device manufacturing apparatus according to claim 1, wherein, The display device manufacturing apparatus further includes: The gas supply unit supplies gas to the gas injection unit; A first gas supply path connects the gas injection unit and the gas supply unit; and Two or more control valves are configured in the first gas supply path.

7. The display device manufacturing apparatus according to claim 1, wherein, The display device manufacturing apparatus further includes: A laser etching machine irradiates the interior of the vacuum chamber with a laser. The laser etching machine is positioned below the vacuum chamber and facing the underside of the electrostatic chuck, so as to irradiate the laser at an angle to the underside of the electrostatic chuck.

8. The display device manufacturing apparatus according to claim 1, wherein, The display device manufacturing apparatus further includes: A laser etching machine irradiates the interior of the vacuum chamber with a laser. The electrostatic chuck includes a laser-through hole, and the laser from the laser etching machine penetrates the laser-through hole. The laser etching machine is positioned above the vacuum chamber and passes through the laser through-hole to vertically irradiate the area below the electrostatic chuck with the laser.

9. The display device manufacturing apparatus according to claim 1, wherein, The display device manufacturing apparatus further includes: A laser etching machine irradiates the interior of the vacuum chamber with a laser. A movable glass element, configured within the vacuum chamber to overlap with the laser etching machine in the height direction; and The glass moving part moves the movable glass along the first direction.

10. A method for manufacturing a display device, wherein, include: The step of adsorbing the target substrate under an electrostatic chuck set in a vacuum chamber; The step of forming a hole by irradiating at least one layer of the substrate containing a light-emitting element with a laser. The step of spraying nitrogen gas containing charges and holes into the electrostatic chuck and the target substrate; as well as The step of releasing the object substrate from the electrostatic chuck. Electrostatic charge is supplied to the electrostatic chuck during a first time period before the nitrogen gas is injected, and the supply of electrostatic charge to the electrostatic chuck is stopped during a second time period after the nitrogen gas is injected.

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